Vitamin D is so important for good health that nature gave us a way to make it. We produce it when the sun’s rays react with cholesterol. However, fearing skin cancer, most Americans now use sunscreen, which blocks vitamin D production. Aging also reduces our ability to make vitamin D.

Because vitamin D is also sparse in the diet, most of us are left with less than research shows we need. Vitamin D is involved in so many bodily functions, its deficiency may increase the risks for health challenges Americans most frequently encounter.

Decades ago, the National Academy of Sciences set 400 IU of vitamin D as the “Daily Value,” because this is what we need to prevent rickets. It had not yet been discovered that vitamin D is involved in other aspects of health. Studies at America’s most prestigious medical schools suggest that optimal health requires 2000 IU to 5000 IU of vitamin D per day. They have also learned that up to 10,000 IU is safe.

To get 5000 IU of vitamin D from food, you’d need six servings of salmon or 20 glasses of vitamin D fortified milk. You can get 5000 IU by exposure to summer sun, but not without the risk for skin cancer or premature aging. Optimal vitamin D levels requires supplements.

Vitamin-D 2000 IU and Vitamin-D 5000 IU are made for those who want the general health protection provided by vitamin D. Use Vitamin-D 2000 IU if you get at least 30 minutes of unblocked sun exposure each day. If not, use Vitamin-D 5000 IU™. Those who get enough sun in the summer, but not in the winter, can switch with the seasons.*