COLUMN: Vitamin D: Getting enough?
Increasingly we hear concerns that Canadians do not get enough vitamin D during the winter months. Vitamin D helps us absorb and use calcium, best known for its role in building and maintaining strong, healthy bones and teeth. Vitamin D has other health benefits too, and may be important in reducing the risk of some types of cancer.
We get vitamin D from two sources. We make it in our skin when skin is exposed to UVB radiation from sunlight. We also get vitamin D from the foods we eat. The challenge is that in a Canadian winter, there is not enough UVB radiation from sunlight to make vitamin D in the skin, and there are few foods that are good sources of vitamin D. Fatty fish, like salmon and sardines, liver, and egg yolks are natural sources of vitamin D. Most vitamin D in food comes from fortified beverages like cows’ milk and soy drinks, and margarine.
Living in Canada, in fact living above 37 degrees latitude which includes the northern United States, places us at risk for not getting enough vitamin D. There are also groups amongst us that are at higher risk and they include the elderly, dark skinned individuals, and exclusively breast fed infants. Those who wear clothing that covers most of their bodies all year round, for example for religious or cultural reasons, and those who eat few food sources of vitamin D are also at higher risk.
As we age, we don’t make as much vitamin D. The ability to make vitamin D also varies with skin pigmentation – those with darker skin produce less vitamin D. While breast milk alone is the best nourishment for infants up to six months of age, it does not contain enough vitamin D for a baby’s needs.
So are you getting enough and if not, what to do about it?
All exclusively breast fed infants should receive a supplement of 400 IU or 10μg/d from birth.
From ages one to 50 years, the recommended intake is 200 IU per day. As a reference, one cup of milk provides 100 IU, while fortified soy or rice beverage provides 80 IU. Meeting the 200 IU through food is probably reasonable.
Once you reach age 51 to 70, the recommended intake is 400 IU per day. After 71, it goes up to 600 IU daily. Both these amounts are more difficult to meet through diet alone, and for this reason Health Canada recommends a supplement for adults over 50 years of age.
The bottom line – breastfed infants should have a daily supplement as noted earlier. Adults who do not eat vitamin D rich foods should think about taking a supplement – most “one a day” or multi vitamin/mineral supplements contain vitamin D. For all adults older than 50, eat well with Canada’s Food Guide, choose a variety of foods and take a vitamin D supplement of 400 IU daily.
For a list of foods and their vitamin D and calcium content, go to www.dialadietitian.org
Andrea Ottem is a registered dietitian with Fraser Health. Reach her at 604-507-5441.