Does milk really help against heartburn?

Cold milk neutralises stomach acid in a laboratory setting just as well as a standard antacid. That sounds impressive, but this was an artificial stomach without real digestion, hormones or oesophageal muscles. What works in a test tube does not automatically work the same way in a human body.

What has actually been studied in people paints a different picture. In a randomised trial of 72 adults who ate three or more servings of dairy per day for twelve weeks, heartburn and reflux symptoms did not change measurably compared with people who ate little dairy. Eating more milk or yoghurt therefore did not help, but it did not make things worse either.

That last point does not hold for everyone. A study of nearly 400 Chinese heartburn patients shows that people with non-erosive reflux (symptoms without demonstrable damage to the oesophagus) more often report that dairy and yoghurt trigger their symptoms. These are self-reported experiences, but they indicate that milk can actually be a trigger for some people.

In infants with regurgitation problems the situation is different and important to be aware of. Two paediatric review articles point out that reflux symptoms in babies are regularly confused with cow's milk protein allergy. When that is the case, milk causes the symptoms rather than relieving them. Unnecessary acid-suppressing medication or unnecessary dietary restrictions are then the result. If you have a baby with persistent reflux symptoms, discuss this with your paediatrician to identify the correct cause.

The well-known home remedy of 'a glass of milk for heartburn' is therefore poorly supported in practice. On paper and in the laboratory, milk temporarily buffers stomach acid, but in everyday life it does not demonstrably change heartburn symptoms. And for some people, milk can actually trigger the symptoms.