Vitamin D and Depression

10 min

Apr 1, 2024 12:00:00 AM

We all feel fed up, miserable and sad at certain times in our lives. Most of the time, these feelings last for a few days, or maybe a week, but don’t really interfere with our day to day lives.

Often times, speaking with a friend or family member will help ease these feelings. However, if you develop clinical depression, also called major depression, these feelings don’t improve and may carry on for weeks, months or even years.

Does vitamin D help with depression? According to some research, it can, but the available evidence is somewhat conflicting. It appears that just as low thyroid can cause clinical depression, low vitamin D can do so as well. Dozens of studies have shown a high prevalence of vitamin D deficiency in depressed patients, and some studies have shown high-dose vitamin D is helpful in decreasing some symptoms of depression. As vitamin D is remarkably safe, and depression is remarkably dangerous (about 36,000 suicides/year in US), it seems reasonable to ensure those suffering from this disorder should maintain a high normal vitamin D status.

If you have depression, we recommend supplementing with physiological or even high dose vitamin D. Doses between 5,000 IU/day (125 mcg) and 10,000 IU/day (250 mcg) are safe and effective in increasing most individual’s vitamin D status to a healthy level. Some patients with depression may benefit from higher doses, such as 20,000 IU/day (500 mcg), but such doses require that you have your vitamin D level [25(OH)D] checked at least twice a year.

How common is depression?

Depression is a common condition. In the United States, around 1 in 10 people have depression, and around 1 in 3 of these cases will be severe. You’re more likely to have depression if you:[1]

Have a long-term health problem, such as diabetes, heart disease or arthritis
Lead an unhealthy lifestyle; for example, if you smoke, drink heavily, are inactive or overweight
Are female
Are between 45-64 years of age
Are black or Hispanic

What does depression feel like?

The symptoms of depression can come on gradually and may go unnoticed for some time. When this happens, it is often a friend or family member who first notices how your behavior and personality have changed. The symptoms of depression can be physical, such as fatigue or muscle aches, and feel like you’re just under the weather or have the flu.

Below are some of the main symptoms of depression; although symptoms range from person to person.[2],[3]

Loss of interest in life and inability to enjoy anything
Difficulty making decisions or concentrating
Feeling unhappy most of the time
Feeling tired and difficulty sleeping
Loss of confidence and self esteem
Antisocial behavior
Feeling numb, despairing and empty
Change in appetite

If you have these symptoms, and they have lasted for more than a few weeks, talk to your physician.

What causes depression?

It appears that many things can cause depression, but we are unsure of the exact cause. Sometimes there is one main trigger, such as the death of a loved one, but there a number of different factors that may play a part. Although the factors leading to depression differs between individuals, the most common causes include:[4]

Major life changes – such as divorce, changing your job, moving home or the death of a loved one
Physical illness – particularly life-threatening illness such as cancer, painful conditions such as arthritis and hormonal problems such as an underactive thyroid gland
Personal circumstances – being alone or stressed, for example
Family history of depression
Individual personality traits, especially emotional resislence
Regular heavy drinking

What is the link between depression and vitamin D?

Vitamin D plays a vital role in many aspects of human health, and researchers are now discovering that vitamin D may play a role in many other areas of health as well.

Vitamin D receptors have been found in many parts of the brain.[5] Receptors are found on the surface of a cell and on the genes inside the cell where they receive chemical signals. By attaching themselves to a receptor, these chemical signals direct a cell to do something, for example, to act in a certain way, to divide or die.

Some of the receptors in the brain are receptors for vitamin D, which means that vitamin D is acting in some way in the brain. These receptors are found in the areas of the brain that are linked to the development of depression. For this reason, vitamin D has been linked with depression and with other mental health problems.

Exactly how vitamin D works in the brain isn’t fully understood. One theory is that vitamin D affects the amount of chemicals called monoamines, such as serotonin, and how they work in the brain.⁵ Many anti-depressant medications work by increasing the amount of monoamines in the brain; indeed the rate-limiting enzyme that makes serotonin is at least partially regulated by vitamin D. Therefore, researchers have suggested that vitamin D may also increase the amount of monoamines, which may help treat depression.[6]

What does the research say in general about vitamin D and depression?

