What does vitamin D do for our physical and mental health?

What is vitamin D?

Interest in vitamin D and its role in our overall health is growing within the scientific community. The main question being “What does vitamin D do to our body?”. Also known as ‘the sunshine vitamin’ because it’s formed in our skin when we are exposed to the sun’s ultraviolet (UV) rays. Cholesterol in the skin is converted to cholecalciferol (D3) and ergocalciferol (D2), which travel in the bloodstream to the liver where they are metabolised to form calcidiol. These then head to the kidneys and are converted to the active hormone, calcitriol. Although the majority of our intake comes from the sun, it’s a fat-soluble vitamin. Therefore, the vitamin is naturally present in a few foods, added to others through fortification, whilst also being available as a dietary supplement.(1)

It’s hard to identify how many people are deficient because experts are still debating the recommended dietary allowances (RDA). Research suggests many people don’t acquire enough vitamin D. Around 24% of people in America are deficient, meanwhile areas of the world including Europe have higher rates of deficiency with about 40% of the population being deficient.(2)

So how much do we need? The average daily level of intake sufficient to meet the nutrient requirements of nearly all (97%–98%) healthy individuals Aged 1-70 is 10mg-600IU. Below we’ll take a look at the benefits of ‘the sunshine vitamin’ on our overall health, wellbeing and where to find it, while answering the question “what does vitamin D do?”.

Arthritis

Arthritis is a common condition that causes pain and inflammation in a joint. In the UK, more than 10 million people suffer from arthritis or other, similar conditions that affect the joints.(3) 

Vitamin D is essential for calcium absorption in the body, which plays a fundamental role in the maintenance of bone health, strength and skeletal integrity. What does vitamin D do in relation to arthritis?

Having enough of both vitamin D as well as calcium helps to protect against disorders including osteoporosis. This is due to the vitamin’s overall ability to promote calcium absorption, which is essential for building and remodelling bone.(4)

Research appears to suggest that vitamin D deficiency is highly prevalent in patients with arthritis. Furthermore, supplementation may be needed for the prevention of osteoporosis and for pain relief in patients.(5)

Immune function

The immune system is the body’s tool for preventing or limiting infection. Therefore, without it, the body would be unable to withstand attacks from bacteria, viruses, parasites, and more. What does vitamin D do in regards to the immune system?

The active form of vitamin D reduces the damaging inflammatory response of some white blood cells, while it boosts also immune cells’ production of microbe-fighting proteins. Hence, its positive effect on immune function. 

Research explored if taking daily vitamin D supplements does prevent influenza. Over a period of four months, half of the study participants received pills that contained 1,200 IU of vitamin D; the other half received placebo pills. Influenza rates in the supplementation group were about 40% lower than in the placebo group. Randomised control trials (RCTs) exploring the effectiveness of the vitamin in preventing respiratory infections have been mixed. However, a meta-analysis suggests that daily or weekly vitamin D does lower the risk of respiratory infections. Additionally, this effect was particularly prominent for very deficient individuals.(6)

Cardiovascular disease

Worldwide, cardiovascular diseases (CVDs) are one of the leading causes of death. Annually, an estimated 17.9 million people around the world die as a result of complications from CVDs. For context, this means that CVDs are responsible for 32% of all deaths globally.(7)

What does vitamin D do when it comes to treating CVD?

A recent study found evidence that vitamin D deficiency can increase blood pressure and the risk of CVD. Scientists collected information from up to 295,788 participants for a study.  Analysis revealed that the individuals with serum 25(OH)D at 25 nmol/l had 11% higher risk of CVD than those with concentrations of 50 nmol/l.(8)

Dr. Rigved Tadwalkar, a board certified cardiologist, stated the following : “this study establishes that it is worthwhile to check vitamin D levels for the purpose of assessing cardiovascular risk and, moreover, supplementing vitamin D for those who are most deficient.” Despite biological plausibility, plus positive research, further trial data needs to be completed before there is sufficient data to inform nutritional requirements.(9) 

Mental wellbeing

Vitamin D is involved in brain processes, and its receptors are present on neurons and glia in areas of the brain believed to be involved in the pathophysiology of depression.(10) 

However, the evidence is not 100% conclusive at this stage, but there is encouraging research which suggests the potential that the vitamin may have when it comes to treating depression. This asks the question: “what does vitamin D do in regards to helping with depression?”.

Various research has explored the link between vitamin D, sunlight and seasonal affective disorder (SAD). SAD is a form of depression which is closely linked with the seasons. Most commonly meaning that people who suffer from SAD have more prominent symptoms during autumn and winter when the days are short, as opposed to spring and summer. Light therapy, which involves exposing yourself to a particular bright lamp (used to mimic sunlight) may help to reduce symptoms of depression in SAD sufferers. 

Further research examined the effectiveness of light therapy against a dose of vitamin D in patients with SAD. The direct dose was more effective in reducing their symptoms.(11)

Additionally an intriguing link between deficiency and mental health complaints was discovered. This study found that people over the age of 65 with minor depression or major depressive disorder had 14% lower levels of vitamin D than the control group.(12)

Although an association between deficiency and depression has been found, clinical trials do not support these findings. The conclusion being that more RCTs examining the effect of supplementation among individuals who are both depressed and deficient are needed.(13)

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Athletic performance

In the context of sport, ergogenic aids are substances or techniques that enhance energy production, recovery and provide athletes with a competitive edge. Ergogenic aids have been categorised as pharmacological, nutritional, physiological, or psychological. They span from the use of legal and safe techniques (e.g. carbohydrate loading) to illegal and unsafe methods (e.g. anabolic-androgenic steroid use).

