The Scoop - April 2014

Vitamin and Mineral Supplements and Chronic Disease

Taking vitamin and mineral supplements does not seem to help prevent cardiovascular disease or cancer, according to a review by the U.S. Preventive Services Task Force. Researchers analyzed the findings from 26 studies, mostly randomized controlled trials. Two studies showed that multivitamin/mineral supplements might slightly reduce the risk of cancer in men. But overall, there is no consistent evidence that healthy people who take vitamin or mineral supplements have a lower risk of getting cardiovascular disease or cancer, or that they are less likely to die from any cause. For more information on individual vitamins and minerals, see our fact sheets.

Multivitamin Use, Cognitive Function, and Cataracts in Men

Taking a multivitamin/mineral (MVM) supplement does not improve cognitive function in older men, a recent study suggests. The Physicians’ Health Study II followed over 5,900 men, age 65 and older, for an average of 8½ years. Those taking an MVM supplement had similar overall cognitive performance (for memory and word association) than those taking a placebo. Since study participants were all highly educated men, it is possible that an MVM would have different effects in other groups, such as women, those with less education, or those with nutrient deficiencies. A more positive finding from the Physicians’ Health Study II was that the MVM takers had a modest (9%) lower risk of developing cataracts. 

FDA: Dietary Supplements Cannot Treat Concussions

Despite some marketing claims, dietary supplements cannot prevent, treat, or cure concussions or other traumatic brain injuries (TBIs), the Food and Drug Administration (FDA) warns. Even if a supplement is safe, taking it with the belief that it could help a concussion heal faster is dangerous because someone might resume activities before he or she should. Dietary supplements also do not help prevent concussions or lessen their severity. TBIs are serious medical conditions that require proper diagnosis, treatment, and monitoring by a health care professional.

I am taking medications (the blood thinner Coumadin® and an antidepressant) and several supplements (green tea extract, CoQ10, and St. John’s wort). Is it OK to take all of these together?

No, probably not. Some dietary supplements can cause problems if you take them with prescription or over-the-counter drugs. For example, St. John’s wort might interact with certain antidepressants leading to potentially life-threatening seizures, altered heart rate, and unstable blood pressure. Also, St. John’s wort, CoQ10, and green tea extract might make blood thinners such as Coumadin® (warfarin) less effective.

These are a few examples of interactions that can occur. If you take medications and also plan to take dietary supplements, talk to your health care provider first and be on the lookout for any side effects or problems.

The Office of Dietary Supplements has a free mobile app called My Dietary Supplements, or MyDS. It helps you keep track of the dietary supplements and medications you take so you can share this information with your health care provider. This can help decrease the potential for interactions between dietary supplements and medicines.

I am pregnant and my friend told me to make sure I get enough iodine. I’ve never thought about iodine before. How can I make sure I’m getting enough, but not too much?

Some pregnant women in the United States might not be getting quite enough iodine. Iodine has many important roles in the body, including proper bone and brain development. Talk with your health care provider about iodine as part of your prenatal care.

Iodine is found naturally in some foods, but amounts vary. Good sources include seaweed, fish, seafood, milk and other dairy products, grain products (like breads and cereals), fruits, and vegetables. Iodized salt is another good source of iodine and is readily available in grocery stores. But processed foods, like canned soups, almost never contain iodized salt.

The American Thyroid Association recommends that pregnant and breastfeeding women take dietary supplements containing iodine (150 mcg per day). Many standard multivitamin/mineral supplements contain iodine, but only about half of prenatal supplements contain iodine. 

Keep in mind that it is possible to get too much iodine, and this can cause problems too. The safe upper limit for adults is 1,100 mcg per day, but for most people it is not a concern. For example, a 3-ounce serving of baked cod has about 100 mcg of iodine, and ¼ to ½ teaspoon of iodized salt contains about 90 mcg of iodine. Have more questions? See our fact sheet on iodine.

I am a 60-year-old woman and have been taking calcium supplements for many years. Recently I’ve heard that they might increase the risk of heart disease. Is that true?

Calcium supplements are commonly taken by women. As you know, it is important to get enough calcium (and vitamin D) for good bone health. And although it is always preferable to get vitamins and minerals from foods and beverages, some supplements can help you get enough of certain nutrients.

Whether calcium affects the risk of cardiovascular disease is not clear. Some studies show that it might protect people from heart disease and stroke. But other studies have found that some people who consume high amounts of calcium, particularly from supplements, might have an increased risk of heart disease.

Much of your risk depends on your diet, lifestyle, current health, and medical and family history. Talk with your health care provider about calcium, bone health, and heart disease to figure out what is right for you. Have more questions? See our fact sheet on calcium.