Vitamin D: The Ultimate Antiviral?
Posted on 23. Nov, 2009 by Kerry D Friesen, M.D. in Nutritional Therapy, Prevention
Vitamin D: Not Just A Vitamin Anymore!
Remember cod-liver oil?
Well a great idea, just got better!
While cod-liver oil is a good source of vitamin D, it contains far too much vitamin A and a only a fraction of the omega 3 fatty-acids recommended.
We now know that vitamin D is the “active ingredient” in cod-liver oil and responsible for most of the benefit.
Here are some little-known facts about vitamin D metabolism:
- Vitamin D is not a vitamin at all—it is a “prohormone” with a profound effect on human immunity
- Summertime sun exposure results in vitamin D levels that average around 50 ng/ml, however, during the winter vitamin D levels may drop to less than 20 ng/ml
- The elderly and the obese are at increased risk for vitamin D deficiency
- Supplementation with 400 IU per day is not adequate to prevent vitamin D insufficiency
- In one study, 2000 IU per day for one year, failed to maintain adequate blood levels of vitamin D in 40% of post-menopausal African-American women
- Low vitamin D levels during pregnancy have been linked to schizophrenia and depression
- Vitamin D supplementation has been shown to decrease the risk of multiple sclerosis, rheumatoid arthritis, Type I diabetes and some cancers including, prostate cancer in men and breast cancer in women
Practically Speaking
It has been my practice to measure vitamin D levels in my patients for the last ten years. During that time, fewer than five out of hundreds of patients had normal vitamin D levels. Conclusion? Most people are vitamin D deficient and unaware.
The “normal range” for vitamin D set by the Food and Nutrition Board is currently considered to be 30-90 ng/ml. Keep in mind, many, many experts consider this level inadequate for the prevention of most vitamin D deficiency related disorders.
This recommended blood level translates into a daily intake of 5000 IU for men and 6-10,000 IU of vitamin D per day for women. It is nearly impossible to maintain healthy levels of vitamin D through diet or sun exposure alone. Supplementation is almost always required.
Vitamin D, immunity and the flu
Based on multiple recent studies and our new understanding of vitamin D metabolism, it is no coincidence that the “flu” peaks in the winter when vitamin D levels are at their lowest. Vitamin D is required for immune system regulation and has a direct effect on our ability to fight viral and bacterial infections.
As the author of one study asks, “where is the virus between epidemics?” From other scientific studies we know that the virus is in fact present in the population year-round, yet has an “explosive” effect only during winter months. The same author goes on to ask another impossible to answer question without invoking the role of vitamin D and immunity, ” why does experimental inoculation of humans (without previous exposure to a virus), fail to cause illness in all the volunteers?”
What to do?
In order for vitamin D to effectively support the immune system, adequate stores must be present. Stored vitamin D is drawn on specifically during viral infections and without daily supplementation of 5-10,000 IU per day, is rapidly exhausted.
- Ask your doctor about having your current vitamin D levels measured.
- Add fatty fish to your diet and consider taking a vitamin D supplement.
- A teaspoon of cod-liver oil now and then can’t hurt either.
Yes your mother does know best!
