Can Vitamin D Reduce Your Risks of the H1N1 (Swine) Flu This Winter?

By , SparkPeople Blogger
Vitamin D research and information is in the news everywhere these days. One of the most shocking results came from a nationwide study in the U.S. that found about 9 percent of the children were vitamin D deficient but 61 percent of them were vitamin D insufficient. Conversations are also ongoing related to how much vitamin D is enough. Last week an Institute of Medicine committee held meetings in Washington D.C. to review dietary reference intake recommendations for vitamin D and calcium. Some preliminary reports imply the recommendation will go up because of the overwhelming information that suggests a high level of insufficiency is present in both children as well as adults.

Hearing about a need for vitamin D for bone health is not new. Information related to the benefits of adequate vitamin D to reduce risks of heart disease or improve inflammation is also not new. What may be new in vitamin D research is the investigation of a relationship between vitamin D levels and a potential role in reducing risks for influenza, especially when the H1N1 pandemic is looming. This may provide a new reason to take your vitamin D intake a little more seriously this fall and winter.

With many fears of a worldwide pandemic of the H1N1 (formerly known as the Swine Flu) virus this fall and winter, many health investigators are looking for new ways to prepare. The Public Health Agency of Canada is looking at the vitamin D levels of individuals who have contracted the disease. Researchers are looking for a link between lower levels of vitamin D and contracting the influenza virus. The hope is that if there is a link this may provide a potential to decrease the likelihood of contracting the virus.

This investigation comes from previous epidemiological evidence that suggests there could be a role of vitamin D related to seasonal influenza according to the agency. The typical pattern of influenza each year is that it is worse in the winter and rarer in the summer. While there can be a variety of reasons for this, one potential reason held by many health experts surrounds the observation in northern and southern hemispheres that the flu tends to be worse when sunshine exposure is the most limited.

A potential link between vitamin D and reducing risks of influenza intrigues me. I typically do not contract the flu and neither do people in my family. Growing up my siblings and I typically only caught a cold and the same was true for my husband's family. Our children to date have never had the flu or a flu vaccine. So, why do we not get the flu when many other people contract it each year? Could it be the way we eat or do we just have great genes? Both my husband and I grew up in milk drinking homes and our family today averages about five to six gallons of milk a week as a family of four. We also drink fortified orange juice daily, and have eggs, tuna and salmon weekly while also getting outside regularly for short periods without sunscreen. I could be reading too much into the coincidences or perhaps there is something to this vitamin D protection theory.

The Bottom Line
You can find vitamin D in oily fish and the yolks of eggs as well as in fortified products like milk, soya, orange juice and vegetable margarines. If you include dairy and eggs in your vegetarian based diet, you may be just fine in your vitamin D intake. However, if you are a strict vegan, you will want to pay close attention to your intake since you do not find vitamin D in plant-based foods. It is ideal to aim for 800-1000 IU of vitamin D each day with at least 400 IU coming from food sources if possible. A multivitamin-mineral supplement may be the way to go to make up the remainder if you find that you are low in other key nutrients as well. If you are not short on other nutrients, you may want to consider a calcium supplement that contains vitamin D so you have both key nutrients to maximize bone health benefits as well as any potential protective benefits from influenza from vitamin D. Check the source of your supplement and select one that contains cholecalciferol or D3 if possible because of its better absorption. In addition, to maximize your supplement absorption, take your supplement with a meal or snack that contains some fat.

I do not know if there is anything to the theory that vitamin D has a relationship to contracting influenza. I do know that there is a great deal of uncertainty related to the new H1N1 virus strain, the availability of enough vaccine and medication for those that need to receive it and what the community related effects of a pandemic might be. Most of those things I have no control over for my family. However, I DO have control over how we eat and if we get some brief sun exposure without sunscreen. I think this fall and winter I will make sure these are part of our health plan in the hopes that we will continue to be a family that does not contract influenza each year.

How about you – will you make any changes in your diet this fall and winter based on this theory?

