Vitamin B and Depression: Links and Treatment Options

Vitamin B12 and Depression

Though individuals tend to overlook the repercussions of common dietary problems, researchers are now underscoring the possible outcome of deficiency in vitamin B12: depression. While depression is often treated with talk therapy or medication, studies are now revealing it also has strong biological underpinnings with evidence-based links to dietary habits.

Read on to learn about the role of B vitamins in the nervous system. Then review how vitamin B12 deficiency relates to depression. Finally, understand the potential role of vitamin B12 in depression treatment.

Vitamin B12 and Depression

The Role of B Vitamins in the Nervous System

The family of B vitamins is composed of three compounds: B1, B6, and B12. Each vitamin has a vital role in the healthy functioning of the nervous system. Their impact is especially prominent in the parasympathetic nervous system, the division of the nervous system that slows the body to rest and restore itself.

Vitamins B1 and B6

Vitamin B1 helps provide energy to cells via carbohydrate metabolism. It also provides a protective antioxidant effect for nerve cells, limiting and preventing damage from unstable cells called oxidants. Vitamin B6 assists the process of synthesizing compounds into chemical messengers called neurotransmitters. This vitamin also helps regulate GABA, an essential inhibitory agent that prevents excessive stimulation of excitation pathways in the brain leading to neuron damage.

Vitamin B12

The most significant impacts of vitamin B12 include its supportive role in protecting the health of neurons and facilitating the production of neurotransmitters.

  • Neuron Myelination

Vitamin B12 is closely involved with the formation of a fatty substance around nerve axons called the myelin sheath. An axon is a slender cable-like fiber branching from the neuron cell and extending toward other neurons. The myelin sheath protects the axon from damage and provides electrical insulation for efficient signal transmission, essential for healthy central nervous system functioning.

Myelination allows for rapid transmission of messages, an especially critical feature for long neural connections between different brain regions. This high-speed communication enables individuals to think and move in purposeful, coordinated ways.

  • Neurotransmitter Synthesis

Vitamin B12 acts as a helper cell when neurotransmitters are synthesized, the process of transforming chemical components into a more complex form. An abundance of vitamin B12 is necessary to supply the body with enough neurotransmitters to support normal brain and bodily functioning.

Vitamin B12 Deficiency and the Link with Depression

Vitamin B12 deficiency can result from a lack of absorption or low dietary intake. When the absorbed supply drops below optimal levels, many physical, mental, and emotional functions can become impaired.

How Can Vitamin B12 Deficiency Occur?

  • Inhibited Intrinsic Factor: Intrinsic factor is a substance produced in the stomach that makes it possible for the body to absorb Vitamin B12. An autoimmune condition called pernicious anemia creates antibodies that impair intrinsic factor from facilitating absorption. Illness or injury to the digestive system can also interfere with intrinsic factor production, leading to poor vitamin B12 absorption.
  • Low Dietary Intake: Excess vitamin B12 can be stored in the liver for between three-to-five years, but if one’s dietary intake does not replenish its supply, symptoms of vitamin deficiency can develop. Vitamin B12 is commonly found in animal products, such as beef, pork, salmon, liver, dairy products, eggs, salmon, clams, oysters, tuna, and fortified cereals.

Does a Lack of Vitamin B12 Cause Depression?

Though causation has not been established between vitamin B12 deficiency and depression, it has been found to be involved with many neurochemical pathways that potentially lead to this mental health disorder. Multiple studies have linked low vitamin B12 levels with impaired cognitive functioning and depressive symptoms, which can result from insufficient neurotransmitter production and damaged myelin sheaths.

One longitudinal study in particular, which was based on adults age 50 and older, showed that individuals with low B12 levels had a 51% increased risk of depression over four years. Evidence shows that one out of eight older adults has low vitamin B12 levels, making this a relevant concern for aging adults.

Depressive and Cognitive Symptoms Related to Vitamin B12 Deficiency

  • Fatigue may develop because a deficiency in vitamin B12 results in decreased red blood cell production and insufficient oxygen delivery throughout the body.
  • Mental fogginess and memory problems can develop due to damage in the microstructure of the hippocampus, an essential region of the brain for memory development.
  • Vitamin B12 helps break down homocysteine, a byproduct of amino acid metabolism. Low levels of vitamin B12 are associated with irritability, possibly indicating that high levels of homocysteine can interfere with mood.

Other Risks Related to Cognition and Depression

  • Vitamin B12 deficiency is linked with cognitive decline, Alzheimer’s disease, and a five-fold increased rate of brain atrophy.
  • Low vitamin B12 levels are associated with melancholic depression, a subtype of depression defined by more severity, worse outcomes, and more physical symptoms than non-melancholic depression.

Vitamin B and Depression Treatment

As research reveals more about the potential causes of depression, more targeted treatments are being developed. Evidence-based therapies such as psychotherapy and magnetic stimulation are proven to help with symptom relief, and the role of nutritional supplementation is being explored more deeply.

Which B Vitamin May Help Ward Off Depression?

While not establishing conclusive evidence, studies have consistently shown how raising vitamin B12 levels can positively impact depression symptoms.

Higher Dietary Vitamin B12 Levels

Research has uncovered associations between healthy eating patterns, including higher dietary levels of vitamin B12, and a low incidence of depression. Despite an observed relationship, the biochemical mechanisms of eating patterns and their relationship to depression are not well understood.

When taken early in treatment, evidence shows that supplemental vitamin B12 may enhance the impact of antidepressants and delay depression onset.

Vitamin B12 for Depression: Supplement Dosage

Very high daily doses of vitamin B12, ranging between 1000 and 2000 mcg, may effectively restore B12 levels within the body and positively impact depression symptoms. Even doses as low as 100 mcg are potent enough to positively impact cognition in adults with depressive symptoms. High doses are usually administered via injection to avoid absorption problems, but studies show that oral administration may also be effective.

Additional Evidence-Based Depression Treatments

When considering depression treatments, individuals may also look to established evidence-based therapies. Psychotherapy and magnetic stimulation therapy are two effective treatments that can be used with vitamin B12 supplementation.


Many types of psychotherapy can be helpful, and finding a good fit may depend on an individual’s preferences. Cognitive-behavioral therapy is focused on the interaction between behaviors, thoughts, and emotions and has shown to be helpful for both depression and generalized anxiety disorder. Psychodynamic therapy helps individuals look at the central experiences of their lives, past and present, and how they contribute to their depression.

Magnetic Stimulation

Deep transcranial magnetic stimulation (Deep TMS) is an FDA-cleared treatment that provides significant symptom relief for depressive disorders, particularly for individuals who have only received partial relief from medication or psychotherapy. Over several weeks, the targeted pulses of magnetic therapy are delivered via a medical device embedded in a cushioned helmet. The pulses stimulate specific brain regions associated with depression symptoms, rebalancing neural activity that results in symptom relief.

Deep TMS has been proven to be safe, noninvasive, and effective, without causing any long-term adverse effects. Treatment sessions are 10-20 minutes long and can be conveniently scheduled around a typical daily schedule.

which b vitamins for depression

B Vitamins and Depression: Looking to the Future

One of the most common nutritional deficiencies linked with depression is of vitamin B. As more evidence links the B vitamin family with episodes of depression, future research may expand the role of nutrition in the evaluation and treatment of depressive disorders.