By Heather Brown

MINNEAPOLIS (WCCO) — Just 15 minutes of sunshine a day can have health benefits. But is it enough to get us the vitamin D we need?

“This far north, most of us are not getting enough vitamin D in the winter,” said April Chu, a nurse practitioner of integrative medicine with Allina Health.

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Our skin needs UVB rays to synthesize and produce vitamin D. During the winter months, the angle of the sun is so low that the atmosphere blocks those UVB rays from reaching people.

“Most of us need to supplement,” Chu said.

(credit: CBS)

Vitamin D is important for our bones because it helps us absorb calcium. It has also been shown to have a positive impact on mood and immune systems.

It can be hard to tell whether a person’s vitamin D levels are too low without a blood test.

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“If in the winter, your mood is off or you’re not sleeping enough or you have aches and pains, those are all good reasons to get your levels checked,” Chu said.

Allina studied its employees in the winter of 2010 and found 60 percent had low vitamin D levels, 30 percent were very low and 6 percent were profoundly low.

vitamin D cannot be stored in the summer and then used in the winter. Any vitamin D supplement should be taken in the morning with food. Foods like eggs and salmon do contain vitamin D, but Chu said people generally do not eat enough vitamin D.

In the summertime, 10 to 15 minutes of direct sunlight will help with vitamin D levels. Windows and sunscreen can block the UV rays that help people produce vitamin D.

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Chu said how much vitamin D a person should take depends on their current levels, the color of their skin and their size. But she said be careful, because people can take too much vitamin D.

Heather Brown