Omega6 fats vs. Omega3's, does the ratio matter for your Mental Health?
One of the potential mechanisms in which mental disorders and challenges manifest is via inflammation. Inflammation is your bodies’ response to injury and is essential for our survival. Inflammation becomes a problem when it becomes chronic. Omega3 fats DHA and EPA are especially important for our mental health and while they help to decrease inflammation, they also contribute to the structural integrity and fluidity for every one of our cell membranes. In fact, DHA makes up about 90% of the omega3 fats in your brain!
Observational studies report deficiencies of Omega3’s in many clinical mental health disorders including depression and anxiety. The current western diet is devoid of many essential nutrients and is thus incredibly deficient in these important brain healthy fats. In fact, consumption of a Western dietary pattern is associated with increased levels of inflammation as well as increased levels of Omega 6 fat arachadonic acid (AA). More recent evidence suggests that the ratio and balance of Omega6:Omega3 in one’s diet may be relevant to disease states including one’s poor mental health. In fact, case controlled studies suggest that individuals with depression have lower levels of omega 3’s and higher omega6:omega3 ratio levels compared to healthy controls. But if you take a closer look at the research, the culprit may not be AA afterall, but instead a lack of enough Omega 3 fats EPA and DHA in the diet.
Both Omega 3 fats and Omega 6 fats are important because they help to provide the structural components of cell membranes and as well as a source of energy and fuel. While Omega 3 fats seem to have been getting more of the positive attention they deserve, Omega 6 fats are instead getting blamed as the cause for poor health outcomes. It is commonly believed that consuming foods with high levels of Omega 6 fats, like vegetable oils including canola oil, will increase levels of inflammation. But studies in humans suggest otherwise in that an increase in the consumption of ARA or LA (Linoleic Acid) does not increase inflammatory biomarkers and instead help to decrease inflammation. In fact, one meta-analyses of over 30 randomized controlled trials reports that increasing consumption of Omega 6 fat LA did not increase any inflammatory biomarkers including interleukin-6 and tumor necrosis factor, two commonly used markers measuring levels of inflammation in the body. And yet another review of 15 human intervention trials investigating the effects of LA on inflammatory biomarkers concluded that “virtually no data are available from randomized controlled intervention studies among healthy, non-infant human beings to show that the addition of LA to diets increases markers of inflammation.”
Let’s take a look at what EPA and AA influences to help us discern whether paying attention this ratio is important.
EPA and AA both act as precursors for cell signaling pathways. Increasing EPA by supplementing helps to reduce the EPA:AA ratio, which is important because they both compete for the same enzymatic conversion pathways. By increasing EPA, it results in the increase of resolvins and other substrates that help signal anti-inflammatory pathways, which help to improve the regulation of neuroinflammation (inflammation that occurs in the brain). This is one proposed mechanism by which EPA helps to reduce depression (future blog post soon). But this is just one proposed mechanism and way EPA has an influence on depression.
We need to be careful about interpreting findings about associations of higher ratios of Omega6:Omega3’s and mental health conditions and immediately relating that to inflammation and dietary recommendations. Omega6 fats are also crucial for brain health and we need them in balance with our Omega3’s to help our mental functioning thrive. Yes a Western style dietary pattern is associated with increased biomarkers of inflammation and levels of AA, but maybe that’s more because there is a lack of beneficial dietary omega3 fats DHA and EPA present in this dietary pattern. Perhaps it’s the deficiency of EPA, fruits and vegetables, nuts, and legumes, that lend itself to promoting further inflammation instead of the consumption of Omega 6 fats. The Western dietary pattern is characterized by a high content of saturated fats, refined grains, sugar, alcohol, and salt. Consuming these foods doesn’t leave much room for the consumption of more beneficial nutrients and foods that help to lower levels of inflammation, like we have seen with the Mediterranean style diet so far. The issue isn’t that you can’t ever consume processed foods because they have Omega 6 fats. It’s that in order to help promote anti-inflammatory mechanisms in the body, you want to focus on limiting your consumption of those foods while also consuming other foods with more brain supporting nutrients (seafood, fruits, veggies, wholegrains, etc.).
That being said, it is important to consume both Omega 6 and Omega 3 fats as both contribute to lowering levels of inflammation. For mental health specifically, omega 3 fats EPA and DHA seem to be particularly significant.
How Inflammation Affects our Brain
There are several proposed mechanisms as to why inflammation may be a major contributor to mental health disorders, particularly for depression. One of the hypotheses is that elevated inflammatory markers activate the HPA axis, which result in the increased release of cortisol. Cortisol receptors become desensitized which increases the activity of proinflammatory immune mediators and leads to disturbances in the transmission of neurotransmitters. Another hypothesis is that inflammatory cytokines and cortisol may lower serotonin precursor availability and can instead lead to serotonin depletion. This is important because serotonin is central to the development of depression. You need to have enough of it in the synapse between cells in order to experience stability in mood. Individuals with Major Depressive Disorder (MDD) have been shown to have increased levels of proinflammatory cytokines, leading to believe that inflammation is a major contributor to this clinical disorder.
Focusing on increasing your consumption of Omega3 fats EPA and DHA with foods like fatty fish will help benefit your mental health, especially if you have clinical depression. Following a whole foods nutrient dense diet like the Mediterranean diet complete with lots of vegetables, fruit, seafood, nuts, beans, legumes, seeds, olive oil, and some red meat will help lower levels of inflammation, helping to promote mental health.
References
Berger, M. E., Smesny, S., Kim, S. W., Davey, C. G., Rice, S., Sarnyai, Z., Schlögelhofer, M., Schäfer, M. R., Berk, M., McGorry, P. D., & Amminger, G. P. (2017). Omega-6 to omega-3 polyunsaturated fatty acid ratio and subsequent mood disorders in young people with at-risk mental states: a 7-year longitudinal study. Translational psychiatry, 7(8), e1220. https://doi.org/10.1038/tp.2017.190
Johnson, G. H., & Fritsche, K. (2012). Effect of dietary linoleic acid on markers of inflammation in healthy persons: a systematic review of randomized controlled trials. Journal of the Academy of Nutrition and Dietetics, 112(7), 1029–1041.e10415. https://doi.org/10.1016/j.jand.2012.03.029
Lin PY, Huang SY, Su KP. A meta-analytic review of polyunsaturated fatty acid compositions in patients with depression. Biol Psychiatry 2010; 68: 140–147.
Su, H., Liu, R., Chang, M., Huang, J., & Wang, X. (2017). Dietary linoleic acid intake and blood inflammatory markers: a systematic review and meta-analysis of randomized controlled trials. Food & function, 8(9), 3091–3103. https://doi.org/10.1039/c7fo00433h
Tułowiecka, N., Kotlęga, D., Prowans, P., & Szczuko, M. (2020). The Role of Resolvins: EPA and DHA Derivatives Can Be Useful in the Prevention and Treatment of Ischemic Stroke. International Journal of Molecular Sciences, 21(20), 7628. MDPI AG. Retrieved from http://dx.doi.org/10.3390/ijms21207628
https://institute.progress.im/en/content/hypothalamic-pituitary-adrenal-hpa-axis-depression
