Sunshine Vitamin Helps Fight Flu

For decades, the “old wives” have been ridiculed as superstitious know-nothings. Now science seems about to vindicate them.

The old wives maintained that a dose of cod liver oil would do a body good. Many children dreaded it because it tasted so awful. But come the dark days of winter, mothers and grandmothers insisted that all family members should hold their noses and swallow a spoonful of cod liver oil.

Over the last couple of decades this practice has gone the way of the manual typewriter. Few children get cod liver oil these days. Doctors don’t recommend it because it seems like such an unscientific relic of the past.

The vitamin D that is abundant in cod liver oil has numerous health benefits though, especially in the winter. That’s because levels of vitamin D frequently drop when people are not exposing their skin to the sun.

Cold, dreary weather and diminished sunlight can create borderline vitamin D deficiency in a surprising number of people. In Boston, 42 percent of people studied had too little vitamin D in winter. In Calgary, Canada, almost no one maintains adequate vitamin D in the winter.

In 2005, a psychiatrist who treated his patients for vitamin D deficiency noticed something odd. Influenza hit the Atascadero State Hospital, a maximum-security psychiatric hospital, hard. His ward was spared, with not a single person catching the flu even though they had been exposed to the virus just like everyone else. The psychiatrist wondered whether the vitamin D he had prescribed had anything to do with their immunity.

This question led to an interesting review of research and a credible hypothesis. Studies over the last 70 years hint at a connection between vitamin D and overall immunity.

The active form of vitamin D greatly increases the body’s production of a natural infection-fighting chemical called cathelicidin. Cathelicidin seems to help fight off illnesses caused by bacteria, fungi and viruses, including influenza.

This may help explain why people are more susceptible to colds and flu in the winter. If their vitamin D levels drop, so does their production of cathelicidin and their overall resistance to infection.

Vitamin D also appears to have anti-cancer activity. People who get regular sun exposure are less susceptible to common cancers that affect the colon, breast, prostate, ovaries and lungs. Even conditions like multiple sclerosis, arthritis and type 2 diabetes are less common in people with ample vitamin D levels.

Vitamin D has long been associated with stronger bones, but there is also research showing that it contributes to stronger muscles and fewer falls in the elderly.

Anyone who would like to know more about the multiple health benefits of vitamin D may be interested in a one-hour radio interview with Dr. Michael Holick, one of the world’s leading experts on this nutrient. For a CD of this show, please send $16 in check or money order to Graedons' People's Pharmacy, No. CD-502, P. O. Box 52027, Durham, NC 27717-2027.

The old wives did not have sophisticated scientific tools or methods, but they were skilled observers. It’s fascinating when the scientists supply the explanation behind their wisdom.