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I drink lots of milk, but cannot remember having Vitamin D checked. Good article. Report
Vitamin D is very important for more than most people realize! Report
I am going to get my vitamin d checked i think that i may be low !! Report
Everyone should be checked for Vitamin D deficiency - even those who get sunshine everyday may need a supplement. The body can lose its ability to convert, but never self diagnose or take mega doses VERY dangerous Report
I dunno, I wonder if a lot of the current hoopla about "we all need MORE VITAMIN D!!!" will stand up to the test of time. It seems like the latest fad.

I heard a good analysis on NPR a few months ago, about why seasonal flu is so seasonal - why it is more common and more easily spread in winter. A lot of it had to do with things like the amount of moisture in the air and similar things that are, indeed, seasonal. Of course I can't find that story now (it was a special science/health podcast just after the height of the swine flu worry), but it was very sound science.

We haven't had flu shots in our family, and we haven't caught the flu. I am, however, considering it for this year for the kids because of the fact that this is a new strain and younger people especially haven't been exposed to it. But then I wonder: they hadn't been exposed to the other flu virii before their first exposure, either, so how is this different? That hasn't been explained to my satisfaction yet. Report
I am high on Vit D, walk daily under the sun. I also take vitamins like OneADay. And my health is very good. I rarely get the flu, have not had to take sick leave in about 2 or 3 years. And I am a teacher! We are exposed to all kinds of bugs. I am 39 yo and have no other conditions that migh have put me at higher risk to get H1N1, yet I have it! Let me tell you I have alcohol-based gel on my desk and I would ask my students to clean their hands too. ANd I have the same gel in my bag at all times and use it constantly. I discard tissues as soon as used. Do not kiss, hug or shake hands with anyone. I have done all this since the virus was first found.Nothing stopped the bug from catching me!
I would say, do your best to keep it away from you. At the very least, you would be increasing your chances of not getting it, and if you get it, it may happen in a milder form because of your precautions. Report
I have been diagnosed as Vitamin D deficient and I am 47 years old! I was put on a supplement (prescription) and was told this would also aid my depression. So far, so good! Report
In regards to post 39, check where the test was done. A large (the Nation's largest) lab was recently (January 2009) fined (over 300 million dollars) for not performing their testing correctly. The physician should have been notified and the testing should have been checked. You can do an internet search to see what the details on this are by searching incorrect vitamin d testing... some tests were reported at low levels, some at high levels. Report
If this were to hold any validity, wouldn't the psoriasis sufferers (inability to process vitamin D) be victims of the flu in extraordinarily large numbers? I doubt this is so. Until there is some factual evidence, I'm going to stick to my Korean kim chi regimen which is thought to be why Koreans are much less likely to come down with a flu virus than others who don't consume kim chi. Scientists don't really know why but it is a fact........... Report
I believe it. I've had a hard time fighting off flu for years, eating a low fat diet and very few eggs, as well as very little fish, (no one else likes it)

