Definition Vitamin D is a fat-soluble vitamin. It is able to be dissolved in fat. Vitamin D is carried throughout the body by fat. The body can store fat-soluble vitamins. Getting too much can be harmful. Vitamin D can be produced in the body, as well as, obtained from the diet.
What food source is the nutrient found in? Vitamin D is present in:
cheese
butter
margarine
some soy milks are fortified
egg yolks
liver
fish (sardines and salmon), especially oily fish
cod liver oil
Vitamin D is called the sunshine vitamin. This is because the body can make vitamin D after sunlight, or ultraviolet light, hits the skin. Ten to 15 minutes of sun exposure 3 times a week is all the body needs. Older people are less efficient with this conversion.
How does the nutrient affect the body? Vitamin D helps build strong and healthy bones and teeth. It does this by increasing the body's ability to absorb two minerals: calcium and phosphorous. Vitamin D helps deposit these minerals in bones and teeth.
Information If the body does not get enough vitamin D and calcium, the person is at higher risk for bone mass loss known as osteoporosis. Low levels of vitamin D also increases the risk of bone softening, known as osteomalacia, in older adults. Children with a significant vitamin D deficiency may develop rickets, or defective bone growth.
Vitamin D is measured as micrograms (mcg) of cholecalciferol (koh-li-kal-sif-ah-rall). The vitamin D status of Australians is determined by exposure to UV light from the sun, so no RDI is available.
Another common measurement for vitamin D is International Units (IU).
Housebound people could benefit from an oral intake of 10 mcg (micrograms) of vitamin D per day if they are not exposed for 1-2 hours per week to direct sunlight in summer.
Vitamin D is the most likely of all vitamins to cause toxicity.
Because vitamin D dissolves in fat, it can be stored in the fatty tissues of the body. This can pose a problem for people taking high doses of vitamin D. While it is almost impossible to get too much vitamin D from foods or sunlight, it is easy to get too much from supplements. Excess vitamin D can be toxic at low levels. It can cause a dangerous build up of Calcium in the blood which leads to a loss of appetite, fatigue, headache, weakness, bone pain, kidney damage, high blood pressure and other serious problems.
Author: Clare Armstrong, MS, RD Reviewer: HealthAnswers Australia Medical Review Panel Editor: Dr David Taylor, Chief Medical Officer HealthAnswers Australia Last Updated: 1/10/2001 Contributors Potential conflict of interest information for reviewers available on request
