Shedding light on Canada’s vitamin D levels as we approach the shortest day of the year

As winter’s chill tightens its grip, there is something else that tends to dip along with the temperatures—our vitamin D levels. Millions of Canadians are falling short of recommended vitamin D levels, with teens and younger adults most in need of this gift from the sun.

Vitamin D: A gift from the sun

Vitamin D is often referred to as the “sunshine vitamin” since direct sunlight prompts our skin to produce this essential vitamin. Vitamin D is key to optimal health and well-being by ensuring that our bones, immune system and heart stay strong.

Preschoolers and seniors most likely to meet vitamin D recommendations

The Canadian Health Measures Survey collected blood samples from a nationally representative sample of 10,761 people from January 2016 to December 2019 to learn more about the overall heath of Canadians. Tests for vitamin D levels in blood were used to determine whether Canadians are getting enough: blood levels below 30 nanomoles per litre (nmol/L) indicate a deficiency, which has been linked to higher risk of poor bone health, while levels equal to or greater than 50 nmol/L indicate a sufficient amount to maintain optimal health and well-being, and levels in between point to risk of inadequacy. Our analysis showed that approximately two-thirds (66%) of Canadians had sufficient vitamin D, just over one-quarter (26%) had inadequate levels, and almost one in ten (8%) were considered deficient.

More than two-thirds of children (67%) aged 3 to 11 had vitamin D levels that are considered sufficient to ensure optimal health. Meanwhile, just over half (53%) of teens aged 12 to 19 had sufficient vitamin D to ensure optimal health—the lowest rate among all age groups and just ahead of men aged 20 to 39 (51%). By way of comparison, close to two-thirds of women aged 20 to 39 (62%) had sufficient vitamin D.

Vitamin D levels rise as Canadians age, with over two-thirds of men aged 40 to 59 (69%) and just over three-quarters (76%) of all women in the same age group having sufficient vitamin D to ensure good health.

Vitamin D levels among Canadian adults peak among those aged 60 to 79, with almost three-quarters of men (73%) and over four in five women (81%) in this age group getting sufficient vitamin D. The higher levels of vitamin D among older adults may be linked to Canada’s dietary guidelines, which recommend that people over the age of 50 take a daily supplement containing vitamin D. 

The likelihood of vitamin D inadequacy doubles during the winter

Vitamin D can be obtained by consuming certain types of foods and supplements, but it is also the only nutrient that can be synthesized by the body when exposed to sunlight. Vitamin D is produced in our body when our skin is exposed to ultraviolet B rays emitted by the sun. Getting enough vitamin D from the sun is especially challenging during Canadian winters as the days are shorter, the sun is less intense, and the cold forces us to either stay indoors or bundle up to stay warm when we do venture outside.

As a result, vitamin D inadequacy (28%) among Canadians more than doubles during the winter compared with the sunny—and all-too-short—Canadian summer (13%).

Food can help boost vitamin D levels when the sun fades

A more in-depth look at our data showed that eating certain foods can help boost your vitamin D levels. 

For example, Canadian adults who ate fish at least once a week were more likely to have adequate vitamin D levels than those who ate no fish (82% versus 76%).

Canadian adults who ate yogurt once a day were also more likely to have adequate vitamin D levels than those who did not (83% versus 78%), as were those who drank one glass of milk a day (85% versus 81%).

Don’t despair, vegans! Canadian adults who drank one or more fortified plant-based beverages a day were more likely to have adequate vitamin D levels than those who did not (80% versus 76%).

Canadian adults who took vitamin D supplements were five times more likely to have adequate vitamin D levels than those who did not.

While Canadian winters may challenge our 'sunshine vitamin' intake, a little creativity and some dietary adjustments can help ensure we weather the season with our health intact.