Lactose intolerance is poorly understood in the Australian community. There are lots of myths and misunderstandings about it, especially when it comes to babies. Contrary to what you may hear:
- There will not be less lactose in the breastmilk if the mother stops eating dairy products.
- There is no relationship between lactose intolerance in adult family members, including in the mother, and in babies. They are different types of lactose intolerance.
- A baby with symptoms of lactose intolerance should not be taken off the breast and fed on soy-based or special lactose-free infant formula.
- Lactose intolerance is very different to intolerance or allergy to cows’ milk protein.
What Is Lactose?
Lactose is the sugar in all mammalian milks. It is produced in the breast. The amount of lactose in breastmilk is independent of the mother’s consumption of lactose and hardly varies. The milk the baby gets when he first starts to feed contains much the same amount of lactose as does the milk at the end of a breastfeed. However, the milk at the end does contain more fat.
Lactase is the enzyme that is required to digest lactose. Lactose intolerance occurs when a person does not produce this enzyme, or does not produce enough of it, and is therefore unable to digest lactose. If it’s not digested and broken down, it cannot be absorbed. If this happens, the lactose continues on in the digestive tract until it gets to the large bowel. It is here that bacteria break it down to make acids and gases.
Lactose Intolerance Symptoms
The symptoms of lactose intolerance are liquid, sometimes green, frothy stools and an irritable baby who may pass wind often. If a baby is lactose intolerant, the medical tests (‘hydrogen breath test’ and tests for ‘reducing sugars’ in the stools) would be expected to be positive. However they are also positive in most normal breastfed babies under 3 months. Their use in diagnosing lactose intolerance in young babies is therefore open to question.
Lactose Intolerance in Babies
Primary (or true) lactose intolerance: This extremely rare genetic condition is incompatible with normal life unless there is medical intervention. A truly lactose-intolerant baby would fail to thrive from birth (ie not even start to gain weight) and show obvious symptoms of malabsorption and dehydration. This is a medical emergency and the baby would need a special diet from soon after birth.
Secondary lactose intolerance: Because the enzyme lactase is produced in the very tips of the microscopic folds of the intestine, anything that damages the gut lining can cause secondary lactose intolerance. Even subtle damage to the gut may wipe off these tips and reduce the enzyme production, for example:
- Food intolerance or allergy. In breastfed babies, this can come from food proteins, such as in cows’ milk, wheat, soy or egg, or possibly other food chemicals that enter breastmilk from the mother’s diet, as well as from food the baby has eaten
- Parasitic infection such as giardiasis or cryptosporidiosis
- Coeliac disease (intolerance to the gluten in wheat and some other grain products)
- Following bowel surgery
Food allergies and food intolerances can cause a baby to be unsettled. The foods to which a baby is allergic or intolerant can pass from through the mother’s breastmilk. In some cases, removal from the mother’s diet of the foods to which the baby is allergic or intolerant, for example cows’ milk products, can sometimes help. If you wish to try eliminating foods from your diet on the suspicion that your baby has an allergy or an intolerance, check with a dietitian to help you identify the culprit foods and to make sure your diet is nutritionally adequate for both your and your baby.
Lactose Intolerance May Actually Be Cows Milk Protein Allergy
Cows’ milk protein allergy (or intolerance) is often confused with lactose intolerance and many people think they are the same thing. This is not the case. The confusion probably arises because cows’ milk protein and lactose are both in the same food, ie dairy products. Since allergy or intolerance to a food protein can cause secondary lactose intolerance, they may be present together, further adding to this confusion.
Secondary lactose intolerance is temporary, as long as the gut damage can heal. When the cause of the damage to the gut is removed, for example by taking the food to which a breastfed baby is allergic out of the mother’s diet, the gut will heal, even if the baby is still fed breastmilk. If your doctor does diagnose ‘lactose intolerance’, continuing to breastfeed will not harm your baby as long as she is otherwise well and growing normally.
