Scurvy These make up one of two major primate suborders, haplorrhini and this group includes humans. The strepsirrhini (non-tarsier prosimians) can make their own vitamin C, and these include lemurs, lorises, pottos, and galagos. Ascorbic acid is also not synthesized by at least two species of caviidae, the capybara and the guinea pig. There are known species of birds and fish that do not synthesize their own Vitamin C. All species that do not synthesize ascorbate require it in the diet. Deficiency causes scurvy in humans, and somewhat similar symptoms in other animals. Animals that can contract scurvy all lack the
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