Vitamin D is often referred to as the “sunshine vitamin” because the main source of the vitamin is the sun. Because of this it is probably the most widely available vitamin and least expensive. Just step outside on a sunny day and your body will start to absorb it. However, despite the fact that it is so readily available recent studies have shown that in recent years the levels of vitamin D in Americans have dropped significantly. This may be due to a number of factors but chief among them is probably the fact that we are spending more and more of our time indoors engaging in sedentary electronic entertainments and activities rather than physically active outside ones. While avoiding the sun certainly helps reduce the chances of skin cancer it also reduces the amount of vitamin D we absorb – which according to recent studies is problematic for our overall health.
In fact, the National Institute of Heath recently released a report in which a meta-analysis showed that having the correct levels of vitamin D “was associated with a reduction in overall mortality from any cause by a statistically significant 7%.” Vitamin D has been shown to boost the overall immune system and fight off viral infections such as the flu. The American Journal of Clinical Nutrition reported that a recent double-blind placebo-controlled study found that the people who took vitamin D got the flu less than those who took the placebo. Harvard Medical School also conducted a study with 19,000 people in which they discovered that those with a vitamin D deficiency where 55% more likely to get an upper respiratory diseases or infection including colds and the flu.
Links have also been found between vitamin D deficiencies and certain cancers including colon, prostate and breast cancers. Vitamin D is also crucial to the process of calcium absorption. Without sufficient amounts of vitamin D the body won’t be able to absorb adequate amounts of calcium to fulfill its needs. Proper levels of calcium, in turn, are necessary for the proper functioning of the nervous system and bone density. Thus having the proper amounts of viatmin D can help prevent osteoporosis and other bone and nervous system diseases.
However, there are not many natural sources of vitamin D outside of the sun. Cod liver oil, oily fish and fortified milk are the only foods with reasonably high amounts of vitamin D. However, in order to get even the minimum suggested amount of 400 IU per day of vitamin D from these foods you would have to eat 5oz of salmon or drink 1/4th of a gallon of vitamin D fortified milk every day. This means that it may be a good idea to take some vitamin D supplements, especially during the fall and winter months when our exposure to sunlight is typically at its lowest.
When looking for multivitamins or supplements to boost your vitamin D intake, be aware that there are two kinds of vitamin D: D2 (ergocalciferol) and D3 (cholecalciferol). Look for the label on the bottle to say either D3 and/or cholecalciferol, Vitamin D3 is the one you want to look for because it is the more effective of the two types. It is recommended that you look for a multivitamin that has between 700-800 IU of D3 during the summer months and increase that amount to between 1,000-2,000 IU in the fall and winter.
However, as with taking any supplements, it is possible that taking vitamin D supplements may react adversely with any medications you may be taking. So make sure you talk with your doctor before you begin taking regular daily supplements of vitamin D.
National Institute of Health Office of Dietary Supplements
National Institute of Health Report on Vitamin D
American Journal of Clinical Nutrition