Depression is a complex mental health condition that affects each sufferer differently. Due to concerns about side effects from conventional drugs, many people seek out natural depression treatment solutions. In this section we outline strong evidence for the role of diet and nutrition in managing depression without medication.
Depression can be extremely debilitating. It is the leading cause of disability worldwide and affects over 350 million people globally; one in 20 people experience depression in any one year. Symptoms and severity of depression vary from one person to another and can be ‘reactive’ – caused by emotional and external factors such as bereavement, or ‘clinical’ – caused by internal or biological factors such as low levels of chemical production in the brain. Bipolar disorder is also a depression-related disorder that is characterised by periods of severe depression followed by very elevated as well as normal mood periods.
Treatment for depression is widely available in modern countries, although less than a quarter of people with depression seek help due to low awareness, social stigma or lack of access to treatment. It is extremely important that people who are suffering with depression, as well as their friends and family around them, recognise the symptoms and seek help. When depression is severe it can lead to suicide; around one million people commit suicide each year, with 20 times as many people attempting to take their own lives.
Symptoms of depression include:
- Persistent low mood
- Feelings of despair and hopelessness
- Loss of interest and pleasure in activities
- Lack of energy
- Disrupted sleep patterns
- Difficulty concentrating
- Feelings of worthlessness
- Anxiety, sometimes in the form of panic attacks
- Changes in appetite, leading to weight loss or weight gain
- Impatience, irritability
- Loss of libido
- Persistent, unrelenting negative thoughts
- Suicidal thoughts
Depression can affect anyone and most people experience some level of depressed feelings at some point in their lives. For many people, periods of depression are short and pass naturally when the emotional reasons causing low mood are dealt with (reactive). For some people, however, periods of low mood can last for very long periods or return on a regular basis – making normal daily activities such as going to work and socialising very hard. This is often when clinical depression is diagnosed.
More information can be found at the World Health Organisation website.
Many factors contribute to the development of depression including physical, psychological and environmental factors.
Brain chemicals called neurotransmitters are responsible for regulating mood, as well as numerous brain functions. These chemicals, specifically dopamine and serotonin, are often found at low or disrupted levels in depressed people and many depression medications try to correct these imbalances to treat depression.
The link between stress & depression
Stress of any type also plays an important role in the onset of depression. When we are stressed, the fight or flight response kicks in. Cells in the nervous and endocrine systems work together to prepare the body for action – hence the phrase, fight or flight. During the stress response there is tremendous cellular communication throughout the cells of the brain and body, which results in a flood of hormones and chemicals including adrenaline and cortisol (the infamous stress hormone). Immune function is also affected as inflammatory cytokine levels increase.
“Excess cortisol affects levels of tryptophan available for serotonin production, and this can lead to depression if stress is not dealt with effectively.”
Since most of the modern-day stresses we encounter are emotional and do not resolve quickly, the body senses an ongoing threat so that this stressed physiological state persists and can be extremely damaging for health in the long term.
Persistent stress causes hyperactivity of the HPA-axis, which is the body’s mechanism for dealing with stress. Overstimulation of the HPA-axis can lead to anxiety and illness due to the damage caused by too many stress signals being present in the blood. The brain chemicals (or neurotransmitters) responsible for making us feel calm and happy, such as serotonin, are made up of various building blocks, such as the amino acid tryptophan. Excess cortisol affects levels of tryptophan available for serotonin production, and this can lead to depression if stress is not dealt with effectively.
Genetics also play a role in depression and someone with a parent or sibling who suffers from depression is more likely to develop the condition also. This could be due to a number of factors, including inherited alterations in stress perception and coping mechanisms, low fatty acid production capacity or due to inheriting a specific gene that increases susceptibility. Environmental risk factors are also likely to be shared within families, such as diet and exposure to repeated stressors. If one of your family members suffers with depression, it is important to be aware of your own mental health and try to reduce the controllable potential causes detailed here to help reduce your risk of developing depression.
Depression and diet
Diet can play a big role in the development of depression. High carbohydrate or low fat/protein diets, for example, can directly impact the body’s ability to cope with stress and repair the damage caused by prolonged periods of stress. People who are depressed often crave high-energy and sweet foods as quick ‘pick-me-ups’, which boost mood in the short term but leave you feeling worse once the energy and sugar has been used up. Consuming these foods often results in fat gain, which can further add to feelings of depression, as fat itself creates inflammatory chemicals and causes lethargy and brain fatigue – cumulatively adding to the problems associated with depression.
