\r\n<h4>By: Dr. Magdy Badran<\/h4>\r\n<h4>Consultant Ped Immunology<\/h4>\r\nScientific interest in vitamin D has increased in recent years. Vitamin D functions as a modulator of as many as 2,000 genes involved in cellular growth, immune function and protein synthesis and in calcium absorbtion . Recent studies showed\u00a0 that it\u00a0 helps in regulating energy metabolism , lowering\u00a0 high blood pressure, prevention of diabetes\u00a0 and stop growing colon, breast and prostate cancers . Getting 1000 IU (international units) of vitamin D every day would cut colon cancer risk by about 50%.\r\n\r\nRecent studies have also suggested a role for vitamin D in lung health.\u00a0 Teens who had a low dietary intake of vitamin D had significantly lower lung function compared with teens who consumed the recommended amount.\r\n\r\nSeveral studies have supported the view that vitamin D deficiency is the cause of the global asthma epidemic. As expectant mothers who take higher amounts of vitamin D may decrease their child's risk for asthma. Vitamin D deficiency is common in areas where asthma is also widespread .Vitamin D also\u00a0 may have an effect on a fetus's developing immune system. Serum vitamin D levels were found to be lowest among children with steroid resistant asthma , with reduced lung function, increased steroid use and asthma exacerbations.\r\n\r\nVitamin D plays a major role in the function of the nervous system. Low levels of vitamin D may play a role in psychiatric disorders, as depression . A maternal deficiency in vitamin D increases the risk of autism in the unborn child. Vitamin D has also shown to improve behaviour in autistic children. Serotonin, oxytocin, and vasopressin, three brain hormones that affect social behavior related to autism, are all activated by vitamin D . Optimal vitamin D levels can help\u00a0\u00a0improve your mood , boost your overall brain function, and improve your well-being.\r\n\r\nModernization and westernization have led to vitamin D deficiency among world population , especially\u00a0 among children, the elderly and women\u00a0 . Since, the\u00a0majority of the population spends time indoors away from sun exposure, leading to vitamin D deficiency .More than one third of populations worldwide may have low levels of vitamin D .\r\n\r\nVitamin D deficiency means\u00a0 higher risk\u00a0 for rickets , a vitamin-D-related bone disorder once thought to be a condition of the past. Studies have also suggested that vitamin D deficiency might heavily impact the elderly by making them prone to developing bone-thinning diseases such as osteoporosis and fractures.\r\n\r\nFor adults, the recommended amount of\u00a0 vitamin D per day should be between 200 to 600 IU. In summer the human body can generate up to 12,000 IU of vitamin D from only half an hour of sun exposure. However, during winter months, the daily intake from food and sun exposure falls below the recommended amount. Sunlight is the main source for most people; skin has the natural ability to produce vitamin D when struck by ultraviolet rays in sunlight.\r\n\r\nSources of vitamin D include\u00a0 fortified dairy products, egg yolks, saltwater fish and cod liver oil. It is often added to milk, cereals, and orange juice. Vitamin D is found naturally in breast milk .