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 D and neurology vitamin D blood concentration standard for diagnosing hypovitaminosis D does not exist. In the past, hypovitaminosis D has been defined by blood concentrations lower than 20 ng/ mL. However, in more recent literature many researchers have considered 30 ng/ mL to be an insufficient concentration of vitamin D. Subnormal levels of vitamin D are usually caused by poor nutrition or a lack of sun exposure. Risk factors for hypovitaminosis D include premature birth, darker skin pigmentation, obesity, malabsorption, and older age. The brain requires the use of many neurosteroids to develop and function properly. These molecules are often identified as