Omega-6 fatty acid could reduce your risk of bipolar

An omega-6 fatty acid that is commonly found in eggs, poultry and seafood could reduce your risk of developing bipolar disorder, according to a new study conducted by the University of South Australia (UniSA) and published in the journal Biological Psychiatry.

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.

Using Mendelian randomisation, a powerful causal inference method, researchers tested 913 metabolites across 14,296 Europeans, finding 33 (mostly lipids) were associated with risk of bipolar disorder. They also found that a bipolar disorder risk gene cluster (FADS1/2/3), which encodes enzymes associated with lipid metabolism, mediated the association between bipolar disorder and the levels of arachidonic acid and other metabolites.

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

“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.

“Intriguingly, we observed a pattern whereby a genetic propensity to higher levels of lipids containing an arachidonic acid fatty acid side chain was associated with a lower risk of bipolar disorder, while the inverse was true of lipids containing a linoleic acid side chain. Since arachidonic acid is synthesised from linoleic acid in the liver, this suggests arachidonic acid synthesising pathways are important for bipolar disorder.”

Stacey explained that arachidonic acid — a polyunsaturated omega-6 fatty acid — can be sourced directly from meat and seafood products or synthesised from dietary linoleic acid (such as nuts, seeds and oils). It is also present in human milk, and so is considered essential for infant brain development and added to infant formula in many countries. Therefore, it may exert an effect on bipolar disorder risk by affecting neurodevelopmental pathways, which would be consistent with contemporary views of bipolar disorder as a neurodevelopmental disorder.

But while we know that arachidonic acid is involved in early brain development, Stacey said it is still unclear whether supplementation for bipolar disorder could or should occur perinatally, during early life, or even whether it would benefit those already diagnosed.

“To our knowledge, ours is the first study to highlight a potential causal role between arachidonic acid and bipolar disorder,” Stacey said. “Preclinical studies and randomised controlled trials will be necessary to determine the preventive or therapeutic value of arachidonic acid supplements, perhaps with a particular focus on people with a compromised arachidonic acid synthesising pathway or with poor natural dietary sources.

“Our findings also support potential avenues for precision health interventions focused on early-life nutrition to ensure that infants and children are receiving enough arachidonic acid and other polyunsaturated fatty acids to support optimal brain development, which may also reduce the risk of bipolar disorder.”

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