MANY Malaysian mothers do not breastfeed their newborn babies. The babies are given bottled milk at birth or within a few months after birth. The bottled milk is usually derived from cow’s milk which comprises protein, fat, sugar, vitamins and minerals mixed with water. Some babies are allergic to the proteins in cow’s milk. This occurs despite the efforts of the milk manufacturers to produce bottled milk that is as close to mother’s breast milk as possible.
It is generally accepted that about 1% to 5% of infants are allergic to the proteins in cow’s milk and its various formulations.
Nasty reaction: Up to 5% of infants are allergic to the proteins in cow’s milk and its various formulations. To avoid the allergy it is advisable to breastfeed the baby for six months or more.
Most infants will, fortunately, outgrow the milk allergies by the time they are two or three years old.
Milk allergy has to be distinguished from lactose intolerance. The former involves the body’s immune system but the latter does not. Milk allergic reactions occur with the smallest amount of milk consumed.
Lactose intolerance is usually dose related – small amounts are tolerated by the body but larger amounts lead to a reaction which may mimic milk allergy.
Lactose intolerance is of slower onset than milk allergy and is not life-threatening. It is a harmless condition.
Milk intolerance is due to lactose intolerance which is the inability of the gastrointestinal system to absorb lactose, the primary sugar in milk and milk products such as milk powder, butter, margarine, cheese, yoghurt and chocolate. The lactose composition of milk products can be found by reading the labels of the products.
Lactose comprises two sugars bound together. Its absorption can occur when it is split up into two smaller sugars by an enzyme called lactase which is produced by the cells lining the small intestine. If the amount of lactase is low or absent, the body cannot or would have difficulty in splitting the lactose into two smaller sugars. The lactose then passes into the large intestine where the bacteria there cause it to ferment, producing a large amount of gas.
The amount of lactase in the intestine is high in babies. As the baby grows, the amount of milk consumed decreases leading to a reduction in the amount of lactase in the intestine.
Many Asians are at risk of developing lactose intolerance unlike adults in Europe and North America. Many people develop lactose intolerance when they have diarrhoeal diseases, during which the lining of the small intestine is slightly damaged by the frequent bowel movements. This results in a reduced production of lactose by the cells lining the small intestine.
Other causes of lactose intolerance are diseases of the stomach or intestines and its surgical treatment.
There are, however, some people who have low lactase levels but who are not lactose intolerant. The reason for this is unknown. The symptoms of lactose intolerance are abdominal distension and/or colic, stomach rumbling, increased passage of wind, nausea and diarrhoea.
There is marked variation in the symptoms of lactose intolerance. Some people do not have problems but others have symptoms with a small amount of lactose. Some do not have problems with certain foods which contain lactose but cannot tolerate other lactose-containing foods.
Self diagnosis of lactose intolerance is not difficult. This is done by refraining from consumption of lactose containing foods for a few days and then drinking two to three glasses of milk. If there is a tummy ache or diarrhoea within 30 minutes or so, it is likely that there is lactose intolerance.
The diagnosis of lactose intolerance can be confirmed by tests done by the doctor. One test involves measuring the blood sugar before and after drinking a lactose containing fluid. If the blood sugar is increased, there is no lactose intolerance. Another test involves analysing the breath for hydrogen gas after drinking a lactose-containing fluid. Hydrogen gas will be present if there is lactose intolerance as the lactose-containing fluid will be fermented by the bacteria in the large intestine. If one has an endoscopic examination, which involves passing a tube-like instrument into the stomach and intestine, the lining of the small intestine may be analysed.
The treatment of lactose intolerance depends on the severity of the symptoms. If the symptoms are mild, all that is necessary is to reduce the consumption of milk and milk products. If the symptoms are severe, a lactose-free diet would be necessary. The doctor will, in such situations, refer the patient to a dietician who will advise on the composition of a lactose-free diet.
Lactose intolerance can be prevented by abstaining or reducing the consumption of milk and milk products when one has diarrhoea or has just recovered from it.
There are two ways in which cow’s milk allergy present: gradually or suddenly. It usually presents gradually before the baby is six months old. The clinical features commonly occur with the passage of loose stools, blood in the stools, vomiting, colic, irritability and poor growth.
It can also present suddenly and rapidly with vomiting, wheezing, swelling of the skin and eyes, and rarely, anaphylactic shock, which is a sudden and severe allergic reaction involving the whole body and which is life threatening. This usually occurs soon after contact with the cow’s milk allergen. Both the cardiovascular and respiratory systems are affected with marked changes in the blood pressure and breathing difficulties. Most babies will outgrow their allergy to cow’s milk by the time they are two to four years of age.
Cow’s milk allergy may also be associated with other allergies like eczema and asthma. If the cow’s milk allergy is not addressed adequately, it may lead to effects on growth with failure to thrive and nutritional deficiencies. The management of cow’s milk allergy is premised on avoiding cow’s milk. This would include a breastfeeding mother avoiding dairy products in her diet, lest it be transmitted to the baby in the breast milk.
The formula for bottle-fed babies has to be changed to one that is soy or hydrolysate-based. The latter contain cow’s milk proteins which are less allergenic because they have been broken down. If the allergy is severe, an amino acid based formula is used. Most manufacturers market “hypoallergenic” formula products.
It is important to remember that there is cross allergy between cow’s milk and soy milk in up to 50% of the late onset type of cow’s milk allergy and 15% of the rapid onset type. If the allergy is severe, treatment with medicines like anti-histamines and adrenaline will be necessary. Vitamin supplementation may also be necessary.
If there is a family history of allergies (eczema and asthma), it is advisable to totally breastfeed the baby for six months or more. This will delay the onset of symptoms if the baby has cow’s milk allergy. There are other benefits of breastfeeding which include improved immunity for the child and bonding.
If one wants to provide cow’s milk in a child’s diet, this may be done when the child is 12 to 18 months old. However, it is advisable to do this under medical supervision. It is important to check all food labels and avoid any food that contains milk or milk products. Advice from a doctor or dietician would be useful if one is unsure.
DR MILTON LUM
Dr Milton Lum is a member of the board of Medical Defence Malaysia. This article is not intended to replace, dictate or define evaluation by a qualified doctor. The views expressed do not represent that of any organisation the writer is associated with.