Soon, we will find ourselves deep in the middle of winter. There are some great things about winter to look forward to like the holidays, snow, winter sports, and cozy times at home. And there are also some drawbacks about winter that aren’t as exciting like shorter days, colder temperatures, bad weather, and less sun.

Less sun doesn’t just get in the way of activities like beach days and picnics. It also poses a potential problem when it comes to our health. You see, our bodies need sunlight in order to make vitamin D, which is an essential nutrient that plays many important roles in the body. 

Let’s talk about what vitamin D is, why we need it, and how to make sure you don’t become deficient this winter.

What is vitamin D and why do we need it?

Vitamin D is a fat-soluble vitamin that acts as a hormone in the body.

We can get a little vitamin D from our diets (there are small amounts in foods like fatty fish, eggs, and fortified foods), but most of the vitamin D in our bodies is produced when our skin is exposed to sunlight. When the sun’s rays hit our skin, a chemical reaction occurs which makes vitamin D.[1-3]

Vitamin D is well known for its role in bone health, but it also has many other important functions in the body. 

Vitamin D helps us to:

• Maintain strong bones
• Increase muscle strength
• Absorb calcium
• Reduce inflammation
• Fight infections
• Keep arteries flexible and relaxed
• Have a healthy immune system
• And so much more [1,2,4,5]

Vitamin D is particularly important when it comes to keeping our immune systems healthy and strong. In fact, it is often considered to be one of the most important immune-strengthening nutrients.[6] And that makes vitamin D especially useful during the winter months when we are most likely to get sick.

Research suggests that vitamin D may play a role in helping to protect against and reduce the occurrence of illnesses like the flu and the common cold.[2,3,7,8]

How much vitamin D is enough?

When we don’t have enough vitamin D circulating in our bodies, it can affect our health. A vitamin D level that is too low is considered a vitamin D deficiency.

Most experts agree that a vitamin D deficiency occurs when your levels are below 20 ng/mL. Levels below 12 ng/mL are considered dangerously low and signs of a severe deficiency. That can lead to serious problems like weak bones and poor health.[4]

Although 20 ng/mL is the common cutoff for deficiency, you likely want your levels higher than that if you want to be the healthiest you can be. Some recommendations suggest that vitamin D levels above 30 ng/mL are ideal and yet others suggest you should be between 40 and 60 ng/mL.[4,10]

Unfortunately, many people don’t have enough vitamin D in their systems. Vitamin D deficiency is incredibly common; about 1 billion people are deficient across the globe. And on top of that, about 50% of the population has levels that are considered insufficient for optimal health.[3]

The dangers of vitamin D deficiency

Vitamin D has the power to influence a wide range of different cells, organs, and body systems. When there are low levels of vitamin D in your body, it can have many detrimental effects and can impact everything from your bones to your nervous system to your immunity. 

Research suggests that vitamin D deficiency can be linked to health concerns like osteoporosis, cardiovascular disease, diabetes, autoimmune diseases, falls in older people, multiple sclerosis, depression, and even cancer.[1,3,5]

And as you learned earlier, not having enough vitamin D may also make it harder for you to fight off infections and may make you more vulnerable to getting sick.[2,3,7,8]

Vitamin D deficiency is a greater risk in winter

Vitamin D levels follow seasonal patterns, and vitamin D deficiency can be more common in the winter months. We need the sun to reach our skin in order to make vitamin D, and in the winter there is simply less sun to go around.[1,2,5,11]

For one reason, there are fewer hours of sunlight each day in the winter, especially if you live farther from the equator at higher latitudes. With the sun lower in the sky, and it being in the sky for a shorter time each day, our chances of absorbing enough rays throughout the day is much lower in the winter.

Additionally, in many areas of the world, winter brings with it worse weather. Clouds, rain, and storms block the sun for a good part of the winter season.[5,11]

And even if the sun is out, many people spend less time outdoors in the wintertime. Unfortunately, the more time we spend indoors, the less chance we have at getting exposed to the sun and making enough vitamin D.[3]

Unless you live in a sunny climate all year long, vitamin D deficiency in winter is something to watch out for, and it is something to remedy if you want to stay healthy. 

How to get enough vitamin D this winter

If you live somewhere where it’s difficult to get enough time in the sun during the winter months, then you’ll want to watch out for low vitamin D levels. It’s a good idea to consult with a doctor to get your levels tested to see where you stand.

So, what can you do if your vitamin D gets low in the wintertime? There are three ways to up your vitamin D intake: 

1. Take a supplement

Supplements are usually the best way to get the vitamin D your body needs. This is especially true if you have a vitamin D deficiency and need to increase your levels, or if you live somewhere where it just isn’t possible to get enough vitamin D from the sun. 

Look for a supplement that contains vitamin D3 and vitamin K as the 2 work synergistically when taken together.

2. Get outdoors and into the sun whenever you can 

Preferably, you’ll get some of your vitamin D naturally from safe sun exposure. That means getting outdoors with your skin exposed to the sun’s rays for at least a few minutes each day. You don’t want to stay out too long and get burned, but you do want to give your body a chance to absorb some UV rays.

Even in winter, try to find time to intentionally get outdoors on nice days and soak up a little sunshine. Getting outside is great for your physical and mental health in so many ways. You can boost your vitamin D intake while also taking the chance to move your body, breathe in fresh air, and spend time in nature all at the same time.

3. Add in more vitamin D-rich foods

There are very few foods that contain vitamin D naturally. Some of these include fatty fish, liver, egg yolks, cheese, and mushrooms. Most vitamin D in the diet comes from fortified foods, where vitamin D has been added during processing, such as milk and plant-based milks.[4] 

But just make sure not to rely on diet alone to get your vitamin D; it is simply not realistic or possible to get all the vitamin D you need just from food.

Key takeaways

Vitamin D is a very important nutrient that your body needs in order to build strong bones, have a robust immune response, and protect itself against a wide variety of health problems. 

Unfortunately, many people across the globe are deficient, and they don’t get enough of this essential vitamin. Deficiency can become an even greater problem during winter, because we make most of our vitamin D when our skin is exposed to the sun’s rays. 

If you don’t live in a tropical climate, then it is important to be aware of the risk of vitamin D deficiency in winter. Get your vitamin D levels tested by a medical professional, and consider taking a vitamin D3 supplement to ensure you keep your levels in the healthy range.

References

1. https://my.clevelandclinic.org/health/articles/15050-vitamin-d--vitamin-d-deficiency
2. https://www.hsph.harvard.edu/nutritionsource/vitamin-d/
3. https://www.ncbi.nlm.nih.gov/books/NBK532266/
4. https://www.ncbi.nlm.nih.gov/pmc/articles/PMC7352291/
5. https://ods.od.nih.gov/factsheets/VitaminD-HealthProfessional/
6. https://www.umms.org/coronavirus/what-to-know/managing-medical-conditions/healthy-habits/boost-immune-system
7. https://www.nature.com/articles/s41430-020-0635-2
8. https://www.bmj.com/content/356/bmj.i6583
9. https://www.frontiersin.org/articles/10.3389/fpubh.2020.00513/full
10. https://www.health.harvard.edu/blog/vitamin-d-whats-right-level-2016121910893
11. https://www.ncbi.nlm.nih.gov/pmc/articles/PMC6121420/