Cortisol is a glucocorticoid produced by the adrenal glands and released on cue from the brain's hypothalamic-pituitary-adrenal (HPA) axis.
In short bursts, it helps you meet a demand. Kept high week after week, it is linked to insulin resistance, weakened immunity, and higher blood pressure, among other problems, according to a 2023 NIH review.
Diet is one of the levers researchers now study. A November 2025 review in the International Journal of Molecular Sciences, titled Feeding the Rhythm, walks through how specific nutrients interact with the HPA axis and shift daily cortisol secretion.
It is one of several recent evidence bases pointing at foods with a plausible calming effect. Below are seven of them, with what the science does and does not say.
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Fatty fish
Salmon, sardines, mackerel, and herring deliver the long-chain omega-3s EPA and DHA.
The Feeding the Rhythm authors write that these fats can regulate the HPA axis by reducing cortisol production, and cite work in which 7.2 grams of fish oil per day for three weeks blunted the stress response in healthy men.
The evidence base for omega-3s as a cortisol lever is among the strongest for any food nutrient.
Yogurt and kefir
A 2026 meta-analysis of 41 randomized controlled trials in BMC Nutrition found that probiotic supplementation significantly reduced serum cortisol, with a weighted mean difference of -0.35 microgram per deciliter. The authors were candid about the caveats.
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Between-study variation was high, and they graded the overall certainty of the evidence as very low. Foods like plain yogurt and kefir are the everyday route to live cultures without a supplement.
Dark leafy greens
Spinach, chard, and kale are magnesium-rich, and magnesium and cortisol interact in both directions.
An NIH-hosted chapter on magnesium and stress notes that magnesium decreases the release of ACTH, the pituitary signal that tells the adrenals to make cortisol, and modulates adrenal sensitivity to it.
Stress and low magnesium potentiate each other in what the authors call a vicious circle, which is why topping up through food may matter.
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Walnuts
Walnuts pack alpha-linolenic acid, a plant omega-3, along with polyphenols. A Penn State randomized crossover trial in the Journal of the American College of Nutrition found that diets high in walnuts and walnut oil reduced resting blood pressure and blunted cardiovascular responses to acute stress in healthy adults.
Direct cortisol effects in humans are less clear, but the profile fits the broader omega-3 story.
Dark chocolate
In a four-week randomized trial published in Antioxidants, 26 adults ate 25 grams a day of high-polyphenol dark chocolate or a control with negligible flavonoids.
Total daily cortisol, morning cortisol, and the cortisol-to-cortisone ratio all fell significantly in the high-polyphenol group.
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The proposed mechanism is that polyphenols inhibit the enzyme 11-beta hydroxysteroid dehydrogenase type 1, which regenerates active cortisol in tissues.
Whole grains
Refined starches and sugar can send blood glucose up and then crashing, which recruits cortisol as part of the counter-regulatory response. The Feeding the Rhythm authors write that a high-glycemic diet is associated with an increase in cortisol secretion, and that an evening high-glycemic meal often raises cortisol through neuroendocrine pathways.
A Nutrients trial in adult women found that within a whole-food diet, larger increases in total carbohydrate intake were tied to dampened salivary cortisol responses to a laboratory stressor over eight weeks. Oats, barley, and other intact grains are the practical form.
Pomegranate
Pomegranate is polyphenol-dense, and the Feeding the Rhythm review lists it alongside dark chocolate among the polyphenol-rich foods that have been reported to reduce cortisol levels. The trials are small, so it belongs in the supporting cast rather than the headline.
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Food is one lever, not the whole system. The same NIH review that catalogs the harms of chronic cortisol also points at sleep, movement, and the underlying stressor itself. If stress or symptoms have persisted, a conversation with a doctor is the next step, not a bigger grocery list.
This article is made and published by Jesper Bengtson, who may have used AI in the preparation.