It’s that time of year, officially. It’s when we trade in our bikinis for sweatshirts and our frosty lattes for hot PSLs. Not only will summer end and fall and winter arrive, but sunshine will also diminish. Yes, this might make for a really comfortable night in—scented candles and a movie, anyone?—but too little sunlight can also be detrimental to our health. For example, it can be difficult to get adequate vitamin D on shorter, darker days.
Here’s how you obtain more vitamin D in the fall and winter, as well as why getting less of the essential can cause health problems.
Why shorter, gloomier days result in lower vitamin D levels
As you may know, exposure to sunlight causes our bodies to create vitamin D. “Shorter days can reduce how much vitamin D we produce during the winter months,” explains Warren, New Jersey-based registered dietitian Jacqueline Gomes, RD. “Our skin needs direct sunlight for this process to take place.” “Our vitamin D levels tend to peak in late summer and early fall, so our vitamin D stores can start to deplete just before the winter months.”
This is how it works in more detail: according to Las Vegas-based primary care physician Raj Singh, MD, FACP, FASN, “Ultraviolet B (UVB) rays penetrate the outer layer of your skin and convert a cholesterol derivative into vitamin D3, which then travels to the liver and kidneys to be further processed into active vitamin D.”
A 2023 study published in the Brazilian journal Revista Paulista de Pediatria suggests that the vitamin D produced by this method may stay in the blood for at least twice as long as vitamin D obtained from supplements. However, the weather prediction matters. “On a clear day, your skin can produce a substantial amount of vitamin D in a relatively short period,” adds Dr. Singh. “On a cloudy day, the process still occurs, albeit at a slower rate because clouds filter a significant amount of light.”
Your skin’s temperature may also be relevant in this situation. Harvard Health Publications states that heated skin generates vitamin D more effectively than chilly skin. Thus, on a hot day as opposed to a chilly one, you will produce more vitamin D.
What happens to your body when you get less vitamin D
An important factor in our general health is vitamin D. In actuality, almost every cell in our body has vitamin D receptors, according to a July 2017 study published in the Annals of the New York Academy of Sciences. According to Drs. Singh and Gomes, the vital nutrient supports heart and bone health, relaxes blood vessels, regulates the immune system, and may even help prevent some malignancies.
Fatigue and frequent illness are indicators of low vitamin D levels. According to Dr. Singh, over time, insufficient intake might result in a deficiency that could be connected to chronic health problems like: increased inflammation in the gut (such as colitis and an imbalance in the gut flora) Reduced bone health and risk of osteoporosis and osteopenia due to bone loss elevated risk of cardiac issues as a result of stiffer blood vessels and worsening heart failure Flare-ups of asthma and chronic lung illness (probably associated with increased inflammation) problems with fertility Enhanced discomfort in those suffering from fibromyalgia and other long-term inflammatory diseases.
How much D should I take every day? Given the importance of vitamin D, what is the recommended daily intake? The National Institutes of Health (NIH) states that the recommended daily allowance (RDA) for adults is 600 International Units (IU), or 15 mcg. The same dosage should be given to children aged 1 to 18, but adults over 70 require somewhat more—20 mcg (800 ICU) each day.
Ways to Increase Vitamin D During Reduced Sunlight.
Fortunately, there are other ways to obtain extra vitamin D in the fall and winter besides the sun. Try these measures now to ensure that by the time the peak cold, dark days arrive, your vitamin D levels will have stabilized.
In contrast, a 3.5-ounce portion of light-canned tuna has 269 IU of vitamin D. Herring and sardines are excellent providers of this vitamin as well. “Add more fish to your weekly menu with options like salmon and sautéed mushrooms for dinner, or a tasty tuna salad for lunch to keep your vitamin D levels up,” Gomes advises.
UV-exposed mushrooms: Mushrooms are special because, when grown in the light rather than in the dark, they are the only adequate plant-based source of vitamin D. “They are similar to us in that they produce vitamin D when UV rays hit them,” Gomes says. Next time you’re grocery shopping, look for the brand Monterey Mushrooms, which are grown under UV light.
Egg yolks: Nine percent of your daily vitamin D intake can be found in two big egg yolks. To consume more of the nutrient, Gomes advises beginning your day with a mushroom and egg omelet, which is high in protein.
Milk: In the United States, vitamin D is virtually always added to cow’s milk. To replicate the nutritional profile of dairy milk, vitamin D is also added to several plant-based milk substitutes. Just be sure to look for the vitamin D content on the nutrition facts label of your milk. “For a snack, consider a smoothie prepared with a vitamin D-fortified milk or milk alternative,” Gomes advises.
2. Take into account a supplement:
Your doctor may advise taking a supplement if blood tests reveals that you are vitamin D deficient. According to the NIH, you will require approximately 6,000 IU of vitamin D3 daily (or 50,000 IU weekly) for eight weeks in order to help recover your levels. After you get a healthy level, you can continue to take 1,000–2,000 IU each day to keep it there.
Choose a supplement brand that has been approved by a third party, such as NSF or USP, when you’re purchasing. “Third-party testing indicates that an independent lab with no connection to the brand has verified the supplement quality and accuracy of its labeling,” Gomes states. Supplements from Nature Made and Thorne are very good.
3. To optimize exposure, step outside when the sun is at its highest
The sun’s rays are at their best between 10 a.m. and 4 p.m., so you should take a break and go outside during that time, even on overcast or rainy days. Walking for 20 minutes at lunchtime is one method to accomplish this, according to Gomes, who also claims that it can improve your brain and vitamin D levels. “Aim to get out at least three days per week,” she states.
One more piece of advice? Gomes suggests trying substituting a run outside for your treadmill time. Even if you’re running in overcast or wet conditions or wearing long sleeves in chilly weather, this can assist increase your vitamin D levels.
4. Consider using a solar lamp
There isn’t much study on this, but some studies claim that utilizing a sun lamp, which emits UV rays that resemble sunlight, could increase the amount of vitamin D your body makes. An earlier study published in October 2007 in Photodermatology, Photoimmunology & Photomedicine found that sun lamps can be particularly beneficial for individuals who have issues absorbing fat or who are unable to absorb enough vitamin D from their diets due to conditions like cystic fibrosis or short-bowel syndrome. Nevertheless, additional study is required to substantiate these advantages.
Dr. Singh suggests that people who live in places with limited sunlight could find it advantageous to use these lamps occasionally. “However, it’s crucial to wear eye protection when using sun lamps to shield the retina from harmful ultraviolet rays,” he states.
Not to be confused with light therapy or light boxes, which do not emit UV rays, are sun lights. (According to the Mayo Clinic, light treatment can be beneficial in alleviating seasonal affective disorder during the darker months.)
Ask your doctor if trying a solar lamp is the correct decision for you and if they have any recommendations for a particular brand.
When to consult a physician if you lack vitamin D
However, get a blood test from your doctor if you’re worried that your vitamin D levels are too low or if you experience symptoms like tingling in your hands and feet, weakness, or muscle discomfort. Blood work can be ordered at any time by your doctor, but Dr. Singh advises having it done with your primary care physician at least once a year.
If the test results indicate that you are deficient in vitamin D, you can next work with your physician to determine the best course of action.
