Vitamin D and Winter

What does vitamin D do?

Strong bones and teeth 

Vitamin D plays an important role in helping your body regulate calcium and phosphorus in the blood. These are minerals that help keep your bones and teeth strong. When we have a deficiency of vitamin D, it can lead to osteomalacia, which is a softening of the bones (1). 

Immunity 

Vitamin D promotes a strong immune system so you’re able to fend off viruses and bacteria that can make you sick. If you’re deficient in vitamin D, you may get sick more often and have more respiratory tract infections such as colds and bronchitis (2).  

Mood

The winter blues are real; and rough. Whether you suffer from seasonal sleepies or whither into  winter sadness, a lack of sunshine could be to blame. If you live far from the equator and experience cold, dark winters, the lack of sunshine may lead to vitamin D deficiency. 

Low blood levels of vitamin D can lead to tiredness and muscle weakness (3). Low levels are also associated with a depressed mood (4). 

Vitamin D deficiency: who’s at risk?

You may be at risk for vitamin D deficiency if you don’t get enough vitamin D rich foods in your diet, if you have a condition that prevents absorption (such as Crohn’s or celiac), or if you don’t have regular access to sunlight. 

• Live far from the equator: if you’re in the northern hemisphere where there’s little access to the sun during the winter months. 
• Dark skin: such as from African, African-Caribbean, or south Asian descent.
• Cover your skin: If you apply sunscreen all the time or wear clothing that covers all of your skin, you may not be able to produce enough vitamin D. 
• Older: skin doesn’t make vitamin D as well as we age (5). 
• Work or stay indoors most of the time: if you have a condition that keeps you homebound or if you work and stay indoors a lot. 
• Don’t eat enough vitamin D foods. 

What foods have vitamin D?

Vitamin D naturally comes from some food, can be added to foods, and is available in supplement form.

Food sources

Vitamin D food sources:

• Oily fish: salmon, tuna, sardines, mackerel. 
• Red meat and liver
• Cheese
• Egg yolks
• Mushrooms: morel, chanterelle, oyster, shiitake, especially when they are exposed to sunlight (6). 

Vitamin D is a fat soluble vitamin, meaning it requires a dietary fat source in order to be absorbed. So when you have vegan sources of vitamin D, it's good to eat it with healthy fat. For example: mushrooms with olive oil. 

Fortification 

Vitamin D is also added to food to ensure we get enough in our diets. Fortification is a food manufacturing process of adding nutrients, whether or not they were originally there. Common vitamin D fortified foods include milk, orange juice, soy milk, and some cereals (7). If food is fortified, it should be declared on the package. So if you are concerned about not getting enough vitamin D - try to find the fortified products.

Supplements

It’s always best to get nutrients from whole food sources, or in this case also the sun. However, if you meet one of the criteria for being at risk of deficiency, you may want to consider supplements during the winter months. 

Since vitamin D is a fat soluble vitamin, it can build up in your body. Too much overtime can cause calcium to build up in the body which can actually end up weakening bones and causing damage to your body. This is why it’s always a good idea to check in with your physician before taking supplements. They can test if you are deficient. 

Vitamins D comes in two different forms: vitamin D2 and D3. Vitamin D3 is the active form of vitamin D, so the one you want for good health (8). 

Sun-light on the matter

If you live in a region where it gets darker during the winter months, you may want to consider boosting your vitamin D intake from about October to early March (5). When the sun is shining, aim to snag some of those rays. Simply getting outside for short periods with your forearms, hands and lower legs uncovered can help. 

Focus on eating more foods rich in vitamin D, such as eggs, low-fat cheese, fortified foods (milk, soy milk, cereals), and oily fish such as salmon. If you follow a vegan diet, you may also want to consider supplements - but as always, consult with your physician before. 

Craving some mood boosting vitamin D? Check out these delicious vitamin D rich recipes: 

Cheese Crisps

Salmon with Oven-roasted Sweet Potatoes

Egg and Avocado Salad with Mustard Mayo