Combining common drugs with herbal, dietary or nutritional supplements can damage health, say researchers.
"'Natural' does not equal 'safe,'" and the effects and interactions of herbal or dietary supplements and functional foods such as energy drinks or nutritional bars can be difficult to predict, says Catherine Ulbricht, senior attending pharmacist at Massachusetts General Hospital.
"If something has a therapeutic action in a human body, this substance can also cause a reaction or an interaction," added Ulbricht, the journal Alternative and Complementary Therapies reports.
The risk for interactions is greatest in younger and older people and in individuals with multiple health conditions or who take multiple medications, explains Ulbricht.
Common examples include an increased risk of significant bleeding tied with garlic, ginkgo, ginger and saw palmetto supplements; decreased blood sugar as a result of chromium, cinnamon, whey protein, and others; hormonal effects of dong quai, black cohosh, kudzu, and saw palmetto; and elevated blood pressure caused by bloodroot, green tea, hawthorn, and mate.