According to the Natural Medicines Database, vinpocetine has been linked in animals to increased risk of miscarriage and low fetal weight. Citing rat and rabbit prenatal developmental studies, the FDA advises women who are pregnant or capable of becoming pregnant not to consume products containing vinpocetine. In addition, the FDA will expedite completion of an administrative proceeding on vinpocetine that began in September 2016 to determine its legal status for sale as a dietary supplement in the United States.

References

Statement on warning for women of childbearing age about possible safety risks of dietary supplements containing vinpocetine. U.S. Food and Drug Administration website. Published June 3, 2019. Accessed June 28, 2019.
Vinpocentine. Natural Medicines Database website. Updated June 13, 2019. Accessed June 28, 2019.

One cup of raw golden berries is a good source of vitamin C and thiamin and an excellent source of vitamin A and niacin. Online articles cite their vitamin A and C content with helping to bolster the immune system and their withanolide (a naturally occurring steroid) content with helping to reduce stress as an adaptogen, but more research is needed.

Consumers can find dried golden berries in grocery stores and online shops. Fresh golden berries grown in Oregon are available in July and August and those grown in New Zealand are available from October to January. Leaves and unripe berries are toxic and should not be consumed.

Golden berries are part of the nightshade family, which has been linked to inflammation and arthritis. However, there is no strong evidence to support this concern. Ripe golden berries may be enjoyed like other fruits.

References

Best Vegetables for Arthritis. Arthritis Foundation website. Accessed June 28, 2019.
Fiegl A. Five Ways to Eat Ground Cherries. Smithsonian website. Published September 2, 2010. Accessed June 28, 2019.
Herbst R, Herbst ST. The Deluxe Food Lover’s Companion, 2nd Edition. Hauppauge, NY: Barron’s Educational Series, Inc.; 2015.
Kendall Reagan Nutrition Center. Nightshades and your health. Colorado State University website. Published September 14, 2017. Accessed June 28, 2019.
Luttjohann B. Ground Cherries. Permaculture Research Institute website. Published June 29, 2017. Accessed June 28, 2019.
National Nutrient Database for Standard Reference Release, April 2018. United States Department of Agriculture/National Agricultural Library website. Accessed June 28, 2019.
Ohio Perennial and Biennial Weed Guide. The Ohio State University website. Accessed June 28, 2019.
Top 7 Benefits of Golden Berriess. Imlak’esh Organics website. Accessed June 28, 2019.

Combined with vending machine calorie labeling, these rules are estimated to save more than $400 million over 20 years, as providing calorie labeling is expected to empower consumers to make “informed and healthful dietary choices.” Published in 2017, an interim final rule extended the compliance date to May 7, 2018, and was followed by a one-year grace period during which the FDA worked with restaurants and retail food establishments to ensure compliance.

The rule states that calorie information must be adjacent to and clearly associated with menu, grab-and-go, buffet and self-service items, including drinks. The rule applies to establishments that are part of a chain with 20 or more locations, including restaurants, bakeries, coffee shops, convenience stores, grocery stores and foodservice facilities within entertainment venues such as movie theaters. The rule does not apply to schools, where nutrition requirements are regulated by the United States Department of Agriculture.

In addition to displaying calories on menus, some nutrition information must be available in written form, such as a booklet or poster; this includes total calories, total fat, saturated fat, trans fat, cholesterol, sodium, total carbohydrate, dietary fiber, sugars and protein. On its website, the FDA provides supplemental guidance for industry about implementing the rule as well as resources for consumers to use the nutrition information.

References

Calories on the Menu; Information for Consumers. U.S. Food and Drug Administration website. Updated May 8, 2019. Accessed May 15, 2019.
FDA Shares New Online Tool to Assist with Menu Labeling Compliance. FoodSafety Magazine website. Published December 3, 2018. Accessed May 15, 2019.
Food Labeling; Nutrition Labeling of Standard Menu Items in Restaurants and Similar Retail Food Establishments; Extension of Compliance Date; Request for Comments. Federal Register website. Published May 4, 2017. Accessed May 15, 2019.
Food Labeling; Nutrition Labeling of Standard Menu Items in Restaurants and Similar Retail Food Establishments. Federal Register website. Published December 1, 2014. Accessed May 15, 2019.
Menu Labeling Requirements. U.S. Food and Drug Administration website. Updated September 14, 2018. Accessed May 15, 2019.
Menu Labeling Rule; Key Facts for Industry. U.S. Food and Drug Administration website. Accessed May 15, 2019.
Menu Labeling: Supplemental Guidance for Industry. U.S. Food and Drug Administration website. Published May 2018. Accessed May 15, 2019.

However, while celery itself is a nutrient-dense vegetable full of water, vitamin K and phytochemicals, there is no research to suggest celery juice is a “miraculous healing remedy.”

A PubMed search of “celery juice” limited to studies on humans published within the last five years returns four results, none of which investigate health outcomes of drinking celery juice. The Natural Medicines Database states celery juice has been reported to have bile stimulating activity, citing one 1996 publication. Other mentions of celery juice in the Natural Medicines Database pertain to possible medication interactions.

According to MyPlate, one cup of 100-percent vegetable juice may be considered a serving of vegetables. If a person enjoys drinking celery juice and there are no contraindications, it is an acceptable way to consume a serving of vegetables. But there is no evidence to suggest that starting the day with 16 ounces of celery juice on an empty stomach will cure disease.

References

All About the Vegetable Group. MyPlate website. Accessed April 8, 2019.
Anselmo, C. Celery: A Nutritious Culinary Staple. Food & Nutrition Magazine website. Published December 14, 2017. Accessed April 8, 2019.
Celery. Natural Medicines Database website. Updated February 12, 2019. Accessed April 8, 2019.
William, A. About Anthony William. Medical Medium website. Accessed April 8, 2019.
William, A. The Global Celery Juice Movement. Medical Medium website. Accessed April 8, 2019.

According to the World Health Organization, global average life expectancy continues to rise and is increasing faster than it has at any other time during the last 50 years. Approximately 9 percent of the world’s population is 65 or older; this number is expected to grow to 17 percent by 2050. With longer life comes more years of living with chronic diseases and disabilities. For instance, the rate of vision impairments nearly triples for Americans as they age from 65 to 85 and older.

Age-related macular degeneration, or AMD, is a leading cause of vision loss in older people in the United States and, as the name indicates, the risk of the condition increases with age. AMD affects 2.5 percent of white Americans 50 and older and more than 14 percent of white Americans 80 and older — significantly more than people who are black, Latino or other races. Between 2000 and 2010, the number of people in the U.S. with AMD grew 18 percent. By 2050, the number is expected to reach 5.4 million.

While risk for AMD partially is impacted by genetics, lifestyle factors including smoking, physical activity and dietary patterns also can modify risk. Research suggests Americans are not eating enough of the foods and nutrients that protect eye health, particularly the antioxidant carotenoids lutein and zeaxanthin. Foods rich in these nutrients include dark leafy greens and green vegetables. Lutein and zeaxanthin are found in high amounts in the retina, and lutein has the ability to absorb blue light that is harmful to the eye.

According to antioxidants and eye health researcher Elizabeth Johnson, PhD, FACN, FICS, “If a generally healthy adult is following the 2015-2020 Dietary Guidelines for Americans, they should get approximately 6 milligrams per day of lutein, which epidemiological research suggests is the amount related to decreased risk of age-related eye disease.” For reference, one cup of cooked kale contains about 6 milligrams of lutein and zeaxanthin.

There is no dietary reference intake, or DRI, for lutein or zeaxanthin and neither is mentioned in the 2015-2020 Dietary Guidelines for Americans. Based on criteria to evaluate if a nonessential bioactive is ready to be considered for specific dietary recommendations, some researchers believe there is enough evidence to develop intake recommendations for lutein. The American Optometric Association recommends consuming 10 milligrams of lutein and 2 milligrams of zeaxanthin per day to slow AMD progression.

Additional antioxidants may play a role in eye health. Catechins found in green tea are thought to positively impact the eyes. Drinking green tea has been linked with significantly reduced risk of age-related cataracts and glaucoma. There is in vitro evidence that melatonin may protect against oxidative stress in retinal cells, and a link has been found between serum melatonin levels and risk of AMD as well as diabetic retinopathy, a condition that causes eye damage in people with diabetes. More research on each of these associations is needed before any certain conclusions may be drawn.

