Winter might be a great time to play in the snow, but it’s severely lacking in sunshine. Our skin produces vitamin D in response to sunlight. It’s a fat soluble vitamin that has numerous functions in the body. It’s necessary for a properly functioning immune system and regulating the absorption of calcium and phosphorus. That means without enough of it, we’re less likely to fight off infections and at risk for bone softening disease.

Winter weather pushes many of us indoors and reduces the amount our bodies can make. Symptoms of a deficiency include tiredness, aches and pains, and a general sense of not feeling well. The good news is, if we can’t get enough sunlight, we can get vitamin D in our food.

Natural vitamin sources 

As we mentioned earlier, the skin produces Vitamin D. But it requires direct sunlight to do so, so sitting in the window doesn’t count. A number of factors can influence how much sun you would need to get to make the proper amount; the time of day, season, cloudy skies, skin tone, and many others.

While everyone is different, 30 minutes to 1 hour of midday winter sun, should get you enough of the vitamin for the day. Learn more about the factors that could affect you here and make sure to be wary of sun burns. The body should generate enough vitamin D well before your skin begins to burn.

If the seasonal weather is keeping you inside, look for some food sources of vitamin D before you jump to supplements. Many juices, dairy, and breakfast cereals are fortified with vitamin D. But if you’re looking for naturally occurring vitamin D, try fatty fish (such as salmon, tuna, and mackerel) and fish liver oils.

Foods with natural levels of vitamin DIUs* per servingPercent Daily Value**
Cod liver oil, 1 tablespoon1,360340%
Swordfish, cooked, 3 ounces566142%
Salmon (sockeye), cooked, 3 ounces447112%
Tuna fish, canned in water, drained 3 ounces15439%
Sardines, canned in oil, drained, 2 sardines4612%
Beef liver, cooked, 3 ounces4211%
Egg, 1 large with yolk4110%
Cheese, Swiss, 1 ounce62%
This table demonstrates foods with natural levels of Vitamin D. Fatty fishes and cod liver oils are the best sources for Vitamin D. While eggs are no where near as potent, they are probably one of the most common sources.
*International Units
**Percent Daily Value based on 400 IUs for adults and children age 4 and older


Vitamin supplements

If sunlight or food sources are insufficient to get adequate levels of vitamin D, you might consider supplements. But, you should always talk with your doctor or chiropractor before starting a supplement regiment.

As a fat soluble vitamin, vitamin D can build up to toxic levels in the body. The biggest culprit is supplements. Sun exposure cannot cause this toxicity and its nearly impossible to do the same with food. You’d have to eat way more food than you’d be in the mood for.

Vitamin D toxicity can cause symptoms such as loss of appetite, weight loss, excessive urination, and heart arrhythmias. More seriously, it can damage the heart and blood vessels.

Tis’ the season

Winter is an important time to try to increase your sunlight time as well as adding a few extra foods packed with vitamin D. In addition to the lower levels of sunlight, we have much more skin covered than summer leading to less sun exposure. If you’re still having trouble navigating your levels, we’re always here to help answer your questions.