Depression is the most common debilitating psychiatric disease. Around the world, it is estimated that more than 300 million people are affected by depression. Studies suggest that depression may have multifactorial origins involving dysfunction of multiple brain areas and alteration in biochemical functions such as gene expression and immune response.
What is Vitamin D?
Vitamin D is sometimes called the sun-shine vitamin. It is essential for efficient working of the brain, and heart. Vitamin D is considered to be a crucial nutrient for calcium absorption and homeostasis, thus it helps in maintaining bone health and metabolism.
It helps the body to absorb calcium and maintain adequate serum magnesium and phosphate concentrations, as these three nutrients are important for teeth, muscles, and bones. From recent studies, it is revealed that Vitamin D is associated with numerous extra-skeletal effects and it plays a pivotal role in the prevention and treatment of multiple diseases.
Vitamin D Mechanism of Action
The vitamin D receptors and vitamin D activating enzyme 1-alpha-hydroxylase are widely distributed in multiple brain regions and many different types of cells, particularly in the neurons in the amygdala and the glial cells in the hypothalamus, which indicates that vitamin D signaling might be involved in the pathophysiology of neuropsychiatric disease.
25-hydroxy vitamin D, [25(OH)D] is the serum vitamin D that is used to characterize vitamin D levels, as circulating 25(OH)D was deemed the best nutritional status indicator for vitamin D. Levels of 25(OH)D are related to many diseases, such as cardiovascular disease, cancer, diabetes, obesity, and asthma. The studies noted that vitamin D could regulate the expression of neurotrophic factors and interleukins. Thus, it may have a role in the prevention and treatment of depression.
Hence, lower serum 25(OH)D levels are associated with an increased risk for depression and depressive symptoms could be eased in people with very low levels of vitamin D through supplementation. Having sufficient 25(OH)D levels in the brain increases the expression of the enzyme tryptophan hydroxylase 2 (TPH2), which is necessary for sufficient serotonin production. Sufficient serotonin in the brain could positively affect, amongst others, mood, cognition, impulse control, and social behavior.
An independent in vitro study confirmed that the active form of vitamin D (1,25(OH)2D) can indeed rapidly (within 24 hours) activate TPH2 in various mammalian neuronal cell populations, such as the prefrontal cortex in the rat brain.
Natural Sources of Vitamin D
Vitamin D can be received in three ways. First, the most important source of vitamin D is sunlight where it can be endogenously synthesized under ultraviolet B radiation in the skin. Second, it can be ingested through dietary supplements and dietary sources, which include food of animal and plant origin, as well as fortified foods. However, Vitamin D can also be obtained from some other dietary sources, such as eggs, and sardines. Third, through vitamin D supplements.
Vitamin D is mainly found in two forms, D3 (cholecalciferol) and D2 (ergocalciferol). In addition to the D3 and D2 forms, 25-hydroxy vitamin D also contributes significantly to dietary vitamin D intake. It is found in many animal-derived products. Fortified food can contain D3 or D2 forms or vitamin D metabolite 25-hydroxy vitamin D.
In addition to this, it was identified that Cholecalciferol (vitamin D3) and calcifediol (25(OH)D3) content in eggs, fish, and milk increased in response to vitamin D3 supplementation of hens, fish, or cows’ diets. Furthermore, evidence from randomized controlled trials indicated that a 25(OH)D3 oral supplement could be absorbed faster and more efficiently raising serum 25(OH)D concentration compared with vitamin D3 supplementation, and therefore serum 25(OH)D is widely used to cure depression.
Most food packages label the vitamin D content as a percentage of DV. This can help people understand what amount of their daily vitamin D requirement the food will provide.
Some of the sources are mentioned below:
- Sunlight: This is the easiest way of getting enough vitamin D. You just need to regularly spend time outside, making sure that the arms, face, and legs have exposure.
- Fatty fish: Salmon is a popular fatty fish and a great source of vitamin D. It is observed that wild-caught salmon has more vitamin D.
- Herring and sardines: Herring is a fish, often smoked or pickled, which is eaten worldwide and has a huge amount of vitamin D. Canned sardines are also a good source of vitamin D.
- Cod liver oil: It is also a popular supplement. If you are vegetarian and don’t like fish, taking cod liver oil is another way to get nutrients that are hard to get otherwise.
- Egg yolks: Egg yolks can also be high in vitamin D. Most of the protein in an egg is found in the white, and the fat, vitamins, and minerals are found in the yolk.
- Mushroom: If a person does not like fish or is vegetarian or vegan, specific mushrooms may be an option. Mushrooms can synthesize vitamin D when exposed to UV light, but they produce vitamin D2, whereas animals produce vitamin D3.
