Special Foods – Milk
Filed under: 4 - Atopic DermatitisA few foods are important enough to deserve special discussion.
Milk.-Milk contains four proteins: lactalbumin, casein, lactoglobulin, and opalisin. Opalisin exists only in traces, lactoglobulin in very small amounts; it is probable that they are of little or no importance in allergy. Lactalbumin and casein are the important ones, and of these lactalbumin is by far the more important. Sensitivity to casein exists, but it not so common as sensitivity to lactalbumin, as casein is coagulated in the stomach and is not readily absorbed before digestion, while lactalbumin is a soluble protein, and is therefore more easily absorbed in antigenic form.
In 153 eczematous infants under 1 year of age, from my old records, there were seventeen positive scratch tests to either lactalbumin or casein or to both. Most were to both proteins, but as it is impossible to obtain a casein preparation which is entirely free of lactalbumin, the authenticity of some of the casein reactions is open to doubt. In a series of sixty-three infants who had negative scratch tests to lactalbumin, about 50 per cent gave positive intracutaneous tests. It has seemed to me that positive scratch tests to milk are almost always of etiological importance in infantile eczema -positive intracutaneous tests sometimes are. In eczema the sensitivity to milk is not of high degree; if it were it would not be possible for the infant to take any milk without violent symptoms, and still he drinks a quart a day with no adverse symptoms except perhaps a bit of colic, and thrives except for his eczema. I think that at the present time altogether too concentrated milk mixtures are being fed to too young babies, and that this is partly responsible for the increase in eczema and other allergic symptoms. I see not a few babies who are taking as much as 3 ounces of whole milk per pound of weight per day. This represents an enormous intake of protein for such a small creature. It is not a bad idea, although it may be difficult with some hungry babies, to stick to the old rule of 1^ to 2 ounces of whole milk or its equivalent per pound per day.
If the skin test to milk is positive it is best to remove milk from the diet and to substitute one of the milk-free foods. Sobee, Mull-Soy, Soyolac, and Nutramigen are at present the most popular. The first three are made from soybean flour with the addition of various fats, carbohydrates, salts, and vitamins. The base of Nutramigen consists of amino acids which have been derived from the breaking down of casein. Fat, carbohydrate, salts, and vitamins have been added. All are excellent preparations, and will nourish a baby as well as milk, even over long periods of time. The trouble is that the soybean preparations are altogether too likely to cause diarrhea and sore buttocks; the younger the baby the more often this happens. It is said that the new liquid Sobee is less likely to do this than the others. I cannot vouch for this from personal experience-I have used too little of it. I think Nutramigen is the best to use for babies under 3 months. The stools with Nutramigen are of thin consistency, as it has little residue, but there is rarely actual diarrhea. The trouble with Nutramigen is that it has a very strong taste, somewhat resembling beef tea, and babies tire of it more easily than they do of the soybean foods. I have seen one child, however, who was fed on it for over two years.
I said twenty years ago that I thought sensitivity to milk was probably the most common single cause of atopic dermatitis in infants. However, most of the eczematous babies that are now brought to me have been on some milk-free food for a considerable period with no benefit whatever. I see, for the most part, only those for whom a milk-free diet does no good, and for a while I had the thought that perhaps my original ideas about milk sensitivity in eczema were wrong. My pediatric friends assure me, however, that this is not so, and that, due to extensive advertising, most pediatricians now use these foods so much that I see, as a consultant, only those in whom they do not work. This may be so.
Whether it is so or not, I am entirely sure that the milk-free foods are being used altogether too much, and, for the most part, without a great deal of intelligence, and that the frequency of milk sensitivity of every sort (gastrointestinal, respiratory, etc.) is being exaggerated; like every good thing it is being worked to death. The tendency is now, on account of superadvertising of the soybean foods, for pediatricians to put every baby they see with any sort of skin rash, from ammonia dermatitis to flea bites, scabies, and often what is obviously contact dermatitis, on a milk-free diet at once. This is not only stupid, but may do harm if the baby develops a severe diarrhea. The milk-free foods are of great value when used properly, and they have been a boon to many babies, but when Harold Stuart and I18 introduced Sobee in 1929, we started something that has gone too far.
Goat’s milk can sometimes be used to great advantage in some forms of milk sensitivity, particularly for patients with gastrointestinal allergy and for almost all of those babies who are so violently sensitive that they go into shock from the ingestion of only a few drops of cow’s milk.19 Although an occasional infant with eczema due to cow’s milk is relieved or even cured by the use of goat’s milk, this does not happen often because the caseins of goat’s and cow’s milk are identical immunologically and chemically, and while the two lactalbumins are somewhat different immunologically, they are by no means entirely species specific; there are many crossed reactions. Some years ago I tested forty-four eczematous infants who had given positive intracutaneous tests to cow lactalbumin, with a specially purified preparation of goat lactalbumin. There were twenty-five positive reactions. “Why it is that goat’s milk is so often tolerated by infants who have severe shocklike symptoms from cow’s milk, and is only occasionally of use in eczema due to cow’s milk, I do not know. I suspect that the antibodies in the two conditions may be different, and that the antibody in the patients with eczema is less specific than the antibody in those with shocklike symptoms.
18Hill, Lewis, W., and Stuart, Harold C.: A Soybean Food Preparation for Feeding: Infants With Milk Idiosyncrasy, J. A. M. A. 93: 985, 1929.
19Hill, Lewis W.: Immunologic Relationship Between Cow’s Milk and Goat’s Milk, J. pediat. 15: 157, 1939.
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