Due to a high level of competition and pressure within sport, many athletes try and gain any advantage they can. Surveys have shown that 76% of college athletes, and 100% of bodybuilders take some form of supplements to improve performance, which highlights the popularity of ergogenic aids.(14)  

Substances such as caffeine and creatine are often at the forefront when it comes to legal ergogenic aids and athletes are always on the lookout for others. Furthermore, research carried out with the purpose of examining what vitamin D does in the context of sports nutrition, and its potential for enhancing athletic performance have produced promising results. So, What does vitamin D do for enhancing performance? 

VO2 max

VO2 max is the maximum amount of oxygen the body can utilise during exercise. It’s a combination of how much oxygen-rich blood your heart can pump and the heart’s efficiency in extracting and utilising oxygen. What does vitamin D do when it comes to VO2 Max?

Vitamin D receptors are present in cardiac muscle and vascular tissue.(15)

Therefore, this indicates that the vitamin may influence VO2 max via transportation and utilisation of oxygen within the blood to various tissues. Multiple studies show a positive correlation between VO2max and serum 25(OH)D concentration (Measurement of serum vitamin D) in non-athletes. A potential reduced recovery time from high intensity training and improved force and power production could be a result of this. Positive correlations however were limited to males only. Confounding variables were also not addressed, such as multivitamin and supplement intake.(16)

Testosterone

Testosterone is a steroid hormone that stimulates development of male secondary sexual characteristics, produced mainly in the testes, but also in the ovaries and adrenal cortex. Moreover, it’s believed to regulate sex drive (libido), bone mass, fat distribution, muscle mass, strength, and the production of red blood cells and sperm.(17)

What does vitamin D do to testosterone levels? 

A cross-sectional study done on 2299 males showed that 25(OH)D levels had a positive correlation with testosterone and androgen levels in men.(18) Testosterone is an endogenous hormone important for muscular adaptations to exercise. Naturally low testosterone levels in young men have a correlation with  decreased protein anabolism, strength, and fatty acid breakdown, therefore athletes aim to utilise testosterone production.(19)

Although results suggest that supplementation may increase testosterone levels further RCTs are warranted to confirm this. 

Should I start taking vitamin D?

So far, there isn’t enough evidence to confirm that ‘the sunshine vitamin’ can treat depression, reduce your risk of arthritis, prevent CVD, improve your immune function and act as an ergogenic aid. Nevertheless, it is correct that many of us are likely to be deficient.

Health authorities recommend that the general public should consider vitamin D during the winter months, due to it being extremely unlikely that we acquire enough sunlight exposure. Furthermore, skin tone may affect the amount of vitamin D production from sunlight. People with a light skin tone seem to produce more of the vitamin from sunlight exposure than those with darker skin tones.(20)

In effect, increasing intake could be a smart health decision for everyone, even if its effects on physical and mental wellbeing are not totally clarified.

Sources of vitamin D

Even though the human body produces vitamin D when exposed to sunlight, it does come with its limitations. To reduce the risk of developing skin cancer, it’s advised to cover up, apply sun cream, and avoid being outside during peak sun hours. In addition, depending on where you live in the world, it may not be feasible to come by enough sunlight exposure all year round. That’s why it’s advised that some of our intake should come from food or supplements.

Taking a supplement may be helpful for some people. However, at Erbology, we always advise you to obtain your nutrients from healthy whole foods rather than tablets or capsules.

This is because you receive greater clarity over what you are consuming. You’re also likely to benefit from gaining a range of other healthy nutrients at the same time if you source your vitamin D from food.

For example, our Organic Hemp Seed Oil is a fantastic source. Yet it also contains vitamin E and omegas 3 and 6, all of which are needed to support your health. Try adding a spoonful to your daily routine to increase your intake. Its versatility means you could take it by the spoonful, use it in salad dressings, or even drizzle it over your favourite dishes.

Alternatively, our Organic Hemp Seed Powder also offers vitamin D, plus a dose of healthy plant-based protein and fibre. It’s ideal for adding into a post-workout smoothie or mixing into breads and cakes.

Fatty fish such as salmon and tuna are famously good sources as well. However, if you follow a plant-based diet, you should also look out for mushrooms (which should be grown in light) and fortified products like plant milks or breakfast cereals.

Does vitamin D improve our physical and mental health?

You should now have greater insight surrounding the question “What does vitamin D do for our physical and mental health?”.  

The majority of us don’t reach the RDA. Although the evidence is not 100% certain, there is encouraging research, suggesting the positive role that vitamin D does play when it comes to our physical and mental health. In addition, increasing intake through your diet is likely to be beneficial for many of us, especially during autumn and winter.  

The research exploring what the vitamin does in the context of sport nutrition is also growing. Therefore, if you happen to be an athlete, or are interested in improving your sporting performance, increasing your intake may be something to consider.

In the case you do decide to take a supplement, do your research because some capsules or tablets can provide you with too much, causing vitamin D toxicity. This can be damaging to your health. Consequently, it could cause too much calcium to build up in the body, which may weaken bones, damage kidneys and be bad for the heart. Instead, we’d advise making a conscious effort to include more vitamin D rich foods as part of your diet and sourcing vitamin D from sunlight if and when you can.

Related reading 

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