Struggling with sleep? Constantly wired? Have to dash to the toilet immediately after drinking your morning brew?
It’s possible that coffee is causing these symptoms. The caffeine contained in coffee is a gastrointestinal stimulant, this means caffeine increases the contractions that move the contents through the bowel, risking diarrhoea and urgency. For those with slower bowels (constipation) caffeine containing food and drinks may help you to go to the toilet, but caffeine does have other effects that should be considered. For those with alternating symptoms it is worth tracking you caffeine intake through the day – you may find that intake might be the cause of problems. Black coffee is not a fodmap containing drink – but it can cause symptoms of IBS – so it is an important dietary factor to consider.
Many people with an overly sensitive digestive tract will experience symptoms with food and drinks high in caffeine, due to these exaggerated reflexes that occur with IBS. Older research suggests that for some people coffee can stimulate bowel function within 4 minutes of drinking it. This cannot possibly be a direct affect of coffee traveling through the bowel – but suggests that a pharmacological (drug like) affect or perhaps due to hormone stimulation?
Production of the hormone gastrin by the stomach is stimulated by coffee, which results in increased movement of the digestive system by the gastrocolic reflex (an involuntary and nearly instantaneous movement in response to a stimulus.) This reflex in some people is caused by the act of drinking coffee (the stimulus) and results in the bowels emptying to ‘make room’ for the next meal. This reflex can often be exaggerated in people who have problems with their bowels.
Coffee has a low osmolality of 58 osmol/Kg – meaning that drinking it black with no sugar can affect how quickly fluids pass from the digestive tract into the body – low osmolality drinks can result in fluids being absorbed more quickly. Drinking coffee with a meal could reduce these effects and so can adding milk/sugar (but sugar is not great for health) – so, having a breakfast of a cup of black coffee or a strong shot of espresso to kick start the day might not be too helpful for those with IBS.
Caffeine also has systemic effects on the body it is a bio-active compound – in other words – it can result in other symptoms in the body that might have consequences for people with IBS. IBS is also systemic condition, symptoms are not just confined to the digestive tract – see here for a comprehensive list of other symptoms https://www.theibsnetwork.org/have-i-got-ibs/what-is-ibs/. Not everyone has the experience of the stimulation of the nervous system as a result of large intakes of caffeine. If you are affected however caffeine can exert the following effects – increases in perception of alertness and wakefulness, palpitations, high blood pressure, insomnia, headaches and sometimes anxiety depending on individual tolerance.
Is it just the caffeine that is responsible in coffee for causing symptoms? Coffee contains many different compounds and whilst caffeine is responsible for some systemic effects there is little evidence that de-caffeinated coffee has and affects on the bowel – but some anecdotal evidence suggests that it might.
Coffee and the bladder
Some people also have bladder problems with IBS – urinary urgency and frequency can be affected by caffeine containing drinks. This is because they can relax the muscles in the pelvic floor.
Coffee, caffeine and sleep.
Health advice for sleep hygiene suggests that drinks containing caffeine should be limited a few hours before bed to avoid insomnia https://www.nhs.uk/conditions/insomnia/self-help/ Poor sleep is also associated with IBS with up to 74% of people with IBS stating that sleep is a problem and insomnia can increase levels of pain and perception of pain the next day. It is worth trying to incorporate some aspects of sleep hygiene into your treatment, if this is a problem for you.
Where else is caffeine found?
It can be very easy to have a large amount of caffeine, as it is found in a number of different foods and drinks – here is a table taken from our book IBS -Dietary advice to calm your gut available here http://amzn.to/2yBk3u7:
| Food | Approximate caffeine content |
| Coffee expresso (small cup) | 200 mg |
| Coffee filter (1 cup) | 140 mg |
| Coffee instant (1 cup) | 100 mg |
| Energy drinks (250ml) | 80 mg |
| Tea (1 cup) | 75 mg |
| Cola (330 ml can) | 25 mg |
| Chocolate (dark 25g) | 20 mg |
| Chocolate (milk 25g)* | 10 mg |
*Also contains lactose and fats, which can also induce symptoms.
Caffeine can also be found in medications – discuss with your doctor or pharmacist if you wish to cut down or change medications.
How do I reduce my intake?
Because coffee is a bioactive compound immediately stopping drinking it can cause symptoms in susceptible people. Symptoms of withdrawal start 12-24 hours after abstinence and can last for 2-9 days. Symptoms are headache, fatigue, depression, difficulty concentrating, irritability and ‘brain fog ‘.
So DO NOT be tempted to go cold turkey, if you are considering cutting down on your intake. Cutting down gradually is helpful for withdrawal effects, slow changes can also help with maintaining the changes you have made.
Try reducing your intake by half a cup a day over a seven day period. Ensure you have other fluids available to drink – water or squash for example, to keep hydrated. You could use decaf tea/coffee if you wish but this might be a problem for some people perhaps.
Don’t be tempted to use coffee weaning products – they are expensive and have no evidence that they work.
Clinical Alimentary 