Sun, vitamin D, population differences

There's a short news feature in the latest issue of Nature Medicine about the benefits of sunlight.

Essentially, the sun is good (vs. TB, MS, cancer, diabetes...) because we get a lot of vitamin D from it..., for example for MS:

"The strongest evidence available is perhaps for the vitamin's protective role in MS. Several studies have documented a dramatic 'sunshine belt' across the center of the globe: MS is rarer near the equator and more common in northern regions, where ultraviolet light from the sun is less intense.

"There's a very, very strong latitude ingredient," says Alberto Ascherio, associate professor of nutrition and epidemiology at Harvard University. In the US, for example, the incidence of MS is up to four-fold higher in the northwest than in the southeast, he notes."

and cancer:

Latitude also seems to play a role in the incidence of hormone-dependent cancers. "There is a fair bit of epidemiological data showing that places with less sunshine have higher rates of cancer," says David Feldman, professor of medicine at Stanford University and the editor of a 1,300-page treatise on the substance.

The effect is almost certainly because of vitamin D, Feldman says. "People tend to think it can't do all these things when it's a vitamin," notes Feldman. "It's not a vitamin, it's a hormone."

I was really struck by this statement:

"How do you write a paper when everybody says race doesn't matter and here you have a subject where blacks have more TB and it has to do with the color of the skin and nothing else?" asks Bloom. "I thought that was pretty challenging." Bloom says scientists are planning to test vitamin D supplements in TB trials in Africa.

"...everybody says race doesn't matter"???... Either this person is over dramatizing, or hasn't been keeping up with "everybody".

By the way, very dark is good too (via melatonin)... so a lot of sun and a lot of good dark time seems to be the way to go.

News feature: The sunshine cure

Apoorva Mandavilli

Nature Medicine - 13, 396 - 397 (2007)

Could ten minutes of sunlight a day be all that's needed to fight multiple sclerosis, cancer and tuberculosis? Apoorva Mandavilli discovers the growing interest in vitamin D's many virtues.