The clocks were turned back one hour this past Sunday, and many gladly welcomed an extra hour of sleep. Although this allows for a little extra light in the morning, night falls earlier, approximately two minutes per day, until the winter solstice on Dec. 21. This week, the sun has been rising after 7 a.m. and, by the end of the month, will set around 4:45 p.m., giving only nine hours of light. With longer nights and less daylight comes a greater need for vitamin D, also known as the “sunshine” vitamin.
Vitamin D is unique because the body creates it when the sun’s ultraviolet rays hit the skin. Vitamin D is essential in the development of bones and teeth, and it helps the body absorb calcium, fight infections and control blood pressure. In severe cases, too little vitamin D results in brittle, fragile bones known as “rickets” in children, and “osteomalacia” in adults. Research reported by the Canadian Cancer Society suggests that vitamin D may also help in the prevention of colorectal and breast cancers.
Colder temperatures lead to more layers of clothing and less opportunity to expose skin to daylight. Low levels of vitamin D have been found in sun-deprived Canadians and those living in more-northern regions. People with higher levels of melanin and darker skin pigmentation are less able to make vitamin D from sun exposure. Aboriginal children and women of childbearing age are also susceptible to vitamin D deficiencies.
In order to combat deficiencies, vitamin D has been added to milk, infant formula, and margarine, as required by the Canadian government.
Health Canada recommends that children over the age of nine and adults have a daily intake of 600 International Units (IU). If you want to make sure you are getting the recommended daily amount, start looking at the vitamin content of the food you eat.
According to information on the Dieticians of Canada website, egg yolks and fatty fish such as salmon, mackerel, sardines, and tuna naturally contain substantial amounts of vitamin D. A three-ounce can of tuna contains 60 IU, canned pink salmon has 351 IU, and an eight-ounce glass of two per cent milk contains 100 IU. Those who are vegetarians or avoid dairy products are also at risk of deficiency. Grains contain very little vitamin D, and milk alternatives like soy must be fortified with vitamin D to be beneficial. Read the nutrition facts labels on food products to find out what you are consuming. If you think you may not be getting enough vitamin D, consult your doctor to find out what you can do.
Eating vitamin D rich foods should get you through the winter, but consider getting outside too. If possible, take a walk around campus in the daylight, perhaps during lunchtime. Not only will your body appreciate the exercise, the sun on your face will stimulate vitamin D production.