Lactose intolerance is when the digestive enzyme lactase is missing and so the carbohydrate or sugar in milk called lactose can’t be digested.
There is primary lactose intolerance which stays with your baby for life and is a genetic deficiency but this is very rare in the western world. It’s often seen in Asia.
More commonly secondary lactose intolerance occurs sometimes after a nasty tummy bug but tends to recover within about 6 weeks.
There is another type of temporary lactose intolerance that we see in very young babies with colic. This usually lasts 2-4 months or so.
What is lactose?
Lactose is the name given to the sugar that’s naturally found in milk. It’s present in both breast milk and most infant formulas.
What are the symptoms of lactose intolerance?
The symptoms of lactose intolerance always involve your baby’s digestive system and are diarrhoea, wind, bloating and sometimes nappy rash. Lactose intolerant babies often cry a lot and are uncomfortable and this is why it’s linked with colic.
If your baby has mucus or blood in her poo too then it’s not lactose intolerance and you should see your GP.
How is lactose intolerance diagnosed?
Lactose intolerance is diagnosed by a doctor taking a detailed history and testing your baby’s poo for acid. Hydrogen breath tests that measure the amount of hydrogen your baby breathes out can also be done but it can be quite difficult to get young babies to comply so tend to be reserved for older children and adults.
Can I still breastfeed?
Breastmilk is very high in lactose but interestingly lactose intolerance is rare in breastfed babies.
Cutting lactose out of your own diet won’t make a difference as your digestive system absorbs this completely before breast milk is produced.
Which infant formula will I need?
Lactose free formula is available which tastes very similar to a standard formula. They are ever so slightly sweeter. There are two brands available to choose from (Aptamil Lactose-Free, SMA LF Lactose-Free) and they can be bought from chemists and supermarkets.
Lactose-free infant formula still contains cow’s milk protein and therefore they are unsuitable for if you suspect your baby has a milk allergy.
Weaning and lactose intolerance
At the start of weaning, you don’t need to do anything differently. The usual vegetables and fruits are perfect for weaning a baby with lactose intolerance. As time goes on (and provided your baby is over 6 months) progress to adding in starchy carbohydrate foods such as bread, rice, pasta, cereals and grains and proteins such as eggs, meat, fish, beans, lentils and other pulses, – so that your baby has a varied diet consisting of three meals a day by 6.5 to 7 months of age.
How strict do I need to be?
You only need to avoid food high in lactose which is found in milk and foods made from milk like custard or ice cream. Hard cheeses, butter and yoghurt are milk products that are naturally low in lactose and are often well tolerated by babies who have lactose intolerance. Softer cheeses such as feta, mozzarella and spreadable cheeses, contain a little more lactose but it’s still relatively low.
Also, you may find that your baby can tolerate a certain amount of lactose-containing foods but has a threshold that she can’t exceed before her symptoms return.
If you want some help figuring out how much lactose your little one can tolerate, speak to a paediatric dietitian who can help you work this out.
What about plant-based milks?
Shop bought plant-based milks like almond milk, oat milk and hemp milk can be used in cooking but are a poor source of nutrition and so shouldn’t replace breastmilk or formula. If you do use these, look for ones enriched with calcium and iodine.
Rice milk is not suitable for children under 5 due to the naturally occurring high levels of inorganic arsenic.
Will my baby get enough nutrition?
Yes, provided you still offer low lactose dairy foods and lactose-free infant formula. If you find that you are having to cut out other food groups, seek the help of a dietitian.
Will my baby grow out of their lactose intolerance?
If your baby has the type of lactose intolerance that is genetic, they will have this for life.
Most cases of lactose intolerance in babies and young children is the temporary type and this should resolve in a few weeks if it’s related to a tummy bug or up to a few months if it’s related to colic, usually by the time they are 7-9 months.