Your doctor can test your vitamin D levels with a reliable blood test - ask to make it part of your annual physical. Talk to your doctor about your blood test results and about your daily sun exposure (in Toronto, on a sunny summer day in a swimsuit, your body can produce 10,000 units of vitamin D in just 15 minutes) to determine a safe level for you and monitor it at regular check-ups.

What kind of vitamin D should I take?

Vitamin D is available at virtually every health food store and pharmacy. It comes in two forms - vitamin D3 which is identical to the natural vitamin D you create in your skin, and a synthetic form called vitamin D2. Simply read the back label. The best form to take is D3 as it has been shown to be more potent than D2.

Can I take too much vitamin D?

The answer is yes. Taking excessive amounts of vitamin D can elevate calcium levels in your blood. It's a rare but serious condition that can lead to nausea, vomiting, even death. People with kidney disease, or primary hyperparathyroidism should not take vitamin D without consulting their doctor.

Today the upper limit of safety set by the European Union is 4,000 IU per day. In North America it is 2,000 IU per day. This upper limit is currently questioned by scientists as perhaps being too low. With lots of research in progress, these limits are now under review.

Source: NUTRITION HOUSE CANADA INC.