Why is it so important? Vitamin D is key to bone health, and a deficiency can lead to rickets (softening and weakening of bones) in young children. In recent years, research has suggested vitamin D deficiency may also be linked to issues like asthma, multiple sclerosis and cancer. “There is concern over the unknown long-term risk of chronically low vitamin D levels,” says Jonathan Maguire, paediatrician and researcher at St. Michael’s Hospital in Toronto and author of the study, published in the American Journal of Public Health.
Skin typically absorbs vitamin D from the sun, but since cold Canadian winters are often spent indoors, food becomes our main source of the vitamin. The problem, says Macguire, is that kids who are breastfed beyond the introduction of solid foods tend to eat less food overall, decreasing their chances of loading up on vitamin D.
Another challenge: many of the foods that are naturally rich in the vitamin aren’t what you would call typically kid-friendly: fatty fish and organ meats, like liver, for example. Most Canadian kids who do get enough vitamin D get it from fortified formula or cow’s milk (or a supplement).
Results from the study, which was conducted with Toronto’s Hospital for Sick Children and included 2,500 kids ages one to five, showed that the risk of being vitamin D deficient rose six percent every month a child was breastfed beyond one year of age. Breastfed two-year-olds had a 16 percent chance of being vitamin D deficient and breastfed three-year-olds had a 29 percent chance of deficiency.
To ward off deficiency during the breastfeeding years, Maguire recommends supplementing children with 400 IU (international units) of vitamin D daily.