Seven benefits of vitamin D

Side view portrait of a happy woman breathing deep fresh air at sunset in a house balcony
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The benefits of vitamin D have long been reported, but are you getting enough of this nutrient in your everyday diet for optimal health and wellbeing? Whether you opt for a daily dose of sunshine, a supplement, or fortified foods, getting enough vitamin D is vital when it comes to keeping your bones strong and your immune system firing on all cylinders. 

Vitamin D is a nutrient with abundant benefits for our physical and mental health. However, very few foods naturally contain vitamin D besides fortified foods and drinks such as milk, breakfast cereals, yogurts and orange juices. The best food sources of vitamin D are fatty fish such as salmon, mackerel, and fish liver oils, while eggs, cheese and mushrooms contain small amounts. 

Our bodies also make vitamin D when our skin is exposed to the sun. But as we all know, it’s important to wear sunscreen and stay in the shade to reduce our risk of skin cancer. Older people and people with dark skin struggle to make enough vitamin D in sunlight. So how can we make sure we’re getting enough of this vital nutrient?

One of the easiest ways to get enough vitamin D into our everyday diet is through the best vitamin D supplements, available in capsules, sprays and chewables. Make sure you check out what levels of vitamin D the National Institutes of Health recommends, depending on your age.

What are the benefits of vitamin D?

According to Rahaf Al Bochi, registered nutritionist and spokesperson for the Academy of Nutrition and Dietetics, there are several benefits to vitamin D. “Vitamin D helps absorb calcium and phosphorus, which is important for bone and teeth health,” she says. “Vitamin D also plays a role in disease prevention such as heart disease and type 2 diabetes, reducing the risk for depression.”

Rahaf Al Bochi, RDN
Rahaf Al Bochi, RDN, LDN

Al Bochi is a registered nutritionist and spokesperson for the Academy of Nutrition and Dietetics. She practices through an intuitive eating approach and specializes in the Mediterranean eating pattern. Al Bochi is a member of the Academy's Nutrition Entrepreneurs dietetic practice group and a graduate of Ryerson University.

We’ve taken a deeper dive into some of these key benefits, along with others, to discover what this important nutrient can do for our physical and mental wellbeing.

1. It supports the immune system

Vitamin D is already known to help our immune system resist invading bacteria and viruses, according to the Centers for Disease Control and Prevention (CDC). But the recent Covid-19 pandemic has shown how powerful vitamin D can be in supporting our immune systems against more severe diseases.

A review released in 2022 into the role vitamin D plays in fighting Covid-19 found that low vitamin D levels may increase the risk of infection and may also increase its severity. Researchers concluded that vitamin D supplementation could protect people from respiratory diseases and prevent it from progressing in severity, reducing the risk of death. 

Proteins are complex structures in the body. Here, the brightly colored and twisty blobs represent different immune system proteins on the outer layer of a T-cell, a type of white blood cell that helps the body to identify foreign invaders.

(Image credit: JUAN GAERTNER/SCIENCE PHOTO LIBRARY via Getty Images)

2. It builds strong bones and teeth

Vitamin D is vital to building and maintaining strong, healthy bones and teeth. It does this by promoting calcium and phosphorus absorption in the gut, which helps bones to mineralize, increasing strength and hardness.

Not getting enough vitamin D can lead to tooth loss and leave bones brittle and weak. It can even cause rickets in children and osteoporosis in older adults. With more than 53 million adults in the U.S. at risk of developing osteoporosis, vitamin D could be a powerful tool in increasing bone health. 

3. It supports a healthy heart

Vitamin D helps to regulate heart function and reduce blood pressure, while vitamin D deficiency is associated with heart problems, stiffening arteries and high blood pressure.

Although there is not enough evidence to support the idea that vitamin D supplementation can lower the risk of cardiovascular disease (CVD), many health experts argue that it reduces blood cholesterol levels and high blood pressure, both of which can contribute to CVD.

A doctor listening to a man's heart using a stethoscope

(Image credit: Getty/ Sarinya Pinngam / EyeEm)

4. May prevent type 2 diabetes

Vitamin D may help the body improve its sensitivity to insulin, which is the hormone that regulates blood sugar levels. This can reduce the risk of insulin resistance, which can lead to type 2 diabetes. Numerous studies, such as one published in the Biochemical Journal, have also linked vitamin D deficiency to developing type 2 diabetes. 

5. May inhibit cancer spread

According to the NIH, vitamin D can inhibit or slow the progressions of certain cancer tumors. This may be because of its anti-inflammatory effect or because it may be able to stop the tumor from growing blood vessels. 

A 2019 meta-analysis of trials into vitamin D supplementation and cancer incidence and mortality published in Annals of Oncology found that while vitamin D did not reduce cancer incidents, it significantly reduced cancer deaths by as much as 13%.

However, one study reported an association between a higher intake of vitamin A and invasive breast cancer, with subjects experiencing a 28% rise in risk. 

People with cancer should always speak to their oncologist before opting for vitamin A supplementation.

cancer cells illustration

(Image credit: Getty Images)

6. May reduce the risk of multiple sclerosis (MS)

Lots of studies over the years, including one published in the journal of Multiple Sclerosis and Related Disorders, have shown that people who get more sunlight exposure and vitamin D from their diet have a reduced risk of developing MS, an autoimmune disease affecting the central nervous system. As the NIH notes, people who live in hotter, more sunny countries rarely develop this condition compared to those who live in cooler, cloudier countries. 

Some experts suggest vitamin D supplements could reduce the risk of developing the disease or improve symptoms associated with MS, as a 2021 article published in Annals of Agricultural and Environmental Medicine argues. However, we need more evidence to be sure of the benefits. 

7. May reduce the risk of depression

More evidence is emerging that vitamin D can be an essential tool to support mental wellbeing. In 2020, a systematic review and meta-analysis published in Depression and Anxiety compared the effect of a vitamin D supplement and a placebo on thousands of participants with ‘negative emotions.’ Researchers found that vitamin D supplementation improved the mood of patients with major depressive disorder.

However, a 2021 review in the Journal of Clinical Medicine that looked into the use of vitamin D in healthy adults did not find consistent evidence to support the use of vitamin D in combating other mental health problems. Researchers also noted that some studies recommended physical activity in addition to supplementation or recommended food sources of vitamin D instead.

So while we can cautiously say vitamin D may have a mood-boosting effect, especially on those with depression, we need more research on how it does this and how it should be combined with other methods of supporting mental health.

This article is for informational purposes only and is not meant to offer medical advice.

Joanne Lewsley

Joanne Lewsley is a UK-based freelance writer and editor, covering health and lifestyle news and features. She mainly creates evidence-based health and parenting content and has worked with a number of global sites, including BabyCentre UK, Medical News Today, Fit & Well, Top Ten Reviews, and Yahoo!