 Vitamin D is essential
In Nordic countries such as Canada, the low level of sunlight characteristic of winter months significantly increases the risk of vitamin D deficiency. This is something we must take seriously because new studies indicate that this vitamin plays an extremely important role in the prevention of cardiovascular diseases.
The majority (80-95%) of vitamin D in our body is produced by the sun's action on the skin (UVB rays). This can inevitably lead to problems for Nordic countries inhabitants, who are significantly less exposed to sunlight during winter.
A study conducted in Great Britain indicates that during winter about 87% of the population 45 years of age has a vitamin D concentration below the recommended levels (30 ng/ml). This deficiency has serious consequences. Indeed, several recent observations indicate that people with a vitamin D deficiency are more likely to develop certain types of cancer, such as breast cancer and colon cancer, and cardiovascular diseases.
Inhabitants of Nordic countries are more affected by heart diseases than those of the equator region, a difference long suspected of being linked to the significant differences in vitamin D blood levels.
This hypothesis is supported by the results of a follow-up study of 18,225 men aged between 40 and 75 years old. In this study, men with the lowest vitamin D blood levels (15 ng/ml) had twice the risk of suffering from a myocardial infarction than those whose vitamin D levels were adequate (30 ng/ml). However, this risk increase is not limited to people who show a serious vitamin D deficiency: even men who had intermediate levels of this vitamin (between 15 and 30 ng/ml) saw their risk of myocardial infarction increase by about 50%. These results are in line with those of another study showing that people who have vitamin D levels below 15 ng/ml have twice as much risk of dying prematurely as a result of cardiovascular diseases than those whose levels are adequate.
Several international experts recently raised the alarm and recommended increasing vitamin D intake from 200 IU to 1,000 IU per day to reduce chronic disease incidence. While it is relatively easy to increase vitamin levels during summer - simply exposing the face and arms to the sun for 10 minutes allows the body to produce some 10,000 IU --the situation is more complex from October to April.
Certain fish, especially fatty fish such as salmon, mackerel or even sardines contain significant levels of this vitamin (see table) and are therefore an interesting choice, since these fish are also rich in omega 3, essential fats that also help prevent cardiovascular diseases and cancer. However, the limited number of foods rich in vitamin D often forces us to turn to supplements to maintain adequate levels in our blood. Thus, the daily intake of supplements containing 1,000 IU of vitamin D from October to April is probably one of the most simple, economical and efficient ways to increase the intake of this vitamin and significantly reduce the incidence of cardiovascular diseases and cancer.
FOODS WITH VITAMIN D (IU)
- Cod liver oil (1 soup spoon): 1,350 IU
- Wild salmon (100 g): 600-1,000 IU
- Farmed salmon (100 g): 100-250 IU
- Canned sardines (100 g): 825 IU
- Shiitake mushrooms (10 mushrooms): 650 IU
- Mackerel (100 g): 345 IU
- Canned tuna (100 g): 200 IU
- Milk (1 cup): 90 IU
Major vitamin D food sources (excerpt from New England Journal of Medicine 2007)
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