Adrenal health: could tired adrenals be the cause of your fatigue?

In the UK, unexplained tiredness is one of the leading causes for people to visit their GP¹. A recent YouGov survey found that around 13% of Britons feel constantly exhausted – a phenomenon so common that it has its own acronym: TATT (tired all the time). A further 25% report feeling exhausted most of the time, and 33% suffer with tiredness around half the time, which can have a huge impact on all aspects of their life.²

Once a specific cause such as anaemia or thyroid function has been ruled out, individuals are often advised to consider more sleep and to increase their exercise to improve energy levels, but what if your fatigue is not relieved by sleep, and exercise makes you feel even more tired? What if your exhaustion is coupled by an inability to cope with daily stressors and increased feelings of anxiety or brain fog?

While still a controversial topic in medical practice, a steep rise in the above symptoms has led many integrative practitioners to look to adrenal health for an answer, in a condition coined ‘adrenal fatigue’.

Today we will discuss the basics of adrenal functioning, their importance in the body and the role that prolonged stress may play in the development of adrenal fatigue. Furthermore, we will explore the health implications of adrenal dysfunction, as well as the controversy surrounding this condition, before looking at therapeutic interventions for the support of adrenal fatigue.

What are the adrenals and why are they so important?

The adrenals are two small glands which sit above the kidneys, that support the production of numerous crucial hormones which are involved in almost every bodily function. Each gland has an outer cortex responsible for producing steroid hormones such as aldosterone, DHEA and cortisol; as well as an inner medulla which controls the hormones required for coping with physical and emotional stress such as adrenaline and noradrenaline. Cortisol, DHEA and adrenaline are the key adrenal stress hormones which support the body in managing stress and adapting to daily demands.

The hypothalamic-pituitary-adrenal (HPA) axis is a central part of the hormonal network where the adrenals interact closely with the pituitary gland and the hypothalamus.  The HPA axis is responsible for neuroendocrine adaptation during the stress response. When a stressor is detected, the hypothalamus releases corticotropin-releasing hormone (CRH), which binds to CRH receptors on the anterior pituitary gland. This triggers the release of adrenocorticotropic hormone (ACTH) which binds to receptors on the adrenal cortex and stimulates adrenal release of cortisol. Once a certain blood concentration is reached, cortisol should exert a negative feedback to the hypothalamic release of CRH. In the case of chronic stress, the repeated and sustained activation of the HPA axis can contribute to hyperactivity of this response which has been linked to immune, metabolic and psychiatric dysfunction.³

Under normal conditions, the adrenals should work on a diurnal rhythm by which bursts of cortisol are released throughout the day to keep you awake, while naturally declining towards the evening in preparation for sleep⁴. Although, research has demonstrated that this rhythm is highly sensitive to external stressors⁵.

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What is adrenal fatigue?

The feedback loop to control circulating cortisol works extremely efficiently, as long as stresses are not too lasting, numerous or severe – but in our modern society stresses are often “prolonged, abundant, multiple and intense”⁶. The term ‘adrenal fatigue’ is used to explain a group of symptoms increasingly observed in individuals who are under long-term physical and/or psychological stress.

Symptoms include⁶:

• Prolonged or excessive tiredness, especially in the morning and after a full night’s sleep – some report not feeling fully awake until after noon
• Difficulty waking in the morning or falling asleep at night
• Inability to cope with stress
• Decrease resilience to infection and illness, with longer recovery time
• Dependency on stimulants such as caffeine or sugar to get through the day
• Strong salt and/or sugar cravings

When under stress, the adrenals will increase their output of cortisol and DHEA, while adrenaline is secreted to boost the energy one might require for survival i.e., when running from a threat. However, when this state is maintained for a prolonged period, for example in chronic stress, the adrenals may struggle to maintain the output for such a high demand of steroid hormones which could prompt drops in DHEA and cortisol levels^7-9. Low levels of cortisol have been associated with fibromyalgia, chronic fatigue, chronic pain syndromes and other functional somatic disorders.¹⁹

A commonly observed pattern for adrenal fatigue is the presence of fatigue upon waking, often with a requirement for stimulants to gain energy during the morning. Energy levels might crash again in the afternoon and rise in the early evening. Cortisol may be raised before sleep causing difficulty in falling asleep. For those with more advanced adrenal fatigue, cortisol output may be consistently low and so exhaustion can be a constant throughout the day, sometimes referred to as “burnout”.