SInce I began eating low carb, my diet includes a lot more eggs and I just whizzed through a bout of flu in the family without even a sniffle. I'll be working harder to get more Vit D from now on. Report
As some one that Has had the H1N1 Swine Flu.I have to say if Vit D will help take extra and drink all the milk u can.It is very hard and it is worse than a regular flu.I know U will not want much of nothing in the middle of it at all not even water.U just want to be left alone totally.Do all U can to protect u and yours from this. Report
Great article, thanks. Report
Interesting---I rarely get colds and don't remember the last time I had the flu---and I work in a high school--which I think has built up an immunity in my system---I do drink milk---usually some every day and go outside at any time without sunscreen---just not for long periods of time. Report
I have been taking calcium w/Vit D for years. I do occasionally have a mild case of the flu. I do not take flu shots. As of the past year I up my dosage of Vit D. Up in the northern hemisphere we haven't seen to much sun this summer. I also from taking the extra Vit D have had no flu or symptons. Will continue to take it. I know people that have had the flu vaccine and still got very sick. Report
I see Vitamin D showing up everywhere these days and yes, it is an important supplement however I am concerned that with all the hype at this point that we will go the other direction and have excessive levels which are damaging. I found I was getting large amounts in a woman's vitamin pill, a second supplement with my calcium and thought I would take a tab as well. I started having back me near my right kidney so have stopped the extra tab. Just a caution. Report
I just cant believe what a difference this vit. has made. I have felt so much better. no sickness although family has been. I take it along with q10 everyday.Also 2oz. of pomagr./blueberry juice and handful of fresh blueberries and steamed broccoli. Not been sick in 2yrs. My oldest daughter is a teacher and was sick at different times so I was worried I would get the bugs but I sure didnt! Report
You have to be careful. My mother in law was told she was deficent and ended up with Vit.D poisoning. I think the reason 61% of children are lacking enough D is the same reason we have obsesity on the rise in children. Kids hardly play outside at all. I've read countless times, get outside for only 20 minutes without sunscreen and that is your vitamin D for the day. How easy is that? For me, I do my workout in the early am, so I water my plants on the porch when the sun comes out. Grab a book. My kids are the only ones in their "group" that don't have X-box, gameboy, Nintendo or Wii... they ride their bikes, bring a blanket outside with legos or art paper. Its 20 minutes... does it get any easier? Report
As a post-op gastric bypass patient, I "donate" blood regularly to my surgeon, who checks my vitamin levels. Recently, he added a Vitamin D check to the list of tests, and my D levels were low. He put me on a Rx Vitamin D for 3 months, and my levels went up. Since having the surgery (and having my vitamin levels monitored), I have not been sick a day (it's been 20 months).

I live in New England, and I struggle with Seasonal Affect Disorder (S.A.D.), sometimes known as Winter Blues. Exposure to the sun on a daily basis helps immensely, but as we don't always have sun, I have a 10,000 LUX light box that I use from the end of August through the beginning of June. The shorter days make it difficult to get in my dose of sun, but exercising outdoors helps a great deal, and I love being outside.

I love salmon and eat it once a week. I also drink skim milk daily. I am eating healthier than I have in years, and I think doing that has kept me from getting sick. I would recommend to any long-term gastric bypass patient, that if you haven't had a blood test in the last year to check your vitamin levels, you should go see your surgeon as soon as possible. It's important follow-on self-care! Report
Vitamin D being a fat soluble vitamin, also requires some level of dietary fat for absorption. Research has also shown that person's with BMI's over 30 have lower levels in their serum because the Vitamin is being stored in the large pools of body fat. Here's the link from the National Institutes of Health:
I'm going to take Vitamin D. I live in a sunny climate but the extra could really help! Report
I am in my mid-60's and we were taught in school that Vit D is essential for good brain health, bone health, and a booster for your immune system. This information is not new but was ignored for many years. Your liver is the organ that absorbs calcium but it cannot work properly without the correct amount of Vit D. It is your liver that is doing all the work here.

This is all information that we grew up with. We never had multiple vitamins as children but had to have "cod liver oil" every day during the winter. I also gave my children the same thing and their teachers were always surprised at how healthy they were; i.e. not catching colds, infections, etc. and always surprised when I told them all my sons got was cod liver oil.

21st century technology is terrific but when it comes to health, many of the old ways are still the best way - and note that I wrote many, not all. Report
Thanks for posting - just a confirmation that we need to be properly nourished to be able to ward off disease. We take vitamin supplements, but they are more of a backup than our front line of defense. Good to know where to find Vit D naturally - although I was sorry to see you promoting margarine.... Report
I think that healthy habits like eating a nutritious balanced diet, getting exercise and fresh air and close attention to personal hygiene habits (like frequent hand-washing) go a long way to protecting our bodies from infection - be it influenza or anything else.

