Vitamin C and the common cold Vitamin C and the common cold The common cold, or simply cold, is a viral infectious disease of the upper respiratory tract. The cold is indeed common, and is a significant cause for absences from work and school. Even before the discovery of vitamin C, folklore had it that certain fruits were effective in both preventing and treating the cold. After scientific identification of vitamin C in the early part of the 20th century, research began into the possible effects of the vitamin against the common cold. Vitamin C has not decreased the frequency of colds in the general population,
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