Summer is unfortunately over and with the days being shorter, you have probably heard about the importance of taking a vitamin D supplement. But is it really essential to resort to supplementation or can we get enough vitamin D from a well-balanced diet?

Functions of vitamin D

First and foremost, let us understand why we need vitamin D. One of the main functions of vitamin D is to increase the absorption of calcium and phosphorus and therefore it contributes to healthy bones and teeth.

Many studies also show that vitamin D has anti-infectious and anti-inflammatory properties which could be favourable for heart health, for boosting the immune system as well as helping to prevent against certain cancers, particularly colorectal cancer.

Sources of vitamin D

Food sources of vitamin D are quite limited. You can find the vitamin in cow’s milk and milk substitutes such as soy or almond milk as they are usually enriched with vitamin D. Other food sources include egg yolks and fatty fish such as salmon, mackerel and sardines. However, to meet the daily needs of 600 IU as recommended by Health Canada for children and adults aged between 9 and 70 years old, we would need to eat a large amount of the vitamin D rich foods, for example we would need to drink 6 cups of milk or eat close to 19 egg yolks in one day.

Another important source is the sun and that is indeed one of the reasons why vitamin D is called the “sunshine vitamin”. When exposed to the sun, our skin is able to produce the vitamin. However, certain factors could decrease the vitamin D production; for instance, over the age of 50 years old, our body becomes less capable of making vitamin D. Furthermore, people with a dark pigmentation of the skin also have a lesser capacity to produce vitamin D.

Should we resort to supplementation?

As we are approaching the colder months and consequently getting less exposure to sunlight, it could indeed be beneficial to take a supplement at this time of the year. This could be particularly relevant as relying completely on dietary sources of vitamin D to meet our needs can prove to be quite challenging. When buying a vitamin D supplement, make sure to choose the active form of the vitamin which is vitamin D3 (usually written on the label). Also, keep in mind that the maximum tolerable intake of vitamin D from food and supplement is 4000 IU per day for children over the age of 9 years old and for adults. In case of doubt, do not hesitate to talk to your pharmacist, doctor or dietitian.