Precision medicine, an individualized treatment and prevention strategy based on a person’s genetics, lifestyle and environment, is becoming increasingly attractive to consumers who no longer wish to be treated like an “average patient” and want a more personalized approach. In 2015, the U.S. Precision Medicine Initiative was launched to improve health and treatment of disease through genomic data in both clinical and public health practices and to better understand how to best provide tailored treatment. Since then, there has been a rise in direct-to-consumer, or DTC, testing options that give individuals information that may help them make more informed health decisions. This includes an ever-growing selection of personalized multivitamins and other supplements largely marketed online through social media, as well as some television, radio and print advertising.
Some reports estimate that more than 50 percent of U.S. adults use some type of dietary supplement, two-thirds of which are multivitamins or multiminerals. As of December 2020, an online search for personalized multivitamins yields nearly 400 million results, many featuring companies that offer delivery of custom supplement packets. Consumers can take an online quiz and order supplement packets directly from their favorite brand. Because of this, patients may no longer see a need to visit their physician for a blood test or a registered dietitian nutritionist for recommendations on treating vitamin or mineral deficiencies.
However, there’s still a place for RDNs in the realm of personalized nutrition, particularly in the provision of individualized nutrition advice. Current data suggests DTC tests, particularly genetic tests, yield better outcomes related to behavior change when interpreted by a qualified provider, rather than when data are provided without explanation. Experts warn that personalized recommendations, including dietary supplement advice based on results from genomic testing should be backed by high-quality research, in addition to considering possible ethical implications. For RDNs, this means using an evidence-based approach in accordance with the professional Code of Ethics to expertly guide patients or clients.
The Rise of DTC Testing
DTC tests can analyze health parameters by obtaining genetic material, blood, saliva, urine or microbiome and stool samples without any involvement of a health care provider. The validity of DTC test claims are reviewed by the U.S. Food and Drug Administration when results are deemed “moderate- to high-risk” medical information, such as carrier screening or tests that indicate genetic health risks; however, general tests for wellness, non-medical or “low-risk” medical purposes, such as ancestry tests or tests that predict athletic ability, are not reviewed. The Federal Trade Commission notes that both the FDA and Centers for Disease Control and Prevention have issued warnings about DTC tests, stating that some lack scientific validity, should be handled in certified and registered laboratories and may require interpretation by a health care practitioner.
DTC tests are not only available online; some are now sold in pharmacies. An editorial article in Expert Review of Precision Medicine and Drug Development describes a scenario where a consumer can walk into a chain drugstore, pick out which blood tests they want, have a phlebotomist draw blood and then be emailed results. Although they are not yet selling personalized supplements based on the results, the article describes several states that now offer ways for consumers to choose and order their own labs without any guidance from a physician.
Trends in Online Supplement Marketing
Many consumers discover online supplements through targeted ads on social media. Many companies offer a free assessment quiz that consumers can take to determine what supplements may be useful based on questions about age, sex, activity level, health goals, dietary patterns and more. Other companies sell DTC testing kits and base recommendations on those results.
After the patient or client has their supplement recommendations, they can enroll in a monthly delivery program to receive individual packets of vitamins, minerals and other supplements. Some monthly programs can cost upwards of $50 and many charge an additional fee for shipping — a significant price for many consumers. An important consideration is client privacy in regard to HIPAA-protected health information being shared on a potentially non-secure platform, such as social media or an online quiz. Some companies may ask about health conditions or other information that is sensitive and should be protected.
Doctors, RDNs and other health care providers are not dominant voices in the online marketing of supplements. Rather, research suggests social media “influencers” play a large role. Influencers often promote regimented diets and exercise routines aimed at achieving a certain body image, all driven by the visual aspect of the social media platform.
