Omega-3s and Cortisol: How They Help Calm Your Body’s Stress Response
We often think of cortisol as the stress hormone, and while it’s essential for survival, persistently high levels can take a toll on our health. Chronic cortisol elevation has been linked to anxiety, poor sleep, weight gain (especially abdominal), immune suppression, and accelerated skin ageing.
Omega-3 fatty acids, particularly EPA (eicosapentaenoic acid) and DHA (docosahexaenoic acid) from fish oil have been shown to help modulate the body’s stress response, supporting healthier cortisol levels.
What Is Cortisol?
Cortisol is a steroid hormone produced by the adrenal glands. It’s released in response to stress and plays a role in:
• Regulating blood sugar
• Controlling inflammation
• Supporting memory formation
• Helping the body respond to “fight or flight” situations
While short bursts of cortisol are protective, chronically elevated cortisol can be damaging to the brain, cardiovascular system, and skin, as well as contributing to hormonal imbalances and excess belly fat.
How Omega-3s May Lower Cortisol
• Anti-inflammatory effects: EPA, found predominantly in oily fish (like salmon, mackerel, sardines) and fish oil supplements, has potent anti-inflammatory properties. Chronic stress is often accompanied by low-grade inflammation, which in turn can perpetuate high cortisol levels. Lowering systemic inflammation reduces overactivation of the HPA axis (a communication system between the hypothalmus, pituitary and adrenal glands that regulates stress).
• Improved membrane function: Omega-3s optimise hormone receptor signalling, including those for stress regulation.
• Neurotransmitter support: EPA and DHA enhance serotonin and dopamine signalling, helping buffer psychological stress.
• Autonomic balance: Improved parasympathetic tone (as shown by better heart rate variability) counterbalances stress responses.
Recent Evidence - 19% Cortisol Reduction
One of the most compelling recent studies (Husmann et al., 2021, PMID: 33875799) found that omega-3 fish oil supplementation using a combination of EPA and DHA reduced morning cortisol levels by 19% in healthy adults after 12 weeks. This drop was accompanied by improvements in heart rate variability (a marker of better stress resilience). The authors suggest that omega-3s may directly modulate the hypothalamic-pituitary-adrenal (HPA) axis.
A study by Kiecolt-Glaser et al., 2011 found that supplementation with omega-3 (EPA + DHA, with a higher EPA ratio) in medical students reduced both anxiety symptoms and inflammatory signalling, suggesting an indirect benefit for cortisol regulation via lowering inflammation.
Another human study (Delarue et al., 2003) showed that fish oil reduced the adrenal activation and cortisol surge triggered by mental stress.
Key Takeaways
1. EPA and DHA omega-3 fatty acids have strong evidence for helping regulate cortisol and reduce the effects of chronic stress. With studies showing reductions of up to 19% in cortisol levels (PMID: 33875799), along with improvements in inflammation and nervous system equilibrium, omega-3s are a valuable tool for both mental and physical health.
2. When combined with good sleep, balanced exercise, and mindful living, omega-3s can help keep your stress response in check, supporting brain health, hormone balance, and skin vitality.
References
1. Kiecolt-Glaser JK, et al. (2011). Omega-3 supplementation lowers inflammation and anxiety in medical students: A randomized controlled trial. Brain, Behavior, and Immunity, 25(8), 1725–1734.
2. Husmann M, et al. (2021). Effects of omega-3 fatty acids on cortisol and heart rate variability in healthy adults. Prostaglandins, Leukotrienes and Essential Fatty Acids, 167, 102275. PMID: 33875799.
3. Delarue J, et al. (2003). Fish oil prevents the adrenal activation elicited by mental stress in healthy men. Diabetes & Metabolism, 29(3), 289–295.
4. Matsumura K, et al. (2017). DHA-rich fish oil reduces stress responses after mental arithmetic tasks. Journal of Oleo Science, 66(11), 1201–1211.
5. Mischoulon D, et al. (2009). A double-blind, randomized controlled trial of omega-3 fatty acids for depression. Journal of Clinical Psychiatry, 70(4), 485–492.