Alcohol and drug consumption can also lead to depression as, like sugar and junk food, this artificially stimulates release of feel-good chemicals in the brain to such an extent that when the alcohol has finally been eliminated from the body, your reserves of these chemicals are so depleted you feel very down and even depressed. Many people then crave sugar, high fat or more alcohol to boost their mood again, further worsening the problem and resulting in the development of depression.
“For people not eating a diet rich in healthy protein, good fats and vegetables, stress and depression may be a direct result of nutritional deficiency.”
Micronutrients such as vitamins and minerals, as well as fat and proteins, interact with our genetics to help switch on or off certain genes. Genes involved in stress regulation, in the production of brain chemicals that make us feel good and immune function are all affected by what we eat, therefore low or very high levels of certain nutrients can alter which genes are switched on and increase how the body perceives and recovers from stress. For people not eating a diet rich in healthy protein, good fats and vegetables, stress and depression may be a direct result of nutritional deficiency.
Foods rich in good quality nutrients are important for general health and mental health alike.
We recommend ensuring that your diet is based around the following foods:
- animal and/or plant proteins
- fats from oily fish, free-range, grass-fed and pastured animals, coconuts, olive oil, avocados, nuts and some seeds
- a broad range of dark green and brightly coloured vegetables
- some low-sugar fruits such as berries and citrus fruits
Incorporating these nutrient-dense foods into your diet will provide most of the nutrients needed to support the body’s chemical and hormonal systems, as well as keep blood sugar under control to support energy, focus and concentration, whilst also preventing cravings and weight gain. We also advise regular exercise (a 30 minute brisk walk several times each week is enough!) for preventing and helping to reduce symptoms of depression.
Fruits, vegetables and good quality protein foods are a much richer source of vitamins, minerals and fibre than whole grains and so keeping these low in your diet will not have a detrimental impact on your health if you are eating lots of the above recommended foods.
We also recommend avoiding or significantly reducing:
- vegetable oils and trans fats frequently found in processed foods and takeaway meals
- high sugar and refined carbohydrate foods such as cakes, sweets, pizza, pasta and bread
For more information, download our depression information pack on the last tab.
Omega-3 fatty acids
Low levels of long-chain omega-3 fatty acids, the fats found in oily fish, is commonly observed in depressed people. The amount of a certain type of omega-6 called arachidonic acid (AA) present in your red blood cells compared to levels of the omega-3 fat eicosapentaenoic acid (EPA) is directly related to depression severity.
Scientific research strongly supports increasing omega-3 levels and restoring the body’s natural omega-6 to omega-3 ratio (specifically the AA to EPA ratio) for significant health benefits and to reduce symptoms in depression sufferers. Over 30 peer-reviewed papers have been published over the last decade indicating that EPA may be an extremely effective and natural depression treatment option.
EPA is a vitally important regulator of the inflammatory response, the body’s ‘first line’ immune defence. Modern diets and lifestyles are a far cry from what humans have evolved to cope with and thus cause high levels of stress within the body. Stress can have very detrimental effects on the immune system, altering the activity of immune cells and directly increasing the amount of inflammatory messengers (known as cytokines) in the blood. Chronic stress can lead to huge increases in inflammatory signals being produced. Inflammatory cytokines are directly made from certain essential fatty acids, with arachidonic acid being the main pro-inflammatory cytokine precursor. Many of the fatty acids we consume through diet also produce cytokines, but are much less inflammatory and therefore less damaging to health. EPA is a unique fatty acid in that it is the only one that directly has the ability to reduce both the AA content of cells and the rate at which AA is released into circulation. Both of these functions of EPA, along with producing its own anti-inflammatory cytokines, directly reduce the level of inflammation occurring in the body.
This is of particular importance in managing depression as high levels of inflammatory cytokines are directly linked to symptoms and severity of inflammation. Cytokines activate a specific enzyme indoleamine 2,3-dioxygenase (IDO), which breaks down and destroys serotonin. IDO also decreases the levels of tryptophan, the direct precursor to serotonin. Since serotonin is a chemical regulator of how happy we feel and the inflammatory process plays a direct role its destruction, both onset of and chances of recovery from depression are heavily reliant on adequate levels of EPA being consumed (Wichers and Maes, 2004).
Not all omega-3 supplements are the same
Fish oil is an effective way of naturally boosting EPA (and total omega-3) levels, but the amount of EPA in relation to DHA within the fish oil determines how effective a supplement will be in treating depression. The higher the EPA content compared with DHA, the greater the benefits for mental health symptoms; there should be 500 mg to 1000 mg of EPA in excess of DHA for benefits to be seen. Many studies have found that oils containing DHA may not be suitable for the treatment of depression, as treatment regimes that use generic fish oils and pure DHA, or DHA-dominant oils usually result in no benefit for depression symptoms.