Eating more vitamin A (found in sweet potatoes, spinach, carrots, cantaloupe, peppers and mangoes), vitamin C (found in peppers, oranges, kiwifruit, broccoli, strawberries and Brussels sprouts) and vitamin E (found in sunflower seeds, almonds, hazelnuts, sunflower oil and wheat germ) has been linked with lower risk of cataracts and AMD.

A 2017 meta-analysis found a significant association between vitamin D deficiency and diabetic retinopathy. Researchers also are investigating mechanisms by which vitamin D seems to lower AMD risk. Additionally, evidence points to a diseasespecific association between AMD and osteoporosis in older women; researchers suspect vitamin D may play a role. Vitamin D-rich foods include salmon, tuna, UV-exposed mushrooms and fortified juices and dairy and plant-based milks. Researchers also have found lower rates of AMD in people who consume higher amounts of zinc, which is found in oysters, crab, beef, pork, baked beans and cashews.

Optimal Dietary Patterns
Eating styles rich in vegetables and fruits are associated with lower risk for cataracts, glaucoma and AMD; high meat consumption, especially red meat, has been linked to increased risk of these conditions. Although research on amounts and types of dietary fat are complex and require further study in a variety of populations, Mediterranean-style eating patterns have been associated with lower risk for AMD. Researchers have found that nutrient-dense eating patterns are most effective for lowering risk of AMD when implemented along with other healthful lifestyle behaviors.

Addressing Dietary Supplements
The National Eye Institute has conducted two large clinical trials investigating the impact of specific supplements on risk for and progression of advanced AMD among older people. In 2001, researchers from the Age-Related Eye Disease Study, or AREDS, reported that the AREDS supplement (vitamins C and E, beta-carotene, copper and zinc) reduced the risk of advanced AMD by 25 percent over five years. Beginning in 2006, a second study called AREDS2 investigated variations of the original formula including one with added omega-3 fatty acids DHA and EPA and another with lutein and zeaxanthin instead of beta-carotene. Results showed no significant benefit from DHA and EPA. Lutein and zeaxanthin in place of beta-carotene slightly reduced risk of advanced AMD; this was especially useful for smokers, since supplemental beta-carotene was found to increase risk of lung cancer in people who smoked. Currently, AREDS formulations are the only treatment for AMD.

Based on AREDS and AREDS2 data, to slow AMD progression, the American Optometric Association recommends consuming 500 milligrams per day of vitamin C, 400 milligrams per day of vitamin E and 40 to 80 milligrams per day of zinc. The American Academy of Ophthalmology recommends considering the AREDS and AREDS2 supplements for patients with intermediate and advanced AMD. Supplements may help treat AMD if a person’s diet does not contain adequate amounts of specific nutrients. There may be no benefit or harm in taking supplements if a person’s diet already contains adequate amounts of specific nutrients. Talk with a health care provider before taking any dietary supplements.

Key Takeaways
An abundance of evidence links eating more vegetables and fruits with better eye health as one ages. Following the Dietary Guidelines for Americans should be sufficient for most people. For those already affected by AMD, health care providers may recommend supplementation. Registered dietitian nutritionists should consider incorporating the topic of eye health into conversations with older patients and clients: It’s another reason to consume ample amounts of vegetables and fruits.

References

Age-Related Eye Disease Study 2 Research Group. Lutein + zeaxanthin and omega-3 fatty acids for age-related macular degeneration: the Age-Related Eye Disease Study 2 (AREDS2) randomized clinical trial. JAMA. 2013;309(19):20015-2015.
Age-Related Macular Degeneration (AMD). National Eye Institute website. Accessed April 17, 2019.
Aoki A, Inoue M, Nguyen E, et al. Dietary n-3 Fatty Acid, α-Tocopherol, Zinc, vitamin D, vitamin C and β-carotene are Associated with Age-Related Macular Degeneration in Japan. Sci Rep. 2016;6(1).
Braakhuis A, Raman R, Vaghefi E. The Association between Dietary Intake of Antioxidants and Ocular Disease. Diseases. 2017;5(1):3.
Carneiro Â, Andrade J. Nutritional and Lifestyle Interventions for Age-Related Macular Degeneration: A Review. Oxid Med Cell Longev. 2017;2017:1-13.
Chang C, Huang T, Chen H, et al. Protective Effect of Melatonin against Oxidative Stress-Induced Apoptosis and Enhanced Autophagy in Human Retinal Pigment Epithelium Cells. Oxid Med Cell Longev. 2018;2018:1-12.
Dehdashtian E, Mehrzadi S, Yousefi B, et al. Diabetic retinopathy pathogenesis and the ameliorating effects of melatonin; involvement of autophagy, inflammation and oxidative stress. Life Sci. 2018;193:20-33. doi:10.1016/j.lfs.2017.12.001.
Facts About Age-Related Macular Degeneration. National Eye Institute website. Reviewed November 2018. Accessed April 17, 2019.
FNOA: ANTIOXIDANTS (2011-2012). Evidence Analysis Library website. Accessed April 17, 2019.
For the Media: Questions and Answers about AREDS2. National Eye Institute website. Reviewed May 2013. Accessed April 17, 2019.
Kang J, Ivey K, Boumenna T, Rosner B, Wiggs J, Pasquale L. Prospective study of flavonoid intake and risk of primary open-angle glaucoma. Acta Ophthalmol. 2018;96(6):e692-e700.
Life expectancy. World Health Organization website. Accessed April 17, 2019.
Lutein & Zeaxanthin. American Optometric Association website. Accessed April 17, 2019.
LV XS, Liu S, Cao Z, et al. Correlation between serum melatonin and aMT6S level for age-related macular degeneration patients. Eur Rev Med Pharmacol Sci. 2016;20:4196-4201.
Merle B, Silver R, Rosner B, Seddon J. Associations Between Vitamin D Intake and Progression to Incident Advanced Age-Related Macular Degeneration. Investigative Ohpthalmology & Visual Science. 2017;58(11):4569.
National Nutrient Database for Standard Reference Release, April 2018. United States Department of Agriculture/National Agricultural Library website. Accessed April 17, 2019.
Nutrition and AMD. American Optometric Association website. Accessed April 17, 2019.
Raimundo M, Mira F, Cachulo M, et al. Adherence to a Mediterranean diet, lifestyle and age-related macular degeneration: the Coimbra Eye Study – report 3. Acta Ophthalmol. 2018;96(8):e926-e932.
Raman R, Vaghefi E, Braakhuis AJ. Food components and ocular pathophysiology: a critical appraisal of the role of oxidative mechanisms. Asia Pac J Clin Nutr. 2017;26(4):572-585.
Ranard K, Jeon S, Mohn E, Griffiths J, Johnson E, Erdman J. Dietary guidance for lutein: consideration for intake recommendations is scientifically supported. Eur J Nutr. 2017;56(S3):37-42.
Roberts AW, Ogunwole SU, Blakeslee L, Rabe MA. The Population 65 Years and Older in the United States: 2016. U.S. Census Bureau website. Published October 2018. Accessed April 17, 2019.
Sheng Y, He F, Lin J, Shen W, Qiu Y. Tea and Risk of Age-Related Cataracts: A Cross-Sectional Study in Zhejiang Province, China. J Epidemiol. 2016;26(11):587-592.
Yoo T, Kim S, Kwak J, Kim H, Rim T. Association Between Osteoporosis and Age-Related Macular Degeneration: The Korea National Health and Nutrition Examination Survey. Investigative Opthalmology & Visual Science. 2018;59(4):AMD132.
Zhang J, Upala S, Sanguankeo A. Relationship between vitamin D deficiency and diabetic retinopathy: a meta-analysis. Canadian Journal of Ophthalmology. 2017;52:S39-S44.

Popular among paleo diet followers, cassava flour can be found in the baking or gluten-free sections of the grocery store. Compared to whole-wheat flour, cassava flour is more expensive at about $9 to $10 per pound. Cassava flour can be substituted 1:1 in recipes calling for wheat flour.

