Fat-soluble Vitamin D is a nutrient that is naturally found in just a few foods, available as dietary supplements, and also produced by the human body during exposure to ultraviolet rays.
Vitamin D interacts with more than 200 genes in the human body. Its importance extends far beyond bone health and regulating calcium and phosphorus absorption. Recent studies have shown that nearly every tissue and cell in our bodies contains Vitamin D receptors. This means that Vitamin D deficiency can cause more than just weak bones and osteomalacia in adults. Recently, it has been reported, that vitamin D deficiency is associated with risk of cancers, heart disorders, Alzheimer's, multiple sclerosis, schizophrenia, depressions, diabetes, and infections. In growing children, vitamin D deficiency causes rickets, a condition characterized by soft bones as a result of a failure of bones to properly mineralize. This vitamin also affects muscle function and the immune system.
Ways to get Vitamin D
| The Sun
The best way to get Vitamin D is by exposing your bare skin to ultraviolet B (UVB) rays. It isn't necessary to tan or burn your skin while sunbathing. An ideal length of the exposure is a half the time that takes for your skin to turn pink or red; for example, 10-15 minutes of sunshine with 40 % of the body exposed (arm and legs) two to three times a week.
An amount of Vitamin D absorbed is highly dependent on the time of day and the place you live in. Those who live further away north from 37-degree latitudes of the Northern Hemisphere in the United States and Europe or further away south from 37-degree latitudes of the Southern Hemisphere are at higher risk of vitamin D deficiency.
Amount of Vitamin D production from the sunlight depends on many other factors:
Darker Skin Tone. People with darker skin tone synthesize a less amount of vitamin D than people with fair skin.
Older age. People of ages over 65, due to their skin conditions, have a reduces ability to sufficiently process the UVB rays from the sun and turn it into vitamin D; also, they more likely stay indoors.
Sunscreen. Sunscreen is a good thing to prevent photoaging, but it reduces the skin's ability to synthesize vitamin D.
Breastfed infants. Typically, human milk doesn't provide an adequate amount of vitamin D, particularly for kids who live in the north or have darker skin. Breastfed infants should be given a vitamin D supplement.
Diseases. Diseases such as inflammatory bowel disease and obesity do decrease the ability to absorb vitamin D from food.
It is, thus, preferable to combine different ways of acquiring Vitamin D to ensure optimum levels in your body.
| Food You Eat
Though the daily value for vitamin D is set at 400 - 600 IU for adults, many leading experts believe that 1,000 IU of vitamin D is required if exposure to ultraviolet is not available.
In the absence of adequate sunlight, consider getting supplements and eating foods that contain vitamin D, including fatty fish (salmon, trout, mackerel, sardines, and herring), fortified dairy and fortified cereal, egg yolks, and white mushrooms. Additionally, when it comes to bone health, calcium and vitamin D work in tandem. Therefore, it is imperative to also consume food such as milk, cheese, yogurt, leafy vegetables, fish, tofu, green beans, almonds, and canned fish to balance your diet.
Most experts agree that supplements are the easiest alternative to vitamin D rich food, as the body is better equipped to process them; particularly, vitamin D3 is the most effectively and efficiently absorbed. There is a conflict between leading medical experts on the appropriate dosage of vitamin D, while some believe that taking lower amounts is better to prevent toxicity, others are sure that taking more than the required amount is needed to make sure that the body absorbs the necessary amount. Since excessive vitamin D intake can lead to toxicity, it is best to consult your doctor before embarking on this venture.
So, there you have it - the importance and the different ways to avoid Vitamin D deficiency. The best approach would be to combine the three ways to always ensure your body has an adequate amount of vitamin D.
On a cloudy day, take vitamin D through food and supplements. When a day is sunny and you stay outdoors, your vitamin D intake might be reduced. Regardless, consult a qualified healthcare professional before starting any new regimen.
1. Rathish Nair and Arun Maseeh. Vitamin D: The “sunshine” vitamin. NCBI. 2012.
2. Ward LM, Gaboury I, Ladhani M, Zlotkin S. Vitamin D-deficiency rickets among children in Canada. NBCI. 2007.
The American Journal of Clinical Nutrition
Harvard Medical School