H1N1 (Swine Flu): Catching a few rays might help? Vitamin D – good news for pandemic influenza?
Many of us are beginning to think – if it is bad in the fall what are some of the things that I could do to protect my family, my community and myself if no vaccine is available? Medical research is now revealed daily about things that helped in 1918. Consider this…catching a few rays or sunshine (Vitamin D) could be a big help…
An estimated 675,000 Americans died from the A/H1N1 pandemic influenza in the United States in 1918-1919. Many of these deaths were from ensuing bacterial pneumonia rather than directly from the viral infection. The United States Public Health Service conducted surveys in twelve cities and rural areas of the country in late 1918 to early 1919 to determine the case-fatality rate in each city or area. Case-fatality rates varied from 0.78 deaths/100 cases in San Antonio, Texas to 3.14 deaths/100 cases in New London, Connecticut. The strong variation with location suggested that solar ultraviolet-B (UVB) irradiance, through production of vitamin D, reduced the risk of death following infection by this pandemic influenza.
To investigate this possibility, the case-fatality rate data were compared statistically with solar UVB doses in July and January. Strong correlations with UVB doses were found for both indices.
There are two mechanisms whereby vitamin D can reduce the risk of death once the pandemic influenza virus infection took hold: reduced production of proinflammatory cytokines and reduced risk of bacterial pneumonia. The hormonal metabolite of vitamin D, 1,25-dihydroxyvitamin D, reduces the production of cytokines from T-helper 1 type (proinflammatory). 1,25-dihydroxyvitamin D also induces the production of human cathelicidin, LL-37, which has both antimicrobial and antiendotoxin properties. LL-37 has been found effective in reducing the risk of several types of bacteria, and is also thought to reduce the risk of respiratory viral infections including seasonal influenza.
Whether this finding is relevant to the current A/H1N1 influenza virus outbreak is unknown but should be evaluated.
“The authors propose a very interesting hypothesis based on intriguing observations that vitamin D deficiency and influenza infection share a similar pattern in incidence during the year. Recent work by several groups has demonstrated that vitamin D induced anti-microbial peptides that may be important for the immune defense against pathogens such as virus. As we are entering the fall and winter season, it may be worth considering addressing vitamin D status in individuals at risk for influenza infection.”
Wow…get out your suntan lotion….