References

All Purpose Flour Substitutes & How to Use Them. Paleo Scaleo website. Published September 18, 2018. Accessed January 22, 2019.
Cassava Flour. Bob’s Red Mill website. Accessed January 22, 2019.
Cassava Inspection Instructions. USDA Agricultural Marketing Service website. Accessed January 22, 2019.
Fessenden M. A Cassava Revolution Could Feed the World’s Hungry. Scientific American website. Published March 24, 2014. Accessed January 22, 2019.
Herbst ST, Herbst R. The Deluxe Food Lover’s Companion. Hauppauge, NY: Barron’s Educational Series, Inc.; 2009.
Otto’s Naturals – Cassava Flour. Otto’s Naturals website. Accessed January 22, 2019.

While there have been no clinical trials on the pegan diet, the emphasis on vegetables, fruits, heart-healthy fats and minimally processed foods makes this a nutrient-dense diet. However, no evidence suggests that avoiding gluten, grains, dairy and legumes is healthier for people who do not have allergies or intolerances to these foods. In fact, whole grains and legumes have been consistently linked with better health outcomes; limiting these foods may be difficult to sustain and could lead to nutrient deficiencies.

References

Hyman, M. Why I am a Pegan – or Paleo-Vegan – and Why You Should Be Too! Dr. Hyman website. Published November 7, 2014. Accessed January 22, 2019.
Melina V, Craig W, Levin S. Position of the Academy of Nutrition and Dietetics: Vegetarian Diets. J Acad Nutr Diet. 2016;116(12):1970-1980.
What is the pegan diet? Dr. Mark Hyman explains what pegan means. Youtube website. Published January 2, 2019. Accessed February 8, 2019.

Purported to be the next “superfood” in the Western world, one ounce of raw tiger nuts (equivalent to ¼ cup tiger nut meal) contains 2 grams of protein, 7 grams of fat, 19 grams of carbohydrate and 10 grams of dietary fiber and is a good source of iron and zinc. Proponents of tiger nuts cite their resistant starch content as a major selling point. There is a lack of human research exploring the health effects of consuming tiger nuts, but given their nutrient content, taste profile and texture, they may be enjoyed as one would nuts and seeds.

References

Bamishaiye EI and Bamishaiye OM. Tiger Nut: As A Plant, Its Derivatives And Benefits. Af J Food Agric Nutr Dev. 2011;11(5).
Herbst ST, Herbst R. The Deluxe Food Lover’s Companion. Hauppauge, NY: Barron’s Educational Series, Inc.; 2009.
Michail N. Heard of tiger nuts? They’re the next superfood ingredient for plant milks and gluten-free baking, says Nordic Chufa. Food Navigator website. Published August 27, 2017. Accessed November 20, 2018.
National Nutrient Database for Standard Reference Release, April 2018. United States Department of Agriculture/National Agricultural Library website. Accessed November 20, 2018.
Nazish N. What Are Tiger Nuts And Why Should You Eat Them? Forbes website. Published September 22, 2018. Accessed November 20, 2018.

According to the Natural Medicines Database, chicken-derived collagen (Type II) possibly is effective when used to reduce symptoms of osteoarthritis and there is insufficient evidence to rate effectiveness of bovine-derived collagen for any health conditions. There are a lack of conclusive human studies on the benefits and health implications of collagen at this time.

Collagen supplements cost up to $70 for a month’s supply. Before beginning any supplement, discuss your plans with a health care provider.

References

Anti-Aging Market To Touch US$ 216.52 Billion By the End of 2021, Globally: ZMR Report. Zion Market Research website. Published August 30, 2018. Accessed November 20, 2018.
Bovine Cartilage. Natural Medicines Comprehensive Database website. Updated January 23, 2018. Accessed November 20, 2018.
Collagen Type II. Natural Medicines Comprehensive Database website. Updated November 11, 2018. Accessed November 20, 2018.
Krieger E. Collagen supplements show early promise for skin and joints, but don’t stock up yet. Washington Post website. Published March 26, 2018. Accessed November 20, 2018.
Marshall L. Collagen: ‘Fountain of Youth’ or Edible Hoax? WebMD website. Reviewed March 8, 2018. Accessed November 20, 2018.
Super Youth. Skinny Fit website. Accessed November 20, 2018.

Fasting is nothing new. It has been a religious practice for centuries and Hippocrates advised medical fasting in 5th century B.C. Beginning in the early 1900s, animal studies demonstrated that fasting extended the life of rats. Animal research continued throughout the 20th century and suggested metabolic improvements as well.

How intermittent fasting works is not yet understood. Hypothesized mechanisms are based on rodent studies and involve the body’s circadian rhythm, or light-dark cycle. Proponents suggest that restricting food for a long period of time decreases insulin levels; they claim that when the gut is allowed to rest, gut permeability decreases, followed by decreased inflammation.

There are three kinds of intermittent fasting:

• Alternate-day fasting alternates days of zero calories with days of unrestricted calories.
• Modified fasting allows 20 percent to 25 percent of estimated caloric needs on fasting days and unrestricted intake on non-fasting days. For example, the 5:2 Diet is popular in the United Kingdom.
• Time-restricting feeding requires a prolonged nighttime fast.

In a 2013 article in the Canadian Medical Association Journal, intermittent fasting was predicted to be the next big weight-loss fad. This appears to be the case: The 2018 Food and Health Survey from the International Food Information Council Foundation found 10 percent of respondents said they follow intermittent fasting. Proponents claim it helps people lose weight, sleep better, improve diabetes and even live longer. But does human research support these claims?

A 2017 trial involved randomly assigning participants with a mean body mass index of 34 to one of three groups for one year: alternate-day fasting (25 percent of energy needs alternated with 125 percent), calorie restriction (75 percent of energy needs) and control (unrestricted calories). The alternate-day fasting group had a high dropout rate: 38 percent compared to 29 percent in the calorie restriction group. This group did not experience significantly different weight loss from the restriction group. Between the intervention groups, there also were no significant differences in blood pressure, heart rate, triglycerides, fasting glucose, fasting insulin, insulin resistance, C-reactive protein or homocysteine concentrations. LDL cholesterol rose significantly in the fasting group compared to the restriction group.

A 2018 study of adults with Type 2 diabetes and a mean BMI of 36 compared the 5:2 Diet to calorie restriction for one year and found both interventions improved HbA1c, fasting glucose and lipid levels but did not differ significantly.

While intermittent fasting appears to offer metabolic improvements for people with Type 2 diabetes, although not significantly different from those achieved by traditional caloric restriction, it may not be safe for all people with diabetes.

“Whether someone has Type 2 diabetes or Type 1 diabetes, what matters most is if they’re dependent on insulin and taking glucose-lowering medications,” says Hope Warshaw, MMSc, RD, CDE, BC-ADM, FAADE, author of Diabetes Meal Planning Made Easy, 5th Ed. (American Diabetes Association 2016). “Diabetes management is not the same for everyone. The safety of intermittent fasting for someone with diabetes depends on their medications and risk for hypoglycemia.”

The Academy’s 2016 position paper on adult weight management does not address any type of fasting and points out that research is very limited on the effect of timing of intake among people with obese BMIs. Additionally, a systematic review performed in 2013 and 2014 and published to the Evidence Analysis Library found that skipping breakfast was associated with higher body mass index and increased risk of obesity.

Recent systematic reviews and meta-analyses of intermittent fasting in humans have found most studies to be of short duration with few participants and mixed findings. Intermittent fasting does not appear to offer superior metabolic or short-term weight control advantages compared to traditional caloric restriction.

While there appear to be no health advantages, some people may find intermittent fasting easier to maintain. “With intermittent fasting, you are restricting food intake but only on certain days or times, and on other days or times, you have the freedom to eat and meet energy requirements,” says Abbey Sharp, RD, a Toronto-based dietitian. “In that sense, some people see this diet as a more flexible approach. Depending on which regime you choose, it also might not be too different from how you’re already eating if you eat an early dinner and late breakfast.”

Conversely, researchers found that some participants overate on fasting days and under-ate on non-fasting days, which may indicate intermittent fasting is difficult to maintain.

