From very early on I found out that my daughter had a problem with milk. As a new mothers, it was really worrying, and I didn’t know if it was colic or reflux, or what it could be. What I did know is that I had to change her baby grow 20 times a day, and every time she fed, most of it came back up, and she seemed very uncomfortable. I took her to a few cranial osteopaths, and ended up being introduced to the wonderful paediatric dietitian Bianca Parau who has written a brilliant piece for us today on lactose intolerance, and what it actually means. 

Lactose intolerance is often confused with cow’s milk allergy, as in both conditions cow’s milk seems to be the culprit. But although these two conditions share similar symptoms, they are not the same.

Broadly looking at the composition of cow’s milk, it is made up of proteins (casein and whey), milk sugar (lactose) and fat.

Lactose intolerance is a digestive condition, where the body is unable to digest milk sugars, this is due to an enzyme deficiency. Cow’s milk allergy on the other hand, is a condition of the immune system and the problem lies with the protein component of milk.

What is Lactose?

Lactose is the natural occurring sugar found in cow’s milk and other mammalian milks e.g. goat or sheep milks. It is a disaccharide consisting of glucose and galactose.

What causes lactose intolerance?

Lactose requires a special enzyme, lactase, to break it down to its two component sugars; glucose and galactose. Lactase enzyme occurs naturally in the gut, but some people do not have sufficient amounts of lactase. So instead of lactose being digested and absorbed, it remains in the gut, feeding the natural gut bacteria. The bacteria release acids and gas that cause abdominal pain, bloating and other symptoms.

Lactase deficiency can be classed into two groups;

  • Primary lactase deficiency – where the body only produces very small amounts of lactase. This is the most common type of lactase deficiency, but it does not usually appear in children younger than 3 years. It is more prevalent in certain ethnic groups (Asian or African-Caribbean), due to the low lactose content of their traditional diets – their digestive system has lost the ability to produce sufficient amounts of lactase.
  • Secondary lactase deficiency – develops when the gut lining is damaged as a result of another illness (i.e. gastroenteritis) or condition, surgery or some medications. The lactose intolerance can be either temporary or permanent.

In very rare cases babies are born with a lactase deficiency (congenital lactase deficiency), where the lactase intolerance is permanent.

What are the signs and symptoms of lactose intolerance?

When lactose is not broken down, it produces excess gas and uncomfortable symptoms in the colon. Although these symptoms are not usually serious, they are very unpleasant and can affect your child’s feeding too.

  • Nausea and feeling sick
  • Bloated abdomen
  • Wind / excess gas
  • Abdominal cramps, aches and rumbling
  • Diarrhoea

Cow’s milk allergy might share some of these symptoms, but because the immune system is involved, other allergy symptoms will also be present i.e. an itchy rash, wheezing, coughs and a runny nose.

Diagnosing lactose intolerance?

If you suspect your child might be lactose intolerant, speak to your health care professional. Your child’s doctor will be able to identify if it is a primary or secondary intolerance.

Lactose intolerance diagnosis can be made by a hydrogen breath test, a lactose tolerance test (measuring blood sugar levels before and after consuming lactose), a milk tolerance test or through a stool sample.

What is the treatment?

Primary lactose intolerance does not go away and is managed through lifelong diet modifications. Most children diagnosed with primary lactose intolerance are able to digest some lactose without experiencing any symptoms, but this depends on the individual child.

As this intolerance is permanent, it is useful to experiment with the diet to determine the individual tolerance level. A dietitian can help to provide detailed expert advice on suitable foods as removing dairy affects calorie, calcium (which will impact bone health) and vitamin / mineral intakes.

Temporary secondary lactose intolerance may initially be managed by a dairy free diet for a couple of weeks or months, allowing the gut time to heal. This is rarely required in the long term. Dairy containing foods are then gradually reintroduced as the lactase producing ability of the gut returns and increases.

Where the lactose intolerance is caused by another long term condition (i.e. Coeliac disease), it is important that this condition is treated first, as the lactose intolerance severity usually depends on how well the other condition can be treated. Diet modifications will not address the root of the problem in these situations.

In general, it is best to avoid foods and drinks containing high amounts of lactose e.g.

  • Cow, sheep, goat’s milk and all other types of mammalian milk
  • Yogurt, fromage frais and ice-cream
  • Hard, semi-hard, soft and cottage cheeses
  • Certain cakes, pastries and biscuits
  • Chocolate (white, milk and some plain varieties)

Suitable alternatives include;

  • Reduced lactose dairy products i.e. lactose free milk, cheese and yogurts
  • Soya milks, yogurts and products
  • Drinks and yogurts made form alternative sources e.g. rice, nuts, coconut and oats. If these are chosen opt for versions with added calcium.
  • Carob chocolate
  • Vegan products

Digestive enzymes are available in liquid and capsule form; they can help your child with the digestion of lactose but should not be used daily. These enzymes can be taken before eating a lactose containing meal, but it is best to limit their use for special occasions.

It is important that you do not make any changes to your child’s diet without an appropriate diagnosis and under the supervision of a healthcare professional.

Bianca Parau, Senior Paediatric Dietitian, Bupa Cromwell Hospital, Cromwell Road, London, SW5 0TU

T: 020 7460 5566 | F: 020 7835 2518 | E:

About The Author

Paediatric Dietitian

Bianca is an experienced Paediatric Dietitian offering expert advice and guidance to children and their families with a friendly yet professional approach. After graduating from the University of the Free State she started her career in South-Africa. Since relocating to the United Kingdom she's worked at various top NHS hospitals as well as private health care centres across the country. She offers private appointments in her London and Home-counties clinics. Her current NHS clinical role at Chelsea and Westminster Hospital includes a multidisciplinary feeding clinic. With 16 years’ experience, Bianca is passionate about helping children of all ages to develop a healthy attitude towards food whilst meeting their nutritional requirements to sustain optimal growth and development. She works closely with paediatricians, paediatric allergists, paediatric gastroenterologist and various paediatric allied health professionals to provide comprehensive multidisciplinary evidenced based treatment. In addition to her private practice and NHS role, Bianca does consultancy work; she is a spokesperson on nutrition related topics and writes peer reviews as well as articles for various publications. Bianca is registered with the HPC-UK and is a full member of the British Dietetic Association.

Related Posts