I believe optimizing our Vitamin D blood levels is one of the best things we can do to protect ourselves from the Swine Flu.
Over the last 10 years our understanding of Vitamin D has evolved from a simple vitamin believed to be useful in preventing rickets to our current recognition that it's a steroid hormone directly affecting over 2000 genes in the body. Its effects on genes are so powerful that a deficiency in Vitamin D over an extended period of time has been associated with 17 types of cancer, heart disease, high blood pressure, osteoporosis, autoimmune diseases including multiple sclerosis, as well as chronic pain and a wealth of other modern chronic diseases.
But most important is its powerful effect on the immune system. Vitamin D sufficiency has been shown to increase the body's natural supply of what are called "Antimicrobial Peptides" ( AMP's). These are small fragments of amino acids, the building blocks of protein, that have very beneficial effects on the immune system's ability to fight against several types of germs including viruses and bacteria.
Let's look at what we know about vitamin D and the immune system with reference to Influenza.
In an article published in 2008 John Cannell M.D. and Cedric Garland Ph.D. and others looked at the epidemiology of influenza.
They point out that in 1987 an epidemiologist named Edgar Hope -- Simpson first brought up the concept of an unidentified "seasonal stimulus" that came from what he called the "solar radiation". He could never identify the seasonal stimulus and not much further work on his hypothesis was carried on. Now with the recognition of the importance of vitamin D and its very beneficial effect on our immune system, it is beginning to appear that this unidentified "seasonal stimulus" may be vitamin D.
In this very technical article, the authors point out that vitamin D is essential to the body's ability to manufacture antimicrobial peptides (AMPs). AMP's have a broad spectrum of activity against not only bacteria but also viruses and fungi. AMP's work much better in the presence of sufficient vitamin D, and will not work as well in a vitamin D deficient environment. This benefit for our immune system is so notable that Science News has called vitamin D "The Antibiotic Vitamin". It is because these AMPs can kill viruses that doctors believe they may protect us from the Swine Flu.
There are already a number of small studies that show taking vitamin D in sufficient quantity can be protective against colds and the flu.
In one of these articles Dr. Cannell reports on his patients in the psychiatric hospital where he works. Because of his belief in the power of Vitamin D, he had been giving the patients on his ward 2000 IU of vitamin D for several months before the flu season hit in the winter. The flu traveled throughout his hospital and yet none of the patients under his care who had been taking vitamin D got the flu that winter. He notes in his article that the study was not statistically significant but it is certainly interesting.
In another study, Adit Ginde, MD,MPH and colleagues looked at the Third National Health and Nutrition Examination survey (NHANES III) data that is collected by the National Center for Health Statistics. In this study, the authors found that Americans with the lowest vitamin D levels (less than 10 ng/ml) were about 40% more likely to have reported a recent respiratory infection than were those people whose vitamin D levels were 30 ng/ml or higher. Furthermore, those people who had asthma and the lowest vitamin D levels were five times more likely to have had a recent respiratory infection. The authors mention that they are planning to conduct clinical trials to test in a prospective way the effectiveness of vitamin D in fighting respiratory infections.
In Dr. John Cannell's Vitamin D Council Newsletter, he quotes a letter from Norris Glick MD from Central Wisconsin Center (CWC). CWC is a long-term care facility in Wisconsin. Dr. Glick and colleagues monitor all the residents' vitamin D levels, and supplement them as necessary to keep their levels normal. In June 2009 when there was a well recognized increase in the Swine Flu cases in Wisconsin, only two of the residents of the hospital out of a total 275 residents contracted the Swine Flu. However 60 of the staff members were documented to have the Swine Flu. Dr. Cannell took this hard data and contacted Dr. Carlos Carmago at Mass General Hospital, to run statistics on these numbers. The statistics were that 0.73% of residents had been affected compared with 7.5% of the staff. This difference was over 10 fold, and was statistically significant. This means that the chance that this difference was a random occurrence was less than one in 1000.
Another anecdotal report came to Dr. Cannell which he reports on in his newsletter. Ellie Campbell DO from Georgia sent an e-mail about his experience with the swine flu. He conscientiously normalizes his patient's vitamin D levels. His physician partner in the office does not. Dr. Campbell states that his partner was seeing one to 10 cases per week of influenza- like illness. In Dr. Campbell's practice he had zero cases.
