This is what I’m trying to find out these days: can an old pall, such as vitamin D help us fight a new enemy – like the swine flu? And, if you haven’t read or heard about it yet, I’m happy that you do it now! What I can tell you so far is that the reading exercise on the subject is not easy as the reading material is extensive. I’m going to post again on the subject during the next few days as I’ll manage to gather my thoughts a bit more. For now, I’ll share with you how I’m navigating through this sea of information.
So, I heard a rumor that vitamin D and sunshine can help fight against the flu. You know the link: if you’re out in the sun you’re skin naturally produces vitamin D. If you’re not having too much sun, say you’re in the wrong hemisphere or you spend lots of time inside, you can still get vitamin D from some food or you can take supplements. Here is a comprehensive site describing vitamin D and which are the products you can get it from. According to them the Chinook SALMON is the best source of vitamin D, followed by SHRIMPS, COW’S MILK, COD FISH and EGG. Btw, Wikipedia says that the Chinook salmon lives in the Pacific and it’s kind of scarce and, therefore, pricy, so I suggest we use this list just to get an idea of the kind of foods we should favor in our diet and leave the Chinook salmon swim happily in the Pacific.
Moving on… I quickly searched PubMed “vitamin D influenza” and got about 30 hits… and that means published journal articles. The role of vitamin D deficiency in an amazing number of diseases (such as cancer, heart disease, multiple sclerosis, diabetes, autism, among others) is far from being news these days, that was 5 years ago. Its role in preventing infections and influenza has been researched and published in established journals – although, speaking for myself, I had no idea about this until recently!
Check out this following para from On the epidemiology of influenza, by Cannell et al, 2008 (Virol J)
“The evidence that vitamin D has profound effects on innate immunity is rapidly growing. In fact, Aloia and Li-Ng presented evidence of a dramatic vitamin D preventative effect from a randomized controlled trial (RCT). […] they discovered 104 post-menopausal African American women given vitamin D were three times less likely to report cold and flu symptoms than 104 placebo controls. A low dose (800 IU/day) not only reduced reported incidence, it abolished the seasonality of reported colds and flu. A higher dose (2000 IU/day), given during the last year of their trial, virtually eradicated all reports of colds or flu.
Recent discoveries about vitamin D’s mechanism of action in combating infections led Science News to suggest that vitamin D is the “antibiotic vitamin” due primarily to its robust effects on innate immunity.”
Two concepts are among the building blocks of this paper: innate immunity and adaptive immunity. The adaptive immune system builds on the innate one (which is apparently evolutionary older). The innate system recognizes and responds to infections immediately but doesn’t “remember” the intruders, while the adaptive system is more specialized in the sense that it recognizes old enemies and responds to them more strongly each time. If you want, you can read the entire article online, free, just google it (personally, I think that if you can put up with a bit of scientific gibberish you’ll find it interesting).
To the question of why the influenza mortality in the elderly has not declined during the past 20 years even though their vaccination rates did (!):
“Given that influenza vaccines effectively improve adaptive immunity, the most likely explanation is that the innate immunity of the aged declined over the last 20 years due to medical and governmental warnings to avoid the sun. While the young usually ignore such advice, the elderly often follow it. We suggest that improvements in adaptive immunity from increased vaccination of the aged are inadequate to compensate for declines in innate immunity the aged suffered over that same time.”
Oh, and I love this sentence:
“Very recently, articles in mainstream medical journals have emphasized the compelling reasons to promptly diagnose and adequately treat vitamin D deficiency, deficiencies that may be the rule, rather than the exception, at least during flu season“.
And here is from Use of vitamin D in clinical practice, by Cannell and Hollis, 2008 (Altern Med Rev)
“The recent discovery–from a meta-analysis of 18 randomized controlled trials–that supplemental cholecalciferol (vitamin D) significantly reduces all-cause mortality emphasizes the medical, ethical, and legal implications of promptly diagnosing and adequately treating vitamin D deficiency. Not only are such deficiencies common, and probably the rule, vitamin D deficiency is implicated in most of the diseases of civilization. Vitamin D’s final metabolic product is a potent, pleiotropic, repair and maintenance, seco-steroid hormone that targets more than 200 human genes in a wide variety of tissues, meaning it has as many mechanisms of action as genes it targets. One of the most important genes vitamin D up-regulates is for cathelicidin, a naturally occurring broad-spectrum antibiotic. Natural vitamin D levels, those found in humans living in a sun-rich environment, are between 40-70 ng per ml, levels obtained by few modern humans. […] Three treatment modalities exist for vitamin D deficiency: sunlight, artificial ultraviolet B (UVB) radiation, and vitamin D3 supplementation. […] Theoretically, pharmacological doses of vitamin D (2,000 IU per kg per day for three days) may produce enough of the naturally occurring antibiotic cathelicidin to cure common viral respiratory infections, such as influenza and the common cold, but such a theory awaits further science.”
You’ll also find good reading on this subject here:
which is beautifully researched, and here
both articles giving recommendations in terms of units/day needed to boost the system.
You can also read that the Public Health Agency in Canada takes seriously the possibility that swine flu can be fought with the help of vitamin D. Read more here…
OK, I’ll leave the drawing board for now and let you think things over! Meanwhile, I’ll get busy during the next days to read on what are the best natural vitamin D supplements and try to schedule an appointment with a lab to check my vitamin D level.