The Score on Dietary Supplements

The dietary supplement aisle at the store has grown from a handful of multivitamins to an expansive selection that rivals breakfast cereals for its overwhelming variety. They promise to help you live longer, support your immune system, cleanse your liver, improve your mental functioning, or maintain a positive mood. Which ones should you be taking? What studies have been done? What should you know about supplements?

Lack of FDA Regulation

The single biggest problem with supplements is that they aren’t regulated by the FDA in the same way that drugs, or even food, are regulated. Here are some facts to note, directly from the FDA website

  • Federal law does not require dietary supplements to be proven safe to FDA’s satisfaction before they are marketed.
  • For most claims made in the labeling of dietary supplements, the law does not require the manufacturer or seller to prove to FDA’s satisfaction that the claim is accurate or truthful before it appears on the product.
  • Dietary supplement manufacturers do not have to get the agency’s approval before producing or selling these products.
  • It is not legal to market a dietary supplement product as a treatment or cure for a specific disease, or to alleviate the symptoms of a disease.

Essentially, the FDA only gets involved after a supplement is on the shelves, and only if it’s causing harm to people. 

How Do You Know What’s in the Capsule?

Good question. You don’t. With no government agency watching over them, you have to take the manufacturer’s word for the contents of the capsules you’re swallowing. According to Tod Cooperman, M.D. and president of, “You could put some stuff in a capsule and put a label on it…you could sell ‘Ginkgo Biloba’ tomorrow.”

A controversy arose earlier this year when the New York State Attorney General’s office tested a variety of herbal supplements on sale at Target, GNC, Walgreen’s and Wal-Mart stores. Only 20 percent of the supplements tested — one in five — had DNA markers for the herb labeled on the bottle. Some contained wheat and beans, known allergens that weren’t included in the ingredients list. The report echoed a 2013 Canadian report in which 1/3 of the supplements tested contained no trace of the herbs advertised. 

The problem is hardly limited to herbs, however. Vitamins and other supplements prove to be no more reliable.

  • A 2013 study on vitamin D supplements found that different capsules, even from the same bottle, varied wildly in the amount of vitamin D they contained, from “9 per cent to 140 per cent of the amount listed on the label.” 
  • A 2011 Consumer Reports test found that fish oil supplements did contain the Omega acids promised — but four of them also contained  levels of cancer-causing PCBs, chemicals that were banned in 1979. Also, one capsule didn’t meet standards for dissolving properly, so you may not get any benefit from swallowing it. 
  • In 2008, the FDA examined 325 multivitamins and found that 99% of them contained lead.
  • In 2007, ConsumerLab ran an independent test on 21 major brands of multivitamins. Only half passed the test. One contained 10 times the amount of lead considered safe. Others didn’t contain what they promised at all; for instance, one only had half as much calcium as the label indicated. Still others didn’t meet solubility tests, which means the contents of the capsule could pass through your digestive system and never be absorbed. 
  • Some supplements carry labeling that assures they’ve been tested by independent labs, but those are meaningful only if you’re certain about the quality of the testing and the impartiality of the lab.

Effectiveness is Another Question Mark

Given the unreliability of our supplement supply, is it any wonder that scientists have trouble creating solid results from their studies? Just last month, for instance, a study found that taking vitamin D supplements didn’t help to improve bone density in women with osteoporosis. Meanwhile, an NIH study found no benefit of Omega-3 or other supplements in fighting against  cognitive decline.

Clinical trials on antioxidants are not living up to the hype, either. According to Harvard’s School of Public Health, antioxidants are mostly failing to show conclusively positive results against heart disease or cancer, although macular degeneration patients seem to show some benefit. Test subjects taking antioxidants have shown increased rates of lung and skin cancer, which makes taking antioxidants “just in case” a risky proposition.

Weight Loss and Body Building

The popularity of supplements for weight loss and body building is frightening in this context. A Massachusetts health report from Harvard states that “supplements for weight loss and muscle building are linked with eating disorders as well as body dysmorphic disorder. More than 30 percent of children and adolescents take dietary supplements on a regular basis, and 11 percent of teens report ever using dietary supplements for weight loss.” Excessive use of workout supplements is considered an “emerging eating disorder among men,” which is deeply disturbing considering their link to cancer. Weight loss supplements have a long history of being pulled off the shelves for life-threatening side effects.

Do Supplements Increase Your Risk of Death?

Harvard cites several studies that have found an increase in early mortality among those who take vitamins and other supplements over those who don’t. The Harvard article cites “the Iowa Women’s Health Study, [which] looked at the use of 15 supplements, including multivitamins, at three different intervals and identified the numbers of women who died over a 19-year period. It showed that women over the age of 55 who took multivitamins were at higher risk for dying than those who did not.  A similar risk was found for other vitamins and minerals, including folate, vitamin B6, iron, magnesium and zinc.” The same Harvard report quotes a second study, “a frequently-cited analysis of 68 antioxidant supplement trials that was published in the Journal of the American Medical Association. That study found that taking beta carotene and vitamin A and E supplements increased the risk of dying.” 

The Harvard article points out that the studies don’t establish cause and effect. It’s possible that people who were already sick had begun to take more supplements than those who felt well, for instance. More tests are needed in this area. 

Should You Take Supplements?

What can you do about all the conflicting information you receive about supplements? The FDA offers some solid advice:

  • Let your health care professional advise you on sorting reliable information from questionable information.
  • Contact the manufacturer for information about the product you intend to use.
  • Be aware that some supplement ingredients, including nutrients and plant components, can be toxic. Also, some ingredients and products can be harmful when consumed in high amounts, when taken for a long time, or when used in combination with certain other drugs, substances, or foods.
  • Do not self-diagnose any health condition. Work with health care professionals to determine how best to achieve optimal health.
  • Do not substitute a dietary supplement for a prescription medicine or therapy, or for the variety of foods important to a healthful diet.
  • Do not assume that the term “natural” in relation to a product ensures that the product is wholesome or safe.
  • Be wary of hype and headlines. Sound health advice is generally based upon research over time, not a single study.
  • Learn to spot false claims. If something sounds too good to be true, it probably is.

The FDA offers a lot of sound advice on the subject of supplements, including this excellent page on Using Dietary Supplements. The best advice is probably to eat a healthy diet with a wide variety of different foods,  only take supplements under the advice of your doctor, and thoroughly research any brand you choose to buy.