Scurvy juice, which is high in vitamin C. Though redundant in the presence of a balanced diet, various nutritional supplements are available that provide ascorbic acid well in excess of that required to prevent scurvy. Some animal products, including liver, muktuk (whale skin), oysters, and parts of the central nervous system, including the adrenal medulla, brain, and spinal cord, contain large amounts of vitamin C, and can even be used to treat scurvy. Fresh meat from animals which make their own vitamin C (which most animals do) contains enough vitamin C to prevent scurvy, and even partly treat it. In some
Vitamin B12 deficiency years worth of vitamin B under normal conditions and functioning. However, the rate at which B levels may change when dietary intake is low depends on the balance between several variables. Vitamin B deficiency causes particular changes to the metabolism of two clinically relevant substances in humans: Methionine is activated to "S"-adenosyl methionine, which aids in purine and thymidine synthesis, myelin production, protein/neurotransmitters/fatty acid/phospholipid production and DNA methylation. 5-Methyl tetrahydrofolate provides a methyl group, which is released to the reaction with homocysteine, resulting in methionine. This reaction requires cobalamin as a cofactor. The creation of 5-methyl tetrahydrofolate is an irreversible