If there‘s such a thing as an all-natural happy pill, vitamin D looks to be it. In fact, scientists recently analyzed vitamin D levels for 8,000 young men and women between the ages 15 and 39. They found volunteers who had a lack of vitamin D were 85 percent more likely to have depression compared to volunteers with adequate levels.

And even though this study looked at young folks, I‘m sure the lack of vitamin D has an even greater effect on older folks, like me.

Truthfully, this vitamin D study should come as no surprise. Vitamin D has a profound effect on the brain. In fact, it helps to boost your body‘s production of the "feel good" neurotransmitter serotonin.

Just consider why so many northerners suffer from so-called "seasonal affective disorder" (or SAD). Could it be any plainer? Most of them just don‘t get enough sunshine (which your body converts into vitamin D) between October and March. As a result, their mood suffers.

So if you‘re feeling a little down over the winter months or you know you have SAD, have your vitamin D levels checked. Optimally, your vitamin D blood levels should be at least 75 nanomoles per liter. In addition, everyone (especially those living in northern parts of the country) should take up to 5,000 IU of vitamin D3 each day. It‘s the form of vitamin D most easily absorbed by the body.