The amount of research about vitamin D and depression, as well as other mental health problems, is rapidly growing. It’s only recently that large scaled studies on vitamin D and depression have been conducted. But the research in this area has given some conflicting results.[7]

Some of the reasons why mixed results have been produced from studies on vitamin D and depression include:

The use of different dosages of vitamin D supplements for different lengths of time
Varying parameters defining vitamin D sufficiency and efficacy of treatment
Different study populations
The use of different tools to measure depression and mental health
Administering vitamin D at different frequencies – in some studies, people are asked to take vitamin D every day, whereas in other studies, people take vitamin once a week or once a month.

In some research studies, the amount of vitamin D given has been small, much less than the 5,000 IU to 10,000 IU a day that the Vitamin D Council recommends. Insufficient doses of vitamin D decreases the likelihood of producing significant clinical findings. Remember, the maxim in the medical field is that “dose makes the medicine.”

There are a number of strong research studies from the last few years that looked specifically at vitamin D levels and depression. For example, in a review of the research about vitamin D and depression,[8] researchers analyzed all of the published research about depression and vitamin D. They included the high-quality research studies that explored whether:

A lack of vitamin D in the blood makes increases the likelihood an individual will develop depression
Taking a vitamin D supplement can improve or prevent depression

The researchers found more than 5,000 research articles; however, just 13 explored this area effectively. More than 31,000 people took part in these 13 studies. The results showed that there is a relationship between low levels of vitamin D in the blood and depression. However, the research didn’t show whether vitamin D was the cause or effect of depression. There was also no clear answer as to whether taking supplements was effective at treating or preventing depression.

A research study from Norway[9] found that people with a low level of vitamin D in their blood had more symptoms of depression. This research also found that taking vitamin D, particularly in large amounts, improved the symptoms of depression. The biggest effect happened in those people with the most severe symptoms.

However, this research only looked at people that were overweight, so it’s not possible to say whether the results would be similar for everyone. All of the participants also took a calcium supplement, and the researchers suggest that this could have affected the results; for example, the effects may be attributed to the combination of vitamin D and calcium, rather than vitamin D on its own.

A second research study from Norway[10] also looked at whether the symptoms of depression were related to vitamin D blood levels. The study also looked at whether taking a vitamin D supplement affected the symptoms of depression in people who had low vitamin D levels. The results showed that:

Low levels of vitamin D in the body are linked to the symptoms of depression
When people with low vitamin D levels took a supplement, it improved their vitamin D levels, but had no effect on their symptoms of depression
Low vitamin D levels could be the result, rather than the cause of depression

Although this study used a sufficient dosage of vitamin D supplement, it lasted only six months. The researchers suggested that because depression is a condition that tends to develop slowly and last a long time; a longer study might have shown different results. The study participants also had either no symptoms of depression or very mild symptoms, which, of course, would influence the results. If one is studying if vitamin D helps depression, it needs to be given to subjects with depression.

A study of people who suffered ischemic stroke caused by blood clot in China found that six months after the stroke, those with low vitamin D levels had a much higher prevalence of depression than those with higher concentrations.[11] Studies such as this one are a reason to take adequate doses of vitamin D if you have depression.

A study in Sweden found that those who attempted suicide had significantly lower vitamin D levels than non-suicidal depressed patients or healthy controls.[12] They also had higher concentrations of pro-inflammatory cytokines, which have been observed in other suicidal patients. Cytokines are small proteins emitted by cells to signal other cells. Vitamin D is known to reduce the levels of pro-inflammatory cytokines.

