Vitamin D

By Trevor Shewfelt, Pharmacist at the Dauphin Clinic Pharmacy

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The information in this article is intended as a helpful guide only. It is not intended to be used as a substitute for professional advice. If you have any questions about your medications and what is right for you see your doctor, pharmacist or other health care professional.

My dad remembers getting his dose of “liquid sunshine” everyday from my grandmother. They were in Wawa, Ontario and like many places in Canada, there wasn’t a lot of sun in the winter. My dad hated, but took his spoonful of Cod Liver Oil daily. That was more than half a century ago, and maybe my grandmother was ahead of her time. Cod live oil has lots of good things in it including Omega-3 fatty acids and Vitamin A. We think people should try to eat cold water fish like cod or salmon twice a week. But today we are going to talk about the wonders another cod liver oil ingredient. Today we will tackle Vitamin D.

What is Vitamin D? As usual, there isn’t a simple answer. There are different forms of Vitamin D, but the most potent form is called calcitriol. The type of Vitamin D your body makes is called Vitamin D3 (or cholecalciferol). The formation is complicated, but it goes like this. A Pre- Vitamin D3 is converted Vitamin D3 in the skin with the help of sunlight (UV Radiation). This is why my grandmother called it “liquid sunshine”. Vitamin D3 is converted to a second form in the liver called calcidiol. The calcidiol is converted to calcitriol by the kidney. Again calcitriol is the most active form. So you can get Vitamin D3 from taking pills, having your skin make it from sunshine or eating things like fish. Then you hope your kidneys are healthy enough to convert the Vitamin D3 to calcitriol. There is another form of Vitamin D called Vitamin D2 . It is formed by plants and it can be converted to calcitriol in your body as well. There are those that argue that Vitamin D2 doesn’t form calcitriol as well at Vitamin D3.

Why do we care about Vitamin D? The most important thing about Vitamin D is still that it helps your gut absorb calcium. We know this because young children who don’t get enough Vitamin D develop rickets. Rickets is a condition characterized by bone deformaties and “soft bones” which don’t have enough calcium. If we treat these children with Vitamin D and/or sunlight, their bones get better. This is why we give breast fed babies a Vitamin D supplement called D-Vi-Sol. We assume that the newborns aren’t put in the sun (mostly because we told the mothers not too) and the mothers aren’t in the sun either. Once the babies go onto formula or milk, they will be consuming Vitamin D.

So we need Vitamin D to absorb calcium. That isn’t a new recommendation. Why is Vitamin D in the news? Well, a few things have changed lately. First, we are all probably getting less Vitamin D than we did before. We are using more sunscreen which is good for preventing skin cancer, but it reduces the Vitamin D our skin can produce. We spend less and less time outdoors, and as people age their bodies are less good at absorbing Vitamin D from their diet. The second thing is the recommendations for how much Vitamin D we need keeps going up. It used to be 400 IU of Vitamin D was fine. Now we don’t think 400 IU of Vitamin D will prevent fractures in adults. The recommendations are for at least 400 IU if you are healthy and less than 50. If you are over 50, you should consider 800 to 1000 IU. Vitamin D is generally considered safe up to 2000 IU, and some of the cancer trials are recommending that much.

Another reason that Vitamin D seems to be in the news more is that it is inexpensive, relatively safe and everytime we turn around it seems to do another good thing for us. Let’s look at some of the new health claims Vitamin D has.

· I was at care home meeting the other day and a patient’s daughter if her mom could be put on more Vitamin D. “It has been proven to reduce falls,” she said. I had no idea, so I looked it up. Sure enough in the February 2008 issue of the Journal of the American Geriatric Society there was a study that said nursing home patients on 800 IU of Vitamin D fell less than one on 600 IU, 400 IU, 200 IU or placebo.

· Dr. Philippe Autier, MD from the International Agency for Research on Cancer in France did a meta-analysis that was published in the September 10, 2008 issue of Archives of Internal Medicine. A meta-analysis lumps a bunch of other studies together to look for trends. It isn’t considered as reliable as a randomized placebo controlled trial, but they often give us interesting information for further study. This meta-analysis showed Vitamin D supplementation seemed to make you less likely to die from all causes (including cancer, diabetes and heart problems). The problem is that a meta-analysis can’t draw any conclusions about which dose of Vitamin D is best or why Vitamin D does go things.

· The Canadian Cancer Society now recommends 1000 IU ( in consultation with your doctor) during the fall and winter.

· Low blood levels of Vitamin D seem to make men more likely to have heart attacks. In the June 9, 2008 Archives of Internal Medicine they looked at a lot of men who hadn’t had heart problems and followed them for 6 years. Then they counted who had heart attacks. Even after they eliminated the differences due to smoking, diabetes, high blood pressure, cholesterol levels and other factors, the men with higher blood levels of Vitamin D had few heart attacks.

Other studies have hinted that Vitamin D may make you less likely to get Multiple Sclerosis, colorectal cancer and/or be more likely to survive breast cancer.

As always if you have any questions or concerns about these products, ask your pharmacist.