As the temperatures cool, you’re probably ready to bust out your parkas and fluffy floor-length scarves to stay warm – or ready to just stay inside and avoid the winter weather altogether.
But bundling up in layers and spending less time outdoors can limit your sun exposure, leading to lower levels of vitamin D, which is produced when your skin absorbs UV rays from the sun.
About 40 percent of the US has a vitamin D deficiencyand is especially prevalent in the northern regions, where the winter months are the most brutal.
So here’s how you can make sure you’re getting enough vitamin D this winter.
Why is vitamin D important?
Vitamin D helps the body absorb calcium, which is essential for bone health. Vitamin D is also vital for nerve function and maintaining a healthy immune system.
So how can you tell if you’re getting enough vitamin D? Unfortunately, many people have no noticeable symptoms, which can make recognition difficult.
“You probably won’t feel it if you’re low in vitamin D,” says Andrea N. Giancoli, MPH, RD. “The best thing to do is get your blood checked regularly to see if you’re in the healthy range.”
This is important because vitamin D deficiency can negatively affect your health. has been linked to seasonal affective disorder (SAD), and research suggests it may also be associated with chronic illnesses such as cardiovascular disease.
And Vitamin D deficiency has been linked to increased mortality — though researchers are still working to determine a causal relationship between the two.
Extremely low levels of vitamin D can also affect bone density. “Vitamin D helps the body absorb calcium and works with calcium to keep our bones strong and healthy,” says Rachel Daniels, MS, RD, a registered dietitian at Virtual Health Partners. “Severe vitamin D deficiency can lead to soft bones and reduced bone density. This can increase the risk for pain, weakness and injury.”
How do we get vitamin D?
There are three ways to get vitamin D: the sun, food and supplements.
1. Sunlight
Sun exposure is the easiest way to get vitamin D, but how much time in the sun do you need to they synthesize enough vitamin D? The ideal range can be anywhere from five to 30 minutes, depending on several factors:
- Time of day (midday sun is strongest)
- Time
- Location
- Altitude
- Age
- Your skin pigmentation (darker skin needs more time in the sun to produce enough vitamin D)
There’s a problem: Sunscreen blocks the absorption of UV rays, which can interfere with vitamin D production.
“UVB rays need to hit your skin to synthesize vitamin D,” says Giancoli. “If you wear sunscreen all the time, you block the absorption of UVB rays – and therefore the ability to synthesize vitamin D.”
Of course, you know how important it is to wear sunscreen every day—even in the winter—because exposure to the sun’s UV rays increases your risk of skin cancer. So how do you strike a balance between getting enough sun to synthesize vitamin D, without damaging your skin?
“You want to get enough sun to synthesize vitamin D, but not so much that you increase your risk of sunburn or skin cancer,” Giancoli says. Her rule of thumb: Make sure you wear sunscreen before you notice any change in the color of your skin, whether it’s a tan or a burn.
2. Food
Although sun exposure is the best and most effective way for your body to get vitamin D, you can also get vitamin D from certain foods. The following foods are considered excellent sources:
Vitamin D does not occur naturally in many foods, so you may have noticed that milk, yogurt, orange juice and cereals are often fortified with it.
3. Supplements
While a balanced diet can help you add more vitamin D to your diet, Daniels says, “you may not reach the Recommended Dietary Allowance of 600 international units (IU) per day this time of year without a supplement.”
If you don’t get much sunlight this time of year, you may want to consider taking vitamin D supplements – but talk to a doctor before doing so.
“More is not always better when it comes to supplements,” says Daniels. Your doctor can check your current vitamin D status with a blood test and recommend the appropriate supplement and dosage.
Can Light Therapy Increase Vitamin D Levels?
Light therapy is a common treatment for seasonal affective disorder. However, most of them phototherapy boxes (sometimes called “happy lights”) are designed to help you limit UV exposure to prevent skin damage — and that means they won’t raise your vitamin D levels. However, one study found that the UV rays from an artificial sun lamp — like the type used in tanning beds — could help improve vitamin D status.
However, the best and most effective way to increase your vitamin D levels is through exposure to natural sunlight. So while fortified foods, oily fish, and artificial sun lamps may help, your best bet is to face the cold for a few minutes each day and soak up some rays. And on those dreary days when the sun is nowhere to be seen, look into getting a supplement.
