By Leena Thomas, Pharmacist
One of the primary sources of vitamin D is sunlight, ultraviolet B exposure. However, absorption of vitamin D in the True North is limited — particularly in winter. In fact, research shows that 70% to 97% of Canadians have a vitamin D deficiency.
We need 20 minutes of sunlight exposure per day with more than 40% of skin exposed; and UVB exposure from sunrays passing through glass windows is inadequate.
Vitamin D plays a key role in the absorption of calcium and phosphorus — important minerals for building and maintaining strong bones. It also supports mood regulation and cognitive function and is linked to conditions like depression and Seasonal Affective Disorder (SAD).
In addition to insufficient sunlight, other factors such as a diet lacking in vitamin D-rich foods, certain medical conditions, or issues with absorption in the digestive tract can cause vitamin D deficiency. Symptoms like fatigue, mood changes, increased susceptibility to illness, muscle weakness, bone pain, decrease in bone strength and increased risk of fractures (osteoporosis) can be attributed to lack of vitamin D.
Vitamin D can be obtained from foods such as fatty fish (e.g., salmon, mackerel), fortified foods (e.g., fortified milk, orange juice), and dietary supplements. Please read the labels of these products to understand more.
During the winter, vitamin D from the sun and food is often not enough to keep the optimum level. So, the medical community recommends daily supplement of 400 IU for children and 800-1000 IU for adults. Individual vitamin D needs may vary; your pharmacist and doctor can help you with that.