Certain dietary supplements can change absorption, metabolism, or excretion of a medication and therefore affect its potency. “Some dietary supplements may increase the effect of your medication, and other dietary supplements may decrease it,” warned Robert Mozersky, a medical officer at the FDA.
Specifically, the FDA cautioned against taking warfarin (a prescription blood thinner) with ginkgo biloba, aspirin and vitamin E, which can also thin the blood and may increase the potential for internal bleeding or stroke.
In addition, drugs for HIV/AIDS, heart disease, depression, treatments for organ transplants, and birth control pills are less effective when taken with St. John’s Wort, an herbal supplement, said the agency.
The full consumer advisory can be found HERE.
The role of healthcare practitioners
A recent survey from the Council for Responsible Nutrition indicated that over 50% of supplement users rely on their doctors for information on what products to use and how to use them.
Speaking with NutraIngredients-USA at the time of the survey’s publication Dr Duffy MacKay, CRN’s senior vice president for scientific and regulatory affairs, told us: “This survey addresses some of the folk tales that are out there about supplements. One of them is that people will take supplements instead of making other health lifestyle choices or in lieu of eating well. Supplement uses are not doing it instead of other healthy things. This is a cohort of people who are taking supplements in addition to other things.”
The survey found that supplement users are more likely than non-supplement users to engage in a primary health behavior—periodic doctor visits. 74% of the supplement users in the survey said they saw their doctor regularly; the figure for non-supplement users was 66%.
In the survey, 78% percent of the more than 1,300 respondents agreed with the statement that, “I believe my physician spends enough time answering my questions about supplement use.” 67% agreed with the idea that “My physician has talked to me about the benefits of supplements,” while 56% agreed with the statement that, “My physician has talked to me about the potential interactions certain supplements can have with drugs and food.”
“The patient-doctor relationship is a partnership in which both parties have responsibilities when it comes to communication,” said Dr MacKay.