- Cheese: Cheese also contributes some vitamin D to the diet, especially if it is made with milk that is fortified with vitamin D.
- Milk: It’s often fortified with other vitamins, especially vitamin D, and is good for nutrition purposes, etc.
What is Vitamin D Deficiency?
Vitamin D deficiency means that the body doesn’t have enough level of vitamin D in the body to maintain overall health including maintenance of bone density or proper functioning of the immune system, and other important functions.
Vitamin D deficiency is considered to be a pandemic, but sadly it is a most under-diagnosed and under-treated nutritional deficiency in the world. Vitamin D deficiency is widespread in individuals irrespective of their age, gender, race, and geography.
Vitamin D deficiency likely contributes significantly to the high prevalence of conditions like rickets, osteoporosis, cardiovascular diseases, diabetes, cancer, and infections such as tuberculosis in India. Fortifying staple foods with vitamin D is considered the most feasible population-based strategy to address this deficiency.
Does Vitamin D Deficiency Cause Depression?
Vitamin D is considered to be a crucial factor that influences symptoms of depression, negative emotions, and quality of life. Hence, it has been linked to depression, and some studies suggest that vitamin D supplements may help improve mood in people with low levels of the vitamin.
Many clinical trials propose that results from Vitamin D supplementation against depression are promising, which indicates that it is a valuable nutrient, especially for individuals who are unable to meet daily Vitamin D intake levels. The studies show that depression is common in individuals with vitamin D deficiency.
Much literature links Vitamin D to the pathophysiology of depression, and this conclusion was based on their evidence. First, a lower serum level of Vitamin D was found in depressed persons. Second, the presence of vitamin D receptors in many parts of the brain’s limbic system, i.e. cerebellum, and cortex, is responsible for controlling emotions and behavior.
Third, vitamin D plays an important role in regulating immunoinflammatory pathways, relevant to the pathophysiology of depression. Apart from this, a meta-analysis investigation was done on the efficacy of vitamin D in reducing depressive symptoms among adults in randomized placebo-controlled trials (RCT) and results were promising.
Vitamin D Deficiency Causes
Recent studies show that low levels of vitamin D may contribute to schizophrenia, anxiety, depression, and seasonal affective disorder. This is because Vitamin D is an important calcium-regulating hormone with diverse functions in numerous tissues, including the brain and proper bone health.
Vitamin D deficiency is considered to be a serious public health problem, as vitamin D insufficiency is estimated to affect about 50% of the global population, and vitamin D deficiency affects approximately 1 billion people, independent of their age and ethnicity. Research suggests that about 35% of adults in the United States are vitamin D deficient and can develop symptoms of depression.
People with more melanin may also produce less vitamin D through their skin, increasing the risk of deficiency. The Food and Nutrition Board (FNB) at the National Academy of Medicine has recommended that most people ages 1 to 70 should get 600 international units (IU) of vitamin D each day to meet essential daily intake levels.
Daily Recommended Doses of Vitamin D
Infants (birth to 12 months): 400 IU
Children (1 to 13 years): 600 IU
Teenagers (14 to 18 years): 600 IU
Adults (19 to 70 years): 600 IU
Seniors (71 years and older): 800 IU
Pregnant and breastfeeding women: 600 IU
Some of the causes that contribute to Vitamin D deficiency are mentioned below :
- Living in a Cold climate: This results in less exposure to sunlight.
- Not going outdoors: People who are at higher risk for Vitamin D deficiency are usually homebound or rarely go outside (for example, people in nursing homes and other facilities) and aren’t able to use sun exposure as a source of vitamin D.
- Avoiding the sun: Due to fear of aging or excessive tanning
- Having dark skin: People with darker skin tones are at higher risk because they have more melanin. Melanin is a pigment that decreases the skin’s ability to procure vitamin D from sunlight.
- Obesity: A link exists between vitamin D deficiency and people with a body mass index (BMI) of 30 or higher. Compared to people with a moderate weight, people with obesity may need to absorb more vitamin D to reach recommended nutrient levels.
- Age: The skin’s ability to make vitamin D decreases with age, so people over the age of 65 years are especially at risk for vitamin D deficiency.
- Vegan diet: This may result in vitamin D deficiency when dietary sources are not sufficient to fulfill daily vitamin D demand.
- Kidney Disease: Vitamin D is converted into its active form in the kidneys, if kidneys are not functioning well, absorption will not be proper and the body will not be able to have sufficient vitamin D.
