It is important to supplement wisely. During my 25 years in medical practice, I have seen thousands of people with common nutrient deficiencies creating health problems. Combining the right foods with the conservative and intelligent use of supplements was imperative for health recovery and even life-saving. However, rather than boosting health, certain multivitamins may be harmful. And because of this, most studies do not show a consistent benefit of taking multivitamin/mineral supplements for preventing chronic diseases.1 A 2006 National Institutes of Health (NIH) State-of-the-Science Conference Statement reported on multivitamin/mineral supplements and chronic disease prevention studies. Their conclusion was:
Most of the studies we examined do not provide strong evidence for beneficial health-related effects of supplement.2
Since micronutrient deficiency is detrimental to your health, picking the right multivitamins is very important. The big question is why have most studies shown no benefit for preventing chronic disease? One important reason is that most multivitamin/mineral supplements on the market contain ingredients that have been shown by studies to be harmful in supplement form.
The following nutrients are beneficial when provided by whole foods, but may be harmful in supplement form.
The synthetic folic acid found in supplements is chemically different from food folate, which is abundant in green vegetables, beans, and other plant foods. Folate is especially important for women of childbearing age, to prevent against birth defects. However, women who take synthetic folic acid in multivitamins may be at increased risk of breast cancer.3-8 Folic acid supplementation also raises the risk of prostate and colorectal cancers.9-11 Luckily, we don’t need to get folic acid from vitamins because folate is plentiful in green vegetables and other whole plant foods. Folate in its natural form protects against breast and prostate cancers.9,12-14 Of course, when we get our folate from food it comes naturally packaged in balance with hundreds of other cancer-protective micronutrients. Consuming folate-rich foods, not folic acid, during pregnancy may also offer protection against cardiac birth defects, childhood respiratory illnesses, and childhood cancers.15-21