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?