So with all this anecdotal, epidemiological and statistical data can we say with certainty that sufficient vitamin D will protect us against the swine flu? Absolutely NOT!
However, we can say that there does appear to be an association with optimized vitamin D levels and flu protection. Before we can say this with certainty however, double blind crossover placebo controlled prospective trials need to be run. These types of studies take many years.
It is my position that until we get further data, given the likelihood that vitamin D will help protect us against the swine flu, there is absolutely no harm in optimizing our own vitamin D levels until further studies are done. Certainly other than the pennies per day that it costs to buy the vitamin D, there will be no harm from optimizing our vitamin D levels. In addition, based on the many other studies that are reported in my book there will be collateral benefit in the protection against cancers, heart disease, osteoporosis and many other vitamin D associated diseases.
Many people ask me "Can't I get enough vitamin D from my food?" The short answer is that food does not contain much vitamin D. One serving of cooked salmon which is one of the foods highest in D has only 360 IU of vitamin D. This is enough to prevent rickets but with our new knowledge that higher doses of vitamin D are safe and help protect us from many of the chronic diseases of modern society including influenza, we all require higher doses. In order to get 2000 IU per day from food you would need to eat 6 servings of salmon, or 10 servings of tuna, or drink 20 glasses of fortified milk every day.
Other people ask me "Can't I get vitamin D from the sun?" The short answer is "Yes if you don't wear sunblock!" But sunblock with a SPF of 15 also blocks 99% of all the vitamin D making rays of the sun. In addition we have the problem of what is called "The vitamin D winter". If you live above the 35th parallel of latitude and that stretches from Memphis Tennessee to Oklahoma City to Santa Fe New Mexico to Bakersfield California, from approximately November through March even on a random winter's sunny day, you cannot get vitamin D from the sun if you go out in your bathing suit. This is because the angle of the sun prevents the right frequency of UV light needed by our skin to make vitamin D.
So what do I recommend? In my book, The Vitamin D Revolution, I recommend that optimum vitamin D blood levels should be in the range of 40 to 70 ng/ml. I also point out in my book that as new data is becoming available, I expected my recommendations to change. Based on the new information about the levels needed in our blood to obtain optimal penetration of all our tissues, it is looking like an optimal level of vitamin D is 50 to 80 ng/ml. This can best be accomplished by taking vitamin D supplements.
This is what I am recommending in my own practice of medicine. Specifically I am recommending to my patients who weigh over 120 pounds, to take 5000 units of vitamin D every day with the understanding that after taking this for three months, we must do a blood test to be sure their levels are not TOO high. For my patients that weigh under 120 pounds, I will be recommending 4000 IU of vitamin D per day. Also with the understanding that they will get a blood test in three months to ensure that their levels are within safety range.
Although I am an internist and do not see many children in my practice, my patients ask me about dosages for their children. I recommend anywhere from 1000 to 4000 IU of vitamin D per day for their children over age 1, depending on their body weight. Some vitamin D experts have recommended 1000 IU of vitamin D for every 25 pounds of body weight. Again when taking these doses the children should have blood tests either with their doctor or an at-home test, after a few months to make sure their levels are not too high.
Unlike the B Vitamins which are water soluble, Vitamin D is fat soluble and can accumulate in our body. This is why I emphasize the importance of blood tests when taking "high" doses of vitamin D. Normal vitamin D blood levels are generally believed to be up to 100ng/ml by leading vitamin D researchers, so I keep my patients below that level at all times.
Another important consideration is that high doses of vitamin D are contraindicated in people with granulomatous diseases including TB, Sarcoidosis and probably Lyme Diease.
For this reason, I would always recommend you check your levels and review your dose of vitamin D with your personal physician. Vitamin D blood tests can be done by every doctor or you can do an in-home test and bring the results to your doctor to review with them, so you may optimize your own vitamin D levels. This will probably contribute to protection from the Swine Flu as well as regular influenza and also help protect you from many types of cancers, heart attacks, high blood pressure, osteoporosis as well as the other chronic diseases that have been associated with low vitamin D levels.
I look forward to continuing the dialog with you about Vitamin D and its importance for our health and will be happy to answer your questions.