OH BABY!: A SPECIAL ADVERTISING SECTION
THE BERMUDA SUN
FEBRUARY 22, 2013
NUTRITION Continued from page 8 The Israelis had 10 to 20 times less incidence of peanut allergies. A 2011 study in Australia found that cooked egg exposure at four to six months reduced allergic responses to eggs, but exposure after 10 months produced an increased risk. The duration of breastfeeding had no influence on the outcome. In 2011 the Finns found that late introduction of potatoes, oats, rye, wheat (most particularly wheat), fish and eggs was associated with increased allergic sensitization if introduced after six months. The Italians in 2012 pointed to a critical period between four and six months when solids should be introduced together with continued breastfeeding. This resulted in less sensitization. A US report (Pediatrics 2011) found no association with wheezing or eczema at four years of age in infants who were given cow’s milk, eggs, tree nuts, soy or gluten before their sixth month.
Science and anthropology The moot point is this — should infants be fed an exclusive diet of breast milk only for six months, with no room for flexibility, or should supplemental foods be introduced at four months? In our practice we encourage breastfeeding for as long as a mother is able to provide it, but we have always adhered to supplemental feeds starting at four months. We continually modify our advice as new research is published. We are not convinced that avoidance of supplemental feeds at four months is biologically sound and have based this decision on basic science research, the studies outlined above, and anthropological considerations. Studies on intestinal activity in newborn mammals show that the intestinal wall absorbs very large molecules and these are absorbed intact — not broken down to their elemental parts which had always been thought to be the case. This is probably how immunoglobulins in human maternal milk are absorbed. All biologically-active molecules, particularly
■ US PUBLIC DOMAIN IMAGE BY MARGARET A. MCINTYRE
EVOLUTION: As humans evolved, supplemental feeding and protein became essential to the survival of infants. large ones like the immunoglobulins, depend on their physical shape and structure in order to function. If the ingested breast milk immunoglobulins were broken down they would be useless in providing immune defence to a newborn. Obviously we cannot perform such experiments on humans but since the studies are done on mammals we can reasonably infer the same thing is going on inside us. The entire intestinal tract from top to bottom is encircled by the immune system. Everything that crosses the intestinal wall encounters the immune barrier first. The function of the immune system is to scan for what is safe and what is not, or more importantly, what is ‘self’ or ‘not-self’. The ‘not-self’ molecules are attacked and destroyed
by several different mechanisms that have evolved over the last half-billion years in almost all multicellular animal life on the planet. Besides absorbing immunoglobulin molecules, it is likely that large food molecules that have not been entirely broken down by digestion through the infant’s immature digestive processes are also being transported across the intestinal wall. These molecules have the potential to elicit an immune response because they are foreign’ (unlike the maternal immunoglobulins which share the same genetic origin as the infant). The immune system functions on a ‘timetable’ during development of the fetus — and infant — where there are periods when potential ‘allergy producing molecules’ (‘self’ versus ‘not-self’) are processed by
■ MCT GRAPHIC BY CAMILLE WEBER
ALLERGIES: Can earlier introduction to certain foods result in greater allergic protection?
immune cells, and thereafter ‘accepted’ as ‘self’ and will not induce an allergic reaction. I suspect that as humans
evolved, supplemental feeding (both plant or animal) in addition to breast milk became essential to the survival of infants.
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This would have had the additional benefit of lessening the energy cost of caloric intake and output on the nursing mother. The caloric expense of chasing and killing whatever member of the Pleistocene Megafauna the particular tribal group took a fancy to was probably borne by everyone else not engaged in nursing a dependent infant. The protein from such a kill would, after being chewed into mush by an adult, be put in the infant’s mouth for consumption — there being no food blenders at the time! It would appear from contemporary data on infant feeding in indigenous cultures (preIndustrial), that mankind has probably been putting all manner of foods other than breast milk into the mouths of three and four-month-old babies, or younger. This has been going on for millennia and the human immune system has adapted accordingly to process and to accept the ‘Big Allergen’ molecules during a ‘window of opportunity’ that would seem to lie between three and six to seven months. Once the window ‘closed’ the propensity to react to the allergens in solid foods would increase accordingly. Our office has conducted an informal survey of our mothers who are from both West and East Africa, and South America. These locations are of particular interest owing to the surprising lack of food allergies observed in the infants and children living in these locales. See NUTRITION, page 10