Preliminary research indicates that inadequate levels of vitamin D may contribute to higher disease rates, and that increasing vitamin D intake has health benefits.
As winter enters its final official month, vitamin D is becoming a conversation topic among sunshine-starved individuals in the northern hemisphere. Research is increasingly indicating the “sunshine vitamin” may be a disease deterrent in addition to building strong bones.
Vitamin D and Health
In the early 20th century doctors prescribed the “sunshine cure” to tuberculosis patients by sending individuals with TB to rest in sunny locales. In the 21st century many individuals use light therapy lamps to combat seasonal affective disorder (SAD), a winter depression brought on by the widespread seasonal lack of sunlight.
Both treatments are related to the amount of Vitamin D in the body. Now research indicates that increasing levels of Vitamin D may be a preventative measure for disease as well. Preliminary research, such as that published in the March 2006 issue of Science, indicates that almost 50 percent of Americans may be vitamin D deficient because of low-sunlight exposure in the winter and high sunscreen usage the rest of the year. This inadequate amount may contribute to higher disease rates.
According to a study published in the November 2007 issue of Scientific American, the impact of low levels of Vitamin D may hold the key to future research. The study found that chronically low levels of vitamin D raised individuals’ risk for major illnesses including breast, prostate and colon cancers, multiple sclerosis, and Type 1 diabetes. These results show promising but inconclusive results, and indicate the need for additional research into the benefit for increasing vitamin D intake or supplementation.
Vitamin D Absorption
While vitamin D can be obtained through food or supplements, people primarily absorb it through exposure to sunlight. Ten to fifteen minutes of sun exposure at least two times per week without sunscreen allows adequate time for Vitamin D synthesis. However, this amount of sunlight can be a scarce commodity during the winter, particularly in northern areas of the country. For example, according to the National Weather Service, western Michigan has only 1 hour 21 minutes of direct sunlight in January 2008.
For this reason as well as skin cancer concerns, the National Institute of Health recommends that individuals with limited sun exposure include good sources of vitamin D and/or vitamin supplements in their diet. While food sources for vitamin D are not abundant, eating foods such as eggs, fortified milk, dry cereal, and fish increase vitamin D levels. In addition, Vitamin D supplements are available. The most easily absorbed is Vitamin D3, which stays in the body’s system for longer and is usually combined with calcium and magnesium.
Regardless of the source, research indicates that increasing the amount of Vitamin D intake may have a substantial public benefit with limited risk.
Sources:
Tavera-Mendoza, L.E. & White, J.H. (2007). Cell Defenses and the Sunshine Vitamin, Scientific American, 62-72.
Modin, R. et al (2006). Toll-Like Receptor Triggering of a Vitamin D Mediated Human Antimicrobial Response, Science, 1770-1773.
