Updated: Sep 11, 2020
Lactose Intolerance, Cow's Milk Protein Allergy, Non-IGE mediated Cow's Milk Allergy (formally CMPI Intolerance); it can be a confusing space especially when it comes to babies and infants, which is why it is so important to use a qualified professional to assist in the assessment and management of any allergy or intolerance. Specifically this post is all about Lactose Intolerance, the types of lactose intolerance and what we commonly see in babies and children (i will discuss CMPA in a later post).
There are 4 main types of lactose intolerance:
Congenital lactase deficiency. This is an extremely rare genetic disorder where a baby is born without the lactase enzyme.
Neonatal lactase deficiency. This can present in pre-terms <34 weeks and it typically resolves
Secondary lactose intolerance. This is usually a short term condition after infections like gastro/infectious diarrhoea or other underlying causes like unmanaged Coeliac disease which has caused inflammation of the small intestine. Treatment of the underlying condition is required and symptoms of lactose intolerance typically resolve. The average recovery time for the gut of a baby to heal after gastro is 4 weeks (breastfeeding will promote gut healing)
Primary Lactose Intolerance. This usually presents at an average 2-3 years of age if including all population groups but generally happens around 4-5 years of age as the lactase enzyme gradually starts to decrease (by this age a child is usually fully weaned). About 70% of people have this type of lactose intolerance and will usually tolerate varying amounts of lactose.
Lactose intolerance in babies and toddlers:
Lactose is the main carbohydrate in breast milk and there is more of it in g/ml than compared to cows milk; breast milk contains 7.4g of lactose per 100ml and cow's milk contains 5g of lactose per 100ml. Due to this babies are primed to digest lactose their small intestines are lined with the enzyme lactase (thank goodness otherwise they would not be able to digest breast milk). When lactose (C₁₂H₂₂O₁₁) is consumed it is broken down in the small intestine by the enzyme lactase, almost all infants have the enzyme lactase and can digest lactose from birth. Because of this Babies and infants typically present with secondary lactose intolerance usually after a bout of gastro/infectious diarrhoea or antibiotic induced diarrhoea, this will resolve once the underlying condition is treated. A few points to remember:
A mother cannot reduce the amount of lactose in her breastmilk by eliminating cow's milk from her diet (nor does she need to remember babies are primed to digest lactose)
There is no relationship between lactose intolerance and family members and babies
Delaying the introduction of dairy foods in infants starting solids will not improve their tolerance to lactose or dairy
A breastfed baby with symptoms of lactose intolerance should continue to breastfeed in all cases
Lactose intolerance is very different to cow's milk protein allergies (IGE and Non- IGE mediated) however the symptoms may overlap.
If a baby or toddler has had a severe bout of gastro or infectious diarrhoea it can be helpful to switch to fermented dairy (eg kefir milk and yoghurt), lactose free milk or remove food dairy from the diet whilst the gut heals for a short term eg 1-3 weeks if they have ongoing symptoms of diarrhoea after milk. This should be discussed with your healthcare provider.
Lactose Intolerance in Children:
In older children typically we see Primary Lactose Intolerance, although again this can be confused with cow's milk protein allergies and the symptoms may overlap. Common symptoms include bloating, diarrhoea, wind and pain after eating foods high in lactose. Lactose intolerance can be diagnosed with a breath test or a clinician led elimination protocol. It is treated by lowering the amount of lactose in the diet however every child is different and children will tolerate different amounts of lactose; some children can tolerate a small amount, while others cant have any at all. Your child’s symptoms will help you decide how strict you need to be.
To get a correct diagnosis use a trained paediatric Dietitian or Doctor/Paediatrician.
Education on how to avoid lactose, food substitutes and any re-introduction of lactose should be completed by a Paediatric Dietitian.