While the baby has symptoms of lactose intolerance, it is sometimes suggested that the mother alternate breastfeeding the baby with feeds of lactose-free artificial baby milk or even take the baby off the breast. Authorities only recommend the use of lactose-free artificial baby milk if the baby is artificially-fed and is very malnourished and/or losing weight. However, human milk remains the best food and will assist with gut healing. In addition, sensitivity of the baby to foreign protein (cow or soy) should be considered before introduction of any artificial baby milk, as regular types, including lactose-free ones, may make this problem worse. You should seek professional advice on the need for hypoallergenic artificial baby milk. A medical adviser should see any baby with long-term symptoms and/or who is failing to thrive.
Before even partially taking a baby off the breast for a short time, thought should be given to other aspects of the breastfeeding relationship. Questions you could ask include:
- How will alternative feeding methods affect my baby?
- Could bottle-feeding other milk products result in breast refusal later?
- How easily will I be able to express my milk to maintain my supply?
Average recovery time for the gut of a baby with severe gastroenteritis is 4 weeks, but may be up to 8 weeks for a baby under 3 months. For older babies, over about 18 months, recovery may be as rapid as 1 week. If a medical adviser orders alternative feeds for the baby, it is important that the mother understands that her breastmilk is still the normal and proper food for her baby in the long term.
You may have heard about giving drops containing the enzyme lactase to babies who have symptoms of lactose intolerance. There is little evidence that these are of much value when used this way, although there are anecdotal reports that relatively large doses may help in some cases. Lactase drops are designed to be put into expressed breastmilk (or other milk) and left overnight for the enzyme to predigest the lactose in the milk. In practice they seem to be occasionally useful for babies.
Lactose Intolerance In Adults
Lactase enzyme levels normally change over a person’s life span. They rise rapidly in the first week after birth, start to fall from about 3-5 years of age and fall sharply in later childhood. Low levels of lactose in colostrum match the low levels of the enzyme present in the first week of life.
Cows’ milk is commonly consumed by adults in some populations, but mostly by people of northern European descent. In about 70% of the people of the world, and in over 10% of Australians, levels of this enzyme fall so low in adulthood that they become lactose intolerant. The tendency to adult lactose intolerance is genetically determined. Some races, such as Asian, African, Australian Aboriginal and Hispanic populations are more likely to be lactose intolerant as adults. Caucasians are more likely to be able to consume milk as adults because they tend to continue producing the enzyme lactase throughout life. Even so, the levels do fall with age. People who have been able to drink milk as adults may find they become lactose intolerant when elderly. An adult who has very low levels of the enzyme can usually tolerate some lactose because normal bacteria living in the gut provide a limited capacity to break it down. However, the person may find it gives them loose stools and ‘wind’.
Human babies of all races can tolerate lactose. In fact human milk has a very high concentration of lactose compared to cows’ milk and that of other mammals. This is thought to be related to a human baby’s rapid brain growth in infancy, compared to other mammals. Removing lactose from any baby’s diet for more than a short period should not be done lightly and then only under medical supervision.
Lactose Overload in Babies
Lactose overload can mimic lactose intolerance and is frequently mistaken for it. An overload is often seen in babies consuming large amounts of breastmilk, that is when their mothers have an oversupply. This may result in an unsettled baby with adequate to large weight gains. The baby usually passes urine more than 10 times a day and has many (often explosive) bowel motions in 24 hours. They may have green, frothy poos that resemble those of a baby with lactose intolerance. This usually occurs in babies under 3 months old. Ironically, a mother may thinkthat she has a low milk supply because her baby always seems to be hungry. The nappies can be the biggest clue to what’s happening. What comes out the bottom must have gone in the top!
