I thought the B vitamins were all water soluble and did not build up in the body, so you would not build up toxic levels. Am I wrong?
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 Upper Tolerable 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
||Skin flushing/pain; liver toxicity; elevated blood sugar
||Nerve damage, skin lesions
|B-9 (Folate/Folic Acid)
||Kidney damage; masking of B-12 deficiency
||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
Also see related CL Answers:
I have been having neurological symptoms, and a blood test showed I have toxic levels of vitamin B-6. My multivitamin contains 75 mg of B-6, but this is below the upper limit of 100 mg per day. Could my vitamin contain more than it lists? >>
Can taking too much vitamin B-6 be dangerous? The label on my multivitamin states it contains 2000% the Daily Value! >>
Can taking too much vitamin B-12 be dangerous? The label on my B-complex states it contains 50,000% the Daily Value! >>
The maker of my multivitamin says it doesn't include folic acid because too much from supplements can be harmful. Is that true? >>
Is it possible to take too much vitamin C? >>
This CL Answer initially posted on 7/4/2015.
Last updated 8/3/2017.