6 ways stress is messing with your gut

By Claire Barnes, Nutritional Therapist at Bio-Kult (

It is clear that in today’s world we are continually experiencing low levels of stress throughout the day, such as morning traffic, juggling work/home life balance, financial concerns and news headlines. Exposure to stress can alter our gut-brain axis and ultimately lead to the development of a broad array of gastrointestinal disorders.1   Whilst it may not be practical to eliminate all these daily stresses, we do importantly hold the ability to improve our gut-brain function to better cope with them.

By taking notice of when digestive ailments occur and whether they coincide with overall levels of stress or anxiety could potentially help provide clarity to explain why you are experiencing these gut complaints and how you could potentially help to alleviate them.  


Heartburn has been linked to stress and an alteration to the gut-brain axis.1 Evidence suggests that 25% of the general population is said to experience heartburn at least once per month.2 Research has historically supported the hypothesis that heartburn is caused commonly by excessive stomach acid, however latest theories suggest the symptoms may actually be associated with hypochlorhydria (low stomach acid).2 Our stomach acid is our first line of defence against pathogenic microbes entering the intestines, therefore low stomach acid could potentially lead to bacterial overgrowth and a decreased absorption of important nutrients, such as vitamin B12, folate, iron, calcium and zinc.2 Deficiencies of these nutrients could lead to changes in the pattern of brain chemical neurotransmitter production3 and potentially increase stress and anxiety.


Approximately 30% of the general population are affected by bloating.4 Many people note that their symptoms of bloating are worse during times of stress and anxiety. This is not surprising as when the nervous system is activated in times of stress, blood flow is diverted away from the digestive system, reducing digestive enzyme production and gut motility. This may result in more undigested foods in the intestines and a slower transit to the bowel, potentially causing inflammation and becoming a food source for our less desirable gut bacteria which may generate more gas.

Taking a shot of diluted apple cider vinegar before eating a meal may help to increase stomach acidity, choose one that contains bacterial cultures to gain the benefits of the beneficial microbes. Ensure that you are feeling relaxed before eating and take time away from all distractions so you can concentrate fully on the meal in front of you and take your time to chew well.

Bowel motility

Psychological stress is known to cause bowel dysfunction.5 Although there may be varying individual factors causing bowel motility, evidence suggests that stress can lead to an altered gut microbiota resulting in increased inflammation and intestinal permeability (leaky gut) and ultimately triggering bowel dysfunction.5

In terms of constipation, an overgrowth of more harmful microbes in the gut can produce chemicals that can slow down stool motility, resulting in stools that are harder to pass.  Whilst in diarrhoea an imbalance of the gut microbiota can result in irregular serotonin levels. Studies have shown that serotonin levels are high in individuals suffering with diarrhoea.6,7 Serotonin can speed up the muscular movements within the digestive tract to move contents through quicker and excrete them from the body; this is useful in terms of infection, however, if you regularly suffer with diarrhoea this can reduce your absorption of nutrients and leave you dehydrated.

Regularly consuming traditionally fermented foods such as sauerkraut, kimchi, milk or water kefir, live yoghurt and kombucha can help to improve the balance and diversity of your gut microbiota. Increasing fibre intake (vegetables, fruits, nuts, seeds, legumes, pulses and wholegrains) and drinking plenty of water through the day can also help to improve bowel movements.

Weight Gain

Evidence is mounting that stress, and particularly, an increase of the stress hormone cortisol plays a role in the development of obesity. Cortisol is known to cause a redistribution of fat cells to the abdominal region whilst also increasing appetite, particularly with cravings towards ‘comfort foods’.8 Stress can also have an impact on sleep patterns, often leading to poor impaired sleep.9 Lack of sleep can further contribute to weight gain as research suggests individuals who report fewer total hours of sleep are more likely to be overweight or obese.10


Many IBS sufferers link their condition to stress and anxiety, not only as the potential cause of their condition in the first place, but also one of the main triggers setting off their symptoms. Evidence now suggests that IBS may have developed from disruption of the gut microbiota,13 suggesting that the condition may actually begin in the gut before influencing our brain health.

Symptoms of IBS vary with each individual; two of the reported symptoms are bloating and abdominal pain or cramps, which are often relieved when passing a stool. Recent findings have further linked the gut microbiota to abdominal pain suggesting the ability of microbes to modulate pain sensitivity and studies have shown that using live bacteria supplements could potentially play a role in regulating abdominal pain disorders.14

Disrupting Gut Microbiota

Psychological stress typically triggers a release of hormones and neurotransmitter production in various parts of the body, which ultimately disturbs the microbiota.11 An altered gut microbiota can then affect the regulation of neurotransmitters,11 suggesting a vicious cycle of continual stress and gut microbiota disturbance.

Live bacteria supplements may help prevent disturbances to the gut flora caused by stress. They have been shown in numerous studies to help reduce digestive symptoms and clinical studies show reductions in feelings of stress through live bacteria supplementation.  For example, one study found significant declines in self-reported negative mood and distress and a decrease in urinary cortisol compared to placebo.12 Research also supports a link between magnesium levels and stress reactions, and many people find magnesium supplementation particularly beneficial in times of stress. Bio-Kult Migréa (RRP £19.94, is a multi-strain live bacteria formulation, also been formulated with magnesium and vitamin B6, both of which contribute to normal functioning of the nervous system.