Based on hundreds of scientific studies, the recommendation is to use a dietary supplement only if a nutrient is lacking in your diet.1
Numerous studies have demonstrated more harm than benefit from taking excessive supplements. Here are a few examples:
In two major vitamin E lung cancer studies, the studies were stopped as individuals with lung cancer or lung disease got worse with the use of vitamin E supplements.
High doses of calcium worsened existing prostate cancer in another study.
Aspirin, vitamin E, and fish oils all keep the blood from clotting readily, so taken at high doses or taking all together, can be dangerous, especially if someone is already on a medication to thin the blood.
Further, there can be interactions with drugs a person may already be taking. It is important to consult with your doctor, pharmacist, and registered dietitian before investing in a supplement that may pose harm.
Consuming a well balanced diet full of colorful and flavorful fruits and vegetables, whole grains, lean protein sources and dairy, is still at the heart of a healthy diet, without posing the risk of a toxic overdose.
1 The American Cancer Society, American Institute for Cancer Research, as well as the US Dietary Guidelines Committee 2015-2020.