Essential nutrient series – vitamin D

Vitamin D plays an important role in health.  Not only it can prevent many diseases, it also regulate many body functions. It is so important for the body that in many countries, a variety of foods are vitamin D enriched. As example, in the United States and in Canada, milk, yogurt, margarine, breakfast cereals and bread often contains added vitamin D

What good can vitamin D do for you?

  • strengthen your immune system
  • protect against influenza
  • plays a role in cancer prevention (bladder, breast, colon, ovarian, prostate and rectal)
  • protect against cardiovascular diseases
  • reduce inflammation
  • reduce the risk of age related diseases
  • help optimize calcium and phosphorus
  • Support mood stability and cognitive functions
  • help control blood sugar and blood pressure
  • Lower the risk of type 2 diabetes

How can I get sufficient vitamin D?

Vitamin D is mainly created by the skin when exposed to direct sun (without sunscreen).  However, maintaining sufficient sunlight exposure in a northern climate can be a challenge, especially in the winter months.  In food, the best natural sources are fatty fish species like herring, catfish, salmon, mackerel, sardines, tuna and eel.  For vegetarians, eggs can be a source of vitamin D. But you don’t have to rely on animal products to get enough vitamin D.

Mushrooms: vitamin D champions

Mushrooms, when exposed to sunlight, can collect a impressive amount of vitamin D.  As example, shiitake mushrooms, when exposed upside-down to sunlight, can collect over 30 times more vitamin D than there is in herring (the best food source of vitamin D per 100g after sunlight exposed mushrooms).

Testing by the Monterey Mushrooms company, demonstrated 5 minutes of UV light exposure made a serving of mushrooms contain four times the FDA’s daily recommendation of vitamin D. (

Can I get too much vitamin D?

While the US population is at far greater risk of vitamin D deficiency than overdose,  it is possible to suffer from the effects of a vitamin D overdose by ingestion, especially when using supplements (it’s not possible to get too much vitamin D through sun exposure).  The safe upper limit set by the National Academy of Science is 2000 UI for adults. According to the research made by the Council for Responsible Nutrition:

The UL established by the FNB for vitamin D (50 microg, or 2000 IU) is not based on current evidence and is viewed by many as being too restrictive […]. Newer clinical trial data are sufficient to show that vitamin D is not toxic at intakes much higher than previously considered unsafe. Collectively, the absence of toxicity in trials conducted in healthy adults that used vitamin D dose > or = 250 microg/d (10,000 IU vitamin D3) supports the confident selection of this value as the UL. […] This demonstrated safety profile of vitamin D should safely permit increased intakes to achieve additional benefits of this vitamin at higher levels than previously recognized.

Several new researches are currently made concerning vitamin D, and we still continue to discover more health benefits associated with this nutrient.

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