Taking a Vitamin D supplement can prevent many auto immune diseases, seasonal affective disorder, prevent osteoporosis and prevent the common cold/flu. So how do we get Vitamin D? The main way our body makes Vitamin D is the sun breaks down cholesterol in our skin and converts it to vitamin D. Vitamin D is also fortified in milk and other foods because the government knows how important vitamin D is for everyone. Living in Minnesota far away from the equator makes it impossible for our bodies to make vitamin D during the winter month until mid May. Many of us use lots of sunscreen in the summer or spend most of the day indoors, making it difficult to produce vitamin D. These factors have made vitamin D deficiency common in Minnesota. Many scientists believe vitamin D deficiency may be a cause for many auto immune diseases because the farther you travel from the equator, the more common auto immune diseases are. Many people get some reversal and relief from their diseases from taking vitamin D. Many people in Minnesota also suffer from seasonal affective disorder, which is common in the winter months leading to eating more in the winter time leading to a bigger waist line. Taking Vitamin D can lessen the winter blues and help you not eat as much preventing the expanding waist line. The body needs Vitamin D to absorb Calcium. So if you are worried about osteoporosis, it is essential to make sure you get enough Vitamin D. Taking a Vitamin D supplement can prevent many auto immune diseases, seasonal affective disorder, and the common cold/flu. Many people think there is enough Vitamin D in their multivitamin, but this is not true. It is wise to buy it separate so there is at least 1000 IU in each pill. The best part of Vitamin D is it is dirt cheap. Many can be bought for $15 for a months supply in the winter time. Michael Kennedy D.C.