"Linus Pauling was right, but he was off by one letter"

That's the final line in this story from the Globe and Mail about vitamin D and cancer risk.

The new findings that prompted the story haven't yet been published, and the story seems one-sided (no prominent skeptics are quoted), but it's a story that mixes traditional anthropological narratives about adaptation with new medical research, and it's full of punchy quotes. Here's the lede:

In June, U.S. researchers will announce the first direct link between cancer prevention and the sunshine vitamin. Their results are nothing short of astounding.
A four-year clinical trial involving 1,200 women found those taking the vitamin had about a 60-per-cent reduction in cancer incidence, compared with those who didn't take it, a drop so large — twice the impact on cancer attributed to smoking — it almost looks like a typographical error.

The story can potentially pull in several other kinds of information, including the lower cancer rates in developing countries, the different rates in U.S. racial groups, and the increase in cancer rates over time. Still, we've seen other correlations in the past that could pull these together, such as diet, stress, and substance use (smoking, alcohol) -- which are sometimes interrelated -- so we'll have to see how the result accounts for multiple correlations. It sounds like a simple treatment-control experiment, which should lead to a strong conclusion.

If vitamin D at the "normal" levels is actually a deficiency, then the obvious conclusion is that people should get out in the sun more. The article doesn't miss this:

Those studying the vitamin say the hide-from-sunlight advice has amounted to the health equivalent of a foolish poker trade. Anyone practising sun avoidance has traded the benefit of a reduced risk of skin cancer — which is easy to detect and treat and seldom fatal — for an increased risk of the scary, high-body-count cancers, such as breast, prostate and colon, that appear linked to vitamin D shortages.
The sun advice has been misguided information "of just breathtaking proportions," said John Cannell, head of the Vitamin D Council, a non-profit, California-based organization.
"Fifteen hundred Americans die every year from [skin cancers]. Fifteen hundred Americans die every day from the serious cancers."

The article includes lots of quotes from the vitamin D industry guy -- it almost sounds like a press release -- so we'll have to see if the results are really as provocative as suggested here. Last year there were other stories that pointed in this direction, so it seems not too unlikely. Vitamin D isn't just for rickets anymore.