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Nutrition

What is vitamin D good for?

29/06/20236 min read

From playing a pivotal role in maintaining healthy bones to helping fight off viruses, learn the benefits of taking vitamin D supplements from our guide.

Explore related topics

Nutrition

Vitamin D (cholecalciferol) plays an essential role in keeping us fit and well.

From helping to form and maintain healthy bones, to supporting good immune function, there are many benefits of making sure you get enough vitamin D each day.

In this article, we'll discuss what vitamin D is good for, why you’d consider taking a supplement, some of the more common symptoms of a vitamin D deficiency, and how it might even help boost testosterone levels in men.

Skip to: What is vitamin D? | 7 benefits of vitamin D | The benefits of taking a vitamin D supplement | Common symptoms of vitamin D deficiency | Vitamin D benefits for men

What is vitamin D?

A slight misnomer, the ‘sunshine vitamin’ isn't a vitamin at all, but instead, a fat-soluble hormone that’s main functions are to control the levels of calcium found in the bloodstream and regulate bone metabolism.¹

There are only 3 known sources of vitamin D: diet, sunlight and supplements.²

Unfortunately, it can be difficult to get enough vitamin D through diet alone. While your body can make around 90% of the vitamin D it needs from just 10-30 minutes of sun exposure each day,³ unless you are in a country with year-round sunshine, you may find yourself deficient in the winter months.⁴

8 benefits of taking vitamin D

Building strong bones

Vitamin D plays a vital role in the musculoskeletal system as it aids the renewal of bone tissue which helps our bones grow strong. It also helps the body to absorb calcium properly, which is essential for bone health, and without sufficient levels of vit D, our bones can become thin, brittle or misshapen.⁵

If the body is not able to absorb enough calcium, you could develop either osteomalacia or osteoporosis – two conditions characterised by weak bones that are more likely to fracture. Increasing your vitamin D levels could help remineralise bone structures, making them more robust and keeping you stronger for longer.

Keeping muscles strong

Muscle weakness may be another side effect of low vitamin D levels, especially in the elderly. Recent studies have recognised that vitamin D could play a significant role in muscle function, strength, recovery and even athletic performance.⁶

Researchers have now located vitamin D receptors (VDR) in muscle cells, the activation of which stimulates enhanced muscle contractions and movement.⁷ VDRs are found on the fast-twitch muscle fibres, which are built for rapid bursts of energy and movement, therefore are often the first to respond to a fall.⁸

It is this finding that may explain the decreased fall risk in the elderly, as improved muscle strength and increased sports performance has been linked to adequate vit D levels.⁹

Managing joint pain

Not only is vitamin D instrumental in the development of strong bones and muscles, research also indicates that it plays a key role in keeping your joints healthy. They have identified a strong link between vitamin D deficiency and various joint diseases, including rheumatoid arthritis (RA).¹⁰

It has been suggested that vit D may have some therapeutic applications in the pain management of autoimmune diseases, such as RA, due to the studied anti-inflammatory and immunosuppressive (reduce/weaken the body's natural immune response) properties of the hormone.¹¹

Supporting general oral health

Another potential benefit of taking vitamin D is its positive effects on your oral health. Finnish researchers recently discovered that low vitamin D levels are linked to periodontitis or gum disease. Their study found that those with chronic gum disease also had very low levels of vitamin D in their blood.¹²

A further study in Norway has also found a link between tooth loss and exposure to sunlight – only 11% of those living in the south of the country lost teeth, compared with 65% in the north.¹³ If only we could get summer holidays on prescription…

Supporting a healthy immune system

Although vitamin D is best known for its role in keeping our bones healthy, there is some evidence that it may play a much larger role in the body through our immune responses.