I take a calcium plus D supplement daily that gives me about 60% of the RDA for both elements. I include oily fish in my diet at least twice a week and add flax seed oil to my breakfast smoothies. I am also careful to include skim milk and eggs in my diet. I make sure to spend at least 10 minutes a day outdoors to soak up some rays. I may consider doubling up on my supplements just to be on the safe side.

I have taken flu shots in the past, and some years it seems to have helped. Other years, not so much. It seems like every time I get a flu shot, I get sick for a couple of days - but that's better than being down for a week or more.

While we are on the topic of protecting ourselves from the H1N1 flu virus, I want mention that wearing a mask when you're in crowds may help, but only if you wear the right kind of mask. I don't have the specifics off the top of my head, but I urge you to research this if you're considering using masks to help protect yourself so you won't waste your money on masks that aren't going to be effective.

I also carry a small bottle of hand sanitizer with me and use it after handling money, after using public restrooms, etc.
Yes, vitamin D can reduce the risk of influenza infection, the cytokine storm that often follows, and the pneumonia that is often the cause of death once influenza takes hold.

Vitamin D is safe at daily intakes of 10,000 IU or more for 99% of the population; one can make 10,000 IU/day in the midday summer sun, so that amount has to be safe; otherwise humans would have died off long time ago. It is estimated that the body can use about 3600 IU/day. Optimal serum 25-dihydroxyvitamin D [25(OH)D] levels are 40-60 ng/mL, and the average white American has about 25 ng/mL. Each 1000 IU/day increases serum 25(OH)D by 6-10 ng/mL. If you want a test, go to (or org) and sign up for a $40 test kit mailed to your home.

The possible roles of solar ultraviolet-B radiation and vitamin D in reducing case-fatality rates from the 1918–1919 influenza pandemic in the United States
William B. Grant and Edward Giovannucci

Volume 1, Issue 4

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Deaths during the 1918–1919 influenza pandemic have been linked to both the influenza virus and secondary bacterial lung infections. Case fatality rates and percentage of influenza cases complicated by pneumonia were available from survey data for twelve United States locations in the 1918–1919 pandemic. This study analyzes case fatality rates and cases complicated by pneumonia with respect to estimated summertime and wintertime solar ultraviolet-B (UVB) doses as indicators of population mean vitamin D status. Substantial correlations were found for associations of July UVB dose with case fatality rates (r = -0.72, p = 0.009) and rates of pneumonia as a complication of influenza (r = -0.77, p = 0.005). Similar results were found for wintertime UVB. Vitamin D upregulates production of human cathelicidin, LL-37, which has both antimicrobial and antiendotoxin activities. Vitamin D also reduces the production of proinflammatory cytokines, which could also explain some of the benefit of vitamin D since H1N1 infection gives rise to a cytokine storm. The potential role of vitamin D status in reducing secondary bacterial infections and loss of life in pandemic influence requires further evaluation.

William B. Grant
Corresponding author:

Sunlight, Nutrition and Health Research Center (SUNARC)

Edward Giovannucci
Departments of Nutrition and Epidemiology; Harvard School of Public Health; and Department of Medicine; Brigham and Women’s Hospital; Boston, MA USA
Definitely fueled my thoughts. I religiously take E, C, B-Complex, Daily Multi, Zinc, and a plethora of other supplements as I work in health care, and since leaving California I am prone to Seasonal Affective Disorder. Seeking the balance with Safe Sun time/Mental benefits has become more important to me as I've grown older with much youthful sun exposure. Thanks for the insight.

Getting enough vitamin D is beneficial for everyone, but during the coming fall and winter, I think it will be especially important for everyone to make sure that he, or she, gets weough vitamin D. Report
I would think that it is just plain common sense that if the human body is not well nourished, it is going to be subject to disease. We are what we eat. Report
Every day, I have a high level of VIT D in my diet, doctor's orders, as I was diagnosed with osteoperosis. Since starting with SP,18 months ago, I have been tracking my food and quite honestly, I have never had the flu since and only had a minor cold once. Report
I think the jury's still out on the benefits of Vitamin D; however I do take a calcium supplement that has vitamin D in it, and I do eat dairy products that are fortified, too; plus I do have sun exposure several times a week.

