Vitamin D for Canadians: Do You Need a Supplement?

Vitamin D helps your body absorb calcium and keep your bones and teeth strong. It also plays a role in muscle function and the immune system. For people in Canada, getting enough can take a little planning.

Why Canadians are at risk of low vitamin D

Your skin makes vitamin D when it is exposed to the sun's UVB rays. Because most of Canada lies far north, the sun is too low in the sky for much of the fall and winter for the skin to make meaningful amounts. In many parts of the country this period stretches from about October to March.

Other factors can lower vitamin D levels further:

• Spending most of your time indoors
• Wearing sunscreen or covering clothing, which is still important for skin cancer prevention
• Having darker skin, which needs more sun exposure to make the same amount of vitamin D
• Being older, as the skin makes less vitamin D with age
• Having a condition that affects fat absorption, such as celiac disease or Crohn's disease, or having had weight-loss surgery
• Living with obesity

How much do you need?

Health Canada sets the Recommended Dietary Allowance (RDA) for vitamin D as:

• Infants 0 to 12 months: 400 IU a day (an adequate intake)
• Children and adults aged 1 to 70: 600 IU a day
• Adults over 70: 800 IU a day
• Pregnant and breastfeeding people: 600 IU a day

Health Canada also advises that adults over 50 take a daily vitamin D supplement of 400 IU in addition to following Canada's Food Guide, because needs increase with age.

Babies and vitamin D

Breast milk is the best food for babies, but it contains only small amounts of vitamin D. Health Canada recommends that breastfed infants, and infants receiving some breast milk, get a daily vitamin D supplement of 400 IU from birth. This usually comes as drops.

Infant formula sold in Canada has vitamin D added, so babies who are fully formula-fed may not need an extra supplement. Ask your health care provider or pharmacist if you are unsure.

Food sources of vitamin D

Few foods are naturally high in vitamin D, but several Canadian staples are fortified.

• Cow's milk, which is fortified with vitamin D by regulation in Canada
• Fortified plant-based beverages such as soy, almond or oat drinks (check the label)
• Margarine, which is fortified in Canada
• Some yogurts, orange juices and cereals with added vitamin D
• Fatty fish such as salmon, trout, mackerel, sardines and herring
• Egg yolks, in smaller amounts

Canada's Food Guide suggests including protein foods such as fish regularly, and choosing unsweetened fortified plant-based beverages if you do not drink milk.

Choosing a supplement

Vitamin D supplements in Canada are sold as natural health products and carry an eight-digit Natural Product Number (NPN) when authorized by Health Canada. Look for the NPN on the label.

• Vitamin D3 (cholecalciferol) is the most common form in supplements
• Tablets, softgels, chewables and drops are all effective
• Take it with a meal that contains some fat to help absorption
• Many multivitamins already contain vitamin D, so add up your total before taking more

Can you take too much?

Yes. Vitamin D is stored in the body, and very high doses over time can raise calcium levels and cause nausea, weakness, confusion and kidney problems. Health Canada sets a Tolerable Upper Intake Level of 4,000 IU a day for adults, with lower limits for infants and children. Do not take more than this unless your health care provider has recommended it and is monitoring you.

Should you get tested?

Routine vitamin D blood testing is not recommended for most healthy people, and in Ontario it is generally not covered by OHIP unless you have certain medical conditions. Your provider may suggest a test if you have osteoporosis, a malabsorption condition, kidney or liver disease, or take medicines that affect vitamin D. A 25-hydroxy vitamin D blood test can be done privately if you want to check your level.

The bottom line

For most people in Canada, following Canada's Food Guide, including fortified foods, and taking a modest supplement where recommended is enough. If you have questions about the right dose for you or your child, our pharmacists can help any time of day or night.