While few dietary sources contain natural vitamin D, fortified drinks and food, such as fortified cereal, milk and orange juice, provide you with this vitamin. Your skin produces vitamin D when exposed to sunlight. This fat-soluble nutrient promotes calcium absorption in your digestive system before moving through your system to promote healthy bone mass. Vitamin D stored in your liver undergoes changes to make it useful as a viable nutrient. According to the University of North Carolina, vitamin D plays an important role in digestion.
Besides enabling normal mineralization of bones, vitamin D modulates cell growth, supports the immune system and reduces inflammation. Cells in your digestive system have vitamin D receptors needed for protein synthesis. The most common symptoms of vitamin D deficiency include rickets, osteoporosis and skeletal deformities, according to the Office of Dietary Supplements. Vitamin D plays a role in preventing prostate, colon and breast cancers. It also may contribute to the prevention of diabetes, glucose intolerance and hypertension.
Vitamin D promotes calcium absorption. Calcium not only supports strong bones, it helps your nerves transmit signals. Nerves in your digestive tract must communicate with one another to control your digestive process. By regulating calcium levels, vitamin D provides your nerve cells with the calcium they need to send the signals that aid digestion. The National Digestive Diseases Information Clearinghouse reports lactose intolerance, which can cause avoidance of dairy foods fortified with vitamin D, may contribute to vitamin D deficiency. Consuming lactose-free milk, fortified soy milk or increasing your dietary intake of foods rich in vitamin D, such as liver, eggs and fortified yogurt, can increase vitamin D consumption.
Vitamin D receptor cells are present all along your digestive system. Cells in your mouth, esophagus and small and large intestines rely on vitamin D to keep various bodily functions operating. Epithelial and fat-forming cells have vitamin D receptors. Hormones and amino acids rely on sufficient vitamin D uptake to continue with their normal processes. Along with its primary role of systemic calcium management, vitamin D also maintains a host of healthy physiological functions in your digestive system, according to the European Journal of Drug Metabolism and Pharmacokinetics.
Exposure to excessive ultraviolet radiation from sunlight can lead to skin conditions such as premature aging and cancer. If you avoid sun exposure because of the risk of side effects or skin complications, talk to your doctor before taking vitamin D supplements to compensate. Vitamin D toxicity can lead to a number of conditions, including anorexia and unexplained weight loss. Too much vitamin D can affect your heart and lead to tissue and vascular calcification. Excessive vitamin D in your body also can cause kidney stones.