A randomised, controlled study carried out in Japan revealed that vitamin D-deficiency in the winter may be one of the reasons we are more susceptible to certain types of seasonal flu.¹⁴ Vit D deficiency has also been linked to various autoimmune diseases such as multiple sclerosis, type 1 diabetes, lupus and inflammatory bowel disease.¹⁵

Although more research is needed to conclusively determine that vit D has some control of the immune system, the studies that have been published do indicate that vitamin D may have some interesting immunomodulatory properties (able to affect/control how the immune system functions).^16,17

Improving psoriasis

Various forms of vitamin D are commonly prescribed to treat psoriasis due to their efficacy and safety.¹⁸

The anti-inflammatory and immunosuppressant properties of the hormone could explain why vit D oral supplements are successful at keeping the autoimmune disease under control from the inside.¹⁹

If you are experiencing a flare-up, talk to your GP or a healthcare professional to see what the most suitable solution/treatment is for you, they may suggest a topical oil or ointment (in the form of calcipotriol).²⁰

Helping with other skin complaints

Scientists have also discovered that there may be a link between vitamin d-deficiency and some forms of acne (both acne vulgaris and nodulocystic acne). Multiple studies have revealed that patients suffering from acne often have much lower serum vitamin D levels, than those without. ^21,22,23

One study even found that the severity of the patient’s acne correlated with the extent of their vit D deficiency, and that taking oral vitamin D supplements led to a significant improvement in their acne inflammation.²⁴

That said, most research into this area have been small-scale studies so far, therefore more research is needed to conclusively establish a link between vitamin D and acne.

Improving your mood

Over the years, the link between light exposure and depressive symptoms has been widely investigated, but there is now an increasing specific research focus on the role that vitamin D may play in depression.

It is apparent that vitamin D interacts with an important part of our neuroendocrine system (the internal system that regulates how our bodies feel, respond and act through hormones) that regulates the production of important neurotransmitters like adrenaline and dopamine.²⁵ A Norwegian trial revealed a significant reduction in depressive symptoms in trial subjects that received a high dose of vit D daily for one year, showing a correlation between vitamin D and depression.²⁶

Another study reported that they found “a significant relationship between depression and vitamin D deficiency”.²⁷ While there is a need for further research to be carried out, if meeting our daily vitamin D requirements for the sake of our mental health calls for spending more time outdoors in the sun, eating a balanced and varied diet, or taking supplements, this would be a cost-effective and relatively simple solution for those at risk of depression.²⁸

Vitamin D benefits for men

The body is a complex ecosystem that requires a fine balance to run properly.

Making sure we have sufficient levels of Vitamin D is key for both men and women to have healthy bones, strong muscles and to keep moving freely.

While many of the benefits of vitamin D apply to everyone, there is some new research to suggest that it may have some impact on certain male hormones.

One study found that vitamin D supplementation resulted in elevated levels of testosterone in subjects, while another similarly revealed that men the tested with sufficient levels of vit D had significantly higher levels of testosterone than those that were deficient.^29,30

That said, research into this is still limited, and while ensuring you have good levels of vitamin D is important for your general health and well-being, it most likely won’t have a massive impact on your sex life.

Handpicked content: The 10 best foods to increase testosterone

The benefits of taking a vitamin D supplement

By now you hopefully have a better idea of the amazing benefits of vitamin D for the body – but why should you take a supplement?

While your body can make most of the vit D you need during the sunnier months, it's estimated that 1 in 6 adults in the UK currently have low levels of vitamin D.³¹

Unfortunately, most food sources are not naturally rich in vitamin D, so it can be hard to meet sufficient levels of the hormone (10 micrograms/400 IU daily) through diet and sun exposure alone.³²That’s why it may be a good idea for all adults to take a vitamin D supplement, especially in the winter months.

Common symptoms of vitamin D deficiency

While symptoms of vitamin D deficiency do vary from person to person, it may be worth checking your vit D levels if you think you might be at risk or experience some of the below signs:³³

Low mood
Weak muscles
Fatigue
Head sweats
Achy bones and joints
Getting sick more often
Weight gain

To find out more, check out our guide to identifying and treating vitamin D deficiency.

If you're keen to check your vitamin D levels, you could speak to your GP or take a simple at-home blood test.

The final say

Vitamin D is actually a hormone that's critical for keeping your body strong and healthy.

Although it's most known for the role it plays in calcium absorption and bone metabolism, there are many benefits to ensuring you have sufficient levels of the sunshine vitamin.

These benefits include regulating your mood, supporting your immune system and ensuring good oral health.

Having a deficiency in vitamin D has been linked to a number of debilitating conditions including depression, osteoporosis and rheumatoid arthritis.

While your body can make the hormone through sun exposure and get a form of vitamin D through certain foods, many people do not meet the daily requirement of 10mg vitamin D daily. Therefore, it is advised that all adults take a supplement from October to March to maintain healthy levels of vitamin D year-round.