Side effects of intermittent fasting include persistent hunger, cold, irritability, low energy, distraction and lower work performance. Those at risk for disordered eating should not attempt any sort of fasting diet; fasting has been found to predict disordered eating and eating disorders. Meanwhile, multiple eating disorder organizations classify fasting as an unhealthy weight control behavior. According to Tiffany Haug, MS, RDN, EDOC, who specializes in behavioral health and eating disorders, “When restricting food, there is a higher dopamine release in the brain when you do eat, which increases the likelihood of binge.”

Another population of concern is athletes. While research is quite limited in this area, one small study found intermittent fasting decreased speed among male athletes.

Intermittent fasting could be risky for women of child-bearing age, since preconception is an important time for women to maximize their nutrient intake. “Going without food means going without energy as well as protein, vitamins, minerals and phytonutrients. In terms of nutrition, there is a lot to make up for on non-fasting days and it’s very difficult to catch up,” explains Elizabeth Ward, MS, RDN, author of Expect the Best, Your Guide to Health Eating Before, During, and After Pregnancy (Academy of Nutrition and Dietetics 2017). Pregnant and breastfeeding women also should not attempt fasting because they need consistent energy and nutrients to support the developing fetus and breast milk. Ward says she would not recommend intermittent fasting to a woman who is pregnant or breast-feeding.

“Premenopausal women have different metabolic expenditures depending on the time of the month. When you’re not meeting your needs due to fasting, you’re increasing your risk for bingeing and fixation on food,” Haug says.

Researchers agree there is not enough evidence to recommend intermittent fasting at this time and that studies have lacked long-term interventions and follow-up periods. There have been few studies investigating the mental, emotional and social consequences of fasting. Additionally, researchers suggest that future studies should investigate cognitive and immunological implications, dietary quality and impact on the microbiome.

The gut-brain axis is a topic of interest in fields from neurology and gastroenterology to psychology and integrative and functional medicine. While most available evidence on the gut-brain axis comes from animal studies, emerging human research is providing valuable insights into the complex integration of psychology and physiology of the human body.

The gut is a busy place. Not only does it house the influential microbiome, it also includes immune cells, neuropeptides, microbial metabolites and enteroendocrine cells, which secrete hormones. The vagus nerve is a key connection point linking the brain and gut, while nerves along the gut allow for direct communication with contents of the stomach and intestine.

The digestive tract is one of the major entry points for external substances, from food and supplements to drugs and bacteria. These substances all have the potential to impact the gut-brain axis.

Intestinal permeability refers to the physical gaps between intestinal cells, which is thought to be partly regulated by the microbiome. The term “leaky gut” was coined to describe when those gaps are enlarged and external substances and waste products are allowed to pass into the bloodstream. This has been associated with changes in mood, immune function and inflammation. Intestinal permeability may be associated with numerous conditions including inflammatory bowel disease and autoimmune disorders such as Type 1 diabetes and celiac disease.

“RDNs can play an integral role in preventing and repairing intestinal permeability,” says Mary Purdy, MS, RDN, the 2017- 2018 chair of the Academy’s Dietitians in Integrative and Functional Medicine dietetic practice group. According to Purdy, consuming adequate amounts of vitamins A and D, with plentiful dietary fiber, prebiotics and probiotics to keep the gut microbiota healthy, can maintain and improve the integrity of the gut.

It also is becoming clear that the microbiome can influence its host’s appetite and eating behavior. Animal and human research has found a link between specific species of microbes and increased host intake of nutrients that the microbes prefer. “Cravings and feelings of hunger we experience may not be just our own,” says April N. Winslow, MS, RDN, CEDRD, who is working toward her doctorate in food science and human nutrition with an emphasis in nutritional neuropsychology.

The metabolites microbes produce and the neurochemicals they influence impact secretion of satiety-promoting hormones; researchers suspect the microbiome also can influence taste, smell, thoughts, impulsivity and compulsivity about food. Short-chain fatty acids, a major metabolite of gut microbes, and their possible link to obesity and metabolic syndrome are an active area of research. In fact, administering the short-chain fatty acid proprionate to the colon of adults who are overweight led to greater satiety hormone release and reduced calorie intake and weight gain.

Disrupting the gut-brain axis already is used as a treatment for obesity through Roux-en-Y gastric bypass surgery, a restrictive and malabsorptive intervention that in 2015 accounted for an estimated 23 percent of bariatric surgeries. This surgery is unique compared to purely gastric restrictive bariatric surgeries, such as laparoscopic adjustable gastric banding, because part of the stomach is stapled off and attached to the middle part of the small intestine, bypassing the lower portion of the stomach and parts of the small intestine. This may affect not only the absorption of certain micronutrients, but also hunger and satiety hormones.

People who undergo gastric bypass surgery tend not to experience the same increase in the hunger hormone ghrelin as people who achieve non-surgical weight loss through diet and exercise alone. Bariatric experts suspect this is a major contributor to the success of the surgery. In addition, sometimes the vagus nerve is severed during gastric bypass surgery, which could affect hunger hormones and innervation of the gut, therefore impacting appetite.

Nina Crowley, PhD, RDN, LD, metabolic and bariatric surgery program coordinator at the Medical University of South Carolina, says it is imperative to counsel bariatric candidates on the mechanisms at work in various bariatric surgeries, how they differ and how this impacts metabolism. “I like to discuss how the change in gut hormones may be what is required for them to see a metabolic change, and keep a focus on biology, rather than blaming the person for their eating habits or behavior,” Crowley says.

When the body is underfed, such as with bariatric surgery recovery and anorexia nervosa, gut microbiota composition and diversity changes. This has been correlated with depression and anxiety in people with anorexia nervosa and may be related to the fact that 95 percent of the neurotransmitter serotonin, which plays a role in depression, is produced in the gut.

Research is examining what happens when fecal samples from people with anorexia nervosa are transplanted into mice born in a germ-free environment, compared to what happens when fecal samples from healthy people are transplanted into germ-free mice. This science serves as a foundation for potential new treatments for anorexia nervosa as well as furthering the understanding of the underlying mechanisms of this complex disease.

There is not enough evidence to explain the role of the gut-brain axis in binge-eating disorder, although some researchers suspect the gut microbiome’s impact on impulsivity and compulsivity may play a role.

While research on the gut microbiome is booming, human research is needed on other parts of the gut-brain axis, especially as it pertains to risk and development of psychological and chronic disease. As more human evidence becomes available, novel intervention strategies involving food and nutrition likely will come to light.

“Registered dietitian nutritionists are the ideal medical professionals to lead research in this area because they have the training and skills to obtain nutritional data from human participants and conduct motivational interviewing,” Winslow says.

Then, TV personality Elisabeth Hasselbeck published The G-free Diet (Center Street 2011), President Bill Clinton promoted his post-heart-surgery gluten-free diet on “The Ellen DeGeneres Show,” Paleo and Wheat Belly (Rodale Books 2014) hit the scene, and a billion-dollar industry was born.

At the time, the scientific community accepted celiac disease as the only adverse reaction to gluten — despite that individuals who tested negative for the autoimmune disease were reporting celiac-like symptoms (“foggy mind,” depression, ADHD-like behavior, abdominal pain, bloating, diarrhea, constipation, headaches, bone or joint pain and chronic fatigue). Eventually new research suggested a spectrum of non-celiac gluten-related disorders that improve when gluten is removed from the diet — now known as non-celiac gluten sensitivity or non-celiac wheat sensitivity.

Today, adults in the U.S. are increasingly self-reporting food allergies without a diagnosis from a doctor. Consumers around the globe are experimenting with elimination diets as a means to identify causal association with symptoms ranging from gut distress to joint pain, lethargy or depression.

Most health practitioners, and registered dietitian nutritionists in particular, do not advocate unnecessary restrictive dieting. Nonetheless, many consumers are finding relief through elimination diets — and the scientific community isn’t sure why.

Confusion over what causes certain responses to foods is a culmination of heated debate among medical researchers, vague terminology with conflicting definitions, gaps in research and, arguably, the inherent discomfort of “the unknown.”