They say this flu, while a panedmic, is actually milder than many influenzas in its effect. Many elderly people may already have immunity from exposure decades ago. Younger people are considered more at risk.

Acquiring immunity, either from contracting the flu itself, or by the vaccine will enhance your immune system. While some people, especially those with compromised immune systems (such as those with AIDS) will die, overall improving the immune system is a good thing.

Many scientists conjecture that lack of exposure to dirt in childhood may contribute to heightened allergic reactions. Lack of exposure to viruses leads to undeveloped immune systems.

As an older American, I don't know whether I'll qualify to receive the vaccine; but, if not, then I hope I contract a mild case of the disease so my immunity is developed for the next time around. Report
I think I will be uping my daughter's vitamin D. I think I already get enough. Report
I am more concerned with making certain that I get enough Calcium, but I do think Vit D is also important to the cycle. Keeping up in these important vitamins and minerals is a good way to prevent fractures. Report
It's the end of winter down under. I haven't had the flu, but I have been taking VTD suppliments for S.A.D. I wonder if there is a link? I don't think we get the severe winters you northern hemisphere ppl do, but I thought i'd give it a go. My 14yr has been sick & her nutritian is shocking. Interestingly, she always gets sick, where as Miss 11, who eats a good variety of fruit & veg, doesn't get sick.
I don't have time to get the flu. I'm not going to get it either!!! Report
I am planning to take my Vit d3 supplement, work out regularly and eat lots of fruits and veg. Also get a flu shot. Lots of handwashing and avoiding crowds. Guess that means we eat at home! One day at a time! Report
I Think we all need more vit. D. Report
What I expect them to find in the future, as further studies are done on Vitamin D, that it is really THE MIRACLE VITAMIN, and the daily recommended amount, has been WAY TOO LOW for WAY TOO LONG!!!!
I know when I started to take MORE for my bones, I had a welcomed side effect of seeing my blood pressure drop to normal. Now I am reading about Vitamin D studies related to Cardiovascular health. ALSO related to Cancers . What more may come???? Report
I will be making sure to keep my levels up, especially during the winter months. Report
I am going to be upping my Vitamin D intake this winter. I have found more information on how important it is to overall health. Report
I personally would count on good personal hygiene to protect myself. Taking vitamins is a good thought but nothing can protect you better than practicing good hygiene habits i.e. wash your hands and cover your mouth when sneeze and cough. Just my two cents. Report
If I make any changes to my diet for the winter, it won't be because of the the H1N1 virus. It strikes me that no matter how well I eat or how many vitamins I take, if a germ has my name on it, that's it I'm getting flu.

If do anything to prevent getting the flu this season, it will be washing my hands more frequently. I honestly don't know if increasing my intake of vitamin D will decrease my risk of getting the flu.

Come winter, I'll do my best to eat right, but I won't be eating any differently for the flu. Unless I happen to catch the flu, then I'll be increasing my intake of chicken soup. ;)

Interesting article.

My father was 18 in 1918 when the Spanish Influenza killed 20 million people worldwide, and he had it and was sick in bed for a year. He lived because my Grandmother used a dropper and gave him water around the clock even though he was in a coma. (That had no IVs then.) But after he got well a year later (he had been down to 70#) she took him to church to than God. The kid behind him in the Pew was coming down with German Measles and my father got a relapse and was back in bed for another year. He had had a healthy diet living on the farm, but the Influenza was just a horrible illness. Today, we'd get IV Fluids and not die the way they did back then. Sadly, most members of the family got the flu and there was no one to take care of the others. Luckily my Grandmother didn't get it. Report
This would definitely help explain why last year I caught the flue but my son did not, even though he often shared my drinks even while sick - he eats much more dairy than I do, although with joining SP I have increased my daily intake of milk and yogurt (thanks to smoothies). I also make sure my son takes his vitamins, even though I almost always forget my own...hmmm...maybe I should add my daily vitamin as a goal to track. I don't often get the flu, but last year's bout reminds me that it's always a possibility, and I'd like to do what I can to avoid it! Report
Hi I take 1000 IU of Vita D a day.
Now what I was wondering is:- WHAT IS THE SHOT FOR THE FLU MADE FROM???
If it is eggs I will not be able to take it, because I can't take the regular flu shot.
Any one know the answer. Report
The incidence of MS in the PNW is considerably higher than in many other parts of the country and it is theorized that the lack of sunny days may be a factor. My girlfriend has MS and her doctor recently checked her Vit D levels. There was barely anything on the test result.

