No health benefit from vitamin pills and supplements

More than half of U.S. adults take dietary supplements or vitamins, despite questions about health benefits. I have never been convinced that popping vitamin pills, minerals, and other substances really leads to a longer, healthier life.  Now a new nationwide medical study suggests that I am correct.

The National institutes of Health funded an analysis of survey data gathered from more than 27,000 people over a six-year period. The study, published in the Annals of Internal Medicine, found that individuals who took dietary supplements had about the same risk of dying as those who got their nutrients through food. What’s more, the health benefits associated with adequate intake of vitamin A, vitamin K, magnesium, zinc, and copper were only found with food consumption, not supplements. In addition, certain supplements might even be harmful to health. For example, people who took excessive supplements calcium or vitamin D were more likely to die of cancer than those who didn’t.

The researchers found that taking vitamins or dietary supplements had no influence on length of life. Taking adequate vitamin A, vitamin K, magnesium, zinc, and copper are less likely to die, but only if obtained from food, not supplements.

Bad outcomes can happen from supplements. People who reported taking more than 1,000 milligrams of calcium per day were more likely to die of cancer. People who took supplemental vitamin D at a dose exceeding 10 micrograms (400 IU) per day without a vitamin D deficiency were more likely to die from cancer. But the same amounts of vitamin D and calcium obtained from food had no deleterious effects. Another recent medical report showed an association between hip fractures in postmenopausal women and high doses of vitamin B12 & B6 supplements.

The supplement industry often reports health benefits from their own surveys, but this is due to sampling errors. For example, study participants who took dietary supplements generally had a higher level of education and income. They also tended to enjoy a healthier lifestyle. They ate more nutritious food, were less likely to smoke or drink alcohol, and exercised more. So, it appears that people who take dietary supplements are likely to live a longer and healthier life for reasons that are unrelated to their supplement use.

Therefore, the regular use of dietary supplements should not be recommended for the most people. Some subgroups of people, including perhaps those following certain special diets or with known nutritional deficiencies, may benefit of course.

This information raises other questions. Why do we have no regulation of the multi-billion-dollar supplement industry, but prescription drugs must go through rigorous testing, not required for dietary supplements? It seems that both have the potential to cause harm, but unlike producers of prescriptions drugs, the manufacturers of supplements don't have to tell the FDA about problems they discover with their products. And even dangerous supplements take years to remove.

This study is also a reminder that dietary supplements are no substitute for eating nutritious food.