The importance of getting enough Vitamin D during the winter months

Vitamin D, the sunshine vitamin, is made in our skin after it is exposed to the UVB rays in sunlight but is also found in oily fish such as sardines, tuna, mackerel and salmon as well as mushrooms and fortified dairy products. 

Vitamin D is essential to good health. But during the winter months, there is less exposure of our skin to sunlight and puts us at risk for Vitamin D deficiency and infections.

So how do we get this important vitamin during winter months? Should we take supplements and how much should we take?

Margherita T. Cantorna is a microbiologist and an immunologist who studies and researches the function of Vitamin D in immune cells. This important vitamin helps fight infections and reduces inflammation.

Cantorna recommends that during winter months, especially in the northern hemisphere where the days are shorter and people are less exposed to the sun because of winter clothing, people should not only consume foods high in Vitamin D but also take supplements. They need to get at least 600 IU per day of this important vitamin.

Vitamin D has been known for a very long time to be important for bone health because the lack of it causes rickets in children and osteoporosis in adults. But in the 1980s, receptors for Vitamin D were discovered in immune cells.

Because of this knowledge, Cantorna and her team of researchers found that Vitamin D plays an important role in a healthy gastrointestinal tract, and reduces a person’s susceptibility to gut and lung infections, Crohn’s disease and inflammatory bowel disease. They found that Vitamin D keeps the microbes in the gut healthy and happy.

Some experts say that a healthy amount of Vitamin D is 200 IU per day up to even 2,000 IU per day for adults. The Endocrine Society recommends maintaining an optimal Vitamin D level with 1500 to 2000 IU per day.

Amounts from food intake would be 600 IU per day or from supplements to maintain Vitamin D at summer levels.

But there needs to be caution as too much Vitamin D supplementation during winter can also be harmful. It can cause kidney stones, bone pain, and vomiting which is not caused by the sun or food. Also Vitamin D toxicity can cause Calcium levels in the blood to rise and lead to kidney disease. 

In order to avoid Vitamin D toxicity, experts in the field recommend no more than 4,000 IU per day for adults.