Why Vitamin D Levels Drop in Fall and Winter and How to Boost Them

While most people associate fall with cozy sweaters, comforting meals, colorful leaves, and all things pumpkin, doctors know that this is also the time of year when Vitamin D levels tend to drop. It can be challenging to get enough vitamin D once the days get shorter and you naturally start spending less time outside as the temperatures plummet. Here is a look at this nutrient and how you can ensure that you are meeting your daily recommended intake.

Everything You Need to Know About Vitamin D

Vitamin D is a fat-soluble nutrient and hormone that is primarily obtained through exposure to the sun. As such, it makes sense that this is the time of year when people struggle to get enough of this crucial vitamin. While vitamin D is not found as readily in foods like some of its counterparts, you can still meet this requirement through proper diet and supplementation.

Why is vitamin D so important? This vitamin is distinguished by its benefits to bone health, helping the body to absorb dietary calcium and phosphorus. Both of these minerals support healthy bones, lowering the risk of fractures. Without proper vitamin D intake, the minerals are not able to do their job.

Beyond bone health, vitamin D also helps to regulate hormones, decrease inflammation in the cells, and boost immune function. Low levels of this vitamin are also linked to mood dips, especially during the long and dark winter months. 

People who are deficient in vitamin D often report feeling sluggish due to low moods and sleep disturbances. Long-term deficiencies can cause rickets in children and osteomalacia in adults.

Most Americans are not getting enough vitamin D. This is particularly true for people who live in colder climates. Vitamin D deficiencies are the most common among Black Americans, women, and people between the ages of 20 and 29.

Because vitamin D is absorbed and processed through the skin via sunlight, it is easy to understand why levels of the nutrient plummet when the weather turns cloudy and cool. This is when it is important to be intentional about consuming foods that are rich in the nutrient or taking a supplement to bridge the gap.

A healthcare provider can run a simple blood test to see where your vitamin D levels land. This will provide the necessary guidance about whether supplements are needed.

How to Boost Vitamin D Levels This Fall and Winter

The recommended daily requirement for vitamin D for adults is 15 micrograms. This amount can be achieved with five to 30 minutes of sun exposure without the use of sunscreen on most days of the week. While SPF interferes with the body's ability to absorb the rays needed to synthesize the vitamin, it is also important to not expose yourself to sunburn. This makes getting enough vitamin D a balancing act for those who are sensitive to the sun.

In addition to moderate sun exposure, there are also several food sources that are beneficial in reaching these daily intake goals. Good choices include salmon, fortified cow's milk, eggs, fortified cereal, sardines, and mackerel.

Nutritionists recommend pairing foods that are rich in vitamin D with a fat source. This is because vitamin D is fat-soluble, meaning that absorption rates increase when it is consumed as part of a balanced meal that also includes a healthy fat component, such as olive oil, nuts, or avocado.

It is often challenging to figure out how much vitamin D you need, as age, skin tone, and other factors play into the equation. The National Institutes of Health (NIH) recommend that infants up to 12 months take in 400 IU daily, while those between the ages of 1 to 70 aim for 600 IU. Adults aged 71 years and older should bump this up to 800 IU.

Groups that tend to need more vitamin D supplementation include breastfeeding infants, individuals with celiac disease or cystic fibrosis, those with darker skin tones, vegans, and people who rarely go outdoors.

If you decide to rely on supplements for your vitamin D, it is important not to consume too much. Taking more than 4,000 IU daily can create too much calcium in the blood, nausea, and kidney damage. While boosting vitamin D intake through supplements during the darker times of the year may be prudent, checking your levels prior will ensure that you do not inadvertently take too much.

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