Vitamin D - A Practical Guide

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With the arrival of good weather and the sun coming out, we are slowly starting to fill up on vitamin D. But why is this vitamin so important and why do we need the sun to benefit from it?

How it works

There are 2 ways to synthesize (create) vitamin D. Either through our diet (i.e. by consuming food and/or supplements), or through our skin, with the help of UV-B rays from the sun. Vitamin D has a very important role in our body. It plays an essential role in the formation of our bones and teeth, regulates the absorption of calcium and phosphorus, and regulates our kidney function. So we can't really function without it! 

In Canada

Because of our latitude, we cannot synthesize vitamin D all year long: the rays are not strong enough when the cold weather arrives, from October to April. The clothes we wear in the winter prevent us from using the sun's rays. Does this mean we should be walking around outside in our bathing suits in the winter? No, the foods and supplements we consume can meet our needs during the colder months! 

For adults, it is recommended that we consume 600-800 IU of vitamin D daily, as well as getting outdoor sun exposure whenever possible. Since the face and forearms are the main areas that absorb the rays, getting your fill of vitamin D in the summer has never been easier. For just 15 to 30 minutes most days, all you have to do is get outside and move around!


Some foods naturally contain vitamin D. Among these, we can find salmon, egg yolks and some mushrooms. On the other hand, others are fortified with vitamin D. This is the case with cow’s milk, plant-based beverages, margarine and certain orange juice. It should also be noted that vitamin D3 is easily absorbed when consumed with fat. Fat is also necessary to transport vitamin D in our body. Therefore, we should not abstain from consuming it, it’s essential!

Supplements: necessary?

A supplement is strongly recommended for all Canadians over the age of 50. For the rest of the population, taking a vitamin D supplement in winter could be beneficial. Adults who stay indoors most of the year may also benefit from a supplement. However, if you decide to take a supplement, it is important to use a trusted brand and preferably talk to a health care professional first, as supplements are not to be taken lightly. Fortunately, your dietitian is there to help you make the right decision regarding vitamin D supplements!

Registered Dietitian Nutritionist