Vitamin D deficiency and Mental Health: Is There a Link? (SQ-150)
Your body needs proper amounts of vitamin D to sustain physical as well as mental health. Vitamin D is required to maintain healthy bones, heart and immunity. Vitamin D deficiency can lead to a range of health problems such as loss of bone density, weak and brittle bones (osteoporosis), softening of bones in children (rickets), heart disease, diabetes, poor immunity, thyroid problems, and other autoimmune disorders. Can vitamin D deficiency cause mental problems? In this blog we are going to explore how Vitamin D and mental health are linked and how does vitamin D affect brain function?
Vitamin D and Mental health
The adequacy of vitamin D in your body is not only important for your bone, heart and immune health but is also important to maintain your mental health and cognitive functions. Studies show that vitamin D deficiency can affect your mental health in many ways. For example, poor vitamin D status is known to increase the risk of depression. It is also being linked to poor memory, poor concentration and reduced cognitive abilities. Before we get to the part how vitamin D affects brain function, let's understand how vitamin D works in the body.
Almost every cell in the body has receptors for vitamin D. Calcitriol, the active form of vitamin D, binds to these receptors and this complex enters the cell's nucleus where DNA is located. These receptors then bind to the DNA, a process that activates genetic expressions leading to the production of proteins. These proteins are required for various cellular functions, such as absorption of calcium from the intestine, production of antibacterial proteins that boost natural immunity, and mechanisms that improve insulin sensitivity. These proteins also contribute to the anti-inflammatory properties of vitamin D. This chemistry between vitamin D and its receptors is responsible for how vitamin D works in the body.
Both vitamin D receptors and the enzymes that are responsible for the synthesis, and metabolism, of vitamin D in our body are present in the brain, especially in the regions that regulate mood and sleep. Did you know that the hypothalamus contains very high concentrations of vitamin D receptors? Hypothalamus is an area in the brain that is responsible for regulating mood and behavior. The presence of vitamin D receptors and major enzymes involved in the metabolism of vitamin D in the brain indicates the role of vitamin D in maintaining your mental and cognitive health.
However, the studies investigating the link between Vitamin D and mental health are mixed. While most studies show that people with mental health disorders such as depression tend to have poor levels of vitamin D, a few studies have failed to identify strong evidence for the benefits of Vitamin D supplementation on depression in healthy adults. 
Mental symptoms of vitamin D deficiency
A deficiency in vitamin D may not produce any symptoms in the beginning, making it difficult to catch. But a chronic deficiency presents as bone pain, extreme fatigue, muscle weakness and muscle pain, back pain and headaches. If you don’t spend enough time in the sunlight, and don’t take vitamin D supplements, these signs could indicate the need to get your vitamin D tested. The psychological symptoms triggered by vitamin D deficiency may look like those of depression and anxiety. Some symptoms of vitamin D deficiency indicating an effect on mental health include:
- Mood swings, and feelings of sadness
- Extreme fatigue
- Poor energy levels
- Trouble sleeping
- Brain fog
- Memory problems
- Poor concentration
These symptoms may indicate depression, anxiety or some other underlying health problem that can be best diagnosed and addressed by a certified health practitioner. But it is always better to get your vitamin D levels checked to understand if these symptoms are due to severe vitamin D deficiency in the body. Studies show that low vitamin D may have an effect on your mood and it may increase your risk of depression and anxiety.
Does vitamin D help with depression?
Depression is a serious mental health disorder that negatively impacts the way you feel, behave and even cope with life's challenges. Some common symptoms of depression include persistent feelings of despair and sadness, loss of hope, mood swings, loss of interest in activities that one previously enjoyed, having suicidal thoughts, insomnia or excessive sleepiness, social isolation, irritability, extreme changes in appetite, fatigue and sudden changes in weight.
Depression has many risk factors such as genetics, emotions surrounding death or loss of a loved one, major life changing events, medications and heavy drinking. It is a well-known fact that nutritional deficiencies can also increase the risk of anxiety and depression. For example, magnesium is one of the very important minerals that you need for a well-functioning nervous system. Magnesium deficiency can reduce your ability to manage stress and to remain calm in stressful situations, leading to anxiety.
Is there a link between vitamin D deficiency and depression? Vitamin D deficiency has been found to be associated with major depression, seasonal affective disorder (SAD), mood-related premenstrual symptoms in women, postpartum depression and decline in cognitive abilities in older adults.
Many studies in the past have found that poor vitamin D levels may have a role in the development of depression and other mood disorders. These studies also show that vitamin D deficiency may be a potential risk factor for depression. Some studies question whether poor vitamin D status causes depression or if depression causes low vitamin D levels.
Does improving our vitamin D level help with depression? Research suggests that vitamin D supplementation may be helpful in alleviating the symptoms of depression in patience with clinical depression. 
For example, this 2021 study supported the positive effects of vitamin D on mental health in children. It concluded that maintaining healthy levels of vitamin D in the blood should be recommended to prevent or reduce mental health problems. 
Another 2021 research published in Nutrients investigated the effects of Vitamin D supplementation on mental health in people suffering from diabetes. The health outcomes that were analysed in this systematic review included overall quality of life, depression, stress, and anxiety among others. Most of the studies in this review confirmed that vitamin D supplementation may have beneficial effect for depression and anxiety in individuals suffering from diabetes. 
This 2019 meta-analysis tried to assess the effect of Vitamin D supplementation on the symptoms of depression in people who are clinically diagnosed with major depression and found it to be favourable. 
