Cow’s milk is a source of much controversy, and the purpose of this article is to try and clear up some of the confusion.
Is cow’s milk responsible of the baby’s eczema? No! but ...
Milk is a complete food, i.e. it contains sugar (carbohydrate), fat and protein, which are the three groups of food we need – not forgetting vitamins, trace elements and water. We need to say something about each of the food groups that milk contains
• The sugar in milk is called lactose.
To digest lactose, our bodies make a molecule called lactase. Asians make very little lactase, while western populations in the North make more than those living in the South. The amount of lactase produced reduces with time, and, in France, there is only 10 to 30% left by the age of 6. Babies, therefore, can digest the sugar in milk.
• Fats and oils are called lipids.
They include vitamin A, a good fat found in uncooked butter, but destroyed by heat, and bad fats, saturated fatty acids, which have the annoying property of being pro-inflammatory, i.e. they make all inflammatory diseases worse, including atopic dermatitis. This mechanism mainly affects people who eat large amounts of cheese, which is not the case for babies!
• It is only the proteins in cow’s milk that can cause an allergic reaction.
You can only be allergic to proteins, never to carbohydrates or fats. So allergy to cow’s milk in babies does exist, but only in 2 to 3% of atopic babies. This adds up to 4,800 babies a year, as compared to the 152,000 a year who develop atopic dermatitis without any true allergy to cow’s milk proteins. The allergy is all the easier to detect as it is accompanied by other signs like diarrhoea, occasionally an ear infection or poor weight gain. In such cases the baby should be seen by an allergist or paediatric allergist, who will run the required tests.
There is currently a rumour going around that a link between atopic dermatitis and cow’s milk is much more common. So what do the numbers tell us?
Consumption of cow’s milk has been falling constantly since the 1950s, while that of yoghurt and cheese has risen. In 1950 it was 74 litres per person per year, as opposed to under 60 litres nowadays, while yoghurt consumption has doubled, going from 9 kg to 18 kg, and that of cheese has tripled, from 5 kg to 18 kg.
Over the same period, AD in children has risen from 3% to 20%. Now, babies eat neither yoghurt nor cheese until they are about 6 months old, while atopic dermatitis often starts in the very first month of life.
These simple figures prove that there is no statistical connection.
Nevertheless, our everyday practice leads us to suggest that stopping cow’s milk can be successful in managing atopic dermatitis. When?
When local treatments (hygiene, emollients, local corticosteroids) are being adhered to but are not working, or not working very well, and recurrence is immediate, two questions need to be asked:
• Is there a problem with the intestinal flora?
• Is it a case of milk intolerance?
The first hypothesis is the more plausible if the mother took antibiotics during pregnancy, and/or the baby has taken them since birth
The second is the more plausible if repairing the intestinal flora has not resulted in an improvement in the condition of the skin.
In practice, therefore, we should:
• Give the baby pre- and probiotics in addition to something to treat thrush if they have taken antibiotics.
• After a month, see whether there has been a definite, stable improvement.
• Otherwise opt for a 90% hydrolysed milk. If the expected improvement is finally achieved, keep the hydrolysed milk for the baby’s bottle and only used goats’ or ewes’ milk yoghurt for a few months. Cow’s milk can be reintroduced a few months later, as it is not an allergy but just a usually short-lived intolerance.
• Avoid soy milk and almond milk – they are vegetable juices, not milk. It’s an important difference, because their nutritional quality is completely different.