There is a vicious cycle here. A large-volume, low-fat feed goes through the baby so quickly that not all the lactose is digested (more fat would help slow it down). The lactose reaching the lower bowel draws extra water into the bowel and is fermented by the bacteria there, producing gas and acid stools. The acid stools often cause a nappy rash. Gas and fluid build-up cause tummy pain and the baby ‘acts hungry’ (wants to suck, is unsettled, draws up his legs, screams). Sucking is the best comfort he knows and also helps move the gas along the bowel. This tends to ease the pain temporarily and may result in wind and stool being passed. Since the baby indicates that he wants to suck at the breast, his mother, logically, feeds him again. Sometimes it is the only way to comfort him. Unfortunately another large feed on top of the earlier one hurries the system further and results in more gas and fluid accumulation. The milk seems almost literally to ‘go in one end and out the other’.
Many mothers whose babies have had this problem have found it helpful to change from an ‘on-demand’ breastfeeding routine. This is usually only necessary for a short time. The aim is to slow the rate at which milk goes through the baby by feeding one breast per feed, or by ‘block-feeding’. To block-feed, set a 4-hour time period (this may be adjusted according to the severity of the oversupply) and every time the baby wants to feed during this period, use the same breast. Then use the other breast for the next 4 hours, etc. Each time the baby returns to the already used breast, he gets a lower-volume, higher-fat feed that helps slow the system down. While block-feeding, check that the unused breast does not get overfull. When the baby’s symptoms are relieved, the mother is able to go back to a normal breastfeeding routine and feed according to need.
Where the problem is severe and/or long-lasting, it is worth trying to work out why there is an oversupply of breastmilk.
- Is the mother timing feeds and switching sides after a set number of minutes?
- Has something caused the baby to be unusually unsettled, resulting in frequent comfort sucking and an oversupply?
- Is secondary lactose intolerance adding to the overload situation?
- Sometimes a mother who is worried about having a low supply overcompensates by offering more feeds than the baby needs and overstimulates her supply.
- Perhaps the baby has been unwell, or is suffering discomfort from a difficult birth, and seeks comfort in more frequent feeds than he needs to satisfy hunger.
- Some mothers just have a tendency to oversupply – there is a normal variation in this as in everything else about our bodies. In days gone by, these may have been the mothers who could have made a living as wet nurses!
Specific ways to help with each of these is beyond the scope of this article. However, individual situations can be discussed with an Australian Breastfeeding Association counsellor, an International Board Certified Lactation Consultant (IBCLC), a dietitian with an interest in infant feeding or other health professional.
As explained above, there are several types of lactose intolerance, but it is very rare for a baby to have to stop breastfeeding because of this condition. Except for the extremely rare primary type, there is always a cause behind lactose intolerance in babies. Getting to the cause and fixing that is the key to resolving the baby’s symptoms.
Revised April 2010
First published as “Lactose Intolerance and the Breastfed Baby”, written by Joy Anderson BSc, Dip.Ed., Grad.Dip.Med.Tech., IBCLC, ABA Breastfeeding Counsellor.
Brodribb W (ed), 2004, Breastfeeding Management. 3rd edn. Australian Breastfeeding Association, Melbourne.
Heyman MB for the Committee on Nutrition, 2006, Lactose intolerance in infants, children, and adolescents. Pediatrics 118(3): 1279-1286 (available here).
Lawlor-Smith C & Lawlor-Smith L, 1998, Lactose intolerance. Breastfeeding Review 6(1): 29-30.
Leeson R, 1995, Lactose intolerance: What does it mean? ALCA News 6(1): 24-25, 27.
Minchin M, 1986, Food for Thought. 2nd edn. Unwin Paperbacks, Sydney.
Rings EHHM et al, 1994, Lactose intolerance and lactase deficiency in children. Current Opinion in Pediatrics 6: 562-567.
Royal Australian College of Physicians 2006, Paediatric policy: Soy protein formula. RACP, Sydney.
Saarela T, Kokkonen J & Koivisto M, 2005, Macronutrient and energy contents of human milk fractions during the first six months of lactation. Acta Paediatrica 94: 1176-1181.
Woolridge M, Fisher C 1988, Colic, ‘overfeeding’ and symptoms of lactose malabsorption in the breast-fed baby: a possible artifact of feed management? Lancet (ii): 382-384.