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 K appear to be much lower than those of vitamin K. Occurrence of vitamin K deficiency bleeding in the first week of the infant's life is estimated at 0.25–1.7%, with a prevalence of 2–10 cases per 100,000 births. Premature babies have even lower levels of the vitamin, so they are at a higher risk from this deficiency. Bleeding in infants due to vitamin K deficiency can be severe, leading to hospitalization, blood transfusions, brain damage, and death. Supplementation can prevent most cases of vitamin K deficiency bleeding in the newborn. Intramuscular administration (known as the "Vitamin K shot") is more effective