Vitamin D-eficiency

When questioned about his favourite vitamin prominent Toronto researcher Dr. Reinhold Vieth's passion comes alive. Vieth director of the bone and mineral laboratory at Mount Sinai Hospital is arguably Canada's most outspoken champion of vitamin D a substance he considers grossly overlooked.

"Vitamin D is the poor boy in nutrition. It's a nobody" says Vieth whose studies on the vitamin have been published in several journals including the European Journal of Clinical Nutrition.

Underrating vitamin D is endangering the lives of Canadians --- including those living in numerous cities and towns in Ontario he says. That's because for six months of the year we don't get enough sunlight the body's main source of vitamin D. (When the sun's ray's hit the skin it manufactures a compound the kidneys convert into vitamin D).

Scientists like Vieth say the skin cannot produce adequate vitamin D during winter months at latitudes above 40 degrees north. If that's the case Ontarians are in trouble; Toronto and London are at 43 degrees and Ottawa even further north at 45 degrees.

Our lack of vitamin D puts us at greater risk for developing bone fractures says Vieth noting that the vitamin not only aids in the absorption of bone-building calcium it also improves balance and muscle strength thereby preventing falls.

The latest research also suggests vitamin D deficiency may play a role in neurological diseases such as Alzheimer's autoimmune diseases such as Type 1 diabetes -- and certain cancers including ovarian and colon among others.

What really irks Vieth is Health Canada's suggested daily intake of vitamin D --- an amount he considers far too low.

The federal agency suggests that those between the ages of nine and 50 get 200 IU of the vitamin and people ages 50 to 70 get 400 IU. Seniors over the age of 70 should get the highest daily dose of the stuff --- 600 IU according to Health Canada.

The Osteoporosis Society of Canada is more vigorous in its approach to vitamin D and recommends those over age 50 get 800 IU. But Dr. Vieth urges all of us to take in at least 800 IU of vitamin D daily. Science backs up his recommendations. He recently presented a study to the American Society of Bone and Mineral Research that revealed more than half of women currently treated for osteoporosis have insufficient amounts of vitamin D in the blood when taking less than 400 IU of vitamin D supplements daily. In another study daily vitamin D intake between 800 and 900 IU combined with 1200-1300 mg of calcium in woman older than 65 resulted in higher bone density and decreased bone turnover and bone fractures.

What worries Vieth is that many people could be walking around with muscle aches weakness and fragility due to vitamin D deficiency. Doctors he says don't think to check for the problem. That's because of the widely held misconception that rickets has been eradicated. (Rickets the childhood disease that causes deformed limbs and bone weakness was a substantial problem before Canadian milk was fortified with vitamin D in the 1960s). But the disease hasn't gone away.

"Rickets is still here. Vitamin D deficiency in adults is still here" says Vieth.

Since vitamin D in food is hard to come by Vieth says supplementation is essential. Most supplements however only contain 200 IU of vitamin D.

"That really bugs me" says Vieth. "The amount of vitamin D in there is essentially a placebo. It's like saying I have a headache so I'm going to take a baby Aspirin."

There are some brands on the market that offer more. Another option he says includes dosing up on a few 200 IU tablets.

Vieth says some higher-dose vitamin D supplements may be available behind the pharmacist's counter. Though everyone agrees that vitamin D is toxic if you take too much where Vieth differs with most doctors is on how much is too much.

Conventional wisdom holds that as little as 2000 IU a day can be toxic to children. But Vieth notes that most people get 2000 IU of vitamin D daily during casual sun exposure in the summer.

Large doses of vitamin D supplements are linked to increased risk for premature heart attack atherosclerosis and possibly kidney stones in people who are predisposed to kidney problems. Vieth says these problems are rare and notes that that doctors and dietitians need to pay attention to the latest research.

Vieth has made it his mission to educate dietitians about vitamin D. "I talk to them and afterwards they go ·Hmm this is really unusual. This is the first nutrient where I have to can't tell people to eat something (to get enough of the vitamin).'"

Gina Sunderland is a registered dietitian who has been following Vieth's research closely. While she recommends that Canadians consciously ingest vitamin D-containing foods such as milk salmon cod liver oil and almonds she knows that's not enough.

"The research is there and the links are so strong for overall health" says Sunderland. "For at least half a year we're not getting enough vitamin D."

Meanwhile Vieth plans to keep on with his life's work --- helping Canadians get what he believes to be their fair share of vitamin D.

"It's such a simple thing. Take a supplement" he says.

Most common dietary sources of Vitamin D in Canada:

* Egg yolk -- 25 International Units

* Cow's milk (fortified) 250 ml (1 cup) -- 88 IU

* Infant formula 250 ml -- 100 IU

* Margarine (fortified) 5 ml (1 tsp) -- 25 IU

* Salmon cooked 30 g (1 oz) -- 103 IU

* Fortified soy beverage 250 ml (1 cup) -- 80 IU