This biological stress or ‘fight or flight’ response has been designed to shut down all non-essential bodily systems such as those necessary for digestion, repair and rest. For this reason, these heightened levels of cortisol and adrenaline can wreak havoc in the body over an extended period.

It should be noted, that as many of these symptoms can be interpreted as common and non-specific, adrenal fatigue is often considered last, once other ailments have been ruled out.

Areas likely affected by adrenal dysregulation:

• Cardiovascular health: dysregulated diurnal cortisol patterns with higher late night cortisol levels are associated with a higher risk of cardiovascular mortality, whereas a greater diurnal cortisol peak-to-bedtime ratio predicted a decreased risk of cardiovascular mortality and stroke¹⁰. Raised morning cortisol levels have also been associated with increased risk of cardiovascular disease (CVD), with the authors suggesting that strategies targeted at lowering cortisol levels could be used as a means of reducing risk of CVD.¹¹
• Immune function: Glucocorticoids have several actions on our immune system. For example, they induce apoptosis of proinflammatory T cells, suppress B cell antibody production, and reduce neutrophil migration during inflammation.¹² Prolonged exposure to high cortisol levels and the resulting HPA axis dysfunction interferes with the anti‐inflammatory and immunological processes.¹³
• Bone health: glucocorticoids can promote bone formation, but in contrast, elevated levels of cortisol directly inhibits osteoblast proliferation and differentiation which can blunt bone formation, resulting in lower bone density.¹⁴
• Sleep: in healthy individuals, light sleep is associated with cortisol increases, whereas deep sleep is accompanied by declining cortisol levels, and induced sleep arousals showed significant increases in cortisol levels. Higher evening cortisol levels have also been linked to lower levels of REM sleep and increased wake.¹⁵
• Fertility: inappropriate HPA activation after chronic stress can potentially produce long-term endocrine changes, namely disruption to the hypothalamic-pituitary-ovary axis that affect female fertility.¹⁶
• Thyroid function: cellular cortisol levels regulate the production of thyroid hormone. Acute stress has been shown to cause transient activation of the hypothalamic-pituitary-thyroid axis, whereas chronic stress is associated with decreased activity, with significantly lower thyroid stimulating hormone and T3 levels being observed in females reporting stress-related mental health problems.¹⁷
• Memory: while acute elevated levels of stress hormones are associated with enhanced emotional memory, chronic stress can have neurotoxic effects on the brain and is associated with a reduced volume of the hippocampus – the part of the brain involved in processing memory.^18,21
• Depression: Chronic stress and elevated cortisol levels play a significant role in the development of depressive disorders. Individuals with major depressive disorder have demonstrated significantly higher cortisol levels when compared with controls.¹⁹
• Glycaemic regulation: stress can increase the risk of Type 2 Diabetes (T2D). Evidence demonstrates that the glucocorticoid negative feedback is impaired in T2D patients, resulting in HPA axis hyperactivity and hypercortisolism. High glucocorticoids, in turn, activate multiple aspects of glucose homeostasis in tissue, leading to hyperglycaemia.²²
• Pain: while in acute stress, raised cortisol can exhibit anti-inflammatory properties. However, after chronic stress, a blunted cortisol response results in an unmodulated inflammatory response to various stressors, and signs and symptoms of stress-induced cortisol dysfunction may include bone and muscle breakdown and pain.²⁰

Is adrenal fatigue a real condition?

