As the days get shorter and temperatures drop, many people naturally spend more time indoors. While cozy winter routines have their perks, they can also mean your body isn’t getting everything it needs, especially when it comes to Vitamin D. During Midwest winters, sunlight can be limited, and your exposure even more so. If you’ve ever wondered whether you’re getting enough Vitamin D this time of year, or what you can do to safely maintain healthy levels, you’re not alone. Here’s what you need to know to support your body through the darker months and beyond.
The benefits of Vitamin D
Vitamin D is essential for life, specifically helping our bodies absorb other nutrients, like calcium and phosphorus, both of which are important to bone health. The body can only absorb calcium if there are adequate Vitamin D levels in the body. Low Vitamin D levels are also associated with depression and anxiety, making proper levels of the hormone important for both physical and mental health.
"Maintaining vitamin D levels can be especially hard during the winter so I would recommend talking to your doctor about getting your vitamin d levels checked and finding a good supplement to take. There are some good studies that show vitamin D supplementation can reduce the risk of acute viral upper respiratory infections and boost immune function", says Jordan Hatch, MD.
How sunlight provides Vitamin D
The visible light perceived by the human eye is only one type within the electromagnetic spectrum. The light that contributes to Vitamin D production is ultraviolet light, the kind produced by our sun. It’s subdivided into three categories, all of which can affect the skin to some degree:
- UV-A. The most common (and the most dangerous), it’s able to penetrate down to the middle part of the skin.
- UV-B. A shorter wavelength than UV-A, it’s only able to impact the outer layer of skin. It’s also the only category that creates Vitamin D.
- UV-C. Almost completely absorbed by Earth’s atmosphere.
When the epidermis (outer layer of the skin) absorbs UV-B rays, it starts the production of pre-Vitamin D, a less potent form, which then enters the circulation system of the body. It gets transported to the liver and kidney which create the active form of Vitamin D. In this way, Vitamin D is actually a hormone, coordinating different functions within the body, not a vitamin.
This is why many people who live in areas with harsher winters, and therefore spend less time outdoors, may be at risk of Vitamin D deficiency.
Are there other sources of Vitamin D?
Sunlight is just one source of Vitamin D. People can also get the hormone from food and supplements. For foods, the flesh of fatty fish, fish liver oils and egg yolks contain Vitamin D. Fortified foods like cows milk, plant-based milk, cheese, yogurt and orange juice, also contain the hormone.
Risk factors that may affect Vitamin D levels
Despite the increased popularity of Vitamin D supplements and testing, not everyone is at risk of Vitamin D deficiency. Before speaking with a doctor, check if you one of these factors is affecting your risk:
Reside in certain areas. If you live in the northern states (anywhere above the latitude line of 37 degrees), you may not be producing enough vitamin D from sun exposure during the winter months.
- Age. You produce less Vitamin D as you age. People over the age of 65 generate only a quarter as much vitamin D as people in their 20s.
- Skin color. People with darker skin typically have lower levels of vitamin D than lighter-skinned individuals.
- Weight. Vitamin D is stored in fat so there is less circulation of this hormone in people who are overweight or obese.
- Certain health conditions. People with conditions such as inflammatory bowel disease, liver disease, or cystic fibrosis, among others, may have trouble absorbing vitamin D.
If any of these factors apply to you, it may be beneficial to chat with your primary care physician about your concerns. They may recommend testing to determine your Vitamin D levels. Not everyone needs to worry about their Vitamin D levels so don't start taking supplements without speaking to your doctor.
How much Vitamin D is necessary
When Vitamin D is taken through foods or supplements, the recommended dietary allowance is 400 international units (IU) for children up to 12 months old, 600 IU for people ages one to 70 years, and 800 IU for people over 70 years.
However, even if a doctor has confirmed with testing that you need more Vitamin D, there are still things to be aware of.
Don’t go overboard with supplementation
While Vitamin D is incredibly important, there is the possibility for over supplementation. The greatest risk is hypercalcemia, a condition that causes a build-up of calcium in the blood, potentially leading to blockages in arteries and soft tissues. Don’t start taking Vitamin D supplements without speaking to your doctor.
Don’t spend time outside in peak sun hours
Getting sunlight is important and the most direct way to maintain adequate levels of Vitamin D. However, too much sun exposure comes with its own health risks. And while sunscreen is critical to preventing skin cancer, it also prevents your body from producing Vitamin D. Even in the winter, sunburn can still happen.
To get Vitamin D safely from the sun, try getting direct sunlight during the early morning hours or later afternoon when UVB rays are lower and you have the least chance of harming your skin.
Light through windows doesn’t produce Vitamin D
You may feel heat and see light coming through the window, even in the winter, but that doesn’t mean you’re producing Vitamin D. Windows block most UVB rays responsible for Vitamin D production, and artificial lights don’t produce those rays at all. So even if you work next to a sunny window, you still aren’t receiving the necessary levels of Vitamin D.
