Nutrition is increasingly being viewed as a significant factor in the development of bipolar disorder (BD) or at least a contributor to worsening of the disease in susceptible individuals.
Dietary intake of proper nutrients is particularly important in children as their brains develop. Children are at high risk for poor-quality diets, which have been linked to behavioral and cognitive problems throughout childhood.1 However, children who consume fruits and vegetables are just as likely to consume high quantities of high-fat and high-sugar foods.2
Research suggests several nutritional links to BD that may offer clues to its development and strategies to reduce its incidence and impact. A 2016 review by Beyer and Payne3 reported that shifts toward lower-quality nutrition, particularly in the Western diet, are contributing factors in BD. At the same time, studies have indicated that patients with anxiety, depression, and BD are more likely to consume nutrient-poor processed foods that are high in sugar and fat.4,5
Co-investigator John L. Beyer, MD, a psychiatrist at Duke University Medical Center in Durham, North Carolina, told Psychiatry Advisor: “We do not have much information about the relationship between nutrition and BD, much less childhood nutrition. In general, it is increasingly apparent that nutritional factors affect mood and other mental disorders beyond just the adequacy of vitamins and minerals, or the increased prevalence of obesity and heart disease.”
The problem is 2-fold, involving underconsumption of healthy, natural foods and overconsumption of processed foods that are high in calories, fats, and sugars. Beyer and Payne3 suggested a number of potential mechanisms underpinning the link between a poor-quality diet and bipolar disorder: it may merely represent a lifestyle factor that contributes to the development of the disease or conversely may be a manifestation of BD or its treatment.
“It is thought that certain lifestyle diets, especially a Western-based diet high in fats and carbohydrates, may increase the body’s challenge in regulating the inflammatory processes, oxidative stress, or mitochondrial activity. These long-term changes may contribute to chronic dysregulation of the cells that modulate moods,” Dr Beyer explained.
Lipid Mechanisms in Bipolar Disorder
The role of lipid metabolism is complex in BD. Diets high in fat appear to significantly influence the development of unipolar and bipolar depression through altered mechanisms of dopaminergic, noradrenergic, and serotonergic activity.1,6
What appears to be more important than the quantity of fat in the diet is the quality. Compared with saturated and monounsaturated fats, circulating levels of polyunsaturated fats (omega-3 and omega-6 fats) have been shown to play an important role in BD. A 1:1 ratio of omega-6 to omega-3 fatty acid is considered the healthiest, although in the United States this ratio is often highly skewed in favor of omega-6. A study by Scola et al6 indicated that individuals with BD tend to consume a significantly higher ratio of omega-6 fatty acids compared with omega-3. Markers of oxidative stress have been shown to be reduced by a diet high in fish protein.7
Sugar Consumption in Bipolar Disorder
Children in the United States consume high amounts of processed sugar, which has been implicated in the inflammatory process that contributes to a range of metabolic and cardiovascular diseases and has been linked to decreased serotonin levels in BD. Because natural carbohydrates (including sugars from fruits) are known to reduce inflammation, shifting to natural fruit-based breakfast and snack foods — as opposed to those that are “fruit-flavored” — is recommended.
Several vitamins have demonstrated an influence in BD, in particular vitamin D. Studies have shown that vitamin D levels are often low in people with BD, although no studies have yet investigated the impact of supplementation.3 Supplement studies of folate and inositol, a plant-based vitamin-like substance, have also been inconclusive despite links to depression.3 The antioxidant glutathione maintains oxidative balance in the brain but is often found to be depleted in individuals with BD. Oral supplementation is inadequate to replenish glutathione, and studies on the administration of its precursor N-acetylcysteine have shown some success.3
Specific Diets for Bipolar Disorder
Evidence suggests that several underlying mechanisms of BD may be improved with dietary interventions, including inflammation and metabolism of omega-3 fatty acid.7 Two diets have been identified as beneficial in BD: the Mediterranean and ketogenic diets, which are widely used by the general population as well.
The Mediterranean diet focuses on consuming mostly fresh fruits, vegetables, whole grains, and fish. It includes higher quantities of omega-3 fatty acids while reducing consumption of the less-healthy omega-6 fatty acids. Recent studies have shown a reverse correlation between depression and adherence to the Mediterranean diet and a lower risk of depression with a whole-foods diet plan compared with the Western diet.3
The ketogenic diet is a high-fat, adequate protein, very low carbohydrate diet that has been successful in helping control neurologic disorders such as pediatric epilepsy. The low-glycemic intake is designed to produce acidosis of the blood, which may reduce inflammation associated with BD.8 Limiting carbohydrates and sugars through the ketogenic diet has also been correlated with increasing dopaminergic and serotonin activity associated with improvements in mood.
Dr Beyer pointed out that good nutrition is associated with better patient outcomes in BD: “There may be a role for some types of diets, such as a ketogenic diet, in certain mood disorders, though we are a long way from determining who would benefit or if there is a specific diet that all patients with bipolar disorder should use.”
- Benton D. The influence of children’s diet on their cognition and behavior. Eur J Nutr. 2008;47(Suppl 3):25-37.
- Anderson SE, Ramsden M, Kaye G. Diet qualities: healthy and unhealthy aspects of diet quality in preschool children. Am J Clin Nutr. 2016;103(6):1507-1513.
- Beyer JL, Payne ME. Nutrition and bipolar depression. Psychiatr Clin North Am. 2016;39(1):75-86.
- Jacka FN, Mykletun A, Berk M, Bjelland I, Tell GS. The association between habitual diet quality and the common mental disorders in community-dwelling adults: the Hordaland Health Study. Psychosom Med. 2011;73:483-490.
- Elmslie JL, Mann JI, Silverstone JT, Williams SM, Romans SE. Determinants of overweight and obesity in patients with bipolar disorder. J Clin Psychiatry. 2001;62(6):486-491.
- Scola C, Versace A, Metherel AH, et al. Alterations in peripheral fatty acid composition in bipolar and unipolar depression [published online January 6, 2018]. J Affect Disord. doi:10.1016/j.jad.2017.12.025
- Lopresti AL, Jacka FN. Diet and bipolar disorder: a review of its relationship and potential therapeutic mechanisms of action. J Altern Complement Med. 2015;21(12):733-739.
- El-Mallakh RS, Paskitti ME. The ketogenic diet may have mood-stabilizing properties. Med Hypotheses 2001;57(6):724-726.