- Individuals With Liver Disease: Vitamin D deficiency has been associated with nonalcoholic fatty liver disease (NAFLD), in which extra fat cells build up in the liver, causing damage to the organ.
- Medical conditions: These conditions make it difficult to absorb nutrients in food, such as Crohn’s disease, ulcerative colitis, and celiac disease.
Alcohol and Vitamin D Deficiency
Studies show that alcohol consumption can negatively impact vitamin D levels, resulting in vitamin D deficiency. It also affects bone density and overall bone health. Chronic alcohol use can impair the liver’s ability to convert vitamin D into its active form, leading to deficiencies. This deficiency can result in weakened bones, increased risk of fractures, and conditions like osteoporosis.
Excessive alcohol use can decrease the nutrient absorption ability of the body from food, and cause vitamin D deficiency. It has been observed that vitamin D helps in maintaining a good immune system and bone density. So, individuals consuming alcohol are advised to keep a regular check on vitamin D levels in the body.
How to test for Vitamin D Deficiency?
Healthcare providers don’t usually advise routine checks of vitamin D levels. Still, they might need to check if a person has certain medical conditions or risk factors for vitamin D deficiency and/or have symptoms of it.
A vitamin D test measures the level of vitamin D in the blood to ensure the proper functioning of the body, usually done by blood test. However, if you have any of the above risk factors. There is very little risk of having a blood test. You may have some pain or bruising at the spot where the needle was put in, but the majority of symptoms go away quickly.
To use vitamin D in the body, first, the liver must change it into another form called 25 hydroxyvitamin D, or 25(OH)D. Most vitamin D blood tests measure the level of 25(OH)D in the blood to screen for low levels of vitamin D so that it can be treated with supplements before it causes health problems.
Other names for vitamin D deficiency tests include 25-hydroxyvitamin D, 25(OH)D, cholecalciferol test, ergocalciferol test, calcidiol test, vitamin D2 test, and vitamin D3 test.
In chronic and/or severe vitamin D deficiency, a decline in calcium and phosphorus absorption by the intestines leads to hypocalcemia (low calcium levels in your blood). This leads to secondary hyperparathyroidism (overactive parathyroid glands attempt to keep blood calcium levels normal).
Both hypocalcemia and hyperparathyroidism, if severe, can cause symptoms, including muscle weakness cramps, and depression. So, to balance it, the body takes calcium from the bones, which leads to accelerated bone demineralization (when a bone breaks down faster than it can reform). A vitamin D insufficiency (mildly low levels of vitamin D) usually doesn’t cause symptoms, until it gets worse.
Signs and Symptoms of Vitamin D Deficiency
- Muscle weakness
- Joint pain
- High blood pressure
- Obesity
- Fatigue
- Respiratory problems
- Digestive problems
- Weak immunity
Psychiatric Symptoms of Vitamin D Deficiency
- Suicidality
- Depressed mood
- Inattention
- Intrusive thoughts
- Anxiety
- Poor concentration
- Sleep disturbance
- Panic symptoms
Psychiatric Illness exacerbated by Vitamin D Deficiency
- Panic psychiatric
- Major depressive disorder
- Bipolar disorder
- Autism spectrum disorder
- Generalized anxiety disorder
- Obsessive-compulsive disorder
- Schizophrenia
- Dysthymic disorder
Medical Illness exacerbated by Vitamin D Deficiency
- Osteoporosis
- Hypophosphatemia
- Hypocalcemia
- Hypoparathyroidism
- Immune system disorder
- Neurological disorder
Consequences of Vitamin D Deficiency
Consequences mean the various negative outcomes or effects that may occur when the body has vitamin D deficiency. These consequences can affect various aspects of health, such as bone health, muscle strength, immune function, and mood, and can cause the risk of developing certain chronic diseases.
Some of the consequences are mentioned below:
- Bone health
- Muscle weakness
- Immune function
- Mood disorder
- Chronic diseases
Bone health: Vitamin D is very important for bone health because it absorbs nutrients like calcium and phosphorous, which are important to maintain the bone health density of the body. But when vitamin D levels are low, it causes bone fractures, osteoporosis, or some other bone abnormalities. It can also lead to osteomalacia in adults and rickets in children.
Muscle weakness: From the above section it can be concluded that vitamin D plays an important role in muscle functioning. But low levels of vitamin D can cause muscle atrophy, muscle weakness, or muscle pain. In severe cases, it can also cause muscle cramps and breathing problems.