The term “adrenal fatigue” has been challenged and rejected by the conventional medical community for decades, with the Endocrine Society asserting that there is no scientific proof that adrenal fatigue exists as a medical diagnosis.²⁴ Currently Addison’s disease and Cushing’s Syndrome are the only medically recognised conditions associated with adrenal insufficiency. To receive a diagnosis, over 90% of adrenal function must be lost. In the absence of this, endocrine function is deemed to be normal.

This has been challenged by naturopathic and integrative practitioners who use the term adrenal fatigue to describe another condition; the point between Addison’s disease and optimal adrenal health. First described in 1998 by Dr. James L. Wilson, adrenal fatigue is a mild form of adrenal insufficiency which can occur following periods of prolonged stress. He hypothesised that during extended periods of stress, the overstimulation of the adrenal glands could lead to erratic blood cortisol levels, leaving the body with either too much or too little. As well as these deviations in cortisol, DHEA; a crucial hormone required for the creation of many other hormones in the body, may also be lacking.⁶

The major challenge faced in creating diagnostic criteria for adrenal fatigue, as well as the primary cause for controversy, lies in the fact that many of the parameters for this condition are non-specific. In 2016, a systematic review concluded that there was a lack of scientific basis for claiming adrenal impairment as a cause of fatigue.²³ While many commended this work, it also received significant backlash for the limitations to its method, as numerous different biomarkers and questionnaires used to identify adrenal fatigue were accepted for review. What this paper did highlight however, is a need for further analysis of the methods required to accurately test the reality of a condition such as adrenal fatigue. Many clinicians agree that a diagnosis for adrenal fatigue is challenging as often cortisol levels will lie within what is considered to be ‘normal’ in conventional medical standards, while patients may still present with many of the associated symptoms.

Currently, a variety of cortisol tests are being used to detect adrenal insufficiency, as well as adrenal corticotrophic (ACTH) and thyroid hormone levels. However, as cortisol testing can often be typical, it is likely that a combination of lab testing considered alongside clinical patient feedback is required to accurately measure the likelihood of adrenal fatigue.

Furthermore, with diet and lifestyle adjustments demonstrating their significance as a primary treatment option for this condition, it would be almost impossible for the conventional scientific model to measure and recognise all the factors which contribute to its diagnosis. Science is only just beginning to unravel the mysteries of how cortisol, HPA axis dysfunction and chronic disease interrelate but when we consider the plethora of areas of ill-health that can be influenced by adrenal dysfunction, it is clear that further investigation and a re-examination of the methods used for the scientific scrutiny of complex and broad conditions such as adrenal fatigue is greatly needed.

Interventions for the support of adrenal fatigue

With all things considered, if the above description of adrenal fatigue resonates with you, the question remains: what to do next?

Firstly, it is always advisable to work closely with a specialist in the area if you suspect adrenal fatigue – especially as the research is ongoing. With that being said, there are several nutrition and lifestyle interventions which have demonstrated an ability to support adrenal health.

Diet

An anti-inflammatory diet consisting of unprocessed, wholefoods should be the foundation of any healing plan to ensure adequate nutrient intake. The removal of food allergens or intolerances should also be considered, while certain things known to negatively impact adrenal health are best avoided completely:

Caffeine: this stimulant has been shown to elevate concentrations of salivary cortisol²⁹ and its activation of the HPA axis is thought to be one way in which caffeine contributes to anxiety.³⁰

Fat: processed and hydrogenated oils such as corn, sunflower and vegetable oil are highly inflammatory²⁸. Instead choose only high-quality sources such as avocado, olives, nuts, seeds, wild-caught oily fish and extra virgin olive oil. This Mediterranean dietary pattern has been proposed to exert a protective effect on the association between stress and inflammation, with cortisol levels and inflammatory markers being inversely associated with high adherence to this way of eating.²⁷

Carbohydrates: focus on high fibre starchy vegetables as your main carbohydrate source and reduce to just a quarter of your plate as this will support glycaemic stability which can be difficult when consuming simpler carbohydrate forms such as rice, pasta and bread, which are higher on the glycaemic index (GI). High GI diets have been linked to increased cortisol levels³⁴ and chronic consumption of high GI foods may lead to perpetually elevated cortisol, triggering a vicious cycle of chronic stress and unhealthy eating behaviours³⁵.

