Omega-6 fatty acids, commonly found in eggs, poultry, and seafood, could reduce the risk of bipolar disorder, according to a world-first study from the University of South Australia.

Using Mendelian randomization, a powerful causal inference method, researchers tested 913 metabolites across 14,296 Europeans, finding 33 (mostly lipids) were associated with risk of bipolar disorder.

Bipolar disorder is a debilitating mood disorder characterised by recurring episodes of mania and depression. Although its cause is still unclear, previous studies have shown that bipolar disease is highly heritable. If a parent has bipolar, a child has a one in 10 chance of also developing the condition.

Globally one in every eight people live with mental conditions, with about 40 million experiencing bipolar disorder. Nearly 3% of Australians (568,000 over the age of 16) live with bipolar disorder.

Chief investigator Dr David Stacey says that the new evidence paves the way for novel potential lifestyle or dietary interventions.

“There’s growing evidence to suggest that metabolites play a key role in bipolar and other psychiatric disorders,” Dr Stacey says.

“This is extremely encouraging, because if we can find factors that connect certain health conditions, we can identify ways to negate these through potential lifestyle or dietary interventions.

“In this study, we found that a genetic propensity for higher levels of lipids containing arachidonic acid*, led to a lower risk of bipolar disorder. And conversely, that lower levels of arachidonic acid had a higher risk for bipolar disorder.

“Arachidonic acid can be sourced directly from meat and seafood products or synthesised from dietary linoleic acid (such as nuts, seeds, and oils). But it is also present in human milk, so is considered essential for infant brain development.

“In fact, in many countries, arachidonic acid is added to infant formula to ensure a child gets the best start to life. So, there is certainly potential to boost this through supplements for people at greater risk of bipolar disorder.

“The challenge is, however, that while we know that arachidonic acid is involved in early brain development, it’s unclear whether supplementation for bipolar disorder should occur perinatally, during early life, or even whether it would benefit those already diagnosed.”

Professor Elina Hyppönen, who co-authored the study, says preclinical studies and randomised controlled trials are required to determine the preventative or therapeutic value of arachidonic acid supplements to combat bipolar disorder.

“We need further studies to rigorously assess the potential for arachidonic acid supplementation in bipolar disorder prevention and treatment, particularly in people who carry genetic risks,” Prof Hyppönen says.

“While our findings support potential avenues for precision health interventions for early life nutrition for babies’ brain development, we need to know more about the connection with bipolar disorder.

“If we can establish how, why and when people respond to arachidonic acid supplementation, then we will be one step closer to helping people who are struggling with this serious and lifelong mental health condition.”

The new study - A Metabolome-Wide Mendelian Randomization Study Identifies Dysregulated Arachidonic Acid Synthesis as a Potential Causal Risk Factor for Bipolar Disorder – by Dr David Stacey, Assoc Prof Beben Benyamin, Assoc Prof S. Hong Lee, and Prof Elina Hyppönen, is published in Biological Psychiatry.

Notes to editors:

*Arachidonic acid is a polyunsaturated omega-6 fatty acid

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Researchers: Dr David Stacey E: [email protected]