2. DIETARY SUPPLEMENTS
Dietary supplements are exactly what they sound like: products that are consumed in addition to a regular diet in order to provide an extra benefit. In some cases, they clearly do provide a benefit. For example, all women of childbearing age are encouraged to take a folic acid supplement to reduce the incidence of spina bifida, a serious birth defect. But in many cases, the benefits of dietary supplements are unclear. This, however, has not deterred people from buying into dietary supplements. Upward of 70% of the American population takes some sort of supplement, supporting a sizeable industry to the tune of $41.1 billion in 2016. This is potentially problematic because beyond being simply unhelpful, some dietary supplements are actually dangerous.
The most familiar and widely used dietary supplements are vitamins. These compounds are vital to human health, but our bodies can’t make them. Instead, we have to consume them, traditionally through food. Vitamins are especially abundant in brightly colored fruits and vegetables such as broccoli, kale, carrots, and blueberries. But conveniently, they now come in pill form. Traditionally, the category of vitamins does not include essential fatty acids, amino acids, or minerals. This keeps the list fairly short. The essential human vitamins are A, B1, B2, B3, B5, B6, B7, B9, B12, C, D, E, and K. We know that these are essential vitamins because deficiency leads to disease. For example, vitamin D deficiency causes rickets, vitamin C deficiency causes scurvy, and vitamin A deficiency is the leading cause of blindness in the world.
Minor vitamin deficiencies can result in less severe, but real, health implications. Certainly, if you have a vitamin deficiency, a vitamin supplement will help. But thanks to the Nobel Prize–winning chemist Linus Pauling, who advocated for the immune-boosting powers of vitamin C, many of us go for vitamin C tablets whenever we get a cold. Unfortunately, this is at best a placebo. There is no convincing evidence that well-nourished adults enjoy any benefit from extra vitamin supplementation. This includes benefits in terms of general well-being, cardiovascular health, cancer, cognitive decline, and all-cause mortality. On the other hand, overconsumption of vitamins can have some negative health outcomes. This is especially true for the fat-soluble vitamins (A, D, E, and K) because they are more difficult for your body to clear. Acute vitamin overdoses can, in fact, be fatal. So if you have them around your home you must keep them out of the reach of children. Iron overdose is actually a common cause of accidental poisoning in children, although iron is not technically a vitamin. All of this is somewhat disappointing, but there is good news. Those brightly colored fruits and vegetables do have demonstrated health benefits, some of which may have to do with the interaction between vitamins and other compounds in the plant. It’s also very difficult to overdose on carrots, although they might turn you orange.
Another popular dietary supplement is fish oil. Fish oil is high in omega-3 fatty acids, which are essential for humans. You can find omega-3s in a number of sources including seeds, nuts, eggs, meat, and, obviously, fish. Omega-3s are thought to have positive impacts on cardiovascular health and to be cancer protective. In addition, with the possible exception of fishy-tasting burps, these supplements are well tolerated by most people.
Protein is another important dietary component that is frequently supplemented, especially by athletes. Typically, these supplements are either dairy based or soy based. Dairy-based protein is generally safe, unless you are allergic to milk. Soy proteins, on the other hand, are the subject of ongoing controversy due to their potentially estrogenic effects. However, the data do not present a clear picture of whether this is a problem or not.
The dietary supplements listed above are really just that: things you need to consume, whether you get them in a supplement or from some other dietary source. But there is another category of dietary supplements that are marketed as providing some sort of bonus. For example, supplements are commonly marketed as body-building and weight-loss aids, sleep aids, sexual and fertility aids, immune boosters, memory enhancers, mood enhancers, hair, skin, and nail strengtheners, and, most disturbingly, alternative or additive treatments to pharmaceuticals. It’s questionable whether these products should really be categorized as dietary supplements, since they don’t have a lot to do with diet. However, it is clearly to the supplement manufacturer’s advantage to have this designation because the FDA regulates dietary supplements as food, not as medicine or drugs. This is important.
The FDA requires that drug manufacturers demonstrate both safety and efficacy before a product can be brought to market. This requires extensive and expensive clinical trials. Supplement manufacturers, on the other hand, are not required to demonstrate efficacy. In return, supplements are not meant to be marketed as treatment or prevention for any particular disease. However, the claims of general health improvement can be made if the packaging includes the following disclaimer: “This statement has not been evaluated by the FDA. This product is not intended to diagnose, treat, cure, or prevent any disease.” Safety does not have to be demonstrated for ingredients that were on the US market before 1994 because their historical usage makes them “generally recognized as safe.” If a manufacturer wants to introduce a new ingredient, it must provide the FDA with notice and reasonable evidence that it is safe for human consumption. But since the safety of a new product does not have to be demonstrated to the FDA before it is brought to market, the product is considered safe until proven otherwise. Once it is on the market, the FDA will track any adverse events that are reported. But unless the symptoms are acute and specific, it can be very difficult to trace these events to the source.
Furthermore, the manufacturer is responsible for accurately labeling ingredients and performing good quality control. But the FDA does not test products for quality. Several research studies have shown that a large percentage of dietary supplements either do not contain the ingredients they claim or contain them in the wrong quantities, contain other unlisted ingredients, and/or in some cases are contaminated with heavy metals or pesticides, or adulterated with pharmaceuticals (e.g., anabolic steroids). Some third parties will provide certification for supplements. However, these certifications are only meant to ensure that the product is accurately labeled and do not indicate that the product is safe or effective.
People tend to assume that if products are commercially available in the United States they are safe, and this is particularly untrue in the case of dietary supplements. Supplements have been linked to liver damage, cardiovascular problems, psychiatric symptoms, gastrointestinal symptoms, bleeding, and stroke. People have died.
Another thing to consider when you are taking supplements is that they can interact with prescribed and over-the-counter medications. If you are taking a supplement—any kind of supplement—you need to disclose it to your doctor. And remember, most of the time you’re better off with the broccoli in your refrigerator than the supplement in a jar.
SUMMARY
Preventability (95)
There are some situations (like pregnancy) in which a vitamin supplement is called for, but most of the time dietary supplements are optional.
The dietary supplement industry is enormous, and most people do not suffer any ill effects. But if you take certain kinds of supplements you increase your risk.
Consequence (87)
Some dietary supplements are effectively drugs that have not been reviewed by the FDA. The consequences of taking these substances should not be underestimated. They can be fatal.
American Cancer Society (2015, March 31). FDA regulation of drugs versus dietary supplements. Retrieved from https://www.cancer.org/treatment/treatments-and-side-effects/complementary-and-alternative-medicine/dietary-supplements/fda-regulations.html
National Center for Complementary and Integrative Health. (2014, June). Using dietary supplements wisely. Retrieved from https://nccih.nih.gov/health/supplements/wiseuse.htm
National Institutes of Health, Office of Dietary Supplements. Multivitamin/mineral supplements. (2015, July 8). Retrieved from https://ods.od.nih.gov/factsheets/MVMS-HealthProfessional/#en3
Nutrition Business Journal. (2017, June 9). 2017 supplement business report: The new (not-so) normal. Retrieved from http://www.newhope.com/market-data-and-analysis/2017-supplement-business-report-new-not-so-normal
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