To Supplement or Not to Supplement?

Numerous research studies have shown that nutrient supplementation does not provide superior health. Many supplements even behave opposite to how we expect them to. Here are just a few of the many examples:

• “The most extensive systematic assessment of effects of omega-3 fats on cardiovascular health to date,” published in 2018, “suggests that increasing EPA and DHA has little or no effect on mortality or cardiovascular health (evidence mainly from supplement trials).”^[1]
• The Beta-Carotene and Retinol Efficacy Trial (CARET) trial involving subjects at high risk of developing lung cancer had to be halted almost two years early because “there were 28% more lung cancers and 17% more deaths in the active intervention group [compared to placebo].”^[2] These alarming results—highly consistent with another study in Finland—contradict the fact that diets rich in beta-carotene–containing foods are associated with lower rates of lung cancer.^[3]
• The US Preventive Services Task Force (USPSTF) concluded in 2003 that there was “insufficient evidence to recommend for or against the use of supplements of vitamins A, C, or E; multivitamins with folic acid; or antioxidant combinations for the prevention of cancer or cardiovascular disease.”^[4]
• A decade later, USPSTF again reviewed the evidence on the efficacy of multivitamin or mineral supplements for healthy adults. Except for beta-carotene and vitamin E—which they recommend against using—they reiterate the insufficient evidence for using supplements.^[5]
• “Conclusive evidence for the benefit of any supplement across all dietary backgrounds (including deficiency and sufficiency) was not demonstrated [in systematic reviews and meta-analyses published in 2018]; therefore, any benefits seen must be balanced against possible risks;” the authors conclude, “In the absence of further studies, the current data on supplement use reinforce advice to focus on healthy dietary patterns, with an increased proportion of plant foods in which many of these required vitamins and minerals can be found.”^[6]

There may be some exceptions, particularly for individuals at greater risk of deficiency (more on this below), but the evidence generally indicates that taking supplements is an unwise strategy for attempting to improve health outcomes. We should not consider supplements a shortcut to better health or an excuse to consume fewer healthy whole foods.

Despite this research, the supplement industry is booming. According to the most recent projections from market research company Grand View Research, the global market size for dietary supplements was nearly 180 billion US dollars last year, with 25 percent of products sold in the US.^[7] They project continued growth throughout this decade.

We could speculate extensively about why the industry thrives despite the absence of high-quality evidence: the epidemics of chronic disease, the enduring appeal of simplistic solutions that require no substantive lifestyle change, the heavy marketing of these supplements, providers who personally profit from selling supplements, many more providers who are insufficiently trained in nutrition, and much more. The Grand View Research report cites the “increased consumer awareness for preventive healthcare,” but a more accurate description may be increased consumer confusion about preventive healthcare.

The under-regulation of supplements has also favored industry growth. Supplement regulation in the US has been fraught for over a century.^[8] “Supplement manufacturers, trade associations, politicians, and especially the public [seeking greater autonomy over healthcare decisions]” have played important roles in limiting the power of regulators. The Dietary Supplement Health and Education Act (DSHEA) established the present regulatory framework in 1994. As a result of DSHEA, the FDA does not have the authority to approve the safety, efficacy, or labeling of supplements before they enter the marketplace.^[9] In other words, it is the responsibility of manufacturers to ensure their products are safe.

One of the most notable consequences of DSHEA was that “Supplements were [thereafter] allowed certain health support claims if they had on file substantiation of such claims. The FDA’s lack of input into the veracity of those claims would be so stipulated on the label, and the claims themselves would not cause supplements to be considered as drugs—and thus they would not have to abide by the level of evidence required of those therapeutic commodities [emphasis added].”^[8]

In other words, this legislation allows supplement manufacturers to make claims on their labels even if the supporting evidence is weak and the research is funded by the manufacturer itself; the only requirement is that they also include the small-print addition, somewhere on the bottle, that “these claims have not been evaluated by the Food and Drug Administration. This product is not intended to diagnose, treat, cure, or prevent any disease.” This is why despite numerous non-conflicted studies above showing a lack of benefit for supplements, companies continue to claim their products are heart-healthy, immune-supportive, etc.

The law does require that supplement manufacturers include a label about dietary ingredients and serving size, but other than that requirement, manufacturers get to do things their way.^[9] Ostensibly, the FDA periodically inspects facilities and monitors adverse event reports, but even then, its power is mostly toothless. When a product is found to be unsafe (and again, remember, the FDA would only know this after the product has been on the market long enough to expose consumers to that danger), the FDA’s first step would likely be to ask the company to voluntarily recall the product. As for products that are not dangerous, only ineffective, manufacturers can happily continue raking in the millions.

Because of this lack of regulation, cheaply produced supplements might not even contain all the ingredients in the amounts they claim.^[10] This is an especially relevant concern for athletes, who can face fines, suspensions, or bans from competitions if they test positive for substances even if they were unaware of the adulteration. A review of more than 630 supplements from more than 200 suppliers found that about 15 percent of samples were adulterated with steroids or steroid derivatives.^[11] Of course, unless athletes and non-athletes tested the supplements themselves, they would never know the difference!

You might wonder about the efficacy of more sophisticated nutrition supplements now on the market—not the synthetic isolates of single nutrients, but complex formulations derived from whole-food ingredients. Do such products support better health? This is the claim made by companies like Athletic Greens and Juice Plus+, which we will assess more closely in a separate article. (Learn more about so-called gut-healthy supplements.)

