More of something isn’t necessarily better. Sometimes too much of a nutrient is as harmful as too little. All nutrients have a toxic load and in some cases the toxicity increases when a nutrient is isolated from the protective compounds that are naturally found in fruits and vegetables (1). Beta carotene is one example – it’s great for you in natural sources but in high doses from supplements it’s been shown to promote lung cancer in people who are at risk for the disease (2). Other examples include high levels of supplemental calcium (1,000mg or more per day) and possibly Vitamin D (3).

Also, there are some studies on animals that indicate when a nutrient is ingested determines the protective benefit. This is mainly related to Indole-3 compounds and sulforaphane which are found naturally in cruciferous veggies. These compounds are known to suppress cancer and seem to work best when they are ingested before being exposed to a carcinogen (such as cigarette smoke). This is how they can provide the most protective effect to help suppress cancer. If ingested in large doses after exposure to a carcinogen, scientists have found that they may promote cancer (4).  Until further research occurs, it’s recommended that we consume the compounds from natural sources.

Memorial Sloan Kettering Cancer Center offers an excellent herbal database to help you determine the value of using herbs and other dietary supplements.  The database includes evidence-based information about proven uses, potential benefits, adverse reactions and interactions with other herbs and medicines.

Consult with a professional such as a registered dietitian or oncologist before adding a herb or supplement to your diet to ensure it won’t interact with your current medications.

Source:

1. Dietary Supplements Taken in Excess Shown to Increase Cancer Risk;  University of Colorado Cancer Centre:                                                                                                        http://www.coloradocancerblogs.org/dietary-supplements-shown-to-increase-cancer-risk/
2. Most Wanted Supplements:  Are They Cancer Killers or Frauds?;  Rogel Cancer Centre, Michigan Medicine:  https://www.mcancer.org/living-with-cancer/mind-body-side-effects/nutrition/most-wanted-supplements
3. Nutrients from food, not supplements, linked to lower risks of death, cancer:  https://now.tufts.edu/news-releases/nutrients-food-not-supplements-linked-lower-risks-death-cancer
4. Indole-3-Carbinol;  Linus Pauling Institute, Micronutrient Information Center:  http://lpi.oregonstate.edu/mic/dietary-factors/phytochemicals/indole-3-carbinol

The above link leads to a website provided by the Linus Pauling Institute at Oregon State University.  I am not affiliated or endorsed by the Linus Pauling Institute or Oregon State University

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