The Connection Between Fatigue, Brain Fog, Headaches, and Gut Health
For a lot of people with symptoms like fatigue, brain fog, or difficulty sleeping, adrenal fatigue seems to offer an explanation. But research shows that the adrenal fatigue theory doesn’t hold up to closer scrutiny. So what do these symptoms really mean, and what can we do about them?
Often, the things that we think of as adrenal fatigue symptoms are actually signs of a different problem, like an imbalance in the gut. Investigating and treating these underlying issues can help to improve symptoms, while nutritional and herbal products can provide simultaneous adrenal support.
Let’s dive in.
Is Adrenal Fatigue Real?
The adrenal glands are responsible for several hormonal functions, including releasing cortisol in response to stress. The theory behind adrenal fatigue is essentially that with prolonged or chronic stress exposure, the adrenal glands become overworked and overtired. Eventually, this renders them unable to produce sufficient cortisol.
However, high-quality research simply has not been able to prove that adrenal fatigue is real.
- A 2016 systematic review concluded that there was no proof of the existence of adrenal fatigue. The review, succinctly titled “Adrenal fatigue does not exist,” looked at 58 different studies and found no evidence to support a meaningful connection between fatigue and cortisol levels or patterns .
- The review also showed that the testing methods used in adrenal fatigue studies were unable to determine adrenal function.
- A 2019 systematic review of 108 observational studies including almost 6500 participants found that cortisol levels and patterns were generally similar between those with PTSD and healthy individuals. This calls into question the idea that stress directly impacts adrenal function and/or cortisol production .
On the whole, endocrinologists don’t support the adrenal fatigue theory. In contrast, Addison’s Disease, or primary adrenal insufficiency, is a true medical condition in which the adrenal glands are chronically unable to produce sufficient cortisol and aldosterone .
In concluding that adrenal fatigue is not a valid diagnosis, though, we want to be careful not to throw out the baby with the bathwater.
Symptoms commonly associated with adrenal fatigue are real and worthy of being addressed seriously. But the adrenal fatigue theory can end up distracting us from what’s really going on and can get in the way of effective treatment.
So let’s explore these symptoms further.
Adrenal Fatigue Symptoms
The symptoms that we associate with adrenal fatigue tend to be what we refer to as “nonspecific.” This means that they are somewhat vague and could be symptoms of many different conditions.
Symptoms may include things like tiredness, brain fog, lack of motivation, or frequent headaches. They’re often hard to pinpoint, and their causes can be elusive.
In my clinical experience, adrenal fatigue symptoms are often caused by what’s going on in the gut. It’s important to note that gut issues don’t always present with obvious digestive symptoms.
In fact, many people who have imbalances like SIBO or Leaky Gut Syndrome don’t seem to have any digestive issues at all. Instead, they may struggle with fatigue, low drive, anxiety or depression, and brain fog [4, 5, 6, 7, 8, 9, 10 11].
Fatigue is one of the most common (and frustrating) concerns people seek medical help for, whether it’s a seemingly isolated issue or one in a cluster of symptoms.
Fatigue or tiredness has been reported as one of the most common symptoms of several gut conditions, including IBS, IBD, non-celiac gluten sensitivity, and leaky gut [4, 5].
- A meta-analysis of 17 studies found that more than half of IBS patients suffer from fatigue .
- Sixty-four percent of patients with non-celiac gluten sensitivity reported tiredness as a symptom .
- Fatigue is a common symptom of intestinal permeability (leaky gut) [7, 8].
- A survey found that patients with IBD felt their fatigue to be more of a burden than their digestive problems .
Fatigue has also been linked to gut infections and imbalances in the gut microbiome [13, 14]. I have seen in the clinic that when we treat imbalances in the gut, chronic fatigue is often resolved.
A limited number of studies show that some gut treatments can help with fatigue and low energy:
- A study on patients with chronic fatigue syndrome found that treating leaky gut helped to improve fatigue symptoms .
- The low FODMAP diet, often recommended to patients with IBS and/or SIBO, has been shown to reduce fatigue in those with IBS and fibromyalgia .
Fatigue can also be a sign of hypothyroidism (low thyroid), hormonal imbalances, infection, high or low blood sugar, nutritional deficiencies, or food intolerances.
Brain fog is another common symptom that can interfere with day-to-day life. Many people describe foggy thinking, difficulty remembering things, or trouble concentrating.
Imbalances in the gut microbiome have been shown to affect cognition . Brain fog is often the result of inflammation in the brain, which may begin as gut inflammation .
A lower sense of coherence has been reported as a common symptom of IBS .
Brain fog is also commonly reported in both celiac disease and non-celiac gluten sensitivity. In these cases, research shows that cognitive symptoms like brain fog may worsen when gluten is consumed, and improve when a gluten-free diet is followed [18, 19].
Salt or Sugar Cravings
We tend to crave things like salt and sugar when we’re tired or stressed, making this a somewhat unsurprising symptom.
Sugar cravings can also point to issues with blood sugar regulation or insulin resistance.
Cravings can also perpetuate a vicious cycle in which more sugary and/or processed foods are consumed, contributing to symptoms like fatigue.
Many chronic fatigue patients describe difficulty falling asleep or staying asleep, in spite of feeling tired. Difficulty sleeping is frustrating and can contribute to a vicious cycle of fatigue.
Difficulty sleeping may be related to gut imbalances. Gut inflammation can disrupt the body’s natural sleep-wake cycle . Sleep disturbances have also been linked to leaky gut .
