The Truth About Multivitamins
by Dr. Sarah Cimperman, ND
The Truth About Multivitamins
More than half of all adults in the United States take multivitamin supplements and lately they’ve gotten some bad publicity. Three recent studies published in the Annals of Internal Medicine have questioned their benefits for brain health, cardiovascular protection, and cancer prevention. This month I explain how poor research design can lead to questionable conclusions, who really needs multivitamins, and how to ensure that products you purchase really are an investment in your health.
Brain Benefits
The study "Long-Term Multivitamin Supplementation and Cognitive Function in Men" looked at brain function in elderly men taking low-potency multivitamins. The supplement used in this study was Centrum Silver, a product that contains concentrations of nutrients well below therapeutic dosages. It also contains potentially toxic additives like aluminum-containing artificial colors which can have adverse effects on brain function. The scientists conducting this study included people who took the multivitamins only two-thirds of the time and they relied on the recollection of participants during a once-a-year telephone interview.
It's no wonder that taking inadequate amounts of vitamins on an intermittent basis didn't show big brain benefits, especially when the supplements in question contained chemicals that can actually harm cognitive function. Numerous well-designed, randomized, placebo-controlled studies, which are the gold standard in medical research, have shown that nutrients in multivitamin formulas are essential for healthy brain function. Specifically, they have been shown to strengthen memory, improve test scores, enhance mathematical processing, slow brain atrophy, and protect brain cells from oxidative damage linked to cognitive impairment and Alzheimer's disease.
Cardiovascular and Cancer Protection
The study "Oral High-Dose Multivitamins and Minerals After Myocardial Infarction" aimed to assess whether multivitamin supplements reduced the risk of disease and death in adults after a heart attack. In this study, researchers measured how long people lived before they had another heart attack, suffered a stroke, were hospitalized for chest pain, required heart surgery (bypass, stent, or angioplasty), or died from any cause. They found that compared to people taking a placebo, those taking multivitamins had an 11 percent lower risk of suffering any of these events and an 18 percent lower risk of dying from cardiovascular disease. The researchers dismissed these benefits because they weren’t statistically significant, which simply means that they were less than 95 percent sure that the effects didn't happen by chance. It doesn't mean there was no benefit at all.
In this study there were more people with diabetes taking multivitamins than taking the placebo. Because diabetes is one of the biggest risk factors for cardiovascular disease, this group was already more likely to develop cardiovascular disease whether they took the supplements or not. And like the brain study, the multivitamins were poorly formulated. They contained small amounts of nutrients like vitamin D, which is essential for heart health. Low levels of vitamin D have been linked to developing and dying from cardiovascular disease. The multivitamins also contained only one of eight compounds that make up vitamin E, alpha tocopherol. Studies show that supplementing alpha tocopherol alone depletes the other compounds including gamma tocopherol which has been shown to reduce rates of cardiovascular disease and death.
The study "Vitamin and Mineral Supplements in the Primary Prevention of Cardiovascular Disease and Cancer" looked at whether multivitamins reduced the risk of cardiovascular disease and cancer. Regarding cardiovascular protection, investigators looked at two trials, one involving Centrum Silver and another utilizing only five nutrients: vitamin C, vitamin E, beta-carotene, selenium, and zinc. In both cases, zinc was supplemented without copper. There was none at all in the five nutrient study and while Centrum Silver does contain copper, for the majority of the trial it was given in the form of cupric oxide which cannot be absorbed. Studies show that taking zinc for long periods of time without copper can deplete copper and that copper deficiency increases the risk of cardiovascular disease.
Regarding cancer prevention, researchers actually found that men taking multivitamins had a statistically significant seven percent lower risk of developing cancer. The same benefit was not found in women. While more studies must be undertaken to investigate the difference, it isn't correct to conclude that there was no benefit at all.
Many large-scale, randomized, double-blind, placebo-controlled trials have shown that multivitamins can protect against developing and dying from cardiovascular disease and cancer. The Physician's Health Study II, which followed nearly 15,000 male physicians including more than 1,300 men with a history of cancer for 14 years, found that multivitamins reduced the risk of having a fatal heart attack by 39 percent. The Supplementation in Vitamins and Mineral Antioxidants Study followed almost 13,000 men and women for eight years and found that multivitamin users were 31 percent less likely to develop cancer. And the European Prospective Investigation into Cancer and Nutrition study that followed almost 24,000 people for 11 years found that compared to people who didn't take multivitamins, those who did were 48 percent less likely to die from cancer and 42 percent less likely to die from any cause.
Who Needs Multivitamins?
There is no substitute for a healthy diet and in an ideal world all of the vitamins, minerals, and antioxidants we need would come from food. But in the real world, it’s almost impossible to get all of the nutrients our bodies need from diet alone because modern-day lifestyles, environmental toxicity, prescription medications, and chronic illness all increase our needs for nutrients while foods today are significantly less nutritious than the wild ones that were available to our ancestors.
Multivitamins can compensate for what’s missing. People who benefit most from taking them include individuals eating too many processed foods or too few vegetables, people who have chronic medical conditions or take prescription medication, growing children, athletes, couples planning to conceive, pregnant and breastfeeding women, vegetarians and vegans, and older adults whose ability to assimilate nutrients has become less efficient with age.
Selecting Supplements
Nutritional supplements including multivitamins are far safer than prescription medications, which are recognized by the FDA as the fourth leading cause of death. However, it’s still important to choose carefully. In the United States supplements are not tested for safety or efficacy and the government relies on manufacturers to self-comply with regulations. Formulation and quality vary greatly from one brand to another and what's inside is as important as what isn't. Many multivitamins contain cheap, inactive forms of nutrients that are not well-absorbed or they contain fillers, binders, and flowing agents that can have adverse effects on health. Some supplements have also been found to be contaminated with feces, pesticides, pharmaceutical drugs, and heavy metals like mercury, lead, and arsenic.
When selecting supplements, opt for capsules over tablets and avoid liquids, powders, and chewables containing sweeteners, flavoring, colors, and preservatives. Look for products with labels that list the name and address of the manufacturer; a lot or batch number; an expiration date; the scientific name, quantity, and part of any plant ingredient; and seals from the United States Pharmacopeia, the National Nutritional Foods Association, Consumer Lab, or National Sanitation Foundation International guaranteeing that supplements contain what they’re labeled to contain. And before you buy, seek guidance from a naturopathic doctor or integrative physician and ask about potential interactions with any other supplements or prescription medications you are taking.
Dr. Sarah Cimperman, ND is a naturopathic doctor in private practice in New York City and author of the new book, The Prediabetes Detox: A Whole-Body Program to Balance Your Blood Sugar, Increase Energy, and Reduce Sugar Cravings (www.prediabetesdetox.com). Follow Dr. Cimperman on Facebook, Twitter and her blogs, A Different Kind of Doctor and The Naturopathic Gourmet. Find her at www.drsarahcimperman.com.
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