Not all studies concur with such findings though. Some studies show that vitamin D supplementation has limited significant benefit in reducing the risk of depression or mood disorders. While more evidence is needed to recommend vitamin D supplementation as a mainstream strategy to manage depression, your overall physical and mental health depends on maintaining healthy levels of the sunshine vitamin. There is enough evidence to recommend that testing for and addressing vitamin D deficiency in people with depression could be a cost-effective approach to improve symptoms and other outcomes. 
Vitamin D and anxiety
Can vitamin D deficiency cause anxiety? Experts believe there could be a link between vitamin D deficiency and anxiety. A 2017 study showed that vitamin D supplementation can improve depression, anxiety and mental health in type 2 diabetic women with significant depressive symptoms and low vitamin D levels.  Another study found that vitamin D supplementation may help in improving the symptoms of anxiety in patients with depression and low vitamin D levels. 
Does vitamin D affect sleep?
Lack of sleep or sleep deprivation is known to increase the risk of health problems such as type 2 diabetes, obesity, heart disease, depression and even cancer. While people with insomnia have an increased risk of depression, people with depression have difficulty falling asleep or staying asleep. Depressed individuals usually find it difficult to get enough sleep in the night. Can low levels of vitamin D interfere with sleep quality?
The link between vitamin D deficiency and sleep quality is well established. It appears that vitamin D has a role in regulating sleep and inadequate levels can interfere with the amount of time you sleep you get and how well you sleep. Studies show that low levels of Vitamin D are not only associated with poor sleep but can also increase the risk of sleep disorders, such as sleep apnoea. [9, 10, 11] Several areas of brain that are involved in regulating sleep-wake cycle are found to have vitamin D receptors as well as the associated enzymes that control their activation. In addition, vitamin D also regulates the production of serotonin and melatonin, hormones that are involved in controlling mood and sleep-wake cycle.
In other words, vitamin D deficiency could be one of the reasons you may have trouble falling asleep and getting a refreshing, restorative sleep in the night. This can lead to excessive sleepiness, fatigue and drowsiness the day after. Can taking vitamin D supplements help you sleep better? This study showed that vitamin D supplements can help improve sleep quality, improve sleep duration and reduce sleep latency in 20-years-old to 50-year-old people with sleep disorder. 
Does vitamin D improve memory and cognitive functions?
Vitamin D is basically a steroid hormone that regulates the production of various neurotransmitters. It is also an anti-inflammatory and antioxidant, thus helps in protecting brain health. Vitamin D is also known for its role in clearing beta-amyloid plaque, sticky clumps of protein pieces that get formed in the spaces between the nerve cells. These plaques damage the neurons and produce symptoms of dementia in people with Alzheimer's disease. Studies have shown that people with Alzheimer's disease and other forms of dementia tend to have significantly low vitamin D levels.
In addition, studies have also long shown that people with low levels of vitamin D have an increased risk of developing dementia and loss of cognitive functions. Vitamin D status may even put older adults at the risk of decline in their cognitive abilities in the future. A 2022 study found that vitamin D status may be linked with risk of dementia and Alzheimer's disease in people with high blood sugar levels. 
Can vitamin D supplements help prevent memory decline or Alzheimer's? The results on this are mixed and we need more data to claim definitively if vitamin D supplementation can be used as a tangible strategy to prevent the risk of cognitive consequences such as a memory loss or to treat Alzheimer's. It is now very clear that vitamin D plays a much bigger role in your overall health, especially in mental health. It won't hurt to maintain a healthy status of vitamin D if you are at a risk for depression or memory loss. A study published in JAMA Neurology suggested that low vitamin D levels may lead to faster memory loss in the elderly. 
How does vitamin D help improve the symptoms of depression, anxiety and other mental disorders? Experts say that vitamin D achieves this through various mechanism. For example, Vitamin D helps in maintaining healthy serotonin levels, hormone associated with depression, anxiety, and other mood-related parameters.
Interestingly, experts believe that many factors contribute to the incidence of vitamin D deficiency in people with mental disorders. For example, it is highly likely that people struggling with depression and other mental health problems may be experiencing social withdrawal and isolation, causing them to spend less time outdoors. They tend to get less sunlight and are also likely to live a sedentary lifestyle with no inclination or energy to get up and engage in physical exercise. Poor diet, excessive alcohol consumption, and use of certain medications for their health issues could also be the reasons why people with mental health problems tend to have very low levels of vitamin D.
Besides adding vitamin D supplements to their treatment, interventions that may help encourage physical activity, healthy diet, sensible sun exposure and other constructive lifestyle changes should be included to prevent and treat vitamin D deficiency in people suffering from mental health issues. 
Chronic vitamin D deficiency is a serious problem. It can lead to osteoporosis (loss of bone density that can cause weak and brittle bones that are prone to fractures), rickets (weak and soft bones in children that can lead to poor growth, joint deformities and muscle weakness), poor immunity and many other health complications. Emerging research tells us that shortage of this sunshine vitamin could mean poor cardiovascular health and increased risk of eye disorders such as age-related macular degeneration, dry eye, and diabetic retinopathy (damage to the blood vessels in the retina caused by high blood sugar). Vitamin D deficiency also plays a role in the development of autoimmune diseases, such as thyroid disorders. With emerging research suggesting its involvement in the development of mental health disorders, especially depression and poor mood, maintaining adequate levels of vitamin D through sensible sun exposure and vitamin D supplementation sounds like a good strategy to keep your physical and mental health vibrant.
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