Sugar: not only is sugar highly inflammatory, but it can contribute to feelings of anxiety. Glycaemic regulation is also closely linked to adrenal health²⁵. Consumption of refined carbohydrates and sugars creates dramatic fluctuations from hyperglycaemia to hypoglycaemia, and this low blood sugar state is a trigger for cortisol release as one of cortisol’s roles is to elevate blood glucose levels. One study found that children who follow a sugary diet displayed an exaggerated cortisol awakening response and overall elevated cortisol levels throughout the day.²⁶ A recent cross-sectional study examining the association between hair cortisol concentration (an indicator of long-term stress) and diet among preschoolers found that higher HCCs were associated with less frequent consumption of fruits and berries and more frequent consumption of sugary beverages. Artificial sweeteners should also be avoided, with the use of natural sweeteners such as honey, dates and maple syrup used only in moderation.

Gut Health

Emerging evidence points to a bidirectional communication between our neuroendocrine system and gut microbiota, further suggested by disorders that are associated with both systems, such as irritable bowel syndrome (IBS), which has been associated with increased HPA axis activation³⁶. An imbalance in the gut microbiome can lead to inflammation and activation of the HPA axis and both probiotics, including strains such as lactobacilli and bifidobacteria, and prebiotics such as fructo-oligosaccharides (FOS) have demonstrated beneficial effects on the development and regulation of the HPA axis³⁷.

Increase Sleep

Sleep disorders are common in the general population and are associated with significant adverse health and behavioural consequences. Sleep, in particular deep sleep, has an inhibitory influence on the HPA axis, whereas activation of this axis can lead to arousal and sleeplessness³⁸ and the vicious cycle become apparent when we also consider that disturbed sleep is associated with an adverse cortisol secretion pattern^39,40. Most adults need between 7-9 hours of good quality sleep⁴¹ but those with adrenal fatigue may require more.

Physical activity

Light-to-moderate physical exercise has been shown to decrease cortisol levels and improve sleep, be it aerobic or mind-body exercise³³. For those who are unable to perform vigorous exercise, regular walking has been shown to improve hormone levels and potentially improve strength and quality of life³¹.

Supplements that may support adrenal health

• B vitamins: B6, B12 and folate are needed for the production of γ-aminobutyric acid (GABA); a chemical compound that affects the hormonal control of cortisol⁴³. Adequate intake of B1, B2, B6 and niacin have also been associated with lower levels of cortisol in athletes⁴⁴.
• Vitamin C: plays a central role in adrenal function, primarily by acting as a potent antioxidant within the adrenal glands⁴².
• Adaptogens: several studies indicate that adaptogenic herbs such as Ashwagandha, Rhodiola and Ginseng may help to lower cortisol levels and mediate stress responses within the body^45,46,49.
• Omega 3: low levels of omega-3 fatty acids have been linked to elevated salivary evening cortisol, which are, in turn, associated with a dysfunctional HPA axis⁴⁷. It has been proposed that omega-3 fatty acids significantly downregulate inflammation, this increasing the negative feedback sensitivity of the HPA axis⁴⁸.
• Magnesium: this mineral plays a critical role in brain function and mood and the correct function of the nervous system, and deficiency increases the risk of raised cortisol and HPA and dysfunction^50,51
• L-Theanine: an amino acid found primarily in green tea leaves can promote a calming effect and support a balanced stress response^52,53.

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If you have any questions regarding the health topics that have been raised, please don’t hesitate to get in touch with our nutritionist team via e-mail or phone:

nutrition@cytoplan.co.uk
01684 310099

Last updated on 3rd January 2024 by cytoffice