While improving access to clean water and sanitary practices remains the best way to combat diarrheal diseases, other options are being explored to bolster children's capacity to fight these problems. For instance, the benefits of breast-feeding in preventing these diseases have been widely documented. As is now well known, breast-feeding promotes the growth of nonpathogenic microorganisms in the gut. The presence of such microorganisms as lactobacilli and bifidobacteria in the human gastrointestinal system helps keep the growth of disease-causing pathogens in check. In other words, "good bacteria" help maintain the balance in the human digestive system.

    Of course, breast milk does more than that, and its many benefits have been the subject of studies great and small. Its superiority over all other infant feed is uncontested, that practically everyone can recite that famous tagline automatically: Breast milk is best for babies.

    Most of these studies are done with support from infant formula developers, who would like to reproduce some of breast milk's properties in supplements. With it being considered the gold standard, the field in which infant formulas play is about which among them approximates breast milk best. An infant formula that perfectly copies breast milk remains a distant possibility, but all efforts to improve supplement formulation, with special attention given to the specific needs of specific populations, are generally looking up.

Hypoallergenic and Immunity-boosting

    In recent years research on the positive effects of breast-feeding on the immune system has received wide attention. Evidence on its hypoallergenic properties as well as its ability to boost the immune system has been building up.

    Studies have shown that infants born into families with a strong history of hypersensitivity experience transient IgA deficiency within the first few months of life. Since the presence of secretory IgA in the gut lumen prevents antigen adsorption in the villi's mucosal cells, introducing breast milk, with its high levels of IgA, can stop the antigen from being absorbed into the bloodstream. In a way the secretory IgA coming from the mother gives the infant's immune system the time to achieve an adequate level of IgA.

    Breast milk's role in boosting the immune system has also been heavily investigated. On the cellular level, breast milk possesses macrophages, lymphocytes, and epithelial cells that provide immunological defenses not otherwise present in other sources. These protect the body against the invasion-and reinvasion-of disease-carrying microorganisms. Its other components also contribute to giving the body protection from gut problems.

Copy Right

    It is also a fact, however, that there are instances when breast-feeding is just not possible. Situations in which it is not resorted to are many-problems with the production of milk (mostly attributed to the mother's general health status), the child's hypersensitivity to the mother's milk (which has been the subject of anecdotal reports), or even problems of lifestyle (which is becoming fairly common). And so, while they remain pale copies of the original, infant milk supplements come in to provide the best infant nutrition science can offer at present.

    And the present understanding of breast milk, while immense, still leaves a lot of issues unresolved. So understandably, there are significant differences in theory and interpretation of what makes breast milk tick-which, in a way, makes the field exciting.

Probiotics

    One area of research covers the addition of probiotics in infant formula. Roughly speaking, probiotics are nonpathogenic microorganisms that, when introduced to a body, give beneficial effects. Most popular of the probiotics are the earlier mentioned lactobacilli and bifidobacteria.

    Yogurt, one of the earliest probiotic foods, has been around for a long time. Such products as Yakult and Chamyto also contain probiotics. The consumption of these products has been reported to improve gastrointestinal function. Usually, the probiotics used in these are lactobacilli.

    For the breast-milk substitutes, what are usually added in are the bifidobacteria. Aside from their benefits in maintaining the delicate balance of microorganisms in the gastrointestinal tract, bifidobacteria have also been proved effective in promoting carbohydrate digestion and the absorption of calcium and other minerals, lowering blood cholesterol levels, synthesizing vitamins, reducing blood ammonia levels, and stimulating immune functions (Guesry, Nutrition Post Volume 5 Number 1).

    How exactly do probiotics work in preventing hypersensitivity and in strengthening the immune system?

    A study on rodent models showed that feeding with probiotics could decrease the production of IgE, which is the active antibody for allergy.

    In the analysis of the mice's cytokine profiles, what was found was an increase in interferon gamma IL2 and IL12, which are associated with promoting cell-mediated immunity and diminishing IL4 production.

    The increase in interferon gamma production (and the decrease in IL4 production) has also been shown in studies on human models. In infants with atopic dermatitis, meanwhile, feeding the infant probiotics has been associated with the decrease in rashes (Brigino-Buenaventura, Nutrition Post Volume 5 Number 4).

Prebiotics

    There is meanwhile, another "camp" in the microorganisms-in-milk war. This time, the idea they further is the addition of "prebiotics" in milk supplements. Although the goal is the same-helping keep the balance of good microbes in the gut to prevent the proliferation of bad microbes-the way through which this balance is achieved is different.

    Prebiotics are, roughly speaking, feed that nourishes the good microbes in the gut. By providing the good microorganisms-which are already present in the GI tract-the food that they need to survive, they thrive and colonize the gut, and therefore keep out the pathogens.

    What the prebiotic proponents point out is that if the good microbes were already added in the milk, many of them would die in transit. What they say is that the upper GI tract is not conducive to the survival of these microbes; even an acidic medium like milk cannot assure that the majority of the good microbes would survive.

    And so they say that the logical step is to add the feed of the microbes into the milk instead, because these don't have to be "killed" in transit. The feed would go through the GI tract and reach the existing lactobacilli and bifidobacteria in the gut intact.

    There are, however, two subgroups among the proponents of prebiotics as an add-on in breast-milk substitutes-there are those who add nucleotides, and there are those who use oligosaccharides.

    Although they are nonessential nutrients, nucleotides have been shown to have beneficial effects on the immune system, small intestinal growth and development, lipid metabolism, and hepatic function. Some of the nucleotides essential to physical and mental growth and development are cytidine monophosphate (CMP), guanosine monophosphate (GMP), uridine monophosphate (UMP), adenosine monophosphate (AMP), and inosine monophosphate (IMP).

    One of the early studies to look into the effect of dietary nucleotides on cellular immunity was by Carver et al., published in 1991 in Pediatrics. In the study, infants were divided into three groups-those on breast milk, those on nucleotide-supplemented formula, and those on unsupplemented formula. It turned that by the second month, those on breast milk and nucleotide-supplemented formula showed increased killer cell activity and interleukin-2 production compared with those on unsupplemented formula. Also, "there was no evidence of toxicity or intolerance to the NT-supplemented formula."

    Oligosaccharides also serve as feed for the healthy bacteria residing in the gut. These carbohydrates, which abound in mother's milk, have been associated with promoting the colonization of bifidobacteria in the intesntines. The oligosaccharides added into breast-milk substitutes are structurally simpler (usually galactooligosaccharides and fructooligosaccharides) than the ones found in breast milk. However, they can adequately mimic the prebiotic effects of breast-milk oligosaccharides.

    There are also those who don't entirely agree with the idea of adding prebiotics into infant formula. For instance, some researchers point out that prebiotics can still be digested and absorbed by the body, because they are still "food." And so by the time they reach the intestines, there might not be enough prebiotics left to feed intestinal microflora and promote their growth and colonization.

The Future in Milk

    Probiotics v. prebiotics, nucleotides v. oligosaccharides-and this is just on the issue of which boosts immune function best. A number of studies are still needed to resolve many issues. For example, still needed are studies to determine what effects the consumption of probiotic- or prebiotic-supplemented formulas has on kids over time. Also, there are as yet no wide-scale, head-to-head comparisons between camps.

    But there's really no need to be confused, as far as parents and infants are concerned-breast milk reigns; all others admit to being second-rate, trying hard, copycats.

 

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