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Over the past few years, adrenal health has become a widespread topic thanks to the popular interest in adrenal fatigue and hypothalamic-pituitary-adrenal (HPA) axis dysfunction. While there are many potential helpful supplements and herbs on the market, starting with a strong foundation of a diet filled with foods for adrenal health can go a long way towards supporting adrenal and HPA axis health. There are many eating patterns and individual nutrients that have been studied for their role in maintaining a healthy stress response and HPA axis function.
The 411 on the Adrenal Gland
Before we begin, a quick look at the biology of the adrenal gland, the HPA axis, and the associated hormones can be helpful. The adrenal gland, part of the HPA axis, regulates the stress response. There are two parts in the adrenal gland: the cortex and the medulla. Within the cortex are three zones, each producing specific hormones. The zona glomerulosa is in charge of producing mineralocorticoids including aldosterone, which controls the water and sodium homeostasis and is involved in blood pressure regulation. The zona fasciculata synthesizes the glucocorticoids cortisol and corticosterone, which are the main hormones involved in the stress response and also play roles in metabolism, behavior, and immunity. The zona reticularis produces dehydroepiandrosterone (DHEA), which can be synthesized into androgens, estrogens, and neuro-steroids. The adrenal medulla in the core of the gland releases the catecholamines epinephrine and norepinephrine for a rapid reaction to acute stress.
The other parts of the HPA axis are the hypothalamus and the pituitary. The hypothalamus secretes corticotrophin-releasing hormone (CRH), which then stimulates the anterior pituitary gland to release adrenocorticotropic hormone (ACTH) to target the adrenal gland to do its work. It works in a feedback loop, with cortisol triggering a decrease in CRH levels.
Because cortisol is the main stress hormone, many studies investigating the impact of nutrition and dietary patterns on supporting the adrenal gland and/or HPA axis utilize this as a measure of function.
Supporting the HPA Axis with the Right Eating Pattern
When determining the best way to eat to support your adrenal gland and HPA axis, it’s best to start with the over-arching eating pattern. Based on the evidence, choosing a generally healthy diet that reduces highly processed foods and added sugar while balancing your macronutrients, rather than the typical Western-style diet, is a good place to start.
According to studies, diet-induced changes that contribute to prediabetes may also lead to impaired HPA axis with an increased stress response, possibly due to the close relationship between the HPA axis and glucose homeostasis. One rat study using a high-fat high-carbohydrate diet to induce prediabetes demonstrated that, in a prolonged prediabetic state, ACTH concentration decreased even in non-stressful conditions. There was also a consistently high level of corticosterone, showing an impairment of the signaling of the adrenal gland. Another rat study found that a high fructose diet during preadolescence led to HPA axis dysfunction, elevated cortisol levels during acute stress, and increased anxiety and depressive behavior into adulthood, while the rats who only had a high-fructose diet in adulthood did not have the same changes. Another animal study showed that a high-fat diet led to hypersensitivity of the HPA axis, especially under chronic mild stress.
The changes from the high-fat diet may impact the organ itself as well as gene expression. In a rat study, a high-fat diet led to negative effects in the morphology of the adrenal gland, including a significant increase in the adrenal gland weight, a significant decrease in the volume ratio of the zona reticularis to the adrenal cortex, and an increase to the number of chromaffin cells per unit of volume (which demonstrated fat accumulation in the organ). Another mouse study found that a high-fat diet led to changes in the gene expression of many aspects of the HPA axis, including the corticotrophin-releasing hormone (CRH) mRNA and glucocorticoid (GR) mRNA that altered both the diurnal regulation, as well as an overall decrease in HPA axis activity.
Even a diet high in healthy fats, such as the popular ketogenic diet, may contribute to HPA axis dysfunction. A ketogenic diet in an animal study led to similar changes in the HPA axis tone as chronic stress, with elevated corticosterone levels but normal plasma ACTH levels and thymic atrophy, as well as an exaggerated corticosterone response to acute stress and a greater response to ACTH. While acute dietary ketosis activates a more transient stress response similar to other acute stressors, a longer-term ketogenic diet leads to alterations in the HPA axis similar to that of chronic stress. While there may be benefits to the ketogenic diet for certain health conditions, it may be important to monitor its impact on the HPA axis if you choose to follow this eating pattern.
While many of these studies were on animal models, human studies likewise demonstrate that diets high in fat, especially saturated fat, negatively impacted the HPA axis. A study on women in the Mediterranean area found that diets higher in dietary fat and saturated fats were more likely to have an HPA axis disturbance than those whose diet was higher in monosaturated fats and closer to the traditional Mediterranean diet.
The right amount of carbohydrates may also be important for adrenal health. A small study assessed the impact of glycemic load diet for 3 days on steroid hormones and found that there was a small but significant increase in salivary cortisol after consuming the high glycemic index (GI) diet, while there was no effect upon consuming a low glycemic index diet that also was a lower-calorie diet. A study comparing different dietary patterns on maintaining weight loss found that, while the low carbohydrate diet led to the best results in many of the markers for metabolic syndrome, it did increase cortisol and C-reactive protein (CRP) levels. A very low carbohydrate diet led to the highest levels of cortisol compared to a low fat and a low GI diet.
Protein may be important as well, at least at certain stages in development. According to a rat study, a low-protein diet during puberty led to hyperactivity of the HPA axis, as well as hypoactivity in the HPG axis that also impacted the insulin response at 60 days. There was also a reduction in ACTH at 120 days. The low-protein diet rats also experienced metabolic dysfunction at an older age even with the restoration of their diet.
Based on many of the studies, finding an eating pattern with the right balance of fats, carbs, and protein as well as rich in colorful plant foods, especially those rich in the following nutrients, can help maintain a healthy HPA axis function. There are many such eating patterns one can follow, such as a plant-based diet, Mediterranean diet, and an anti-inflammatory diet. In one study on adolescents, there was an inverse association between cortisol levels and the Mediterranean diet pattern and also a reduction in inflammation, demonstrating a potential for it to mitigate the impact of stress on inflammation.
Supportive Dietary Components
In addition to a general healthy eating pattern, certain dietary components play an important role in maintaining a normal HPA axis and healthy adrenal gland including:
- B-vitamins, especially thiamine, folate, B6, and B12
- Beef, chicken, fish, leafy greens, legumes, organ meats, and whole grains
- Electrolytes (sodium, potassium, magnesium, and calcium)
- Sodium and potassium-rich foods include avocado, leafy greens, sweet potatoes, and tomatoes
- Calcium-rich foods include chia seeds, dairy products, leafy greens, and sardines
- Magnesium-rich foods include bananas, chia seeds, leafy greens, nuts, and pumpkin seeds
- Fermented foods and prebiotic fibers to support the gut microbiome
- Omega-3 fatty acids
- Chia seeds, flaxseed, salmon, and other fatty fish
- Phytochemicals, such as flavonoids
- Vitamin C
- Broccoli, kiwis, oranges, peppers, and strawberries
Adding foods rich in these nutrients, such as the examples above, can assist in building a strong foundation for adrenal health and HPA axis function.
While there are many other nutrients and herbal considerations found in supplements supporting adrenal health and the HPA axis, starting with these basic foundational nutrients and food sources in your daily eating pattern can go a long way towards maintaining a healthy adrenal organ and HPA axis. For those who may have a dysfunctional HPA axis or questions about your adrenal gland and HPA axis functioning, talk with your doctor, nutritionist, dietician, or another member of your healthcare team about additional adrenal support options.
