Vitamin D is known as “the sunshine vitamin” because our skin produces it when exposed to sunlight. All well and good in the spring and summer, but what’s a Vancouverite to do at this time of year when the days are short and the sun seldom shines?
Fortunately, there are other ways to get our daily dose. Anja Webster, a Registered Dietitian with the Renal Program at St. Paul’s Hospital, did some digging and breaks down how much we need, where we can get it, and why vitamin D is so important for good health.
What is vitamin D?
Vitamin D is a fat-soluble vitamin best known for the role it plays in bone health. It maintains calcium and phosphorus levels in the blood, aids in bone growth and remodeling, and helps our bodies absorb calcium from foods.
“Vitamin D is needed to keep our bones strong and healthy,” Webster says. “Getting enough helps prevent bone softening, which can lead to bone diseases in adults and rickets in children.”
Meanwhile, vitamin D may also play a role in immune health, reducing the risk of certain types of cancer, decreasing the risk of heart disease, and preventing diseases like diabetes and multiple sclerosis; however, more research is needed in this area.
Where can we get it?
Our bodies make vitamin D when the skin is exposed to the sun. But in Canada we don’t get much sun in the fall and winter, so it’s difficult to get enough vitamin D during this time. That’s not to say we should forgo sunscreen and hit the beach whenever the sun makes an appearance.
“Continue to be sun smart and have proper sun protection as we only need a small amount of skin exposure to get enough vitamin D from the sun in the summer months,” Webster explains.
Only a few foods contain vitamin D naturally, namely fatty fish like salmon and mackerel and egg yolks. Much of the vitamin D we get from our diet comes from fortified foods and supplements. In Canada, all cow’s milk and margarines must be fortified with vitamin D. Most milk alternatives, like soy milk, are also fortified, but be sure to check the label.
“In order to get vitamin D from the diet, try to drink at least two cups of milk or milk alternatives daily and include fatty fish regularly,” Webster says.
Who is at risk of vitamin D deficiency?
People who may be at risk include those living in northern areas, like Canada, due to our high latitude and lack of sun exposure in fall and winter. Others at risk include older adults, people with darker skin, people who do not get sun exposure (for example, those who are homebound or who cover their skin with clothes), people who have digestive problems, such as Crohn’s disease, and people with kidney and liver disease, among others. Some medications can also affect vitamin D levels.
How much do we need?
According to Health Canada, the recommended daily dietary allowance for vitamin D is 400 International Units (IU) for infants under 12 months; 600 IU for children and adults aged 1-70; and 800 IU for adults over 70.
Health Canada also recommends adults over 50 take a vitamin D supplement of 400 IU daily, and that all exclusively or partially breastfed infants receive 400 IU daily.
These recommendations are for healthy individuals. Individuals with certain medical conditions or who take some medications may have different requirements. Your health care provider can help determine an appropriate amount for you.
Is there such a thing as too much vitamin D?
It is possible to get too much of a good thing. The tolerable upper intake level, meaning the maximum amount of vitamin D a person could take daily without likely adverse effects, is 4000 IU for adults and children over 9 years.
Too much vitamin D can lead to too much calcium being absorbed into the blood and the calcium can deposit into soft tissues like your heart. You can’t get too much vitamin D from sun exposure or from food; vitamin D toxicity typically occurs when people take too much in supplement form.
If you are concerned about your vitamin D levels talk to a registered dietitian or your doctor who can make recommendations specific to your needs.
For more information on vitamin D, check out the sources Webster consulted: