Contrary to the claims of many sellers of supplements (including bad advice from health food stores), we should strive to get most of our nutrients from produce not pills, though there are rare diseases that require supplementation.
There are tens of thousands of phytonutrients in plants that can display synergistic effects and have not been successfully isolated efficaciously in supplement form. For example iron, which is important during pregnancy, may be harmful in pill form. Similarly, folate in beans and greens is preferable to folic acid in pills. Flax seed, but not flax seed oil, lowers cholesterol. Citrulline supplements may aid erectile dysfunction, but a better source is watermelon. Similarly, eating soy foods, rather than taking soy supplements, may reduce the risk of breast cancer recurrence. And it is whole produce, not pills, which has been shown to increase physical attractiveness.
However, for those on plant-based diets, there are two vitamins not produced by plants that may require supplementation. They are vitamin D from sun but not from tanning beds (see also here, here, here, here, here, here, here) and vitamin B12 (see also here, here, here, here, here). Among vegans, B12 deficiency is an epidemic if no supplements are used, which can have devastating consequences for their infants (see also here). Vegetarian’s myelopathy is a syndrome coined to describe vitamin B12 decficiency, which can result in paralysis. Another nutrient vegans should keep an eye on is iodine, which is especially important during pregnancy (though harmful in too too great quantities).
One of the most commonly used supplements is fish oil. It has been found to contain DDT as well as other industrial pollutants, including high levels of dioxin, PCBs and mercury (which are neural and cardiac toxins). This includes distilled fish oil, cod liver oil and those labeled ‘Toxin-Free’. Instead, there are safe plant sources of omega-3; alternatives include algae and yeast derived EPA and DHA, which also lower inflammation.
While there are some harmless vitamin supplements such as vitamin C and Airborne supplements, others may do more harm than good, such as multivitamins, which may actually increase breast and prostate cancer risk, and antioxidant vitamin supplements such as Vitamin E that may shorten one’s lifespan.
A variety of other potentially harmful supplements exist including: Herbalife (for its liver toxicity, possibly due to vitamin A), Juice Plus+ (which is really just another vitamin supplement), glyconutrient supplements, lutein pills, creatine, copper supplements (which may contribute to Alzheimer’s), zinc gel, kombucha tea, noni juice, and rice bran. Ayurvedic medicine (see also here) has been found to contain lead. Spirulina and blue-green algae supplements may contain neurotoxins and/or liver toxins (a safer alternative is chlorella).
See also the related blog posts: Vitamin D: Shedding some light on the new recommendations, Multivitamins and Mortality, Vegan B12 deficiency: putting it into perspective
Topic summary contributed by Eitan.
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