How companies are promoting dietary supplements online also has been questioned. Research on internet marketing of omega-3 supplements, for example, found that in the cardioprotective category, risk reduction claims and structure or function claims were made more often than an FDA disclaimer was used. (According to law, if a dietary supplement includes such a claim, it must include a disclaimer stating the FDA did not evaluate it.) Although warnings were made more available to consumers, many of the websites analyzed did not offer information about adverse effects. Researchers suggest that internet marketing is leading to significant increases in both the sale and consumption of dietary supplements.
Appropriateness of Supplement Usage
According to the Academy of Nutrition and Dietetics Micronutrient Supplementation Position Paper, “micronutrient supplements are warranted when requirements are not being met through the diet alone.” The Scientific Report of the 2020 Dietary Guidelines Advisory Committee found that Americans age 1 and older generally do not get enough vitamin D, calcium, potassium and dietary fiber from their diets. Certain populations may be at higher risk for insufficient amounts of nutrients such as iron for infants, children, adolescent girls, and premenopausal and pregnant or lactating women. If a person’s DTC test reveals a low iron or vitamin D level, their doctor or RDN could help guide them to further testing and appropriate supplementation. Through this process, patients and clients could feel more empowered to improve their health.
Conversely, there are risks of exceeding the recommended dietary allowances for nutrients through supplementation. Excess amounts of vitamin D are toxic and can cause hypercalcemia (too much calcium in the blood), hypercalciuria (too much calcium in the urine) and renal failure. Iron supplementation exceeding 20 milligrams per kilogram in adults can cause gastric upset and constipation, impair zinc absorption and, at doses higher than 60 milligrams per kilogram, cause iron overdose, organ failure and even death. Some nutrients interact with medications or other supplements. Even at supplement intake within the RDAs, iron supplementation could reduce the absorption of certain medications, such as levodopa and levothyroxine, or the concurrent use of proton pump inhibitors could reduce iron and vitamin B12 absorption.
Some common supplements, such as probiotics, digestive enzymes and herbs, do not have RDAs. Therefore, it is important for patients and clients to discuss the safety and appropriateness of supplementation with a health care provider to understand the potential benefits and dangers. Research should be assessed to understand a safe duration for taking a particular supplement; some supplements may not have been studied for long-term use or may have potential negative effects or interactions over time.
A final consideration for consumers is how dietary supplements are regulated in the United States. While supplements must follow labeling and marketing regulations required by the Dietary Supplement Health and Education Act of 1994, FDA and FTC, they are presumed to be safe and do not require the FDA’s review for safety or effectiveness before they are marketed or sold to consumers. However, supplements sometimes contain higher or lower levels of ingredients listed on the label or contain ingredients other than what is listed. RDNs can help educate consumers about supplement quality and regulation, encouraging extra protection by looking for brands that pay for third-party certification. The same is true with DTC tests in terms of encouraging patients or clients to evaluate any claims that are made regarding the test or its results.
The Role of the RDN
RDNs are uniquely qualified to educate and inform their patients or clients about dietary supplements, helping them weigh the pros and cons of investing in personalized supplements and evaluating whether the supplements are necessary and safe.
When patients or clients have questions about personalized multivitamins, supplements or DTC testing, approach them with an open mind and curiosity. Use open-ended questions to guide the conversation and learn why they are interested in supplementation or where they may have knowledge gaps about obtaining nutrients through a balanced diet. In addition to sharing FDA advice, RDNs can encourage patients or clients to discuss DTC test results with their health care provider and to avoid making dietary or health changes based on these tests without the guidance of a health care provider. RDNs also may need to educate themselves, as well as their patients or clients, about the accuracy and validity of specific tests and their relevance to a patient’s or client’s overall health status.
Ways that RDNs can support patients or clients include taking an individualized approach to their health, educating in a food-first manner and referring more testing if the patient or client may need to exceed the RDAs due to a nutrient deficiency, health condition, stage of life or other circumstance. Although patients and clients have more access than ever to personalized information online, they still need to partner with their RDN for safe and relevant supplement use and dietary information for optimal health. The area of personalized supplements and how DTC testing influences consumer health continues to grow, and RDNs will need to stay informed of updated research and resources.
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