Can Vitamin and Mineral Supplementation Prevent Cancer or Cardiovascular Disease?

Patients often come to us with questions about vitamin and mineral supplements. Sometimes they come to us with bags full of the things they are taking. The Internet is full of the wonders these nutritional supplements can do, from turmeric curing cancer to vitamin D curing COVID. It is hard to keep up with medicine itself without learning a whole new field of nutritional supplements.

Linda Girgis, MD

However, for cardiovascular disease (CVD) and cancer prevention, the answer is pretty easy according to USPSTF (United States Preventative Services Task Force) guidelines. They evaluated 17,459 unique citations as well as 379 full-text articles that included randomized clinical trials and observational cohort studies. The conclusions of their research showed that there was little to no benefit in taking vitamin or mineral supplements to prevent CVD, cancer, or death. In fact, beta-carotene supplementation was associated with increased risk of lung cancer and other adverse outcomes in patients at increased risk of lung cancer.

Although they are often marketed like drugs, nutritional supplements are regulated as foods, with less stringent standards. Our current medical culture pushes us to practice evidence-based medicine. Without evidence, we simply cannot counsel patients about supplements because there is little evidence to support their use.

Additionally, many patients assume that they are safe. While this may be true for many of them, some of them can be harmful in several ways. They can interact with medications the patient may be taking for medical conditions. Some of them have been shown to cause liver and other organ damage. When they are used to replace traditional medicine, they can also lead to harm by delaying appropriate medical care. For example, a patient who believes a supplement can treat cancer when it does nothing is delaying care that might save their life. By the time they realize it is not working, the cancer may have advanced too far to be treatable.

While there may be a few studies that do show some efficacy for vitamins and minerals in certain diseases, these guidelines are looking only at use in terms of preventing cancer and CVD. As primary care physicians, we all know the screening guidelines for cancer prevention. We are better off recommending screening mammograms and colon cancer screening tests. And we all know the risk factors for CVD and how to mitigate these risks.

What can we do when patients come to us with false claims regarding supplements?

• Hear what they are saying. They don’t know who to trust. We will never become their trusted source of medical information if we don’t listen to their concerns.

• Answer their questions, no matter how ridiculous they may seem to us. Many people who sell supplements sound convincing. That is how they sell their products. Our advice may seem just as ridiculous to them. We need to explain the facts clearly and be sure the patient understands.

• Give the patient resources. Know what websites to direct them to so that they can get accurate information.

• Know what’s out there. I was once surprised when a patient told me she was going to try turmeric as a treatment for uterine cancer. We cannot combat misinformation when we don’t know what’s being said.

• Become a voice for medical information. There is so much misinformation being spread. We need more doctors to speak up about the right medical information.

Currently, patients often look for medical information online. We do them a disservice when we brush aside their questions regarding supplements, no matter how trivial they seem. We need to take a firm stand and tell them the evidence regarding these supplements: They are neither FDA approved nor studied for safety and efficacy. Anyone can sell a supplement and make any claim regarding it that they want. It is much better to eat a healthy, balanced diet to get the vitamins and minerals that you need. Not only do we need to show them the evidence, we need to convince them that it is true.

Dr. Girgis practices family medicine in South River, N.J., and is a clinical assistant professor of family medicine at Robert Wood Johnson Medical School, New Brunswick, N.J. She was paid by Pfizer as a consultant on Paxlovid and is the editor in chief of Physician’s Weekly.

This article originally appeared on MDedge.com, part of the Medscape Professional Network.

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Cite this: Can Vitamin and Mineral Supplementation Prevent Cancer or Cardiovascular Disease? - Medscape - Nov 28, 2023.