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B Vitamins


Although B vitamins are water soluble and don't stay long in your body, large doses of certain B vitamins can cause serious toxicity, as summarized below. The same is true of vitamin C, the other water soluble vitamin.

Unfortunately, there is no requirement for supplement labels to warn of these toxicities. As we have shown in our B Vitamin Supplements Review, many vitamins and energy drinks exceed the established Tolerable Upper Intake Levels (which vary by age) for B vitamins. If you have an established deficiency, high doses may be necessary; otherwise, remember that "more" does not necessarily mean "better."

Toxicities from B Vitamins

B-3 (Niacin) Skin flushing/pain; liver toxicity; elevated blood sugar
B-6 Nerve damage, skin lesions
B-9 (Folate/Folic Acid) Kidney damage; masking of B-12 deficiency
B-12 Acne/rosacea a side effect in some people


More information about the beneficial and toxic effects of these vitamins, including associated dosage, is found in the B Vitamin Supplements Review.


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