Evidence for pure EPA as a natural depression treatment
A double-blind, randomised trial conducted by Jayazeri et al has shown that the omega-3 EPA is as effective as Fluoxetine in the treatment of depression and, when used in combination, is even more effective. The same group duplicated these findings two years later showing EPA’s ability to improve symptoms and reduce levels of both cortisol and inflammatory markers. Whilst EPA can be used effectively in combination with conventional antidepressants, the UK neuroscientist and psychiatrist Professor Basant K. Puri has found the use of pure EPA to be an effective natural depression treatment, particularly in individuals who do not respond to conventional pharmaceutical medication. Furthermore, given the potential side effects associated with common pharmaceutical drugs, pure EPA supplementation is a safe treatment alternative for managing depression without medication.
Homocysteine is naturally produced in the body by a metabolic process called the methylation cycle. This process is vitally important for the production of mood-enhancing neurotransmitters. High homocysteine levels occur due to deficiency of the key nutrients vitamin B12, vitamin B6 and folate, which can lead to low production of neurotransmitters and, in turn, negatively impact mood. There is a clear association between elevated homocysteine and major depression.
Depressed people with the highest homocysteine levels have significantly reduced levels of the B-vitamin co-factors and a corresponding reduced capacity to create mood-enhancing neurotransmitters. Having higher concentrations of homocysteine increases the risk of depression and thus lowering homocysteine levels can be very helpful for reducing the risk of developing depression.
Adams PB, Lawson S, Sanigorski A, Sinclair AJ: Arachidonic acid to eicosapentaenoic acid ratio in blood correlates positively with clinical symptoms of depression. Lipids 1996, 31 Suppl:S157-161.
Almeida OP, McCaul K, Hankey GJ, Norman P, Jamrozik K, Flicker L: Homocysteine and depression in later life. Archives of general psychiatry 2008, 65:1286-1294.
Ebesunun MO, Eruvulobi HU, Olagunju T, Owoeye OA: Elevated plasma homocysteine in association with decreased vitamin B(12), folate, serotonin, lipids and lipoproteins in depressed patients. African journal of psychiatry 2012, 15:25-29.
Folstein M, Liu T, Peter I, Buell J, Arsenault L, Scott T, Qiu WW: The homocysteine hypothesis of depression. The American journal of psychiatry 2007, 164:861-867.
Jazayeri S, Tehrani-Doost M, Keshavarz SA, Hosseini M, Djazayery A, Amini H, Jalali M, Peet M: Comparison of therapeutic effects of omega-3 fatty acid eicosapentaenoic acid and fluoxetine, separately and in combination, in major depressive disorder. The Australian and New Zealand journal of psychiatry 2008, 42:192-198.
Jazayeri S, Keshavarz SA, Tehrani-Doost M, Djalali M, Hosseini M, Amini H, Chamari M, Djazayery A: Effects of eicosapentaenoic acid and fluoxetine on plasma cortisol, serum interleukin-1beta and interleukin-6 concentrations in patients with major depressive disorder. Psychiatry research 2010, 178:112-115.
Martins JG: EPA but not DHA appears to be responsible for the efficacy of omega-3 long chain polyunsaturated fatty acid supplementation in depression: evidence from a meta-analysis of randomized controlled trials. Journal of the American College of Nutrition 2009, 28:525-542.
Martins JG, Bentsen H, Puri BK: Eicosapentaenoic acid appears to be the key omega-3 fatty acid component associated with efficacy in major depressive disorder: a critique of Bloch and Hannestad and updated meta-analysis. Molecular psychiatry 2012, 17:1144-1149.
Puri BK, Counsell SJ, Hamilton G, Richardson AJ, Horrobin DF. Eicosapentaenoic acid in treatment-resistant depression associated with symptom remission, structural brain changes and reduced neuronal phospholipid turnover. International journal of clinical practice 2001;55(8):560-3.
Puri BK, Counsell SJ, Richardson AJ, Horrobin DF. Eicosapentaenoic acid in treatment-resistant depression. Archives of general psychiatry 2002;59(1):91-2.
Sublette ME, Ellis SP, Geant AL, Mann JJ: Meta-analysis of the effects of eicosapentaenoic acid (EPA) in clinical trials in depression. The Journal of clinical psychiatry 2011, 72:1577-1584.