Complaints & connections · borters.ch
Peristalsis · Motilitas intestini
Three mechanisms that exclude each other: cramp, stasis, or normal movement felt too strongly. The gap after eating says most about which it is.
Also known as: peristalsis · motility · gastrocolic reflex · migrating motor complex · visceral hypersensitivity · enteric nervous system
Open in the tool — with search and all the links →This compilation is for information and replaces neither medical diagnosis nor treatment. If you have symptoms, see a doctor.
The gut moves ceaselessly, and it does so largely on its own: its wall holds a nerve network of its own with several hundred million nerve cells that measures stretch, sets off waves and steers the forward push — even when the connection to the brain is cut. The most important messenger in this is serotonin, and not the kind from the brain: around ninety to ninety-five per cent of the body’s serotonin lies in the lining of the gut, in the enterochromaffin cells. As soon as food stretches and touches the lining, they release serotonin. Through one docking site it pushes the wave forward, through a second it reports upwards what is happening — stretch, nausea, urgency. Too much of it after a meal makes cramp, urgency and diarrhoea; too little makes sluggishness and constipation. Beside it stand further messengers: cholecystokinin slows the stomach and makes the gut more sensitive to pain, motilin drives the cleaning wave between meals — the rumbling of an empty belly —, GLP-1 and peptide YY from the lower small bowel brake from behind, ghrelin speeds things up, and VIP relaxes. The vagus nerve sets the background tone. For belly pain after eating this falls into three mechanisms that exclude each other and are treated quite differently: too much or uncoordinated movement, that is cramp; too little movement, that is stasis; and normal movement that is felt too strongly. The third is the most common when all investigations come back normal — and it is not imagination but a measurable process at the nerves of the gut wall.
Before movement and sensitivity are left standing as the explanation, the question of the supply belongs answered — above all when the pain grows with the size of the portion and weight is lost.
For two weeks: time of the meal, time of the pain, size of the portion, fat content, bowel movements. The gap separates stomach from small bowel from large bowel, and the dependence on portion size separates the blood supply from everything else. No test replaces these two weeks.
Lie on the back, find the painful point and press. Then lift head and shoulders, tense the belly wall and press the same point again. Weaker means: from inside the belly. Stronger means: from the belly wall — and that changes the whole direction of the search.
Opioids including cough medicines, drugs for bladder weakness and for nausea, tricyclic antidepressants, calcium blockers, iron, aluminium in stomach remedies — and the new weight and diabetes injections, which slow the stomach on purpose. This list explains more cases than any rare diagnosis.
The cleaning wave in the small bowel only runs when nothing arrives. Anyone eating something every two hours — even milk in the coffee or a sweet — suppresses it all day. Three meals with real breaks in between is the simplest attempt with a bloated belly.
A quiet walk speeds up stomach emptying measurably, lowers the rise in blood sugar and eases fullness. It is the lever with the best ratio of effort to effect — and it costs nothing.
Peppermint oil relaxes the smooth muscle of the gut; the coating keeps it from being released in the stomach, where it causes heartburn. It is one of the few freely available remedies consistently described for the cramp pattern.
If movement and inflammation have been checked and are in order, the sensitivity remains as the target. Tricyclic drugs in a very low dose — a fraction of what is given for depression — and gut-directed hypnosis are the two routes with the best backing. That is not a psychological diagnosis but a treatment at the nerve.
Fructose, lactose, sorbitol and the short-chain fibres draw water and are fermented — that turns into stretch, and in a sensitive gut stretch turns into pain. Four to six weeks with a targeted reintroduction afterwards makes sense, not a permanent avoidance.
Psyllium husk and oats bind water and make the stool supple. Wheat bran and a lot of raw vegetables increase bloating and pain in a sensitive gut. This distinction is the most common reason why more fibre makes things worse at first.
A few minutes of quiet breathing with a long out-breath before the first forkful shifts the background tone from the tension mode to the digestion mode. Eating at the table rather than on the move, without a screen, chewing slowly — that is the same lever, put differently.
If the pain comes reliably shortly after eating, grows with the size of the portion and weight is lost with it, an ultrasound of the abdominal vessels belongs with it. Narrowing of the gut arteries can be treated — and on average it is recognised very late.
It sets the background tone of the movement: under lasting tension the stomach becomes slower and the colon faster — both at once, which makes the picture confusing. That is why the same meal is tolerated on a quiet day and not on a tense one.
Antispasmodics and peppermint oil in gastro-resistant capsules act on the gut muscle and release the spasm — they change nothing about how far the gut is stretched. What works most reliably in reviews are low-dose tricyclic antidepressants: they lower not the movement but the pain signal from gut to brain, and they need four to eight weeks. Laxatives for constipation take the stretch away — and it is the stretch that causes the pain.
The small bowel moves in waves of about two to three centimetres a second; the colon, by contrast, only a few times a day in large mass movements, mostly after getting up and after eating. The gut has about a hundred to two hundred million nerve cells and works largely on its own. In irritable bowel it is not the movement that is stronger but the perception that is more sensitive — at the same stretch, those affected report pain measurably earlier.
