How Vitamin D Impacts Stress, Mood, and Depression

Vitamin D is well-known for its role in bone health and immunity but did you know that this vitamin also plays a crucial role in emotional well-being? 

Many people that are low in vitamin D report feelings of lethargy, depression, and general low mood. While the exact mechanism for vitamin D’s role in emotional health hasn’t been nailed down, there are several theories behind the connection.

In this article, we’ll walk you through the role that vitamin D plays in your brain and highlight some of the research linking low vitamin D levels to depression, anxiety, and general mood disorders. 

Vitamin D and Your Brain

As mentioned, the connection between vitamin D and mood is still not completely understood. That said, there is strong evidence that vitamin D plays a crucial role in the health and function of your brain. 

For example, vitamin D receptors can be found throughout your brain and are specifically robust in the hypothalamus. Your hypothalamus plays an important role in keeping your body in a state of homeostasis, and it works by influencing your autonomic nervous system (ANS). When your ANS is out of balance, it can create feelings of stress and anxiety as sympathetic activation overwhelms parasympathetic mode, and you get stuck in fight or flight [1][2].

Vitamin D also appears to be important for brain development and has more recently been recognized as a neurosteroid and neuroprotective nutrient. In a rat study, offspring deficient in vitamin D displayed neurological issues such as learning and memory problems [3][4].

All in all, while there’s certainly more to learn about vitamin D’s activity in the brain, what’s clear is that this nutrient plays a crucial role in maintaining homeostasis in this vital organ. 

Which brings us to the subject at hand; how does vitamin D impact mood?

Vitamin D and Depression

The most well-studied connection between vitamin D and mood is its place in depression. Study after study shows a significant correlation between low vitamin D levels and the incidence of depression. 

In a recent review of the research to date, the authors concluded that, in general, depressed subjects tend to have lower levels of vitamin D [5][6]. 

That said, the link between depression and vitamin D is a bit tricky; some questions have been raised as to whether low vitamin D causes depression or if people that are depressed stay inside more, limiting their access to sunlight, and are therefore creating a vitamin D deficiency.

On the other hand, evidence shows that people with low vitamin D experiencing depression observe a therapeutic effect when they start supplementing with vitamin D. Therefore, we may say that low vitamin D was, in fact, contributing to depressive symptoms. Does this mean vitamin D cures all depression? Not so much. 

Evidence also shows that although vitamin D can boost the mood of those deficient, in those replete in vitamin D, supplementation doesn’t seem to do much [5].

The takeaway? If you’re experiencing feelings of depression, check your vitamin D levels – if they’re low, there’s a good chance that supplementation will help to boost your mood. 

A great example of the vitamin D – depression connection is seen in people with seasonal affective disorder (SAD). Individuals with SAD are notoriously low in vitamin D due to lack of sunlight, and they’re also notoriously…sad. SAD is a condition caused by a lack of sunlight and is generally seen in areas with more dark, cloudy skies than sunny days [7].

While the connection between SAD and weather is pretty clear, it also appears that vitamin D plays a significant role in the onset of depression associated with this condition. In one study, subjects experiencing SAD that received 100,000 IU of vitamin D showed significant improvement in their depression scores [8].  

Again, although there is no clear explanation for the relationship between SAD and vitamin D, researchers have offered a few potential theories:

1. Low vitamin D may cause an imbalance in calcium homeostasis, which in turn impacts the equilibrium between GABA (an inhibitory neurotransmitter) and glutamate (an excitatory neurotransmitter) [9]. 
2. Due to its role in the immune system, low vitamin D may instigate inflammation and therefore enhance the progression of depressive symptoms [10][11].
3. Vitamin D modulates the HPA axis, which is responsible for the production of dopamine and serotonin. With low vitamin D, these two neurotransmitters may become imbalanced or deficient, directly impacting mood [12][13].

Vitamin D and Anxiety

Many of the same mechanisms suggested for the relationship between vitamin D and depression also apply to the connection between vitamin D and anxiety. 

For example, vitamin D’s role in regulating your HPA axis could create imbalances in your nervous system, instigating feelings of stress or anxiety. Similarly, as vitamin D impacts the balance of GABA and glutamate, high levels of glutamate with low levels of GABA could increase feelings of anxiety and general unease [14][15].

And finally, some research suggests that, much like depression, inflammation and oxidative stress are at the root of anxiety. Given vitamin D’s role in regulating the immune system, it could also play a role in these pathways [16]. 

Aside from these potential mechanistic explanations, clinical research also shows an inverse relationship between vitamin D status and anxiety. Specifically, several studies show that lower levels of vitamin D are a strong predictor for anxiety symptoms [17][18][19].

Furthermore, research also supports the use of vitamin D supplementation for calming signs of anxiety. In one randomized controlled trial, participants receiving 1600 mg of vitamin D for six months showed improved anxiety symptoms. In another trial, participants with Crohn’s disease were given either high-dose or low-dose vitamin D supplements. While only the high-dose group saw changes in Crohn’s symptoms, all participants saw improvements in anxiety [20][21].

Vitamin D and General Mood and Well-being

While depression and anxiety are pretty easy to spot, many people struggle with general feelings of malaise or low mood. Of course, myriad factors can contribute to feeling low, but studies indicate that vitamin D may be one of those factors. 

In one randomized trial, researchers examined the effect of vitamin D supplementation on feelings of well-being by providing a dose of either 600 IU of vitamin D per day or a higher dose of 4000 IU per day. With consistent supplementation, both groups in the trial reported a significant improvement in well-being as quantified by a well-being questionnaire [22]. 

In a systematic review of the literature on vitamin D and psychophysiological variables, investigators found that vitamin D plays a strong role in regulating and maintaining psychological health. In general, they found strong evidence that an increase in circulating vitamin D levels can play an important role in mental well-being, while low vitamin D levels are associated with a greater risk of developing psychological disorders [23]. 

Takeaway

Mental health is a subject that’s received a lot of attention in the last several years as research continues to unveil the many factors that go into maintaining a state of optimal well-being. 

While life circumstances can throw you for a loop, there are other aspects of emotional well-being and resilience that are less obvious, including nutrient status and hormonal balance.

Among the nutrients studied for their impact on emotional well-being, vitamin D has garnered much-deserved attention due to its role in immunity, brain function, and hormonal balance. 

We still have a lot more to learn, but the key takeaway from the research so far is this: if you are experiencing any type of mood or mental imbalance, check your vitamin D status. If you find you’re low, try to include more vitamin D-rich foods in your diet like fatty fish, eggs, or mushrooms. And if you can’t get sufficient vitamin D from your diet,  start supplementing with our Vitamin D3 Complete to ensure your body is getting what it needs.

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