Immune function: Studies show that Immune cells, including dendritic cells, macrophages, and T and B cells, express the vitamin D receptor and 1α-hydroxylase. And the active form of vitamin D has an anti-inflammatory effect. This clearly indicated that vitamin D plays a crucial role in immune function, and a deficiency in it is shown to increase susceptibility to infection.
Mood disorder: It was found that vitamin D is involved in the synthesis of neurotransmitters such as serotonin and dopamine, and these neurotransmitters play a significant role in mood regulation. When vitamin D levels are low in the body, it causes depression-like symptoms, mood fluctuations, poor concentration, etc.
Chronic diseases: Vitamin D deficiency has been linked to various chronic diseases such as cardiovascular disease, diabetes, and certain types of cancer. However, it is clinically proven that adequate vitamin D levels may help reduce inflammation, improve insulin sensitivity, and regulate cell growth, all of which are important factors in the development of these diseases.
Vitamin D Deficiency Treatment
Vitamin D deficiency treatment focuses on maintaining an optimal level of vitamin D in the body and sustaining it over the long term.
Some of the treatment approaches are mentioned below:
- Sunlight exposure
- Dietary sources
- Supplements
- Lifestyle adjustment
- Medical supervision
- Education and Awareness
Sunlight Exposure: Spending time in the sunlight is a natural way to restore vitamin D levels in the body. Depending on skin type, geographical location, and lifestyle, about 10-30 minutes of midday sun exposure several times a week can significantly help.
Dietary Sources: Vitamin D-deficient individuals need to incorporate foods rich in vitamin D into the diet which can help in alleviating the deficiency symptoms. For example; fatty fish (like salmon, mackerel, and sardines), fish liver oils, fortified dairy products, egg yolks, and certain mushrooms.
Supplements: There are two forms of Vitamin D supplements, that are used commonly, vitamin D2 (ergocalciferol) and vitamin D3 (cholecalciferol). These are recommended to those having less exposure to the sun and have significant vitamin D deficiency, but it is advised to take supplements only after consulting a healthcare provider.
Lifestyle Adjustments: Individuals with limited sun exposure due to a lifestyle busy schedule or geographic location, should make small changes in their lifestyle like taking short walks during lunch breaks or trying to spend some more time under the sun whenever possible, like on weekends.
Medical Supervision: Individuals who are at risk of developing vitamin D deficiency, should go for regular checkups to monitor vitamin D levels, which will help in ensuring that levels are within the optimal range.
Education and Awareness: Educating individuals and making them aware of the importance of vitamin D and how to maintain adequate levels through lifestyle, diet, and supplementation can help prevent deficiencies.
Supplements for Vitamin D Deficiency
Vitamin D supplements are typically vitamin D3; although some formulations contain vitamin D2. Taking a vitamin D supplement correctly is very easy. You simply need to have the right dose (usually in the form of a gel capsule), pop it into your mouth, and swallow it with water.
These supplements can be purchased online, at your local pharmacy, or you may obtain a prescription from your physician. You can safely supplement up to 10000 units a day, but if taking more than 5000 units a day you should check calcium levels after three months.
Anglo-Saxons typically do not need to supplement more than 1000 units a day while dark-skinned individuals living in cold climates may need to supplement 2000- 5000 units daily for optimum effect.
Most importantly remember that vitamin D supplement is best absorbed when taken with food containing fat. So, don’t take it on an empty stomach or in between meal times, just take it when having a proper meal.
Toxicity from Vitamin D Supplementation
The risk of toxicity is typically low. Hypervitaminosis D is rare and usually caused by excessive vitamin D intake, which leads to hypercalcemia and an imbalance in the regulation of bone metabolism; the resultant hypercalcemia leads to clinical manifestations and symptoms of toxicity.
Symptoms of hypercalcemia can include:
- Nausea
- Increased thirst and urination
- Poor appetite
- Constipation
- Weakness
- Confusion
If the total vitamin D level shows too much vitamin D in the blood, it is most likely from getting too much from supplements. This is very uncommon, but if it happens, the person needs to stop taking supplements to reduce vitamin D levels.
Too much vitamin D can cause serious damage to organs and blood vessels. Before taking vitamin D supplements, it’s important to ask your provider what dose is right for you.
Less commonly, poisoning from exposure to rodenticides containing cholecalciferol can also lead to vitamin D toxicity. Excessive sun exposure does not cause vitamin D toxicity.
Factors that increase the risk for vitamin D toxicity:
- Fortification of foods or supplements with higher than intended amounts of vitamin D.
- Patients taking inadvertently increased amounts of highly fortified milk.
- Medical ailments like granulomatous disorders and lymphomas can produce excessive 1,25(OH)2D.
