In the past year, much attention has been brought to vitamin D in light of the pandemic with some research emerging that vitamin D might help safeguard people from severe cases of COVID-19. But beyond its potential protective role in the ongoing war against coronavirus, vitamin D is also a boon for overall immune health.

So how can you make sure you’re getting enough of this essential nutrient? Vegans or those who are predominantly plant-based, in particular, need to pay close attention to their diet to make sure they’re getting enough vitamin D. “Vitamin D is one of the fat-soluble vitamins (along with vitamin A, E, and K) that is naturally present in a handful of foods, fortified into other foods, or available in supplement form,” says Mackenzie Burgess, R.D., nutritionist and recipe developer at Cheerful Choices. “For the average adult, you should be getting 600 IU or 15 mcg/day to hit the Recommended Dietary Allowance (RDA),” she adds, noting that it’s also possible to get vitamin D from being outside in the sunshine as the sun's UV rays help convert vitamin D to its active form in the body.

“Researchers suggest about 10-30 minutes of sun exposure daily to meet your vitamin D needs,” she says, cautioning that vitamin D becomes more of a concern in the colder months with less time outside and less exposure to the sun. Take note that we always recommend wearing sunscreen when you're outside, even on cloudy days, to reduce your risk of sun-damaged skin.

For those over 70, it is 800 IU daily and some experts think our vitamin D needs are much higher, such as the Endocrine Society, which says people may require 1,500-2,000 IU per day.

Also worth noting: “A person’s ability to manufacture vitamin D [from UVB sunlight] decreases with age, so by the time people enter their senior years, their bodies make as little as 40% of the vitamin D made in childhood,” shares Elizabeth Somer, M.A., R.D., author of Food and Mood, and medical advisory board member to Persona Nutrition, a personalized nutrition program. “As a result, dietary/supplemental intake becomes increasingly more important with each passing decade with every season and all year long.”

Plant-Based Foods With Vitamin D

Mushrooms are the only plant-based food that contains vitamin D naturally, and while plant-based milk, orange juice, cereals, and the like may be fortified with vitamin D, it may still be tough to get enough vitamin D from food sources alone. That’s why a supplement may be your best bet: “When choosing a supplement, look for one that is third-party tested to ensure the best quality. Look for either a USP or NSF label on the bottle. Vitamin D supplements can range from 200 IUs and 10,000 IUs,” offers Burgess “The amount to take may vary from person to person but in general, Vitamin D3 is typically preferred because it’s converted more efficiently than vitamin D2. When in doubt, talk to your doctor or dietitian about the best vitamin D supplementation for you.” More specifically,

Now that we’ve got the three bases of vitamin D sources covered—getting direct sunlight, food, and supplements—let’s dive into the health benefits of vitamin D.

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The Benefits of Vitamin D

1. It can support immunity

“Vitamin D is known to have positive effects on the immune system. It can strengthen aspects of the immune system that are able to fight off colds and flu,” says Dr. Nicole Avena, Ph.D., Assistant Professor of Neuroscience, Mount Sinai School of Medicine and Visiting Professor of Health Psychology, Princeton University, who penned the book What to Eat When You’re Pregnant. These days, vitamin D is making headlines because of its potential impact on the severity of coronavirus. “It has been found that people who are vitamin D deficient are more likely to catch COVID-19, and the mortality rate in this population is also higher. Patients treated with high doses of vitamin D while having the coronavirus needed less intense treatment in order to return to health,” says Avena. Of course, all this research is new and emerging, so that’s worth keeping in mind when evaluating the strength of these findings.

2. It helps with bone formation and maintenance

For bone health, you’ll want to ensure you’re getting enough vitamin D, too. “Vitamin D is responsible for assisting with calcium absorption in the small intestine and helps the body maintain adequate serum calcium levels. Because of this, it’s necessary for bone growth and remodeling [the lifelong process where mature bone tissue is removed from the skeleton and new bone tissue is formed] and helps reduce the risk of bones becoming thin or brittle,” says Somer.

“A vitamin D deficiency in children can result in rickets, and in adults is seen as osteomalacia and osteoporosis,” she adds.

3. It may help with depression

Time in the sunshine each day keeps the doctor away? There’s a growing body of evidence that vitamin D may help with depression. “Almost all cells in the body have receptors for vitamin D, which implies this vitamin is important for many more functions than just bone,” explains Somer. “For example, recent research suggests vitamin D is important in the prevention and treatment of depression,” she continues, pointing to this meta-analysis of vitamin D deficiency and depression in adults.

Expanding on Somer’s words, Trista K. Best, MPH, RD at Balance One, says: “Vitamin D has been shown to significantly improve and prevent depressive symptoms.” She notes that this is an especially important benefit during the winter months when we have limited exposure to the sun.

4. And with Seasonal Affective Disorder

Another important link between vitamin D and mood: Low levels of vitamin D have been found in people with Seasonal Affective Disorder, or SAD, a type of depression that’s typically linked to the fall and winter months.

“One study reported in the 2014 issue of Medical Hypotheses found a link between vitamin D deficiency and SAD. Lack of this vitamin appeared to be a contributing factor in the development of this depression,” comments Dr. Carrie Lam, M.D., “The lack of seasonally available sunlight seemed to be the primary factor in the development of SAD. This may be because vitamin D is involved in the synthesis of serotonin and dopamine, neurotransmitters involved in the development of depression. Low levels of these chemicals are associated with depression. When there is less vitamin D being produced by sunlight, lower levels of these chemicals can lead to SAD.”

5. It may reduce your risk of certain cancers

File this under impressive: “Research has shown breast cancer cells grow faster in an environment with low levels of vitamin D. This research from the Stanford University School of Medicine indicates a significant and direct link between the amount of vitamin D circulating in the body and the expression of ID1, a gene that is known to be involved in tumor growth and metastasis of breast cancer,” explains Lam, citing this study.

Vitamin D deficiency may also play a role in the development of prostate cancer. “The journal Clinical Cancer Research published a study in 2014 showing a link between low levels of vitamin D and prostate cancer. Prostate cancer is the most frequently occurring cancer in men and the second most common cause of death for American men,” says Lam. “This study showed that low levels of vitamin D led to aggressive growth of prostate cancer in European-American and African-American men. In the study, 667 men between ages 40 to 79 underwent prostate biopsies. African-American men with low levels of vitamin D had an especially increased risk of testing positive for prostate cancer.”

6. It may lower your risk of heart disease

Protecting your heart is another important reason to ensure you’re getting adequate vitamin D. “Low levels of vitamin D have been associated with increased risk of heart disease,” says Lam. Research shows 70 percent or more of those who underwent a coronary angiogram [a type of procedure to detect blockages in the coronary arteries] had a low level of vitamin D,” she continues, adding that the American College of Cardiology says that more severe heart disease has been found in patients with vitamin D deficiencies.

7. It may help you slim down

“Vitamin D may also help with weight loss efforts,” says Best. “One study showed vitamin D may reduce appetite in such a way that weight loss resulted,” she continues, referencing this study on calcium plus vitamin D supplementation and fat mass loss in females who have very low calcium intake.

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