May 21 2010
Vitamin D is the sunshine vitamin - we make it when our skin is exposed to UV rays. In a perfect world everyone would eat fresh, organic foods, get outside, and enjoy a little sunshine all year round. But with today's busy lifestyles and concerns about skin cancer many people are vitamin D deficient and don't know it. Concern for vitamin D deficiency is not confined to northern climates, but is becoming more frequent in hot climates where people stay out of the sun.
Dark-skinned individuals may need much higher exposure to sunlight - six to ten times as much - than white-skinned people to produce the same amount of the vitamin D. Therefore people with dark skin can be particularly at risk of health problems associated with vitamin D deficiency.
What are the signs of vitamin D deficiency?
Often you may not be able to tell if you're lacking vitamin D. But the most common signs of deficiency include a loss of muscle strength, pain and weakness, especially in the elderly. You may have difficulty going up and down stairs, difficulty walking, back, hip or leg pain, or difficulty getting up out of a chair. Another common finding is a pronounced body sway.
What if we don't get enough vitamin D?
Vitamin D has important benefits for your entire body. It's needed for growth and formation of bones and teeth, maintaining muscle strength, and for the absorption of important bone-building minerals like calcium and phosphorus. It is critically important in pregnancy, protecting the health of the mother and baby.
New studies show Vitamin D has a much wider role in controlling blood pressure, cholesterol levels, supporting the immune system, maintaining a healthy brain, and supporting cell growth in every tissue of the body. It may aid in the prevention of some cancers including breast, colon, lung and prostate cancer as well as preventing health problems including diabetes, heart disease, rheumatoid arthritis, multiple sclerosis and other autoimmune diseases. Many cases of fibromyalgia may actually be misdiagnosed vitamin D deficiency.
If there is a severe deficiency of vitamin D, children can develop rickets, adults can develop osteomalacia or a softening of the bones.
What can I do?
Few foods naturally contain Vitamin D. Milk, margarine and cereals are often enriched, but the amount doesn't meet the daily recommended intake. For example, you would have to drink 10 glasses of milk a day to receive the 1,000 IU recommended for winter consumption by the Canadian Cancer Society or 20 glasses a day to get the 2,000 IU recommended for pregnant women by the Canadian Paediatric Society. But it is easy and inexpensive to supplement with vitamin D.
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.