Known as the sunshine vitamin, we produce Vitamin D naturally in the summer months when we are exposed to the sun light, however as winter rolls in our vitamin D levels drop and we become more susceptible to viruses.
The immune system's front-line defence are T-cells, which are latent until they are set in motion detecting and killing infections caused by viruses and bacteria. A Danish study recently found that the first stage of T-cell activation involves Vitamin D. When a T-cell detects a virus or bacteria it sends out a signal to search for Vitamin D in the blood. Without Vitamin D, T-cell activation is jeopardised.
I have my Vitamin D levels checked two or three times a year with a simple blood test. It's an expensive test, so you might have to talk your Doctor into it! My Vitamin D level in my last test was 154, the normal range is between 75 and 200. The first time I took a Vitamin D test, it was in the spring after a long, cold, dark winter, my level was 27! It took me almost a year to build it to 100.
Why do we need vitamin D?
· It is crucial for the absorption and metabolism of calcium and phosphorous, which have various functions, especially the maintenance of healthy bones.
· It is an immune system regulator.
· It may be an important way to arm the immune system against disorders like the common cold, say scientists from the University of Colorado Denver School of Medicine, Massachusetts General Hospital and Children's Hospital Boston.
· It may reduce the risk of developing multiple sclerosis. Multiple sclerosis is much less common the nearer you get to the tropics, where there is much more sunlight, according to Dennis Bourdette, chairman of the Department of Neurology and director of the Multiple Sclerosis and Neuroimmunology Center at Oregon Health and Science University, USA.
· Vitamin D may have a key role in helping the brain to keep working well in later life, according to a study of 3000 European men between the ages of 40 and 79.
· Vitamin D is probably linked to maintaining a healthy body weight, according to research carried out at the Medical College of Georgia, USA.
· It can reduce the severity and frequency of asthma symptoms, and also the likelihood of hospitalizations due to asthma, researchers from Harvard Medical School found after monitoring 616 children in Costa Rica.
· It has been shown to reduce the risk of developing rheumatoid arthritis in women.
· A form of vitamin D could be one of our body's main protections against damage from low levels of radiation, say radiological experts from the New York City Department of Health and Mental Hygiene.
· Various studies have shown that people with adequate levels of vitamin D have a significantly lower risk of developing cancer, compared to people with lower levels. Vitamin D deficiency was found to be prevalent in cancer patients regardless of nutritional status, in a study carried out by Cancer Treatment Centers of America.
Researchers at the University of California, San Diego, suggested in the March 2007 issue of the American Journal of Preventive Medicine that taking 2,000 IU of vitamin D daily along with 10 to 15 minutes in the sun and a healthy diet could reduce the incidence of colorectal cancer by two-thirds. The same authors found that breast cancer rates were 50 per cent lower in people with high levels of vitamin D in their blood, and suggested that the average person could maintain those levels by taking 2,000 IU of vitamin D daily and spending 10 to 15 minutes in the sun.
Vitamin D has acquired its health-cult status because many studies have found that people with more of the nutrient circulating in their blood have lower rates of some cancers. As well, other research – based on epidemiology or the study of disease distribution in large populations – has found that there is more cancer, diabetes, and other chronic ailments among those living at northern latitudes than among people living further south.
Katie Couric speaks to Dr. Jon LaPook about the benefits of vitamin D and the best ways to get it.