Let’s Start with the Known

A food allergy exists when exposure to a specific food results in an adverse response in the immune system. Because a one-time reaction is not definitive, a criterion for a food allergy is that the immune response be reproducible.

Symptoms range from mild itching and hives to severe anaphylaxis, which can cause difficulty breathing, dizziness, loss of consciousness or death.

Most food allergies are IgEmediated, meaning the immune system identifies an allergen as an “invader” and overreacts by producing antibodies called immunoglobulin E. However, some food allergies — such as eosinophilic GI disease and protein-induced enterocolitis — are not IgE-mediated.

A food intolerance refers to malabsorption in the digestive tract and does not involve the immune system. The inability to break down certain foods may be the result of enzyme deficiencies or reactions to naturally occurring chemicals in foods. Unlike food allergies (in which even a microscopic morsel of an allergen can cause an adverse reaction), food intolerances are dose dependent: the more one eats of the offensive food, the worse the symptoms — usually along the lines of nausea, stomach pains, vomiting and diarrhea.

Here is Where it Gets Tricky

There also appear to be adverse food reactions that do not fit current diagnostic criteria for food allergies or food intolerances. Some practitioners refer to these as food sensitivities; however, food sensitivity has no universally accepted definition — and to compound confusion, the term has different meanings, depending on who you ask.

For example, the American Academy of Allergy, Asthma and Immunology uses “food sensitivity” interchangeably with intolerance. According to the Guidelines for the Diagnosis and Management of Food Allergy in the United States, the term “food hypersensitivity” often is used to describe food allergies, while other groups use “food sensitivity” as an umbrella term that includes both allergies and intolerances. And a 2012 study in the Canadian Medical Association Journal defines “food sensitivity” as “a nonspecific term that can include any symptom perceived to be related to food and thus may be subject to a wide range of usage and interpretation.”

These mysterious non-allergic adverse food reactions have many practitioners perplexed.

For example, take sulfite sensitivity, which is more common in people with asthma, especially those taking steroid medications. Reported symptoms include respiratory reactions and asthma, hypotension, GI reactions, dizziness and hives. Currently there are no validated lab tests to diagnose a sulfite sensitivity and the mechanism is yet to be determined. Medical history, symptom diaries and controlled exposure to test for reactions (known as an oral challenge) are used to make the diagnosis.

Other reports of triggers for adverse food reactions run the gamut, including various fruits and vegetables, grains, protein foods and dairy. Often these cases have already gone through allergy testing, excluded GI health conditions and exhausted diagnostic processes by physicians, including general practitioners, endocrinologists, gastroenterologists and allergists.

Debra Indorato, RDN, LDN, CLT, a nutrition and food management consultant in Tampa, Fla., has specialized in food allergies for nearly 30 years. It was early in her career when some of her referrals experienced persistent symptoms, even after testing negative for food allergies, and she began researching food sensitivities and immunology. Her personal working definition for food sensitivity is “a nonallergic inflammatory reaction that can affect any area of the body.” But identifying such a broad, enigmatic occurrence of inconsistent, overlapping symptoms is a challenge.

Food allergy assessment tools — skin pricks or the double-blind, placebo-controlled food challenge — are not applicable for these cases since allergic reactions are immediate and often dramatic, while “food sensitivities” are delayed and hit-or-miss. Carbohydrate intolerances, such as lactose intolerance, can be diagnosed with a hydrogen breath test or fecal test, while blood tests, endoscopies or biopsies may be used to rule out other conditions.

In an attempt to identify specific foods to which individuals are sensitive, medical testing companies have developed various proprietary blood panels. Some measure antibodies in the blood, such as the “IgG test” (which, since IgG is a “memory antibody,” actually only confirms exposure to a food, not a reaction to it). Others are centered on studying white blood cells as an indication of an inflammatory response — including the Alcat test and the enzyme-linked immunosorbent assay, or ELISA.

Recently, the mediator release test, or MRT, has gained favor among some practitioners, including a segment of registered dietitian nutritionists who then implement the Lifestyle Eating and Performance, or LEAP, diet based on the assay results. The MRT measures levels of cytokines, histamine, leukotrienes, prostaglandins and other mediators released from white blood cells after exposure to 150 foods and food chemical profiles. MRT supporters cite evidence indicating correlations between the immune system mediators, ensuing inflammation and risk of chronic disease such as osteoporosis and cardiovascular disease, as well as other conditions including GERD and cognitive decline. But while there is plenty of anecdotal vouching for MRT’s effectiveness in identifying potential sensitivities, there are no peer-reviewed, published studies validating the test.

Laura Matarese, PhD, RDN, LDN, CNSC, professor at the Brody School of Medicine at East Carolina University and co-editor of The Health Professional’s Guide to Gastrointestinal Nutrition (Academy of Nutrition and Dietetics 2013), says that in addition to the lack of research, there also is no consensus or endorsement of food sensitivity panels by any allergy or immunology organizations, noting that most insurance companies will not cover them.

Janice Vickerstaff Joneja, professor at the School of Family and Nutritional Sciences at the University of British Columbia and author of The Health Professional’s Guide to Food Allergies and Intolerances (Academy of Nutrition and Dietetics 2014), also is an MRT skeptic. However, she says the elimination and challenge components of LEAP therapy are useful.

Los Angeles-based consultant Christine Bou Sleiman, MS, RDN, CLT, has been a certified LEAP therapist since 2016 and experienced significant improvements in her own digestive health and inflammatory skin disorder since following the immune-calm LEAP protocol. “The MRT gives us a starting point, rather than taking a stab in the dark,” she says, “especially when many of these referrals are already on some form of elimination diet.” Bou Sleiman adds that she sees profound symptom relief in her clients and often helps increase the variety of foods in their diets.

Still, Emily Fonnesbeck, RD, CD, CLT, says that practitioners need to understand clients’ underlying issues, such as disordered eating, that may be exacerbated by an elimination diet. Before she suggests food sensitivity testing, Fonnesbeck works with new clients to identify potential causes of the symptoms and address primary issues, such as the stress caused by not being able to pinpoint why they don’t feel well.

“Even for clients who feel better on the elimination diet, it is difficult to know exactly why they are seeing benefits,” Fonnesbeck says. After all, the virtue of being more mindful about eating may in itself help ease physical symptoms.

A study in the journal Social Science and Medicine explored the perspectives of British general practitioners when confronted with patients who believe they are experiencing adverse reactions to certain foods. Although working with the patients’ beliefs was seen as important to preserving the doctor-patient relationship, skepticism among the physicians was strong.

However, it was “tempered by an element of self-awareness and an awareness of the limitation of modern medicine,” wrote the authors. “With the transitional nature and constant evolution of medical knowledge, several of the participants entertained the idea that this condition might be recognized and understood in the future.”

There is no concrete evidence to support the use of activated charcoal to lower cholesterol, decrease flatulence, remedy hangovers or help the body “detox.” It can bind nutrients in the digestive tract, prevent absorption of prescribed medicines, lead to constipation and is not advisable for consumption without instruction from a medical provider.

According to National Health and Nutrition Examination Survey data, obesity in adults more than doubled over half a century — from 13.4 percent in 1962 to 38.2 percent in 2014 — and the National Bureau of Economic Research reports the estimated annual health care costs of obesity-related illness to be nearly 21 percent of annual medical spending in the United States.

With links between higher body mass index and increased risk for disease, including Type 2 diabetes, cardiovascular disease and certain cancers, public health messaging to the masses and patient advice from medical practitioners have centered on weight loss as both prevention and treatment for many chronic diseases. However, there isn’t a single therapy (dietary, surgical, pharmaceutical or otherwise) that has been shown to sustain long-term weight-loss maintenance in a significant number of people.

Researchers are only just beginning to understand the myriad factors that affect body weight and body fat, including genetics, hormones, medications, diseases, age, sleep, stress, environmental pollutants, sex, ethnicity, socioeconomic status, dietary quality and physical activity. And some epidemiological studies actually support conflicting theories on body weight and health.

For example, the “Obesity Paradox” refers to the anomaly of some people with BMIs in the overweight and obese categories, especially older adults and even with chronic disease, outliving people with normal BMIs.