And what about individuals with a whole food, plant-based (WFPB) lifestyle? Do they require special supplementation to overcome their lack of meat and dairy? T. Colin Campbell, PhD, and Thomas Campbell, MD, answer this question in The China Study.^[12] There are only four nutrients found in animal-based foods but not in plant-based foods: cholesterol and vitamins A, D, and B12. Our bodies produce cholesterol, meaning it is not an essential nutrient, and we can also make vitamin A from plant-supplied beta-carotene. The best way to get vitamin D is through moderate exposure to sunshine—“depending on the time of year and the pigmentation of your skin, you could get enough vitamin D in as little as 5–30 minutes a day”—and many foods are fortified with vitamin D, but individuals living farther away from the equator might choose to take a supplement.

That leaves only vitamin B₁₂. They write in The China Study, “Research has convincingly shown that plants grown in healthy soil that has a good concentration of vitamin B₁₂ will readily absorb this nutrient [. . . But] in the United States, most of our agriculture takes place on relatively lifeless soil, decimated from years of unnatural pesticide, herbicide, and fertilizer use.” It’s not uncommon to find vitamin B₁₂ in fortified foods, but we recommend individuals on an exclusively plant-based diet get their blood levels checked and choose a low-dose vitamin B₁₂ supplement if necessary. (Learn more about B₁₂ here.)

To conclude, here is Dr. T. Colin Campbell’s answer to the question about supplements:

To argue that supplements of individual nutrients work for long-term health diverts attention away from the importance of consuming whole plant-based foods. These supplements may increase tissue levels and, in some circumstances, assist in attenuating early lesions and reactions thought to lead to long-term outcomes. But these effects do not prove long-term health benefits, as has now been summarized in several published meta-analyses of numerous clinical trials during the past 2–3 decades.

Moreover, I strongly disagree with the assertion that taking vitamin and mineral supplements represents “nutrition.” It does not. I consider nutrient supplements to be nothing more than an extension of the drug industry—to illustrate, consider that Hoffman-LaRoche controlled more than 60 percent of the early market on vitamin C. These products are offered earlier than conventional drugs in the course of disease development, but this distinction is becoming ever more blurred.

I do not subscribe to the view that medical practice can be best improved by the use of these supplements. And in contrast to many who support the use of supplements, I receive no funding from the drug industry, either personally or professionally.

References

1. Abdelhamid AS, Brown TJ, Brainard JS, et al. Omega‐3 fatty acids for the primary and secondary prevention of cardiovascular disease. Cochrane Database of Systematic Reviews. 2018;7(CD003177). doi:10.1002/14651858.CD003177.pub3.
2. Omenn GS, Goodman GE, Thornquist MD, et al. Risk factors for lung cancer and for intervention effects in CARET, the Beta-Carotene and Retinol Efficacy Trial. J Natl Cancer Inst. 1996;88(21):1550-1559. doi:10.1093/jnci/88.21.1550
3. Alpha-Tocopherol, Beta Carotene Cancer Prevention Study Group. The effect of vitamin E and beta carotene on the incidence of lung cancer and other cancers in male smokers. N Engl J Med. 1994;330(15):1029-1035. doi:10.1056/NEJM199404143301501
4. U. S. Preventive Services Task Force. Routine vitamin supplementation to prevent cancer and cardiovascular disease. Nutr Clin Care. 2003;6(3):102-107.
5. Moyer VA; U.S. Preventive Services Task Force. Vitamin, mineral, and multivitamin supplements for the primary prevention of cardiovascular disease and cancer: U.S. Preventive services Task Force recommendation statement. Ann Intern Med. 2014;160(8):558-564. doi:10.7326/M14-0198
6. Jenkins DJA, Spence JD, Giovannucci EL, et al. Supplemental Vitamins and Minerals for CVD Prevention and Treatment. J Am Coll Cardiol. 2018;71(22):2570-2584. doi:10.1016/j.jacc.2018.04.020
7. Grand View Research. Dietary Supplements Market Size & Trends. Accessed March 8, 2024. https://www.grandviewresearch.com/industry-analysis/dietary-supplements-market
8. Swann JP. The history of efforts to regulate dietary supplements in the USA. Drug Test Anal. 2016;8(3-4):271-282. doi:10.1002/dta.1919
9. U.S. Food & Drug Administration. FDA 101: Dietary Supplements. Last updated June 2, 2022. Accessed March 8, 2024. https://www.fda.gov/consumers/consumer-updates/fda-101-dietary-supplements
10. Harvard Health Publishing. Should you take probiotics? February 2, 2022. https://www.health.harvard.edu/staying-healthy/should-you-take-probiotics
11. Jagim AR, Harty PS, Erickson JL, Tinsley GM, Garner D, Galpin AJ. Prevalence of adulteration in dietary supplements and recommendations for safe supplement practices in sport. Front Sports Act Living. 2023;5:1239121. Published 2023 Sep 29. doi:10.3389/fspor.2023.1239121
12. Campbell TC, Campbell TM. The China Study, Startling Implications for Diet, Weight Loss, and Long-Term Health. (BenBella Books, Inc., Dallas, TX, 2006)