7 Potentially Harmful Nutrients in Multivitamins

Vitamins
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If you are one of the 50 percent of Americans that take one or more supplements regularly, then you should be aware that certain ingredients in multivitamins may be harmful.

One interesting study made news when its findings suggested that multivitamin use was linked to longer telomere length, an indicator of slower cellular aging. However, overall, the research on multivitamins does not imply any substantial benefits for reducing the risk of cardiovascular events, cancer, or premature death.

 Any study on a multivitamin is examining the effects of a mix of many different nutrients, which may be one reason why the findings have been inconsistent or neutral. However, the results from clinical trials and other studies on individual ingredients help to clarify which may be problematic. Here are seven supplemental nutrients you should be concerned about if they are in your multivitamin:

  1. Vitamin E supplementation is associated with an increase in risk of heart failure and all-cause mortality. An extended trial of thousands of older people with a history of cardiovascular disease or diabetes who were randomly assigned to take either 400 IUs of vitamin E or a placebo found there was a 19 percent increase in the risk of heart failure in those who took the supplement. An earlier analysis conducted by Johns Hopkins University researchers also found a link to a six percent increased risk of death in those who consumed a daily dose of 400 IUs or more of vitamin E. Since this nutrient is abundant in raw nuts and seeds, there is no need to expose oneself to a potential risk.
  1. Beta-carotene supplementation has a strong link to increased cancer risk. A study was halted early because it showed participants in the group taking beta-carotene and vitamin A had increased their risk of developing lung cancer. Before it was halted, the study showed a 28 percent greater incidence of lung cancer and 17 percent more deaths from all causes compared with those who did not take beta-carotene. A follow-up showed that for women, these negative effects lingered even after stopping the supplementation. Supplementing with beta-carotene may interfere with the absorption of other important carotenoids from food (of which there are more than 600). 
  1. Vitamin A supplementation may dramatically weaken bones, increasing risk of hip fracture. Adverse effects have been reported at levels found in most multivitamins on the market. One study found that a 1.5 mg of vitamin A (5000 IUs, 100 percent of the Daily Value listed on Supplement Facts labels) was associated with reduced bone mineral density and increased hip fracture risk compared to a 0.5 mg. In addition, vitamin A supplementation has also been associated with a 16 percent increase in death from any cause in a meta-analysis of studies investigating supplementing with it. It is wiser to get your vitamin A from plant food-derived, provitamin A carotenoids, such as alpha-carotene and beta-carotene.
  2. Folic Acid is a synthetic form of the B vitamin folate. I strongly recommend avoiding supplementing with folic acid, which has the potential to disrupt normal actions of food folate and is associated with an increased risk of breast, prostate, and colorectal cancers. Folate is important in growing and dividing cells and for preventing neural tube defects in developing fetuses. Consuming beans and green vegetables – rich sources of food folate – daily helps women of childbearing age to enter pregnancy in a folate-adequate state; this is important, since folate acts to prevent neural tube defects during the first four weeks of pregnancy, when most women don’t yet know they are pregnant. Since beans and greens contain plenty of folate, there is no reason to worry about being deficient if you are eating healthfully.  On the other hand, synthetic folic acid supplementation is associated with later-life cancer and outcomes and cannot duplicate the health benefits of eating folate-rich food for both mothers their children.
  1. Selenium at high levels is linked to diabetes, elevated cholesterol, prostate cancer, cardiovascular disease, amyotrophic lateral sclerosis (ALS), impaired immune function and impaired thyroid function. Paradoxically, too little selenium can be harmful, too. The best course of action is to get sufficient amounts from healthful foods. Those who are eating a healthful diet rich in produce, with nuts and seeds don’t need extra selenium.   
  2. Copper should not be taken as a supplement because excess copper is linked to increased cancer and overall mortality and increased risk of Alzheimer’s disease. Reducing meat intake and avoiding multivitamins containing copper are effective ways to prevent copper excess.
  3.  Iron should only be taken if there is a defined need or deficiency. Heme iron is found in animal products and non-heme iron is derived from plant foods and supplements. The heme iron in meat is more absorbable than that in vegetables, making the risks associated with excess iron more likely. There is evidence that excessive iron stores – because iron is an oxidant – increase the risk of colon cancer, heart disease, and neurodegenerative diseases. However, supplemental non-heme iron can be useful if one has suboptimal iron levels, for example, due to pregnancy or heavy menstrual bleeding.

So Why Take Vitamins and Minerals at All?

With so much concern surrounding these nutrients, why take any vitamin and mineral supplement? The job of a multivitamin and mineral supplement is to fill in nutritional gaps to prevent deficiencies or insufficiencies. Suboptimal intake of some vitamins is common and is a risk factor for chronic diseases. Typically, Americans eat insufficient produce and as a result consume below the recommended amounts of fiber, magnesium, potassium, food folate and vitamins A, C, and E. Very few people eat so healthfully that they get the ideal amount of every vitamin and mineral needed in optimal amounts from food alone.

Even eating a nutrient-dense, plant-rich diet and minimizing animal products for longevity benefits, you run into the issue of being suboptimal in certain nutrients: vitamins B12 and K2, found primarily in animal products; zinc, which is more bioavailable from animal products; iodine which is derived primarily from iodized salt; and vitamin D, which our skin produces when we are exposed to the sun. But taking in more animal products is not the answer, as then you run the risk of too much animal protein, animal fats, heme iron and other animal-based food pollutants. Therefore, for most people, using a safe, well-designed multivitamin can be helpful.

Eat Better, Live Longer

Although not every diet is perfect, no multivitamin or supplement can adequately take the place of a nutrient-dense, plant-rich diet of whole foods. If you want to live a healthier, longer life, eat a better diet. Real, nutrient-rich, natural foods supply much more than just vitamins and minerals. Eating a superior diet can provide you with a full spectrum of both discovered and undiscovered nutrients. That is something no multivitamin can replicate.

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