MINNEAPOLIS (WCCO) – One vitamin often mentioned as a way to help fight cancer is vitamin D. We know sunshine is the key to D.

But Deb Stewart from Minneapolis emailed to ask if we get enough vitamin D from the sun?

Dr. Greg Plotnikoff is a vitamin D evangelist, researching its effects and encouraging Minnesotans to take action – because the sun isn’t getting the job done.

“None between Labor Day, early September, and Tax Day in mid-April…Not a drop in Minnesota,” Plotnikoff said.

The sun’s angle in a Minnesota winter is too low. It doesn’t hit the skin the right way to stimulate vitamin D. The doctor researched Allina Health employees.

Sixty percent had low vitamin D levels.

Thirty percent extremely low.

And 6 percent were profoundly low.

“So if it’s true for health professionals, it’s likely true for other people as well,” Plotnikoff said.

The darker your skin and bigger your body, the bigger dose you’ll need. Any brand name will do.

“Vitamin D is vitamin D is vitamin D. So no need to pay big bucks,” Plotnikoff said.

During the summer, car and house windows generally block vitamin D, and so does sunblock. Just SPF 8 blocks production by 95 percent.

The big question is how much should we take?

Unfortunately, there’s not a ton of good data on it yet. If you have ongoing pain or muscle weakness symptoms, the only way to know if you’re too low is to get a blood test.