Lactose Intolerance in teens and tweens

If you have a child with unexplained digestive issues, then it may be an intolerance to the lactose in milk. A year ago my teenage daughter was suffering with unpleasant symptoms of bloating/diarrhoea for months and with the help of our GP we finally worked out the cause. It is not a great age to get this type of symptom so it was good to sort it out.

What Is Lactose Intolerance?

The body digests lactose using a substance called lactase. This lactase breaks down lactose into two sugars which can be easily absorbed into the bloodstream.

People with lactose intolerance don’t produce enough lactase to do this, so it stays in the digestive system where it is fermented by bacteria. This fermentation leads to the production of gases, which cause the symptoms associated with lactose intolerance. So it is not the milk itself causing the problem, but a constituent of milk – lactose.

Lactose intolerance is, therefore, not an allergy and although the symptoms are unpleasant they are not doing any permanent damage. The gut reacts but corrects itself once the cause is removed, although if you ignore it for long enough it can trigger IBS. Lactose intolerance in teens is no fun but is easily managed with a bit of patience and an appropriately adjusted diet.

How to tell if it is a lactose intolerance?

The best approach to diagnosing lactose intolerance in teens is to completely remove lactose from their diet for a couple of weeks, and be very strict about it. If things improve you can then confirm it by reintroducing lactose to the diet to see if the symptoms return. If they do, contrary to popular belief, it is not necessary for lactose-intolerant individuals to completely avoid all dairy products. Some are naturally low in lactose and in moderate amounts they are usually well tolerated.

Some people can tolerate more than others because they may still produce a small amount of lactase, so gradually work out how much they can eat before they feel unwell.

It is helpful to know the milk-based foods that are naturally lower in lactose –

hard cheese


probiotic yoghurt

Lactose intolerance in teens

Future Health

If your child is ill with an unrelated intestinal disorder, you may find their tolerance falls to zero again. Have a break from lactose for a while and then reintroduce it slowly, as appropriate for them.

Also as your teens get older, their lactase production might slow and they need to be aware that they may find they begin to experience more symptoms after consuming dairy products that never caused problems in the past. A readjustment might be necessary.

How to manage lactose intolerance

This is simpler than you might think as there are now so many ‘lacto-free’ versions of milk, cheese, yoghurt etc from most, if not all, supermarkets. Luckily lactose can be removed without changing the taste too much (but adding a small amount to the price and availability).

Soya products are another option. They are not dairy-based and so are naturally lactose free. Although there is no need to use a cow’s milk alternative (just one that has had the lactose removed), there are some great ‘milk’  alternatives such as oat, almond and coconut. They do taste different from conventional milk but obviously it is personal preference.

Keeping well

Depending on what dairy products you can tolerate your tween or teen may also need additional calcium and vitamin D supplements to keep their bones strong and healthy. It is definitely worth having a chat with your GP about their diet and tolerance levels. Occasionally your GP may refer them to a dietitian for further advice.

NHS Choices Lactose Intolerance

RELATED: Gluten Intolerance V Coeliac Disease – Know the difference and act on it