How a Lack of Sunshine in the Winter Can Impact Your Bone Health
Vitamin D, often known as the sunshine vitamin, plays an important role in your bone health.1 It is mostly made by the body through exposure to sunlight. This is unique to vitamin D since most vitamins come from the foods you eat.1 Having too much or too little vitamin D in your body can affect the amount of calcium in your bones and can take a toll on your overall bone health:
- Low levels of vitamin D can lead to decreased bone mass (osteoporosis) which can increase your risk of fractures.1
- Too much vitamin D can lead to calcium deposits in the kidneys (kidney stones), or calcium build-up in other soft tissues like the heart, lungs, and blood vessels.2
More than 90% of a person’s vitamin D requirement tends to come from casual exposure to sunlight.3This poses some unique challenges for those whose environments limit their exposure to the sun.2 For example, in Canada and other countries in the northern hemisphere during the winter months, people are exposed to less ultraviolet light. This means in the winter in Canada our bodies produce little to no vitamin D.1 Statistics Canada reported that, in the winter months, 40% of Canadians had vitamin D levels that were below the recommended range.1 In the summer, that number is much smaller, but still a whopping 25%.1 This means that as a northern country, we often lack the exposure to ultraviolet light that is needed for enough vitamin D to be made in the body year-round.
You can get vitamin D naturally from a few foods, including egg yolks or fatty fish such as salmon or mackerel.1 In Canada, some foods are fortified with vitamin D by law to prevent the risk of vitamin D deficiency in the general population, including milk, soy milk, rice beverages, and margarine.4
This winter, increase your vitamin D intake and keep your bones strong by reading nutritional labels and seeking out products during your regular grocery shop that are fortified with vitamin D. It also never hurts to add a little bit more sunlight to your day!
For questions about keeping your bones (and the rest of your spine, muscle, and nervous system) in good health this winter (and throughout the year), you can ask Dr. Luciano Di Loreto & Associates.
- Vitamin D blood levels of Canadians. Statcangcca. 2015. Available at: http://www.statcan.gc.ca/pub/82-624-x/2013001/article/11727-eng.htm. Accessed October 17, 2016.
- Vitamin d and calcium: updated dietary reference intakes – nutrition and healthy eating – health Canada. Hc-scgcca. 2016. Available at: http://www.hc-sc.gc.ca/fn-an/nutrition/vitamin/vita-d-eng.php. Accessed October 17, 2016.
- Holick M. Vitamin D: important for prevention of osteoporosis, cardiovascular heart disease, type 1 diabetes, autoimmune diseases, and some cancers. Southern Medical Journal. 2005;98(10):1024-1026. doi:10.1097/01.smj.0000140865.32054.db.
- Food sources of vitamin D. Dietitians of Canada. 2014. Available at: http://www.dietitians.ca/Your-Health/Nutrition-A-Z/Vitamins/Food-Sources-of-Vitamin-D.aspx. Accessed October 17, 2016.