Not enough sun is probably primary, but obesity can also be a contributor. Vitamin D is absorbed by fat cells, where it can't be used as well.

Fish and mollusks are good sources of Vitamin D, but we are warned not to eat too much fish due to chemical toxicity. Other sources are soy milk, butter and eggs.

Keep in mind that a 5,000mg supplement sounds like a lot, but is only the amount of Vitamin D naturally produced by your body when exposed to 10 minutes of strong sunlight (with no sunscreen).

Sue