“In general, there is a strong relationship between BMI and health outcomes,” says Hollie Raynor, PhD, RD, LDN, obesity researcher and co-author of the Academy’s 2016 position paper on interventions for the treatment of overweight and obesity in adults, “but there are individual differences.” Among limitations inherent to epidemiological research, according to Raynor, is that studies correlating body weight and morbidity and mortality may not control for moderating factors affecting disease risk, such as high intake of calorie-rich, low nutrient-dense foods, low intakes of nutrient-dense foods, physical inactivity and smoking.

Other concepts — including “metabolically healthy obesity” (individuals with BMIs of 30 or higher who have normal blood lipids, blood sugar and insulin levels) and “metabolically obese normal weight” (people with normal BMIs and negative health outcomes) — are countered by a much higher proportion of people with obese BMIs who are not metabolically healthy.

However, it is well recognized in behavioral health research that weight stigma (stereotyping and bias based on one’s size) is associated with increased calorie consumption and binge eating, negative body image, depression, greater likelihood of becoming obese, and reduced desire to engage in healthy behaviors.

Other studies suggest that a focus on weight in health care settings may increase false positives and negatives. For instance, if physicians look for certain diseases in patients with overweight or obese BMIs but not in individuals with normal BMIs, some conditions may be overdiagnosed in larger people or underdiagnosed in smaller people.

According to a 2014 review of unintended harm associated with public health interventions, weight loss messaging is not only ineffective, but actually can promote body dissatisfaction and disordered eating. Campaigns centered on healthy behaviors without mention of weight are better received and are more likely to result in healthy behaviors among targets, wrote the authors.

Enter the “weight-neutral” movement: a therapeutic approach to improving the health of individuals by focusing less on BMI, and more on lifestyle behaviors.

“In light of having no validated methods to help more than a small number of people lose weight and keep it off,” says Marci Evans, RD, CEDRD, CPT, who specializes in body image issues and emotional eating, “we need to use tools that will enhance clients’ health at their current weight without causing more harm — remembering to consider long-term harm as well.”

Some evidence suggests dietary restriction and a history of weight loss are associated with eating disorders. In addition, a key concern cited by weight-neutral proponents is that dietary restriction often leads to weight cycling — repeated gain and loss of weight — rather than sustained weight loss. Some research associates weight cycling with loss of lean body mass, reduced metabolic energy expenditure, increased inflammation, hypertension, insulin resistance, dyslipidemia, osteoporotic fracture, some types of cancer, cardiovascular risk, mortality risk and emotional distress. Other studies suggest weight cycling is more strongly linked with certain adverse health outcomes than is having an obese BMI.

But many obesity researchers do not agree with these conclusions, citing studies that show losing even 3 percent to 5 percent of body weight reduces some health risks in people with elevated BMIs.

“Lifestyle interventions that include dietary, physical activity and behavior components typically do not lead to eating disorders,” says Raynor, adding that structured eating can even help with bulimia nervosa and binge-eating disorder — although robust, multidisciplinary intervention programs designed by researchers may not be accessible for many people or covered by insurance.

On the other hand, there is limited research on the efficacy of weight-neutral interventions; although some studies have found significantly better physiological, behavioral and psychological outcomes compared to weight-centric models and dieting, including low dropout rates and no adverse events, those study samples were small and did not include individuals classified as morbidly obese. Other criticisms include that a weight-neutral approach gives people a “free pass” to engage in unhealthy lifestyle behaviors — and that weight loss should be pursued as soon as possible for people with obese BMIs.

But weight neutrality is not in conflict with, and actually helps support, the Nutrition Care Process, according to Jennifer McGurk, RDN, CDN, CDE, CEDRD, who advocates for the inclusion of weight-neutral concepts in continuing professional education for registered dietitian nutritionists.

“Many weight management trainings do not address binge-eating disorder,” says McGurk of a behavior that is prevalent in up to 30 percent of people seeking weight loss treatment. “Behavioral health is a critical component of health care, yet many weight management approaches address food and diet only — without taking into consideration individuals’ genetic predispositions, preferences and feelings surrounding food.”

Evans agrees, adding that while dietetics is grounded in compassion and individualized care, there is tremendous pressure as practitioners to focus on weight loss. “As registered dietitian nutritionists, we need to self-assess,” says Evans, “And determine whether an intervention will truly improve a client’s health, or if it comes from a desire to make them smaller.”

Physicians David Jenkins and Thomas Wolever invented the glycemic index in 1981 by first plotting curves to show how a specific amount of glucose raised study participants’ blood sugar over two hours. Then they had participants consume the same amount of carbohydrate via foods and plotted the resulting rise in blood sugar. A food’s glycemic index is the percent by which it raises blood sugar compared to glucose and is expressed on a scale of 0 to 100. 

During the next several years, Jenkins and Wolever published additional studies with participants from various populations, including healthy adults and people with hyperlipidemia and diabetes. Glycemic index seemed to be a useful tool for people with diabetes to control blood sugar, as well as a way to lower cholesterol and triglycerides in people with high blood lipids. Additionally, Wolever found when healthy adults consumed low-glycemic index meals for dinner, they tended to experience lower glycemic responses to carbohydrates at breakfast the next day than they did when they had high-glycemic index meals at dinner. 

A main criticism of the glycemic index is that people usually consume a variety of foods in a single meal. Since a balanced meal typically contains a blend of foods with different glycemic indices, the glycemic index of an individual food in a total meal may be insignificant. Jenkins and Wolever addressed these concerns in a 1986 study showing how a meal’s glycemic index may be calculated. Research participants experienced expected rises in blood sugar based on calculated glycemic indices of the meals they ate. 

More recently, studies have addressed glycemic index in a variety of populations with differing results. In 2002, Jenkins authored a review paper promoting a low-glycemic index diet for people with diabetes and for reducing cardiovascular disease risk. For individuals with diabetes, the American Diabetes Association says the glycemic index may be used to help fine-tune blood sugar, but the amount of carbohydrate a food contains is more important than its glycemic index. The Academy of Nutrition and Dietetics’ Nutrition Care Manual includes information on glycemic index as an alternative to the ketogenic diet for people with epilepsy.  

Emerging evidence suggests a low-glycemic diet may help improve insulin sensitivity in children with obesity and elevated insulin. The 2013 International Carbohydrate Quality Consortium, convened by the Glycemic Index Foundation, asserts glycemic index is a valid strategy for controlling blood sugar in healthy adults and it can be used to prevent diabetes, heart disease and obesity. However, the Natural Medicines Database says there is insufficient evidence to rate claims for the glycemic index. Additionally, the 2015-2020 Dietary Guidelines for Americans do not mention glycemic index, leading one to reason it is not of concern for the average, healthy American. 

Using the glycemic index as a weight-loss strategy lacks strong evidence. When used in addition to caloric restriction, a low-glycemic index diet can produce weight loss. However, one of the diet’s modern selling points is users don’t have to count calories and can still lose weight, which is a claim yet to be supported. A 2015 study of 91 adults with obesity found a low-glycemic index diet had no effect on weight loss, fat mass, lean mass nor metabolic adaptation during a 17-week weight-loss period compared to an isocaloric high-glycemic index diet. But a small 2013 study found when participants consumed high-glycemic index meals, they experienced increased hunger and cravings. 

Skepticism about using the glycemic index as a dietary tool exists for several reasons. The glycemic index of a food tells nothing about its nutritional qualities. For instance, watermelon has a higher glycemic index than ice cream, but most would say watermelon is a more nutritious option and may be eaten by people with diabetes, without need for concern, in accordance with their carbohydrate patterns. Academy spokesperson Jim White, RDN, ACSMEP- C, says he sees clients who are afraid to eat nutritious high-glycemic index foods such as potatoes, melon or pineapple, but these foods should not be avoided. When it comes to healthy eating, following the key recommendations of the Dietary Guidelines while using a total diet approach and MyPlate are more realistic and applicable strategies for most people. 

Academy spokesperson Marina Chaparro, MPH, RDN, LD, CDE, finds the glycemic index to be too variable and impractical to recommend to her clients with diabetes. Both Chaparro and White suggest clients use glycemic load, rather than glycemic index, to take portion size into account. “I teach my clients to focus on wholesome food, learn how to count carbs and focus on the right portion size,” Chaparro says. 

