Lifestyle,  Nutrition

Vitamin D & Depression: Is there a link?

Feeling depressed? Vitamin D, often referred to as the ‘Sunshine Vitamin’, may be just what you need to improve your mood.

Recent research is bringing to light the link between vitamin D status and a host of health conditions like depression, obesity, type II diabetes, autoimmune diseases, cardiovascular disease, and osteoporosis. 

Vitamin D deficiency is fast becoming a worldwide health epidemic, and we are seeing more clinical rates of deficiency. We are spending more time indoors with technology and less time in the sun. Deficiencies in children and teenagers are common in Spring and Winter with more activities based indoors.

A recent study confirmed that vitamin D deficiency is associated with a 75% increased risk of developing depression in later years. 

Depression is a common and debilitating illness and is one of the most prevalent diseases in the world. According to the latest World Health Organisation (WHO) report, a staggering 300 million people suffer from depression globally.

First line treatment usually involves the use of antidepressant drugs. Unfortunately, there can be limitations in the effectiveness of antidepressants for some people. Particularly in Major Depressive Disorder (MDD) which has led to research into other treatment interventions, such as nutritional deficiencies, diet, lifestyle, and supplementation. 

Common Signs & Symptoms of Depression

Depression is recognised as a persistent state of sadness or loss of interest in daily activities affecting everyday functioning and quality of life. 

Over time, depression can become a serious health condition, affecting a person’s ability to function at work, at school, and interact with family and friends. 

Tragically, at its worst and most severe, depression can lead to suicide. 

Symptoms of depression:

  • Persistent low mood, sadness
  • Fatigue
  • Irritability & anxiety
  • Difficulty concentrating
  • Insomnia
  • Loss of appetite or excessive hunger
  • Feelings of helplessness, worthlessness, hopelessness
  • Disinterested in hobbies or activities
  • Social isolation
  • Headaches
  • Gut dysfunction – irritable bowel
  • Suicidal thoughts
  • Suicide attempts

Risk Factors for Depression

There may be a combination of biological, genetic, environmental, and psychological factors underlying the development of depression. 

Risk Factors include:

  • Trauma, stress, major life changing events
  • Physical illness, injury, and medications
  • Family history of depression

Conventional Treatment & Therapies

Depression is traditionally accepted as an imbalance in neurotransmitters in the brain. Treatment usually involves medications and/or talk therapy.

The Role of Vitamin D 

Despite its name, vitamin D is not actually a vitamin. Vitamin D acts like a hormone in the body and consists of two forms: ergocalciferol (vitamin D2) and cholecalciferol (vitamin D3). It’s involved in many biological processes such as mineralisation of bones and teeth, and the absorption of calcium, magnesium, and phosphate. 

Evidence has now found Vitamin D receptors (VDR) in the central nervous system (CNS), suggesting vitamin D plays a role in brain development that affects both our emotional and cognitive functioning.

Vitamin D2 and D3 differ in two different ways. D2 can be found in plants and varieties of fatty fish, liver, eggs, and some fortified milk products. Diet is only accountable for about 10 percent of vitamin D intake.

Vitamin D3 is produced when our skin is exposed to the ultraviolet rays of the sun (UVB). This form is more effective at raising levels in the blood than vitamin D2.

Risk Factors for Vitamin D Deficiency:

  • Geographic location
  • Staying mostly indoors, like shiftworkers
  • Obesity
  • Reduced vitamin D absorption from the diet
  • Dark skin

Vitamin D Deficiency Symptoms

  • Chronic fatigue
  • Weakness
  • Depressive symptoms
  • Insomnia
  • Anxiety
  • Weakened immune system
  • Weak and brittle bones– prone to breaking
  • Inflammation

Undergoing a 25-hydroxyvitamin D blood test will normally be requested by your doctor if you are at risk of deficiency. 

In Australia, levels below 40-50 nmol/L are considered vitamin D deficiency, and normal levels vary (based on researchers and opinion) between >50-75 nmol/L up to 200 nmol/L. 

How is Vitamin D Deficiency Treated?

If you do have a deficiency you may need to take a supplement. Toxicity is rare but can occur with taking large doses (doses up to 10 000 IU per day are considered safe). Large doses run the risk of causing increased absorption of calcium from the gut and may increase bone resorption.

Did you know that 90% of your vitamin D is derived from sunlight, and only a fraction absorbed via the diet? It’s estimated that spending 3 to 6 minutes in the midday sun, and exposing 25.5% of your body surface area, will synthesize around 400 IU of vitamin D.

But how much do we need?

Studies have shown that even usual sun exposure, such as walking to work, gardening, and having lunch outside (with sunscreen or without) will provide an increase of vitamin D.

Just how much sun exposure you need is very individualised. It depends on a few different factors — including where you live, the time of day and season, cloud cover, clothing, your skin type and the amount of skin area exposed. 

Fortunately, there are ways you can naturally increase your vitamin D levels.

How to Increase Your Vitamin D:

  • Sunlight exposure: Spend 10-20 minutes in the sun daily. This will give you around 10,000 units of vitamin D. Note, this can vary between individuals.  Make sure you know when the UV index is high, you can find International UV Index Pages HERE
  • Increase outdoor physical activity
  • Eat fatty fish like salmon, mackerel, halibut, sardines
  • Eat mushrooms – 7-10 IU per 100 grams (like Maitake & Portobella — exposing them to UV light for a few hours increases their vitamin D content)
  • Cod liver oil – 10,000 IU per 100 grams
  • Eggs – approx. 87 IU per egg

Whilst vitamin D supplements are inexpensive and can be found easily, keep in mind that the best way to find out the dosage you need is to have blood tests first.

Final Thoughts

If you have concerns about your vitamin D status, discuss this with your doctor. The major causes of vitamin D deficiency are usually a lack of exposure to sunshine, and not eating enough vitamin D containing foods.

Eating foods that are natural sources of vitamin D, like fish, eggs, and mushrooms will only increase your intake by a small amount. Getting moderate amounts of sunshine is the best way to increase your vitamin D and improve both your physical and mental health.

If you are concerned about your mental health or of someone close to you, consult your general practitioner.

For more information, here are some useful resources: