Contributing Factors


Diet and Depression

Diet is commonly considered the most important mediator of health and disease. Healthy diets can help prevent anxiety while poor diets can promote and sustain anxiety.

Patients with psychiatric disorders often have poor food patterns, either from a reduced appetite, skipping meals, consuming fast or processed foods, or a general lack of interest in food altogether. (Greenblatt & Brogan, 2016)

Risk of depression has shown to increase with fast food consumption (Sánchez-Villegas et al., 2012), while a diet based on vegetables, fruit, and fish decreases depression risk (Akbaraly et al., 2009).

Mediterranean diet and Depression

The Mediterranean diet is considered a good model for a healthy diet. It includes foods that are beneficial and reduces or elimates foods that promote mental health issues.

General components of the Mediterranean diet include:

  • plenty of vegetables and fruit
  • healthy fats including olive oil
  • regular consumption of seafood
  • poultry, beans, and small amounts of red meat
  • small amounts of dairy such as yogurt and cheeses.
  • whole grains instead of refined grains

Following a Mediterranean-type diet decreases risk of anxiety and depression. (Sadeghi, O., Keshteli, A. H., Afshar, H., Esmaillzadeh, A., & Adibi, P., 2019)

Additional information

Mediterranean diet for heart health
Mayo clinic


Alcohol and Mental Health

  • Alcohol consumption can lead to issues with memory and learning, and promote development or worsening of mental health conditions (Kelley et al., n.d.).
  • Heavy alcohol use affects brain function and alters aspects of brain chemistry involved in the development of many common mental disorders (Alcoholism and Psychiatric Disorders, n.d.).
  • Alcohol abuse can cause signs and symptoms of depression, anxiety, psychosis, and antisocial behavior, both during intoxication and during withdrawal (Alcoholism and Psychiatric Disorders, n.d.).

Alcohol and Depression

  • Excessive alcohol consumption is frequently associated with depression (Gaby).
  • Alcohol can promote depression, either by direct brain cell toxicity/death, or by promoting nutritional deficiencies (Gaby).
  • Long-term alcohol consumption can lead to vitamin B1 (thiamine) deficiency as a result of poor nutrition. Thiamine deficiency can cause mental confusion, as well as learning and memory problems  (Kelley et al., n.d.).
  • Depression may worsen during the early stages of alcohol withdrawal, but it often improves in the weeks after stopping drinking (Gaby).

Medications that promote depression

Medications and Depression

Some medications that may promote depression (Rogers & Pies, 2008, Bruce, n.d.):

  • Antidepressants (MAOIs, SSRIs, SNRIs, tricyclic antidepressants)
  • ACE inhibitors
  • Alpha interferons
  • Beta blockers
  • Carbidopa, levodopa
  • Corticosteroids
  • Cyclosporine
  • Levothyroxine
  • Methylphenidate (for ADHD)

Depression is a potential side effect of oral contraceptives. Women taking oral contraceptives have been suggested to have vitamin B6 deficiency, as shown by abnormalities in tryptophan metabolism.

This can be addressed by:

  • Supplementation with 20 mg/day pyroxidone (Vitamin B6 Requirements CNGBdb, n.d.).
  • Supplementation with 20–50 mg/day of vitamin B6 (Baumblatt & Winston, 1970) (Adams et al., 1973) (Adams et al., 1974).

Depression and manic depression have been associated with glutathione deficiency (Holecek, 2002). Acetaminophen, a common analgesic, causes reduction of glutathione (Hibbeln & Gow, 2014).

Nutritional deficiencies and dependencies


  • When the minimum amounts of nutrients needed for normal body function are not met by diet
  • A nutrient deficiency results in depletion of nutrients in body tissues, and changes to mental and physical functioning from diet, medications.


  • The metabolic need for a nutrient exceeds what can be supplied by diet and results in impaired biochemical processes and functions.
  • A nutrient dependency results from long-term environmental and genetic stressors.


Depression and Inflammation

Inflammation is a normal part of the body’s defense to injury or infection. However, inflammation is damaging when it occurs in healthy tissues or lasts too long (months or years).

Causes of chronic inflammation include (Inflammation, n.d.):

  • Environmental chemicals
  • Poor nutrition
  • Imbalanced microbiome
  • Sleep issues
  • Stress
  • Personal environment

Inflammation and Depression

Inflammation plays a mediating role in both the risk and progression of depression (Berk et al., 2013).

Depression is a symptom of inflammation. Symptoms include (Greenblatt, 2018) :

  • Lethargy/Malaise/Fatigue
  • Decreased concentration
  • Decreased appetite
  • Decreased interest in pleasurable things
  • Weakness

Cytokines and Depression

Depressed patients have been found to have (Huang & Lee, 2007):

  • Higher levels of Pro-inflammatory cytokines (TNF- α & CRP) than healthy patients
  • Lower levels of Anti-inflammatory cytokines than healthy patients

Pro-inflammatory cytokines are responsible for activating indoleamine 2,3-dioxygenase (IDO), a tryptophan and serotonin-degrading enzyme (Müller & Schwarz, 2007). Increased levels of IDO, and increased consumption of tryptophan and serotonin, results in a reduction in serotonergic neurotransmission (Müller & Schwarz, 2007) (Greenblatt, 2018).



Hypoglycemia is a condition of abnormally low levels of blood sugar. Reactive Hypoglycemia is the condition of low blood sugar following a meal.

Reactive hypoglycemia and Depression

Reactive hypoglycemia can trigger or worsen symptoms such as anxiety, depression, fatigue, and paranoia. (Gaby, 2011)

Depression is a common symptom of reactive hypoglycemia. It has been reported to improve after starting a dietary program that helps to stabilize blood glucose levels. (Salzer, 1966) (HoffmanN & Abrahamson, 1949)

Blood sugar can cause depression in multiple ways (Gaby 2011):

  • Low blood sugar can cause depression, fatigue, difficulty concentrating, and related symptoms.
  • The body can respond to low blood sugar (hypoglycemia) by releasing norepinephrine. Repeated release can cause epinephrine depletion.
  • Reactive hypoglycemia is often associated with insulin resistance. Insulin resistance may cause neurotransmitter deficiencies since it is required for uptake of tryptophan and other required amino acid precursors.

Patients with depression that is caused in part by reactive hypoglycemia may experience worsening of symptoms before mealtimes and an improvement of symptoms after eating. These patients often crave sweets and may find that consuming refined sugar will temporarily relieve symptoms, followed by symptom worsening (Gaby 2011).

Reactive hypoglycemia – overview

  • Consumption of a high-carbohydrate meal or drink causes a rapid rise in blood glucose.
  • The high glucose causes the pancreas to release an abnormally high amount of insulin into the blood. This causes an abrupt drop in blood glucose.
  • The excessive drop in blood sugar triggers the release of the hormones epinephrine and norepinephrine, which in turn, trigger the “fight or flight” response.
  • The “fight or flight” response will show as hunger, irritability, sweating, palpitations, and anxiety.

Causes of hypoglycemia include (Hypoglycemia – Symptoms and Causes, n.d.):

  • diabetes
  • medications
  • excessive alcohol consumption
  • liver and/or kidney disorders
  • overproduction of insulin

Identifying hypoglycemia

Signs of hypoglycemia:

  • tendency to crave sweets
  • consuming sugar or refined starches temporarily reduces hypoglycemia symptoms
  • symptoms worsen in the late morning or late afternoon
  • mental and anxiety symptoms occur after fasting, late at night, or first thing in the morning (Eaton & Konner, 1985)

Symptoms of hypoglycemia (Hypoglycemia – Symptoms and Causes, n.d.):

  • irregular or fast heartbeat
  • fatigue
  • pale skin
  • shakiness
  • anxiety
  • sweating
  • hunger
  • irritability
  • tingling or numbness of the lips, tongue or cheek

Typical medical tests to assess blood-sugar metabolism are:

  • fasting glucose
  • HbA1c
  • insulin, cortisol, ketone bodies, lactic acid, free fatty acids, and thyroid hormone may also be included (Mandal, 2019)

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Greenblatt, J. M., & Brogan, K. (Eds.). (2016). Integrative Therapies for Depression: Redefining Models for Assessment, Treatment and Prevention (1st edition). CRC Press.

Hibbeln, J. R., & Gow, R. V. (2014). The potential for military diets to reduce depression, suicide, and impulsive aggression: A review of current evidence for omega-3 and omega-6 fatty acids. Military Medicine, 179(11 Suppl), 117–128.

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