A study in the Netherlands, involving 1,102 people aged 18-65 years with current depressive disorder and 790 with former but not current depressive disorder, found lower vitamin D levels among those with current depressive disorder and lower symptom severity for those with higher vitamin D levels. There was also a significant correlation between vitamin D status and developing depressive symptoms at a 2-year follow up.[13]

A cross-sectional study in Finland found a significant inverse correlation between depressive disorder and vitamin D status. Those with vitamin D levels above 22 ng/mL (56 nmol/L) had a 35% lower risk of depressive disorder than those with vitamin D levels below 14 ng/mL (34 nmol/L).[14]

Key points from research

Research shows a link between low levels of vitamin D in the blood and symptoms of depression.
However, research hasn’t yet shown clearly whether low vitamin D levels cause depression, or whether low vitamin D levels develop because someone is depressed.
Lack of vitamin D may be one of many factors that contribute to a depressed mood.
The effects of vitamin D on depression may take a long time to work, years for example.[15] This means that research carried out over short periods of time may not show any impact of vitamin D on depression.
People who have depression go outdoors less, so they are less likely to have adequate vitamin D in their blood.
Some researchers have suggested that giving vitamin D supplements may work for depression when someone has very low levels of vitamin D to begin with. Taking a vitamin D supplement would not help people who already have sufficient vitamin D levels.

What does this mean for me?

Research does seem to show that there is a link between vitamin D and depression. However, we don’t know exactly what that link is.

Research has not yet clearly shown whether low levels of vitamin D cause depression, or whether depression causes low levels of vitamin D. We don’t know whether taking a vitamin D supplement or getting more vitamin D by exposing the skin to the sun will help to prevent or ease the symptoms of depression.

If you have depression, and want to take vitamin D, it is unlikely to make your symptoms worse or cause you any harm (as long as you’re taking less than 10,000 IU/day). However, you may not see any improvement in your symptoms either. It is reasonable for every patient with depression to take 5,000 to 10,000 IU/day (125 to 250 mcg/day).

If you have depression you shouldn’t take vitamin D in place of other treatments or anti-depressant medicines. Speak to your physician for more advice about treatments and taking supplements.

Did you know?

Exposing your skin to the sun to get vitamin D enhances your mood and energy. Generally, a little bit of sun exposure is linked to a better mood, while tanners commonly report feeling more relaxed than non-tanners. One research study found that β-endorphins increase after sun exposure, and β-endorphins make you feel good! Thus, those feeling depressed should try to spend some time in the sun when one’s shadow is shorter than one’s height, daily if possible.

References

[1] Treatment Works: Get Help for Depression and Anxiety. Centers for Disease Control and Prevention.

[2] Depression. Royal College of Psychiatrists.

[3] Depression. Mind, the mental health charity.

[4] Depression. Royal College of Psychiatrists.

[5] Eyles, D.W., Smith, S., Kinobe, R., et al., Distribution of the vitamin D receptor and 1 alpha-hydroxylase in human brain. J Chem Neuroanat, 2005. 29(1): p. 21-30.

[6] Kjaergaard, M., Waterloo, K., Wang, C.E, et al., Effect of vitamin D supplement on depression scores in people with low levels of serum 25-hydroxyvitamin D: nested case-control study and randomised clinical trial. Br J Psychiatry, 2012. 201(5): p. 360-8.

[7] Anglin, R.E., Samaan, Z., Walter, S.Det al., Vitamin D deficiency and depression in adults: systematic review and meta-analysis. Br J Psychiatry, 2013. 202: p. 100-7.

[8] Anglin, R.E., Samaan, Z., Walter, S.Det al., Vitamin D deficiency and depression in adults: systematic review and meta-analysis. Br J Psychiatry, 2013. 202: p. 100-7.

[9] Jorde, R., Sneve, M., Figenschau, Y, et al., Effects of vitamin D supplementation on symptoms of depression in overweight and obese subjects: randomized double blind trial. J Intern Med, 2008. 264(6): p. 599-609.

[10] Kjaergaard, M., Waterloo, K., Wang, C.E, et al., Effect of vitamin D supplement on depression scores in people with low levels of serum 25-hydroxyvitamin D: nested case-control study and randomised clinical trial. Br J Psychiatry, 2012. 201(5): p. 360-8.

[11] Yue, W., Xiang, L., Zhang, Y.J., et al., Association of serum 25-hydroxyvitamin D with symptoms of depression after 6 months in stroke patients. Neurochem Res, 2014. 39(11): p. 2218-24.