- Sleep disorders are more common in those with IBS than in healthy individuals. A meta-analysis of 36 studies found that sleep disorders occur in 37.6% of IBS patients .
- Healing the gut may help to resolve sleep issues. A number of studies have shown that probiotics can improve sleep quality in those with and without IBS [23, 24, 25, 26, 27].
Both high and low blood sugar can also contribute to challenges with falling or staying asleep.
Anxiety or Depression
Anxiety, depression, and low mood are common symptoms of gut disturbances, as research into the gut-brain connection continues to show:
- Depression and anxiety are among the most common non-digestive symptoms of IBS . They are also common symptoms of non-celiac gluten sensitivity and have been linked to leaky gut [9, 10].
- A meta-analysis of 10 clinical trials found that probiotics are effective at treating mild to moderate depression .
- A systematic review of 21 studies found that more than 50% of individuals with anxiety had improved symptoms with the use of probiotics and/or diet intended to support the gut microbiome .
Headaches are another surprisingly common symptom of gut disorders.
- One study on patients with non-celiac gluten Sensitivity found that dietary changes (adopting a gluten-free diet) improved migraine symptoms .
Other Symptoms May Include:
- Low motivation or drive
- Dizziness when standing up quickly
- Low libido
- High or low blood pressure
- Unexplained weight gain or difficulty losing weight
Adrenal Fatigue, Stress, and the Gut
The adrenal fatigue theory posits that ongoing stress leads to impaired functioning of the adrenal glands and adrenal hormones.
While adrenal fatigue may not be a valid diagnosis, chronic stress certainly interferes with how the body functions.
For example, stress might be causing you to sleep poorly at night, which will cause you to feel tired and experience other poor health symptoms as a result.
Stress affects endocrine function, immune system function, and overall health. We also know that stress affects gut health, and gut health affects stress . Again, many non-digestive symptoms are actually related to what’s going on in the gut. The impact of gut health on the body’s stress response and hormones, and the way in which that can lead to “adrenal fatigue” symptoms, is one example of this.
A gut imbalance like SIBO or a fungal infection creates stress for the body. Chronic inflammation caused by a leaky gut creates stress. Even eating inflammatory foods creates stress.
How To Treat ‘Adrenal Fatigue’ Symptoms
If you’ve been struggling with symptoms like fatigue, brain fog, or trouble sleeping, it’s time to get to the true root of the issue and start to heal.
There’s generally no need to spend time or money on saliva tests or blood tests that look to diagnose adrenal fatigue.
When it comes to healing the gut, reducing stress, and improving symptoms like fatigue, the first step is to establish healthy diet and lifestyle habits. Good places to start include following an anti-inflammatory diet and prioritizing 7-9 hours of sleep every night. Stress reduction techniques may include practicing mindfulness meditation or getting regular, moderate exercise.
Next, we want to identify and treat any underlying gut imbalances that may be contributing to inflammation, hormonal dysfunction, and the symptoms we associate with adrenal fatigue.
There are also a few nutritional and herbal products documented to help with energy support, burnout, and overall wellness. There’s a certain amount of overlap between supplements that support the stress response and those that improve gut health. For example:
- Probiotics offer plenty of benefits for gut health. Research has also shown that probiotics can help to lower levels of the “stress hormone” cortisol .
- The adaptogenic herb ginseng, best known for helping the body’s stress response, has also been shown to boost levels of beneficial bacterial species in the gut .
There are a few nutritional and herbal products that may help to support hormone function and cortisol levels, and which have been shown to help with symptoms like fatigue and brain fog.
You don’t need to go through any expensive or unnecessary testing to get these supports, and they may be effective alongside a gut healing protocol.
Nutritional products that may be helpful include:
- B vitamins [34, 35]
- Vitamin C [36, 37]
- Magnesium 
Adaptogenic herbs can also provide energy support. Adaptogens are a category of herbs that can help support a healthy stress response. The use of many of these herbs dates back centuries, and today, they are often recommended as adrenal supplements.
Ashwagandha and Rhodiola are two adaptogenic herbs that have been shown to help decrease symptoms of fatigue and the effects of chronic stress and burnout [39, 40, 41, 42].
The Ideal Diet for Adrenal Fatigue Symptoms
Adopting a healthy, balanced diet is one of the most important and effective ways to improve gut health.
When it comes to choosing the best diet for symptoms associated with adrenal fatigue, we want to focus on a few key things:
- Avoid processed and refined foods, sugar, and alcohol. All of these foods can contribute to gut imbalances, feed bacterial and fungal overgrowths, and increase inflammation. Focus instead on fresh, whole foods.
- Eat to balance blood sugar. Consuming adequate, high-quality protein and monitoring carbohydrate intake can help with this.
- Identify any food intolerances or sensitivities that may be contributing to inflammation and symptoms. Keeping a food and symptom diary is one good way to do this.
The paleo diet is a good option that can help to reduce inflammation, support gut health, and get you feeling better.
One of the most effective ways to support gut health alongside an anti-inflammatory diet is with the use of high-quality probiotic supplements. Probiotics can help to boost levels of beneficial microbes in the gut and promote bacterial diversity. The widespread health benefits of probiotics are well-documented.
Heal the Gut To Improve Adrenal Fatigue Symptoms
Many of the symptoms that we associate with adrenal fatigue, including tiredness, brain fog, and headaches, may actually be signs of an underlying gut imbalance.
Treatments that target the gut including diet and probiotics have been shown to help with fatigue, anxiety, and other symptoms of adrenal fatigue. For a step-by-step process for healing the gut, check out my book, Healthy Gut, Healthy You.
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