Bipolar disorder (BD) is a chronic mental health condition characterised by extreme mood fluctuations ranging from manic or hypomanic episodes to depressive episodes.
Traditional treatment for bipolar disorder primarily involves pharmacotherapy, antidepressants, and adjunctive psychotherapy to manage symptoms and improve functioning but nutritional psychiatry has highlighted how dietary choices and specific nutrients may serve not only as preventive measures but also as adjuncts to conventional bipolar disorder treatment. In this article we will discuss the impact of diet and nutrition on bipolar disorder treatment.
Inflammation, Oxidative Stress, and Neuroprotection
One key mechanism by which diet influences bipolar disorder is through modulation of inflammation and oxidative stress.
Chronic low‐grade inflammation and oxidative stress have been implicated in the pathophysiology of BD. Diets that are rich in anti-inflammatory foods—such as fruits, vegetables, whole grains, and healthy fats—can help reduce the production of pro-inflammatory cytokines and free radicals.
For instance, a Mediterranean-style diet, which emphasises olive oil, nuts, legumes, and fish, is associated with lower levels of inflammatory markers and has been linked to better mood stability and reduced cardiovascular risks in patients with BD.
Conversely, diets high in ultra-processed foods, refined sugars, and unhealthy fats contribute to systemic inflammation, which may exacerbate mood symptoms by affecting neurotransmitter metabolism and mitochondrial function.
Omega-3 Fatty Acids and Brain Function
These essential fatty acids are vital components of neuronal membranes and play an important role in cell signalling, neurotransmission, and neuroplasticity.
Multiple studies and meta-analyses have evaluated the efficacy of omega-3 supplementation as an adjunct treatment for depressive symptoms in bipolar disorder.
Although the evidence is mixed—with some trials showing improvement in depressive symptoms and others finding little benefit—the balance of research suggests that omega-3s, especially when the supplement is high in EPA relative to DHA, may reduce inflammation and stabilise mood.
Weight Management and Metabolic Health
A substantial challenge in managing bipolar disorder is the high prevalence of metabolic syndrome and obesity, partly due to the side effects of mood stabilisers and antipsychotic medications.
Diet plays a critical role in mitigating these adverse effects. A balanced, nutrient-dense diet that emphasises whole, unprocessed foods can help maintain a healthy weight and improve insulin sensitivity.
Conversely, diets high in refined sugars and saturated fats can lead to chronic hyperglycaemia and insulin resistance, which not only affect physical health but may also impact brain function through mechanisms involving neuroinflammation and oxidative stress.
Gut Microbiome and the Gut-Brain Axis
The gut-brain axis is a bidirectional communication pathway between the gastrointestinal tract and the central nervous system. Recent research has underscored the role of the gut microbiome in mental health, including bipolar disorder.
A diverse and balanced gut microbiota supports the production of neurotransmitters (such as serotonin, for which approximately 95% is produced in the gut), modulates immune function, and reduces systemic inflammation.
Diet profoundly influences the composition and function of the gut microbiota. Diets high in fibre from fruits, vegetables, whole grains, and legumes promote the growth of beneficial bacteria.
In contrast, diets rich in processed foods and sugars can lead to dysbiosis—an imbalance in the gut microbial community—which is associated with increased inflammation and has been linked to mood disorders.
Probiotics, found in fermented foods like yogurt, kefir, sauerkraut, and kimchi, may help restore gut microbial balance. Studies have indicated that probiotic supplementation can reduce symptoms of mania and depressive episodes in bipolar disorder by altering inflammatory markers and modulating the gut-brain axis.
Micronutrient Deficiencies and Supplementation
Micronutrients—including vitamins and minerals—play a critical role in brain function. Research has shown that deficiencies in several key micronutrients are common among individuals with bipolar disorder.
For example, low levels of B vitamins (such as B6, B9/folate, and B12) have been associated with altered neurotransmitter synthesis, elevated homocysteine levels, and increased risk of cardiovascular complications.
Vitamin D deficiency is also prevalent in bipolar disorder and is linked to poorer mood regulation and higher inflammatory markers. Magnesium and zinc, minerals involved in neurotransmission and enzyme function, are other nutrients whose deficiencies have been implicated in mood dysregulation.
Supplementation with these micronutrients can help correct deficiencies and may have a beneficial effect on mood stabilisation.
Special Dietary Patterns: Ketogenic and Mediterranean Diets
In recent years, particular dietary patterns have attracted attention for their potential therapeutic effects on bipolar disorder. Two diets, in particular, have been the focus of both clinical research and anecdotal reports: the ketogenic diet and the Mediterranean diet.
The Ketogenic Diet
Originally developed to treat refractory epilepsy, the ketogenic diet is a high-fat, low-carbohydrate eating plan that induces a metabolic state called ketosis. In ketosis, the body shifts from using glucose as its primary fuel to using ketone bodies produced from fat metabolism.
Some preliminary case studies and small clinical trials have suggested that the ketogenic diet may offer mood-stabilising benefits in bipolar disorder, but the long-term safety and efficacy of the ketogenic diet in bipolar disorder remain under investigation, and should only be implemented under medical supervision.
The Mediterranean Diet
The Mediterranean diet, characterised by high consumption of fruits, vegetables, whole grains, legumes, nuts, fish, and olive oil, and low consumption of red meat and processed foods, has been widely studied for its cardiovascular benefits.
Observational studies and controlled trials suggest that adherence to a Mediterranean dietary pattern is associated with lower levels of depression and better mood stability. The anti-inflammatory and antioxidant properties of the Mediterranean diet are thought to underpin these effects, making it a potentially effective strategy for managing both the physical and mental health challenges associated with bipolar disorder.
