Lactose: what it is and where it is found

The word "lactose" appears on packaging, in formula ingredients, and on test reports. Behind it is ordinary milk sugar, which we encounter every day. Let's break down without scare tactics what it is and where to look for it.

What lactose is

Lactose, or milk sugar, is a carbohydrate from the disaccharide group. It is found in milk and in products made from milk. The Latin lac translates as "milk" — hence the name.

Lactose is not an additive or something artificial. It is a natural sugar of animal milk.

What milk sugar consists of

The lactose molecule consists of residues of two simple sugars — glucose and galactose. The formula is C12H22O11. While these two pieces are stuck together, the body cannot absorb them: first they need to be separated.

Lactose is obtained from milk whey and used as a filler in the pharmaceutical industry — sometimes it is in the composition of medicines where there seems to be no milk.

Which foods contain lactose

First of all, it is the milk of animals — cows, goats, sheep — and everything made from it: cream, butter, cheese, yogurt, ice cream. In Ukrainian cuisine, this includes cottage cheese for breakfast, a spoonful of sour cream in borscht, and a piece of bryndza with a casserole.

Lactose is also found in processed products: in muesli and chocolate cereals, in baked goods — bread, crackers, cookies, pies, in sauces and salad dressings, in protein and "diet" shakes.

Infant milk formulas contain a lot of lactose — around 85%.

How the body digests lactose

The enzyme lactase is responsible for breaking it down. It splits lactose into glucose and galactose, which are absorbed in the small intestine. If there is not enough lactase, milk sugar remains in the intestine in its original form and binds water — hence loose stools. Intestinal bacteria ferment the sugar, and bloating occurs.

What lactase deficiency is

Lactase deficiency is when the body lacks the enzyme lactase, and milk sugar is not absorbed. Then after dairy, the following complaints may appear:

• pain or discomfort in the abdomen, rumbling;
• bloating and increased gas formation;
• diarrhea or constipation;
• nausea, sometimes vomiting;
• complaints unrelated to digestion — headache, fatigue, joint and muscle pain.

Complaints begin a few minutes or a few hours after eating. Lactose intolerance itself is not dangerous, but similar symptoms occur with other conditions.

The causes vary. Most often it is because the body produces little lactase, and this can start at any age. Sometimes intestinal diseases are to blame — inflammatory diseases, celiac disease, intestinal infections, surgery or trauma. In premature infants, the intestine is not yet mature, and over time this usually resolves. Complete absence of lactase is very rare.

Frequency varies greatly: in Sweden and Denmark — about 3% of adults, in Finland and Switzerland — 16%, in England — 20–30%, in France — 42%, in Russia — 16–18%, and in Southeast Asia — in almost everyone.

When to see a doctor

It is better to sort out recurring complaints with a doctor. They will ask what and when you eat and may suggest examinations: a trial lactose-free diet, blood tests, a hydrogen breath test, and for severe symptoms — gastroscopy with a tiny sample of small intestine cells.

You should make an appointment if symptoms return and often appear after eating; if your stool has changed and remains so for three weeks; if for three weeks there is blood in the stool, bloating, and discomfort; if weight decreases without reason.

Lactose intolerance itself is not a reason to call an ambulance. 103 or 112 — if lips, mouth, tongue, or throat suddenly swell; if it is difficult to breathe or the person is choking; if the throat tightens and swallowing is difficult; if the skin, tongue, or lips turn blue, gray, or pale; if the person suddenly becomes very confused, drowsy, or dizzy; if someone loses consciousness and cannot be woken; if a child becomes limp and unresponsive. Together with hives, these are signs of a severe allergic reaction, not intolerance.

If after dairy your stomach regularly makes itself known, it is better to tell your doctor about it: they will ask what and when you eat. And do not remove dairy from your or your child's diet for long without the advice of a doctor or dietitian — milk and products made from it are for many the main source of calcium.

This text is for reference and does not replace a doctor's consultation — discuss your health with them.

This content is for reference and does not replace a doctor's consultation. Medical disclaimer