Breastmilk Protein Childhood Cancer

Porro et al., 1993;

Haemophilus influenzae, type b

10 years

Silfverdal et al., 1997

Hodgkin's disease

6 months

Not specified

Davis, 1998

many other health problems that are discussed throughout this book. The longer the duration of breastfeeding and the more complete exclusivity of breastmilk, the greater its protective effect.

Childhood Cancer

Does a mother's milk modulate the interaction between the developing infant immune system and infectious agents that helps protect an infant against carcinogenic insults? When Davis (1998) reviewed nine case-control studies on the association between infant feeding and childhood cancer, she confirmed that children who are never breastfed or are breastfed short-term have a higher risk of developing Hodgkin's disease than those breastfed for at least 6 months. It is possible that a type of human alpha-lactalbumin found in breastmilk lessens the risk of childhood cancer. This alpha-lactalbumin, a protein-lipid complex called HAMLET, induces apoptosis-like death in tumor cells but leaves fully differentiated cells unaffected (Hakansson et al., 1995; Svanborg et al., 2003). Other researchers contend that evidence showing that breastfeeding is protective against childhood cancer is limited and that further evidence is needed to support this conclusion (Heinig & Dewey, 1996).

Allergies and Atopic Disease

The incidence of food-induced allergic disease in children has been estimated to be between 0.3 to 7.5 percent (Metcalfe, 1984). Heredity is a significant predictor of allergic disease, even when the mother is on a milk-free diet during late pregnancy and lactation (Lovegrove, Hampton, & Morgan, 1994). Sixty percent of all those who will develop atopic eczema do so within the first year of life, and 90 percent do so within the first 5 years. Before 6 to 9 months of age, the infant intestinal mucosa is permeable to proteins; moreover, secretory IgA, which will later "paint" the mucosa and bind sensitizing proteins to itself, is not yet functioning effectively. After following 150 infants from birth to 17 years of age, Saarinen and Ka-josaari (1995) concluded that breastfeeding is prophylactic against allergies—including eczema, food allergy, and respiratory allergy—throughout childhood and adolescence.

Bovine milk is the most common single allergen affecting infants. Proteins in bovine milk known to act as allergens include lactoglobulin, casein, bovine serum albumin, and lactalbumin. Modern heat treatment of formula has reduced—but certainly not eliminated—the allergic potential of these proteins. The problem is probably increased by the sizable dose of allergens in formula and by the large volume of formula ingested. At 2 to 4 months of age, for example, infants consume their body weight in milk each week. This is the equivalent of nearly 7 quarts per day for an adult—truly a macrodose!

Vomiting, diarrhea, colic, and occult bleeding are symptoms of allergy. It also affects the respiratory tract (runny nose, cough, asthma) and the skin (dermatitis, urticaria). Because the symptoms are varied and nonspecific, the diagnosis is often mistaken or missed.

At birth, the IgE system is defective in the potentially allergic infant, and problems arise if this system is activated by allergens. When the introduction of foreign proteins is delayed for 4 to 6 months, the baby's own IgA system is permitted to become more fully functional; thus allergic responses may be minimized or entirely avoided. Exclusive consumption of breastmilk facilitates the early maturation of the intestinal barrier and provides a passive barrier to potentially antigenic molecules until the baby's own natural barriers develop. The rationale for delay of solids for the first half year after birth is thus reinforced.

High levels of neonatal blood IgE are thought to predict later development of atopic symptoms. When the relationship between fecal IgE levels (a reliable indicator of serum IgE levels) was compared in infants 1 month old, formula-fed babies showed a higher incidence of high fecal IgE levels than did the breastfed infants (Furukawa et al., 1994).

A few breastfed infants develop atopic eczema. Of those who do, the culprit is often foods ingested by the mother—especially cow's milk. Cow's milk antigen can be detected in breastmilk (Axelsson et al., 1986; Cavagni et al., 1988; Odze et al., 1995; Paganelli, Cavagni, & Pallone, 1986). Early and occasional exposure to cow's milk protein sensitizes neonates so that even minute amounts of bovine milk protein in human milk may later act as booster doses that elicit allergic reactions (Host, Husby, & Osterballe, 1988). Prolonged breastfeeding exclusively or combined with infrequent exposure to small amounts of cow's milk during the first 8 weeks induces the development of IgE-mediated cow's milk allergy (Saarinen et al., 2000). By almost completely excluding milk, other dairy products, eggs, fish, beef, and peanuts throughout pregnancy and lactation, Chandra et al. (1986) documented a significant reduction in the incidence and severity of atopic eczema among breastfed infants of these mothers.

Problems in conducting research on allergies and breastfeeding are manifold. Because it is not possible to classify mothers randomly into breastfeeding and nonbreastfeeding groups, are those infants with a family history of atopic eczema more likely to be breastfed because the parents are aware that it has a protective effect? When the infant is identified as breastfed, does that mean that the baby received no other nutriments? If so, for how long was breastfeeding continued? After conducting a meta-analysis of 22 original research reports on infant feeding and atopic disease, Kramer (1988) decided that errors in research methods are conflicting and seriously flawed, which thus, precludes definitive conclusions.

Asthma

Outcomes of epidemiological and clinical studies on asthma and breastfeeding are inconsistent and the longstanding question of whether breastfeeding prevents or reduces the incidence of asthma has been controversial. To help settle the question Gdalevich, Mimouni, and Mimouni (2001) conducted a meta-analysis of research on the effect of breastfeeding on bronchial asthma. They found 41 studies that showed a protective effect, five studies that had no association, and two studies that had a positive association. Twelve of these studies were prospective and met the standards for study methodology as determined by Kramer (1988). Meta-analysis of these 12 showed that exclusive breastfeeding during the first months after birth is associated with lower asthma rates during childhood (Odds Ratio 0.70, 95% CI 0.60 to 0.81).

Finally, in regard to breastfeeding's protective effect against chronic disease, Palmer (1998) makes a convincing case that artificial feedings alter normal early oral cavity development so much that it can cause later problems such as snoring, sleep apnea, and malocclusion. For the mother herself, breastfeeding promotes health because it helps to prevent breast and ovarian cancer (see Chapter 16).

New Mothers Guide to Breast Feeding

New Mothers Guide to Breast Feeding

For many years, scientists have been playing out the ingredients that make breast milk the perfect food for babies. They've discovered to day over 200 close compounds to fight infection, help the immune system mature, aid in digestion, and support brain growth - nature made properties that science simply cannot copy. The important long term benefits of breast feeding include reduced risk of asthma, allergies, obesity, and some forms of childhood cancer. The more that scientists continue to learn, the better breast milk looks.

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