Five to thirty minutes after the first bite, often with an urge to open the bowels and the feeling of having to get up at once. That is the gastrocolic reflex: the stretching of the stomach sets off large movements in the colon. In some this answer turns out much too strong.
A few bites are enough, the belly stays full for hours, nausea accompanies the day, and vomit contains food eaten hours before. That is the stasis in the stomach — common with long-standing diabetes, after a viral infection or under certain medicines.
A belly that grows measurably larger over the day, with loud gurgling and much wind. If the cleaning wave between meals fails, bacteria gather in the small bowel where there are usually hardly any — and they ferment what arrives. Constant snacking suppresses this wave.
All investigations are normal and yet every meal hurts. Then the gut wall reports a perfectly ordinary stretch as pain — visceral hypersensitivity. Mast cells sitting close to the gut nerves release histamine and make these nerves more sensitive. That is measurable and treatable.
A dull, cramping pain fifteen to thirty minutes after every meal, stronger the larger the portion, with fear of eating and marked weight loss. Then the gut is not moving wrongly — it is getting too little blood for the work of digestion. That is a picture of its own, treatable, and often overlooked for years.
Always exactly the same point, which can be shown with one finger. The test: lying on the back, tense the belly wall by lifting head and shoulders, then press again. If it gets stronger instead of weaker, the pain comes from the wall and not from the gut — and further bowel investigations lead nowhere.
If the complaints are stronger month after month on the same days of the cycle, with pain on opening the bowels or blood during the period, the gut is not moving wrongly — tissue sitting on the outside of the bowel wall is following the cycle.
An underactive thyroid slows the whole gut and causes constipation and fullness, an overactive one speeds it up and causes diarrhoea. A single value that can explain both directions.
A sugar raised over years also damages the nerves that steer the stomach. Delayed stomach emptying in diabetes is one of the most common causes of fullness, nausea and pain after eating.
A low potassium paralyses the smooth muscle of the gut wall and can on its own explain a sluggish, bloated belly — often under water tablets or after longer vomiting.
Magnesium works in both directions: a lack favours cramps of the smooth muscle, an excess from supplements drives the stool. Both belong to the picture.
The value that separates a true inflammation of the gut wall from a pure disorder of movement and sensitivity. It does not appear in the blood and has to be asked for separately.
An empty iron store belongs here for two reasons: iron preparations themselves slow the gut and colour the stool, and a deficiency without a recognisable cause shifts the question away from movement.
Soluble fibres like psyllium and oats bind water and make the stool supple. Wheat bran and a lot of raw vegetables, by contrast, increase bloating and pain in a sensitive gut — this distinction explains most of the failures.
Fibre without water makes the stool harder instead of softer. The two belong together, and the effect only sets in after some days.
Draws water into the bowel and therefore works with a sluggish stool. The belly shows the upper limit: if the stool gets too loose, the dose at once was too high.
Yoghurt, kefir, sauerkraut and the like bring living cultures with them. Many tolerate them well; with a strongly bloated belly they can also do the opposite in the first weeks.
A soluble fibre that binds water rather than irritating. 5–10 g a day with at least 200 ml of water — taken dry it can swell in the throat.
Magnesium citrate draws water into the bowel and therefore has a laxative effect — a side effect elsewhere, the purpose here. 200–400 mg in the evening is the usual range.
The starting signal for every wave. Ninety to ninety-five per cent of the body’s serotonin lies in the lining of the gut. Too much after eating makes cramp and urgency, too little makes sluggishness — remedies against nausea and against constipation act at the same docking sites.
The timekeeper of the cleaning wave between meals — the rumbling of an empty belly is its audible side. If it fails, bacteria gather in the small bowel.
Released with fat and protein, it squeezes the gallbladder and slows the stomach. It also raises the pain sensitivity in the gut — which explains why fatty food hurts especially in a sensitive gut.
Released in the lower small bowel when nutrients arrive there, it brakes from behind — the ileal brake. It makes sure nothing is pushed on from above while work is going on below.
It slows stomach emptying and dampens appetite. That is exactly what the new weight and diabetes injections rest on — and where their most common side effects come from: fullness, nausea and belly pain after eating.
The counterpart: it rises before the meal, makes hunger and speeds up stomach emptying. A flat ghrelin curve belongs to the picture of stasis.
The relaxing messenger of the gut wall. It makes the section ahead of the wave open — without that slackening there is no ordered movement, only pressure.
Mast cells in the gut wall sit close to the nerve endings. What they release — histamine and tryptase — makes these nerves more sensitive. That is the bridge between movement and pain, and the reason some people respond to an antihistamine.
Fibre without fluid makes stool firmer, not softer. 25–30 g a day with 1.5–2 litres; with sluggish peristalsis soluble fibre such as psyllium is tolerated better than bran.
Enteric-coated capsules relax the gut muscle. In irritable bowel it is among the best-studied plant remedies — studied at 0.2–0.4 ml three times daily over 4 weeks. With reflux it can worsen heartburn.
Warmth on the belly relaxes the smooth muscle. The effect lasts as long as the warmth itself — relief, not treatment.