Yet more evidence on the dangers of supplements: New research shows that selenium pills could markedly increase your risk of developing type 2 diabetes.Most Americans already get nearly twice the daily requirement of selenium, found in foods such as Brazil nuts, halibut, tuna and shiitake mushrooms. Higher selenium intakes have been linked to preserved mental faculties, cancer prevention and a lower risk of osteoarthritis — leading scientists to speculate the mineral might help ward off diabetes as well.
Just the opposite turned out to be true.A study in the Annals of Internal Medicinemonitored 1,200 non-diabetic patients, half of whom were given selenium supplements (200 micrograms/day — or four times the RDA), the other half were assigned a placebo. After eight years, the selenium-takers had a 50% increased risk of developing diabetes compared to the control group. Even more disturbing, supplement takers in the top third of selenium blood levels were roughly 2.7 times more likely to develop diabetes.
Diabetes isn’t the only problem associated with excessive selenium supplementation. Ingesting more than 400 micrograms/day can lead to selenium toxicity or “selenosis,” characterized by brittle hair and nails. A manufacturing error at one vitamin company resulted in 13 individuals ingesting 400 times the RDA in a single tablet — yet one more reason to choose food over supplements! Other problematic supplements include vitamin E (found to increase LDL or “bad” cholesterol levels in animal studies), beta-carotene (which doubles lung cancer risk among current/former smokers) and folate (fortification has been linked with colon cancer). Antioxidant pills in particular appear to increase overall mortality, according to a large-scale review in The Lancet.
To protect yourself from type 2 diabetes, favor whole foods over supplements. Maintain a healthy weight by filling up on fruit and vegetables. Lower your risk with healthy magnesium sources such as spinach, black beans and artichokes.
Vitamin D also stands for diabetes defense: get it from sunlight, canned sardines and canned salmon.
Published October 1, 2008