I've recently added extra Vit D to my regimen. I already take a calcium supplement (I have osteopinia) with Magnesium and Vit D but have added an extra 1200 for a total of 2000 IUs. As long as I get adequate sleep, I'm feeling much better despite fibromylgia, chronic fatigue, diabetes and CHF.

Oddly, the one thing I haven't noticed is a reduction in the flu, just the opposite, in fact. The one thing I could say about the fibro was that I didn't get other illnesses like colds or the flu or, if I did, they were extremely mild. But this past winter I got both the flu and colds that went into pneumonia. I don't know if there is a correlation or not but it was annoying at best since I didn't get a reduction in the other conditions. Oh well...

Interesting article though. Report
It would be interesting to study the rate of occurance of the various forms of influenza in countries that receive limited sunlight during certain times during the year. Since the flu is more common during the winter months, do we conclude that the cold weather has less of an effect on the rate of occurance than limited sunshine does? Are there other factors that affect the rate of occurance? Very interesting, would like to see a follow-up story. I maintain a healthy lifestyle and I don't get a flu shot (save my shot for someone who really needs it). I also don't get the flu. Report
I have several chronic conditions so I get a flue shot every year. I still get the flu, but don't think it is a severe as it would or could be without the shots.

I am deficient in D so my doc told me to take 4 (1000 iu) each a day so I take 2 am and 2 pm. Don't know yet if it helps.........

I have also read reports which claim Vit D deficiency has been linked to MS (my sister has), type 2 Diabetes (I have), and so forth. Don't know if it is true, but it appears there is a higher prevalence of MS in northern climes.

While it is important to boost our immunity to illness with proper diet and other healthful-living practices, I think proper handwashing and avoidance of face touching (particularly nose, mouth, and eyes) makes the most difference when it comes to avoiding colds and flu. Be sure to wash your hands with soap for at least 20 seconds, several times a day. I do have a problem with itchy eyes (allergies!) so I always use a tissue to gently relieve the itch without exposing my eyes to many germs. Germs are everywhere, of course, but if we use care and common sense in our daily lives, there's no need to fear illness. Report
I love being in the sun a little each day. I do it for my fibromyalgia. I am glad to know I am boosting my vitamin D also. Report
Yea for vitamin D! Report
Sunshine DEFINITELY helps.. Not only does it keep you from getting toxic amouts of synthetic vitamins in your body. It also aids in boosting your immunity defenses. Keep doing everything naturally that you can to avoid infection. But by all means, GET OUTSIDE. Soak up Health and Well-being as much as possible. I had a total of 3 sick days this winter. and I usually get bronchitis and pneumonia every year! Dress appropriate for weather. Wash hands after toilet and blowing your nose (many forget that second one!). Eat properly and healthfully . Have a healthy day...everyday! HUGS to all! Report
This is really interesting. I don't completely buy in to it only because of our experience. In our family, we drink a ton of fat free milk and eat vitamin D-rich foods....Plus I take a vitamin D supplement daily. But we still get the flu. My husband got the flu last year after having a flu vac think some people are just more prone to illness.

Airborne and Emergent-C and zinc has helped reduce the duration of our illnesses though...Colds, anyhow. I am not worried about h1n1...but I will definitely increase our hand washing and hand sanitizer use. Report