vitamin D...the sunshine of your life

A couple of years ago I had a skin cancer diagnosed on my nose. I commented hopefully to the dermatologist that I had the best kind of skin cancer you could have and with a withering look she replied that there were no good kinds, but at least mine wasn’t the worst. True enough. She then went on to recommend that I cover myself completely every day with a # 60 sun screen. When I asked what she told her patients about vitamin D after warning them to completely avoid the sun and wear sun-screen, she replied that she told them nothing. “What’s the big deal?” was her attitude.

Well, it’s a very big deal. While I’m unaware of any dermatologist ever being held liable for telling a patient to totally avoid the sun and not recommending vitamin D supplements, I bet it won’t be long before such a case comes to light in our neighbour to the south. Vitamin D deficiency is widespread, and not just in people who are being treated for skin cancer. It’s been estimated that roughly two-thirds of the Canadian population has a vitamin D deficiency.

For a long time it was thought that the only real upshot of inadequate vitamin D would be rickets in children. Fortification of milk with the vitamin pretty well put an end to that, but lately, for a variety of reasons, rickets has been reappearing. Northern First Nations children were among the first to be seen in this resurgence of the condition, but now there is also evidence of the vitamin D deficiency disease called osteomalacia in adults as well. Particularly vulnerable are those women who immigrate to Canada from countries where fluid milk is not routinely consumed and whose religion or culture requires them to be covered from head to foot. And, osteoporosis is not just the result of inadequate dietary calcium; poor vitamin D status plays a role as well. A favourite aunt of mine was confined to a nursing home thanks to complications from diabetes and the subsequent amputation of one of her legs. Though I kept nagging them to give her vitamin D supplements they neglected to do so. One day I received a call saying that she had rolled over in bed and broken her remaining leg. The next day she was dead from complications of the break.

Unfortunately it’s not just the bones that pay a price for insufficient vitamin D. There is now pretty persuasive evidence that an inadequate intake of this vitamin plays a role in the development of hypertension, heart disease, certain cancers, diabetes and autoimmune illnesses.

This naturally enough leads to the question as to why so many people have inadequate vitamin D and what are the natural sources of it. The industrial revolution is partly to blame for this sad state of affairs…that and the fact that nature didn’t think we’d move to places like Edmonton (she figured we’d stay in the Garden of Eden wearing only a fig leaf and getting plenty of sunshine). But the move to cities and the development of polluting industries coupled with the need to wear clothes and the invention of sun-screen did us in. Don’t get me wrong: I’m not suggesting that we shouldn’t use sun0screen, I’m simply pointing out that it pretty much does away with the skin’s production of vitamin D. Because of Canada’s geographical setting little or no vitamin D is made in the skin between October and April (not to mention the fact that we’re all bundled up during those months). And as for food, don’t count on it. Milk is fortified with vitamin D but still only gives 100 IU’s per 250 mL. Not enough. Contrary to popular belief, most other dairy products have none. Unless you’re eating very large quantities of oily fish, your diet is highly unlikely to provide you with all the vitamin D you need.

So then, what to do? You may know that dietitians are usually reluctant to recommend supplements since for most nutrients food is the best source. But for vitamin D we must make an exception. I would suggest that for most people a supplement of 1000 IU of vitamin D3 (cholecalciferol) per day would be appropriate. You might be tempted to take cod liver oil but I think that’s a bad idea since a tablespoon of the stuff will also give you about 14,000 IU of vitamin A…way too much. I would opt for a capsule that contains only vitamin D.

Can you get too much? Yes. Toxicity can occur since the vitamin is fat-soluble and can be stored over time. Most evidence indicates that you’d need 20,000 IU a day over a long time to have problems, but to err on the side of caution I think you should not exceed the 2000 IU level. Are there people who shouldn’t take vitamin D? Yes: Those with a condition called sarcoidosis (or any other granulomatous disease), cancer (especially lymphoma) or hyperparathyroidism.

The bottom line here is that most of us are not getting enough vitamin D and the result can be serious.