Earlier this month, a study was published by Tuft’s University researchers in the Annals of Internal Medicine. It looked at a large government database of Americans, focusing on vitamins and mineral intake from food and supplements, and outcomes such as cancer, cardiovascular disease, and death.
As a VCS dietitian, supplement questions are on our frequently asked list. The good news? Patients are more informed than ever and taking charge of dietary changes that can decrease cancer risk and increase survivorship. The downside? There’s much misinformation out there and each patient needs to be considered as an individual with respect to cancer site, nutrient status, lifestyle, and recommendations for getting adequate nutrients. And this can be confusing when you are navigating information on the Internet.
First, supplement use remains high in our country. The study authors showed that more than half of individuals reported use of dietary supplements overall, and close to 4 out of 10 had used multivitamin and mineral supplements, in the previous 30 days. The most commonly used vitamin supplements included vitamin C, vitamin E, and vitamin D. The most common mineral supplements included calcium, zinc, and magnesium. How does supplementation match up with intake? The study found that more than half of all surveyed had inadequate intake of vitamin D, vitamin E, choline, vitamin K, and potassium.
The only supplement that demonstrated promise in reducing risk of dying from cancer and cardiovascular disease was lycopene (the nutrient that is often associated with tomatoes).
Taking high doses of calcium supplements appears to increase the risk of dying from cancer. Note that this relationship is not seen when consuming foods with calcium.
High doses of vitamin D supplements is associated with increased risk of death and cancer. Note that this does not apply to those who have vitamin D deficiency.
Our advice? When in doubt, do not begin supplementing on your own without talking to your doctor or dietitian.
See: Medscape article Dietary Supplements Have No Effect on Mortality Risk for additional study details and a VCS RD if you have questions about your own nutrient needs.