Although the glycemic index is not perfect, it can be a useful tool in addition to evidence-based strategies for controlling blood sugar in people with or at risk for diabetes, as long as they are not unnecessarily restricting foods. Prediabetes and diabetes are not caused by eating high-glycemic foods; they are complex diseases with a variety of risk factors, including other dietary variables, activity level, age, race, sex and family history. A wellness plan including assessment of all these factors helps health care professionals develop individualized strategies for patients and clients. 

As it turns out, these claims are backed by little science and likely surfaced due to spirulina’s impressive nutrient profile. One ounce, or approximately 4 tablespoons, of dried spirulina contains 81 calories, 16 grams of protein, 60 percent of the daily value of riboflavin, 44 percent of the daily value of iron and thiamin, 14 percent of the daily value of magnesium and 11 percent of the daily value of potassium.

The Natural Medicines Comprehensive Database lists all health claims associated with spirulina as having insufficient evidence to rate, and warns that women who are pregnant or breast-feeding should avoid it. There also is some evidence that spirulina could interact with anticoagulant, antiplatelet and immunosuppressant drugs. Due to its high protein content, people with phenylketonuria, or PKU, should not consume spirulina.

After the Natural Medicines monograph was updated in 2015, a double-blind, placebo-controlled, randomized trial of 40 individuals with hypertension was published in 2016. It found that consuming 2 grams of spirulina for three months led to improved BMI, body weight and blood pressure in this small sample. While spirulina is very protein-dense and these results seem promising, there is not enough information at this time to recommend it as a supplement for specific health conditions.

Due to its growing popularity, spirulina is cultivated in ponds and mass-produced all over the world, including Hawaii and China. Spirulina’s distinctive and strong seaweed flavor leads many people to consume it via capsule, while others mix the powder form into water, juice or smoothies. Contamination by toxins and heavy metals is a serious concern, so it is important to choose a spirulina supplement with reliable third-party testing and quality assurance.

While diet does not cause IBS, individualized nutrition therapy can significantly lessen symptoms through identification and restriction of trigger foods. Fermentable oligosaccharides, disaccharides, monosaccharides and polyols, or FODMAPs, have been identified as a group of short-chain carbohydrates that are rapidly digested and poorly absorbed in the gut, thus provoking excess fluid and gas in the bowels of many people with IBS. FODMAPs are naturally occurring carbohydrates found in foods such as apples, watermelon, asparagus, broccoli, milk and beans and are sometimes added to food as sweeteners.

Although some carbohydrates under the FODMAP umbrella, such as lactose and fructose, have been targeted in IBS therapy in the past, research on diet therapy addressing all FODMAPs as a group only began within the last decade. Research started in Australia in 2006, and subsequent studies have occurred elsewhere, including the United Kingdom, New Zealand, Scandinavia and the U.S. The results have been clear: When people with IBS consumed high amounts of FODMAPs, their symptoms got worse; when they restricted FODMAPS, their symptoms improved.

Now with enough evidence to support its use, a low-FODMAP diet is recommended as a nutrition prescription for patients with IBS in the Academy of Nutrition and Dietitics’ Nutrition Care Manual. Client education materials for a low-FODMAP diet will be available in the NCM later this year.

Nonetheless, doctors caution that low-FODMAP diet therapy is not a cure for patients with IBS. Individual response to the diet varies, and some people with IBS experience little relief from following a low-FODMAP diet. And while a low-FODMAP diet produces significant results in most IBS patients, it doesn’t always eliminate all symptoms. For instance, some patients may experience relief from gas and bloating, but their irregular bowel patterns remain.

FODMAP expert Patsy Catsos, MS, RDN, LD, began using low-FODMAP diet therapy in her private practice almost a decade ago. To date, she has helped thousands of patients through the diet and says that “the FODMAP elimination diet is more than just a list of foods — it’s a process. To get the best outcomes, patients need a strategic plan, and that’s where the dietitian comes in.”

One concern about following a low-FODMAP diet is the effect it may have on a patient’s gut microbiota. Evidence shows IBS patients have different gut microbiomes compared to the healthy population. Preliminary research suggests taking a probiotic supplement during low-FODMAP diet therapy can prevent the washout of beneficial gut bacteria, leading some FODMAP experts to recommend this type of supplement to people with IBS on the diet.

In addition to IBS, limited evidence shows promise of a low-FODMAP diet for people with inflammatory bowel disease, which is a separate medical condition (an autoimmune disease characterized by chronic inflammation; includes Crohn’s disease and ulcerative colitis). Some researchers suspect a low-FODMAP diet may help alleviate digestive symptoms in people with non-celiac wheat sensitivity, but the diet has not been validated in this population.

Not all FODMAP-containing foods worsen IBS symptoms for all patients, which is why the diet therapy is conducted in two phases. To identify specific foods that trigger symptoms in a patient, phase 1 restricts all high-FODMAP foods and phase 2 gradually reintroduces them.

Phase 1 typically lasts up to eight weeks and is when patients feel most challenged by the restrictiveness of the diet. Elimination and reintroduction of FODMAP-containing foods is the only effective strategy to identify trigger foods in patients with IBS. Reliable assessment methods such as hydrogen breath tests are available to detect some, but not all, FODMAP malabsorption, but these tests are capable of false positives and are not perfect. Because long-term evidence is not available and there is a risk of nutritional inadequacy if the diet is poorly planned, restricting high-FODMAP foods should be temporary and reintroduction should be as quick as possible in accordance with the patient’s symptoms.

Patients and physicians should work with an RDN who is trained in administering a low-FODMAP diet to ensure the success of the nutritional therapy. According to low-FODMAP diet educator Kate Scarlata, RDN, LDN, “The low-FODMAP diet has many nuances, and online resources are often outdated, making the IBS patient confused and frustrated. The role of the dietitian is to be well-prepared with the latest and most accurate low-FODMAP diet research to successfully guide the patient with this effective nutrition intervention.” While research shows good patient compliance of about 75 percent following the diet, it is restrictive by nature.

Barriers include expense of low-FODMAP specialty foods, dislike for the taste, unwillingness to follow the diet and the challenge of identifying and selecting low-FODMAP foods when eating away from home. Additional challenges are the lack of defined cutoff values for high- and low-FODMAP foods and shortage of FODMAP content on food packaging.

Two voluntary certifications for low-FODMAP food products are available, one from Monash University and the other from FODMAP Friendly, both of which have access to FODMAP laboratories to conduct food testing. These seals are on few products in grocery stores today, but likely will increase as the diet gains popularity. Dietitians interested in learning more about FODMAP diet therapy are encouraged to read books by reputable FODMAP experts, seek continuing education opportunities such as workshops and trainings led by FODMAP experts and use the Monash University low-FODMAP diet app.

Don’t Ditch Fiber

Picks for low-FODMAP fiber sources include chia seeds, rolled oats, oat bran, white potatoes with skin, navel oranges, strawberries, blueberries, raspberries and quinoa.

Stay Hydrated

Hydration is important for people with digestive issues such as IBS. In addition to water, try iced tea, seltzer water or club soda with a splash of 100-percent fruit juice and a squeeze of lemon or lime.

You Can Still Have Dairy

Modifying lactose doesn’t mean the low-FODMAP diet is dairy-free. Choose low-lactose foods such as hard cheese and lactose-free milk, yogurt and cottage cheese.

Keep Snacks on Hand

Being prepared means you’ll never go hungry or feel forced to eat high-FODMAP foods. Try nut butter with gluten-free crackers, rice cakes or a banana.

Eat a Nutritious Breakfast

Make your own single-serving instant oatmeal by combining ¼ cup quick oats, 1 tablespoon walnuts and 1 teaspoon chia seeds with hot water.

Know Your Soy Options

Soy can be confusing when it comes to FODMAPs. Soy milk and silken tofu are high in FODMAPs, but firm tofu is low in FODMAPs and soybean oil contains no FODMAPs.

Not only are there many other nutrients involved in developing and maintaining bone, but also exercise is imperative. People who exercise more have higher peak bone mass, and research suggests exercise plays just as important a role in bone health as nutrition.

