Low Vitamin D Levels Linked to Colds

Individuals with low levels of vitamin D may be more likely to catch colds or the flu, a new study suggests.

Vitamin D is found in many foods, including milk, eggs, cheese and beef. Exposure to sunlight also helps the body produce vitamin D. Recommended daily intakes range from five to 15 micrograms, depending on a person's age and health.

Preliminary evidence suggests that vitamin D may play a role in immune function. However, these earlier studies have not been conclusive.

In this latest study, researchers analyzed data on vitamin D levels and respiratory infections in 18,883 individuals (aged 12 and older) who participated in the Third National Health and Nutrition Examination Survey (NHANES III) from October 1988 to October 1994.

The researchers found that cold and flu infections were significantly more common among those with the lowest vitamin D levels (less than 10 nanograms per milliliter of blood) compared to those with the highest levels (30 or more nanograms per milliliter of blood). On average, they were 36 percent more likely to develop upper respiratory tract infections.

These results were consistent throughout spring, summer and fall and were strongest among those with histories of asthma or chronic obstructive pulmonary disease (COPD).

However, additional research is needed to determine if vitamin D supplementation can help prevent infections. The authors call for randomized controlled trials in this area.

For more information about vitamin D, please visit Natural Standard's Foods, Herbs & Supplements database.

Comments

[Chelsea]

The fact that vitamin D may help ward off colds is great news! I am unsure as to what is the best way to get more vitamin D. I guess you have to find a balance between eating foods like eggs, cheese and beef and getting enough sunlight? Anyone have any ideas?

[MHD]

Although this blog reports that vitamin D is fortified in certain foods, such as milk, eggs cheese and beef, the daily requirement needed for adequate consumption is not at the level needed. It is now recommended that 1,000mg of vitamin D be consumed daily. One of the greatest sources for this is the sun.

This study makes sense, as increased incidences of colds and flu arise during the winter, when adequate levels of vitamin D is most difficult to attain (for those living in winter conditions, such as in the Northeast). This is one of the many studies that I have read about within the last few months about vitamin D. It seems like vitamin D may be important for a variety of systems in our bodies.

[stan shunley]

Vitamin D is popping up a lot lately. About a month ago, Natural Standard reported on a study that found a link between Vitamin D and cognitive function, and now here's evidence that may also play a role in preventing colds and the flu. Another reason to check your diet, make sure you get some regular sunlight (with sunscreen, of course), and consider a multivitamin that contains D. And here we all thought it was vitamin C that was key.

[SC]

I agree with Stan. It seems like vitamin D deficiency may be connected to many underlying causes of many diseases and symptoms that many people suffer from. While vitamin D supplementation in deficient individuals sounds like a potential way to prevent colds, I still think vitamin C plays a major role in colds. Also, there has been some promising information on the role of zinc in colds and maybe infections.

[tracey]

I agree with everyone’s comments. It might be interesting to know the exact mechanism of how vitamin D levels are associated with colds, but it reinforces the important of vitamin D in our daily diet to optimal bone health.

And would there be a link between vitamin D and vitamin C since vitamin C is long associated with having immune-boosting properties that help prevent colds?

[jaz]

It looks like vitamin D has a lot more going for it than you'd expect. I've been reading recently about how vitamin D deficiencies can affect the immune system, leading to an increase in the incidence of autoimmune diseases.

Here are some good abstracts:
http://www.ncbi.nlm.nih.gov/pubmed/19090978
(Vitamin D or hormone D deficiency in autoimmune rheumatic diseases, including undifferentiated connective tissue disease)
http://www.ncbi.nlm.nih.gov/pubmed/18510590
(The complex role of vitamin D in autoimmune diseases)

[PK]

It is interesting to see that the vitamin D cutoff levels (30ng/ml) in this study were the exact same cutoff levels as the study done by the AHA ~1yr ago, which evaluated the relationship between low vitamin D and cardiovascular health. It would be great to see a well-designed randomized control trial on vitamin D and immune function.

[Mark Burns]

While I find it interesting that different studies show a link between vitamin D levels and immune function, I am curious to what other factors the study looked at. There may be some confounding variables or other links that may play a role, but I do believe that vitamin D has a part in immune function. I am curious to see what other studies come about.

[katie]

I saw an article in Reuters UK mentioning a new study from the journal Pediatrics. The researchers suggested adopting a new cut off for vitamin D deficiency, raising it from 11ng/mL up to 20ng/mL. If that were the case, 14% of teenagers aged 12-19 would be vitamin D deficient, and 50% of black teenagers would be as well. Another study showed that 40% of U.S. babies and toddlers are not getting enough. It seems that getting enough vitamin D is harder than we thought, and we should all take proactive measures to protect our health.

[RA]

Interesting. If the UK is raising the bar on vitamin D deficiency, are there data suggesting that the UK population is more prone to vitamin D deficiency? Or simply that a large proportion of the pediatric population there are already deficient?

[AJ]

Vitamin D is such a growing hot topic nowadays. It seems like doctors are testing everyone's vitamin D levels. As recent as last week, I've seen a teenager being prescribed high-dose vitamin D supplementation (50,000 units vitamin D)...crazy stuff.

[Melissa]

As a vegan, I was diagnosed with vitamin D deficiency. Most vegans and vegetarians are faced with this problem, since our diets do not allow us to consume the types of foods that are high in vitamin D. If you are a vegetarian or vegan, it is important to take vitamin D supplements and multivitamins. Most vitamin D supplements are packaged in gelatin, which is made from animal bones. There are tablet and liquid form alternatives. Also, calcium pills with vitamin D are a good alternative because calcium works with vitamin D to maintain healthy bones. Other foods that contain vitamin D are: mushrooms, orange juice, fortified vitamin D cereals, and soy milk.

[BMF]

Melissa, that is extremely helpful information! For the viatmin D supplements packaged in gelatin, are you referring to over-the-counter supplements, or the ones that you get at the pharmacy? Also, is there a difference between synthetic and natural sources of vitamin D?

[Jessie]

An interesting theory states that low vitamin D levels may cause the flu and colds by decreasing the production of cathelicidin (an antimicrobial peptide), which in turn negatively impacts the immune system. Oral vitamin D may increase the production of cathelicidin, which simulates the immune system; thereby, helping the body fight off infection.

[J.Plick]

D is the new C! I was just reading an online article, http://www.westonaprice.org/basicnutrition/vitamindmiracle.html#miracle, that says that vitamin D is involved in calcium transport, which promotes healthy bones (rickets, osteoporosis) as well as a healthy brain (Parkinson’s, Alzheimer’s, dementia). It is also involved with the immune system (cancers, autoimmune diseases, inflammatory response), anti-oxidation (cancers), insulin levels (diabetes), hormone levels and mood disorders.

In the article they say people should be getting up to 10 times the current RDA of vitamin D (4000 i.u./day instead of 400 i.u./day). When you think about all the money spent on doctor’s visits and medications for the above disorders, it might be worth it to but a buy a bottle.

[How to Prevent Flu]

I've always felt worse living in the Pacific Northwest than I do down here in California. More sun equals me feeling better. Go figure.