Complaints & connections · borters.ch
A missing enzyme, not a disease — most people still tolerate small amounts well.
Also known as: lactose intolerance
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.
Not an allergy but an enzyme deficiency: without lactase in the small intestine, milk sugar reaches the colon undigested, where bacteria ferment it — causing bloating, cramps, diarrhoea and rumbling, usually one to three hours after eating. Worldwide this is the normal state: most adults lose lactase after weaning; lifelong tolerance is the genetic exception, though the rule in northern Europe. Diagnosed by breath test. Important: almost everyone tolerates small amounts, and matured hard cheese and yoghurt are often fine — complete avoidance is rarely needed and would needlessly cost calcium.
After a giardia infection a temporary intolerance often remains for weeks to months. It should not be filed away as lifelong.
Most tolerate about twelve grams of lactose at once — that is a glass of milk. Spread over the day and taken with a meal it is considerably more. Complete avoidance is rarely needed.
Long-matured cheese contains practically no lactose, and in yoghurt the cultures bring their own enzyme. Both are usually well tolerated even by people with a marked intolerance.
Cutting out dairy loses the biggest source of calcium. Hard cheese, mineral water rich in calcium, fortified plant drinks, almonds and green vegetables close the gap.
Lactase preparations work if taken with the first bite, not afterwards. For invitations and travel they are more practical than any explanation at the table.
If bloating and diarrhoea persist after four weeks of strict avoidance, lactose is not the whole story. Coeliac disease, fructose, bacterial overgrowth and irritable bowel are then the next questions.
A lactose intolerance that began suddenly after a journey or a bout of diarrhoea is often the result of injured small-bowel lining — and settles after treatment.
Lactase tablets supply the missing enzyme — for that one meal. The amount is what counts: most people tolerate about twelve grams of lactose, a glass of milk, spread over the day. Avoiding it entirely is rarely necessary.
Worldwide about two-thirds of adults lose lactase activity; in northern and central Europe it is only about fifteen to twenty in a hundred. So it is not a defect but the human norm — being able to digest milk is the exception.
Bloating, gurgling, cramps and diarrhoea thirty minutes to two hours after milk, cream or fresh cheese. Whatever appears hours later, or without any dairy at all, has a different explanation.
A splash of milk in the coffee is fine, a large glass is not. This threshold is personal and changes with what is eaten at the same time — unlike an allergy, where traces are enough.
Long-matured cheese contains practically no lactose, and yoghurt cultures bring their own enzyme. Tolerating both while still not tolerating milk confirms the picture.
Weight loss, blood in the stool, night-time diarrhoea, fever, anaemia — or complaints that stay unchanged after four weeks of strict avoidance. Then milk is not the whole story.
The most important distinction: coeliac disease causes similar complaints but is a different illness with different consequences. The value only holds while gluten is still being eaten.
With a plain lactose intolerance, uptake in the bowel stays intact. An iron shortage alongside speaks for something else being present as well.
The blood value stays normal for a long time, because the body holds it up from the bone. What matters more is whether enough calcium is eaten when dairy is dropped.
Lactase tablets with the meal, if dairy is not to be left out. They work only for that meal and must be taken with the first portion, not afterwards.
Only if dairy largely falls away and the gap is not covered otherwise. 1000 mg a day is the need, and above 500 mg at once the absorbed share falls.
Leaving out dairy removes the most important calcium source. This hormone then raises uptake from the gut — up to a point. Beyond that the body takes the calcium from bone.
If the calcium from food is not enough, this hormone rises and releases calcium from bone. The blood value stays normal — which is why a calcium shortage does not show in the blood.
Most tolerate 12 g of lactose at once — about a glass of milk — and more when spread over the day with other food. Hard cheese contains almost none, yoghurt brings its own lactase.
Cutting dairy entirely removes the largest calcium source. 1000 mg a day is the reference; fortified plant drinks, almonds, sesame and calcium-rich mineral water fill the gap.
Certain cultures bring the enzyme themselves — which is why yoghurt is often better tolerated than milk.
The amount decides: most people tolerate small portions, spread out and with a meal.