November 26, 2006

WHY DOES FLU SPREAD IN THE WINTER?

In a paper scheduled for publication next month in the journal Epidemiology and Infection, a Harvard University-led team proposes that a vitamin D deficiency caused by inadequate winter sun exposure may predispose people to infection.

If this theory proves correct, it would not only solve a long-standing mystery, but could also have major public health consequences.

Influenza kills an average 36,000 people in the U.S. each winter, mostly the very old and very young. If scientists could pinpoint the secret behind its seasonal recurrence and somehow alter it, “the potential impact would be far greater than the current influenza vaccine,” says Dowell. . . . In their new paper, which draws together strands from more than seven decades of vitamin and flu research, Cannell and his colleagues argue that vitamin D stimulates production of a natural infection-fighting substance in the body called cathelicidin.

Although cathelicidin has yet to be studied directly on influenza, recent research has shown that it attacks a variety of fungi, viruses, and bacteria – including the bug that causes tuberculosis, researchers reported last March in Science.

Just to be safe, I think I’ll plan a tropical vacation this winter. And wash down some cod liver oil capsules with a medicinal glass of red wine. Can’t be too careful.