Vitamin D rich foods are very important for your overall health. Vitamin D plays two key roles. One aspect ensures optimal mineralization of bone during growth, but also throughout their lives for their renewal. Another aspect modulates the intestinal absorption of calcium and contributes to the stability of calcium in the blood and tissues. Vitamin D foods are found in two forms: ergocalciferol, which is found in plants and cholecalciferol, which comes from animal products. Although vitamin D belongs to the category of fat-soluble vitamins, it operates as a hormone. Our skin contains a precursor of vitamin D: 7-dehydrocholesterol. This precursor, under the action of sunlight, is converted into cholecalciferol (which has a structure similar to cholesterol).
Two steps are necessary to make vitamin D active when received through nutrient rich foods. The first occurs in the liver where it acquires a hydroxyl group (= OH). The second transformation occurs in the kidney where the molecule receives a second hydroxyl group. The molecule formed is calcitriol, the active form of vitamin D. For the last step, parathyroid hormone is needed.
Role of Vitamin D Rich Foods
Vitamin D is essential for us to absorb calcium and keep bones and teeth healthy. It allows the intestinal absorption of calcium and reduces the elimination of it through urine. It regulates calcium and phosphorus metabolism. Vitamin D foods appear to help in the treatment of psoriasis and increase our resistance to tuberculosis. It also protects against cancer of breast and colon.
Recommended Intake of Vitamin D Rich Foods
It is not easy to determine dietary intakes of vitamin D because they are dependent on sun exposure. Recommended daily intakes in micrograms per day:
0-12 Months: 25 mcg (1000 IU /day)
Healthy children and adults: 50 mcg (2000 IU/day)
Pregnant women: 150 mcg (6000 IU/day)
Who Is At Risk?
Those with insufficient sun exposure are at risk. This is often the case with babies, small children, pregnant women and elderly. The elderly are particularly at risk as they usually don’t go out much and don’t consume enough vitamin D rich foods. The ability of skin to synthesize this vitamin is reduced and moreover some of them also take drugs that interfere with the absorption of vitamin D. Alcoholics and people with kidney, intestinal and liver disease are also put at a state of risk.
A severe deficiency of vitamin D in children causes rickets (bone deformities). In adults, a deficiency results in osteomalacia (softening of bones due to a lack of mineralization). This disease is different from osteoporosis which causes weak bones and makes them porous.
Sources of Vitamin D Rich Foods
Nutritional yeast, mushrooms, wheat germ, fatty fish and fish oils are all rich in vitamin D. For the vegetarian, choices are limited, but if they regularly consume these vitamin D foods or supplements and spend time out in the sunlight, they do not have to worry. Sun exposure is by far the best source of vitamin D. 10-15 minutes of sun a day on the face, arms and hands can work wonders on your skin and will also give you the much required dose of vitamin D. You only need 15 minutes of exposure per day.
Precautions of Eating Too Many Vitamin D Rich Foods
Vitamin D enters the family of fat-soluble vitamins. The body can store it but too much vitamin D can be toxic. The main sources can be harmful to growth and can lead to calcification of soft tissues (kidney, vascular walls) or can cause hypocalcaemia (high blood calcium). Be aware that some drugs block the metabolism of vitamin D (barbiturates, drugs to lower cholesterol, cortisone). In some countries, vitamin D foods such as milk is fortified with vitamin D. It is important to be careful because you can consume too much vitamin D. If you decide to take supplements of this vitamin be sure not to exceed 25 micrograms per day.