Vitamin D Benefits
Vitamin D plays an important role in the maintenance of an intact and strong skeleton. Its primary task seems today to be to regulate the amount of calcium and phosphorus in the blood by ensuring correct intake from intestines and secretion. However, other related tasks are still under investigation
Several studies show that vitamin D also regulates the growth of skin cells. Psoriasis gives shell-like skin as a result of uncontrolled cell growth. A synthetic vitamin D analogue called calcipotriene is used in the treatment of this disease.
The human body produces its own vitamin D in the skin - this is done by activating some chemicals in the body. This process is dependent on ultraviolet radiation from sunlight. However, vitamin D should not be excluded from the diet, especially for people who do not receive sufficient exposure to UVB sunlight.
Vitamin D is best known for its role in the development and maintenance of healthy teeth, bones, and cartilage in children and adults. Vitamin D helps the body keep bones and teeth strong by increasing absorption of calcium and phosphorus from the small intestine.
Vitamin D is one of those vitamins for which a deficiency can cause severe effects. Children that do not get enough vitamin D in their diets are at increased risk of developing rickets, a disease that causes malformations of bones and teeth in children. Adults with low levels of vitamin D are more likely to develop osteomalacia (similar to rickets) and to suffer from osteoporosis, a bone-weakening disease. Vitamin D also regulates the nervous system, aiding in the treatment of insomnia. A glass of warm milk before bed may indeed help you sleep soundly! Vitamin D deficiency has also been linked to the development of other illnesses, including type I diabetes, muscle and bone pain, and cancer.
There are two forms of Vitamin D: ergocalciferol, which is found in such foods as fortified milk, herring, mackerel, tuna, salmon, sardines, eggs, fortified cereals and baked goods; and cholecalciferol, which is manufactured when the body is exposed to sun.
Vitamin D is fat-soluble. This means that excess amounts of it are stored in the body tissues. Long-term high doses may be deposited in the soft tissues, irreversibly damage the kidneys and cardiovascular system. Like other fat-soluble vitamins, vitamin D can be toxic. Symptoms of too much vitamin D include nausea, weakness, constipation, irregular heartbeat, weight loss, seizures, and irritability.
Sunlight is the best source of vitamin D, because sunlight exposure does not cause vitamin D toxicity, and 10 minutes of sun on your hands and face provides enough vitamin D to reach the daily value. However, getting the necessary amount of vitamin D from the sun is not as simple as it sounds. For one thing, people in northern hemisphere may have difficulty getting vitamin D from sun in the winter due to infrequent exposure to direct sunlight (light coming through a glass window of a car or building doesn’t count, because it filters out vitamin D). Also, the recent explosion in the number of skin cancer cases has caused the public to use more and stronger sunscreen, which inhibits the body’s ability to manufacture its own vitamin D from sunlight. In his book, The UV Advantage, Dr. Michael Holick, one of the world's most respected authorities on vitamin D, discusses the health benefits of natural sunlight. However, if you have a history of skin cancer, or are simply trying to avoid anything that could cause more wrinkles, it is probably best to try to get the vitamin D needed from your diet instead rather than the sun.
The major source of vitamin D in our diet is fortified milk, but it would take one quart of fortified milk to provide the Daily Value. Because there are relatively few foods that contain vitamin D, you may wish to rely on a vitamin supplement to meet your daily needs.
The Recommended Dietary Allowance (RDA) of vitamin D is 800 International Units (IU) for children 18 and under, 600 IU for adults 19-22, and 400 IU for anyone over 23 years. Healthy infants are born with enough vitamin D to last them three months.