Vitamin C C deficiency. Beyond that, a role for vitamin C as prevention or treatment for various diseases is disputed, with reviews reporting conflicting results. A 2012 Cochrane review reported no effect of vitamin C supplementation on overall mortality. It is on the World Health Organization's List of Essential Medicines as one of the most effective and safe medicines needed in a health system. The disease scurvy is caused by vitamin C deficiency and can be prevented and treated with vitamin C-containing foods or dietary supplements. It takes at least a month of little to no vitamin C before symptoms occur. Early
Vitamin B12 deficiency pregnant vegetarians and vegans, and not harmful in others. Risk of toxicity due to vitamin B is low. Vitamin B deficiency in the US and the UK is estimated to occur in about 6 percent of those under the age of 60, and 20 percent of those over the age of 60. In Latin America rates are estimated at 40 percent and they may be as high as 80 per cent in parts of Africa and Asia. Vitamin B deficiency can lead to anemia and neurological disorders. A mild deficiency may not cause any discernible symptoms, but as the deficiency