Like muscles, bones are living tissue, and they require stress to stimulate growth and maintain integrity. Just as consuming extra protein without exercising will not result in strong muscles, consuming calcium without exercising will not result in optimal bone mass. Consider astronauts floating around in a spacecraft with little to no gravity — they experience significant bone mineral loss. But when astronauts participate in heavy resistance exercise, bone loss is reduced.

Exercise positively affects bone health in a number of ways. High-impact exercise has a site-specific effect on bones, meaning the area of the body worked in the exercise is where the most benefit is seen.

Stress in the form of a load stimulates calcium uptake and new bone formation, especially in children. Exercise also promotes stronger muscles and enhances coordination and balance, thus reducing the risk of falling and possibly fracturing a bone.

According to the National Osteoporosis Foundation’s 2016 position statement on peak bone mass development and lifestyle factors, lifestyle behaviors affect 20 percent to 40 percent of adult peak bone mass, and only calcium intake and exercise received evidence with a grade A. All other lifestyle factors — including intakes of vitamin D, dairy and protein, and smoking — received lower grades, suggesting they do not have as significant an impact on bone health as calcium and exercise.

It’s important to note that all forms of exercise are not equal when it comes to bone health. Weight-bearing exercise provides the stress load that bones need to stimulate mineral uptake. While this does occur in both children and adults, weight-bearing exercise is particularly important early in life as the most significant gains in bone mass are made during puberty. A 2014 meta-analysis found that weight-bearing activities in conjunction with high calcium intake resulted in optimal bone mineral content among prepubertal children.

Exercise is important for maintaining healthy mature bones, too. The impact of weight-bearing exercise on bone mineral density of premenopausal women is significant, and in healthy young men, even short-term exercise can boost bone mineral density. Analyses of National Health and Nutrition Examination Survey data found that the impact of physical activity on bone density and risk of osteoporosis is significant even when controlling for factors such as age, sex, race and ethnicity, body mass index, calcium and vitamin D intake, tobacco use and socioeconomic status.

Even postmenopausal women, who are at a particularly increased risk for osteoporosis, experience an increase in bone density from performing resistance exercises. Additionally, studies of osteopenia rehabilitation programs demonstrate feasibility and effectiveness of exercise on bone mineral density.

According to the National Institutes of Health, children between 6 and 17 should get 60 minutes of activity per day with bone-strengthening activities three days a week. Bone-strengthening activities for children include walking, jogging or running; playing tennis, racquetball, soccer, basketball or hockey; climbing stairs; jumping rope or other types of jumping; dancing; hiking; and lifting weights. While there are no specific recommendations for children younger than 6, the NIH recommends they play actively several times a day.

The National Osteoporosis Foundation recommends adults engage in weight-bearing exercise for 30 minutes most days of the week, with muscle-strengthening activities two to three days per week and balance, posture and functional exercises every day. Similarly, the surgeon general recommends daily physical activity with strength-building and balance-enhancing activities at least twice per week. Regarding type and duration, the surgeon general notes that five to 10 minutes of high-impact, load-bearing exercises may be sufficient, while 30 to 45 minutes of lower-impact exercises are needed to effectively impact bone health.

When discussing bone health with patients and clients, registered dietitian nutritionists should assess physical activity behaviors and reinforce physical activity recommendations to promote bone health. RDNs may find explaining cardiovascular and musculoskeletal benefits of exercise to clients while de-emphasizing weight and image-related motivations for exercising may increase clients’ motivation and adherence.

While RDNs are qualified to communicate physical activity guidelines, clients interested in learning advanced exercises or starting new exercise regimens should consider working with a certified fitness professional, such as an American College of Sports Medicine-certified personal trainer or certified exercise physiologist. For specific guidance on balance, posture and functional exercises, a physical therapist should be consulted.

The public health push to reduce sodium intake is not exactly new. The first Dietary Guidelines for Americans, published in 1980, encouraged Americans to “avoid too much sodium,” and every edition since has included a key recommendation on limiting sodium in the diet.

The 2015 Dietary Guidelines recommends consuming less than 2,300 milligrams of sodium per day, and no more than 1,500 milligrams per day for individuals with prehypertension and hypertension. The Institute of Medicine agrees that limiting sodium improves high blood pressure but states there is insufficient evidence to recommend the entire population go low-sodium — pointing to a link to adverse health outcomes in some individuals. And currently, the American Heart Association recommends everyone consume no more than 1,500 milligrams of sodium per day.

The History Behind Dietary Sodium Research

To understand the evolution of these recommendations requires a brief summary of dietary sodium research. In the middle of the 20th century, strong evidence first emerged in favor of restricting sodium to combat hypertension. A series of studies from the 1980s and 1990s, called Trials of Hypertension Prevention (or TOHP) provided additional data in favor of limiting sodium in prehypertensive populations. A TOHP follow-up study in the early 2000s found a significant correlation between sodium intake and cardiovascular disease, suggesting a 17-percent increased risk for every 1,000 milligrams of sodium consumed daily. The TOHP researchers concluded there were “overall health benefits of reducing sodium to 1,500 to 2,300 milligrams per day in the majority of the population,” consistent with Dietary Guidelines at that time. TOHP data also suggest the ratio of sodium-to-potassium intake has a significant impact on cardiovascular outcomes.

A limitation of the TOHP data is there were no controls for energy intake. Individuals who consume fewer calories naturally will consume less sodium, and that won’t necessarily put them at a lower disease risk (and vice versa). In addition, how individuals respond to sodium can depend on their baseline blood pressure. TOHP participants already had elevated blood pressure, and when blood pressure is high, eating less sodium has a profound blood pressure-lowering effect. However, when blood pressure is normal, lowering sodium intake has little to no effect on blood pressure.

Fast-forward to 2014, a big year in dietary sodium research. A systematic literature review concluded there is limited evidence that daily sodium intakes greater than 3,400 milligrams and less than 2,900 milligrams increased incidence of cardiovascular disease events, all-cause mortality and hospitalization in the general population. Also that year, authors of a meta-analysis found that individuals with daily sodium intakes of 2,645 milligrams to 4,945 milligrams have the lowest cardiovascular disease and mortality risks — and that plotting sodium and mortality creates a U-shaped curve with significantly increased risks at the highest and lowest intake levels. Some of the more compelling and controversial findings came from a large-scale epidemiologic study following more than 150,000 individuals in 17 countries.

Participants with the lowest mortality and cardiovascular risk consumed between 3,000 milligrams and 6,000 milligrams of sodium per day, and greater than 1,500 milligrams of potassium per day. High sodium intake was only linked with increased risk of death and cardiovascular events when blood pressure was high, while people with normal blood pressure who consumed more than 6,000 milligrams of sodium daily did not experience increased risk of death and cardiovascular events. Additionally, those who consumed less than 3,000 milligrams experienced increased risk when blood pressure was normal.

Skeptics of these studies cite a lack of intervention trials, questionable sodium assessment tools and statistical analysis prone to random and systematic error. There also is a question of reverse causality: When people are sick, they tend to eat less, therefore consuming less sodium — and epidemiological studies cannot determine whether less sodium causes poor health, or poor health causes less sodium.

Both Sides Make Their Cases

In 2015 during the American Heart Association’s Scientific Sessions, prominent researchers on either side debated the complexities of this issue. Low-sodium proponents asserted that to protect their health, Americans must limit sodium intake — and that given the majority of Americans’ sodium intake comes from processed food, this effort should focus on industry-wide interventions. The opposing side maintained that for people without elevated blood pressure, there is no benefit to consuming less than 2,500 milligrams of sodium per day, that it actually may be harmful in some cases, and that to base general guidelines on extrapolations of data is unsound.

Currently, the perfect study to settle the sodium controversy does not exist. Large randomized controlled trials with long follow-up periods are difficult and expensive, and an ideal sodium intake assessment tool is yet to be discovered. In the meantime, the DASH diet — which places more emphasis on fruits and vegetables than sodium (DASH trials averaged around 3,000 milligrams of sodium per day) — is the most effective dietary intervention for hypertension.

And for patients and clients with normal blood pressure, practitioners should continue to develop individualized eating patterns based on clinical judgment, guideline recommendations and scientific evidence.