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Can Vitamin D reduce anxiety?

Vitamin D is usually associated with healthy bones. But it could also have a link to anxiety and mental health? Research suggests it might.

What is it?

Let's start with a definition. Here is what Wikipedia says:

"Vitamin D refers to a group of fat-soluble secosteroids responsible for increasing intestinal absorption of calcium, magnesium, phosphate, and zinc and multiple other biological effects."

That definition is a rather technical explanation, so let's break it down into something the rest of us can understand.

First, it is not actually a vitamin. It is a type of hormone, like testosterone and oestrogen. In that sense, it is poorly named.

This is an important difference. Vitamins are things that we need but that the body cannot make itself, so has to acquire from food. With Vitamin D, this is not the case: the body can make its own.

There are five different kinds of Vitamin D. We are primarily concerned with cholecalciferol, also known as D₃.

Why do I need it?

Vitamin D is essential for strong and healthy bones, and also affects your teeth and muscles as well. It does all of this by helping to regulate the amount of calcium and phosphates in your body.

It boosts your immune system, too.

Research also suggests it affects your mental health. I will discuss this research below.

How do we make it?

D₃ is produced by our skin. There are several factors which affect how effectively this is done:

• How much sunlight you get. In the winter the sunlight is weaker, days are shorter, and we spend less time outside. This can result in us not getting enough.
• Age. Older skin produces less D₃. Therefore, as we grow older, we are able to produce less and less of it.
• Skin colour. Lighter skin has less Melanin, which blocks D₃ being produced. Therefore, if you have darker skin, you will find it harder to produce D₃.

As a general rule, anything that stops you getting sunburnt will also reduce your ₃ production. For example, covering up with clothing or sunglasses, or wearing suncream, will reduce the amount your skin produces.

How does it affect mental health?

Our levels of D₃ seem to affect our mood. Ensuring we have enough D₃ will mean we feel more positive about life and therefore worry less.

A study looking at Vitamin D supplements found that they reduced the symptoms of depression¹. They split participants into two groups. Half of them received supplements, and the half received nothing (this is known as the control group).

They found:

"A trend toward a greater decrease in the BDI [Beck Depression Inventory] was observed in the vitamin D group than in the placebo group."

Similarly, a meta-analysis published in 2014² concluded:

"A meta-analysis of all studies without flaws demonstrated a statistically significant improvement in depression with Vitamin D supplements. Vitamin D supplementation (≥800 I.U. daily) was somewhat favorable in the management of depression in studies that demonstrate a change in vitamin levels, and the effect size was comparable to that of anti-depressant medication."

You can find out if your mood is low using our online assessment tool.

It can also be effective in fighting seasonal affective disorder (SAD) as well as providing a range of physical health benefits. See this article on Jen Reviews for more information.

How do we explain these results?

There are several ways in which we could interpret a correlation between D³ levels and mood.

First, we know that going outside and getting some fresh air. This also causes you to have higher D³ levels. So, it could be that there is a correlation here, but it is not that D³ improves your mood: it could be that going outside both improves your mood and levels of D³.

The research above suggests there is a stronger link, though. This is because just using supplements, rather than going outside, seems to improve mood.

Another possible explanation is that some people's anxiety and depression is caused by lack of D³, but that other people's is not. Therefore, it will only help the people who are D³ deficient but won't help the rest of us.

Do I need more of it?

It is difficult to generalise the answer to this question because it depends on you and your specific circumstances.

If you spend a lot of time outdoors, for example, you probably get plenty. However, if you spend most of your time indoors (elderly people in care homes being a classic example), you may not get enough.

The time of year also has an effect as you will get more during the summer and less during the winter.

Vitamin D is fat-soluble³, though, which means that when the body has enough of it, it stores the extra in fat tissue to use later.

As a rule of thumb, you want to be spending one hour outside per week during the middle of the day (10 am to 3 pm)⁴.

If you think you are at risk, speak to your doctor.

What are good sources?

The best way to get vitamin D is being outside in the sunshine.

This can be difficult in Winter if you live at a high latitude such as Northern Europe. However, you can also get Vitamin D from some foods⁵. These include:

• Oily fish
• Red meat
• Liver
• Eggs

Only small amounts are found in food, so sunlight is a far better source.

Should I take supplements?

Maybe. There is mixed evidence on whether supplements help.

In 2014, the Cochrane Collaboration published a major review looking at 159 clinical trials². They concluded:

"Vitamin D₃ seemed to decrease mortality in elderly people living independently or in institutional care."

So, there is some evidence that taking supplements is helpful for the elderly, who are a risk group. For the rest of us, there is limited evidence that it is helpful. A 2016 study by the University of Auckland⁶ concluded:

"Vitamin D supplements unnecessary for healthy adults. There is no high quality evidence to suggest that vitamin D supplementation is beneficial for other conditions such as heart disease, stroke, and some cancers - and ongoing trial results are unlikely to alter these conclusions."

So, supplements may or may not be beneficial for everyone. However, that does not take account of mental health. When we add this into the mix, and the research showing that healthy levels of D³ do seem to improve our mood, the argument is far more compelling.

You could discuss it with your doctor, or you could just try them and see if you notice a difference.

What are the side effects?

Taking supplements is, on-the-whole, safe. Studies show that it taking supplements will make you healthier and live longer⁷.

However, this should only be done within prescribed limits. Taking 10mcg is fine, taking 100mcg is less safe⁵. That is because it can build up in the body and cause adverse effects.

These include:

• Elevated blood calcium levels, which can cause hypercalcemia
• Kidney damage
• Excessive thirst
• Changes in cholesterol levels⁶

There is no evidence that taking supplements at the recommended levels is harmful⁸.

Conclusion

Vitamin D, specifically D³, affects our mood. The evidence shows that when we are D³ deficient, our mental health suffers.

Most people probably get enough sunlight to generate sufficient levels of D³. But, if you are in a risk group, or don't get enough time outside, you may be deficient.

This can be fixed by taking supplements. These are safe if used at low levels, but discuss with your doctor if you have any concerns.

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Published 28 August 2017. Written by Chris Worfolk.

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