Infant Formula

Breast milk is widely accepted to be the ideal nutritional choice for babies during their first year. However, many parents, for any number of reasons, do not choose to breastfeed at birth. And of those who do choose to breastfeed initially, 78% stop doing so by the time their baby is six months of age.1 These families are faced with having to choose an infant formula. Any trip to a local grocery can prove how difficult a task this can be. The questions these parents most likely would ask would be: is one formula better than another? Does brand name matter? Does "new and improved" or "enhanced" formula mean better? Are infant formulas really a safe and nutritious choice for feeding babies?

The Federal Drug Administration (FDA) regulates over forty different brands and types of infant formulas in the United States.2 They can be milk-based, soy-based or protein hydroslysate formula (hypoallergenic).7 They can be a name brand or generic brand. In addition, they can be further broken down into many other categories including formulas with iron or with low iron, lactose-free formulas, nutrient-enhanced formulas, and even formulas for preventing excess spit-up.3 Then, if that isn't enough, there are also ready-made, concentrate and powdered forms!

The American Academy of Pediatrics Committee on Nutrition, despite its strong endorsement for breastfeeding, advocates the use of iron-fortified formulas for non-breastfed babies.6 Due to this recommendation, this paper will cover the reasoning behind this endorsement. In addition, this paper will look at the new enhanced formulas containing the two nutritional fatty acids, docosahexaenoic acid (DHA) and arachidonic acid (AHA).

The need for breast milk supplementation is not new. Before the era of modern medicine there were circumstances, just as today, which would prevent a new mom from nursing her baby. It was common then under those circumstance to employ a "wet-nurse."9 A wet-nurse was in fact a lactating woman who would be paid to nurse other people's babies. When a wet-nurse wasn't available or wasn't financially feasible, babies where fed milks from cows, goats, mares & donkeys.9

During the 19th century wet nursing did fall out of favor. More attention was focused towards trying to find an adequate substitute for mother's milk.8 Cow's milk became more of the norm for supplementation due to its ready availability. It was during this time observations were made that infants fed cow's milk had a higher mortality rate as well as were more prone to indigestion and dehydration as compared to infants that were breastfed.9

A German scientist in 1838, Johann Franz Simon, published the first biochemical analysis of the nutrient contents of human and cow's milk. It served as a basis for formula nutrition science for decades to follow.9 This analysis is actually very similar to modern determinations.19 Simon discovered that cow's milk had a higher protein content and lower carbohydrate content than human milk.8 In addition, he believed that the larger curds of cow milk, as compared to the smaller curds of human milk, were responsible for the indigestibility of cow's milk.8 Simon was also the first scientist to link estimates of the metabolic rates (energy requirements) of infants and the calorie content of milk.19 He, with the work of others, estimated that infants have a caloric need of 100 calories per kilogram per day during the first few months of life.19 This is remarkably similar to currently estimated requirements.

By 1860, a German chemist, Justus von Leibig, developed the first commercial baby food.9 It was a powdered formula made from wheat flour, cow's milk, malt flour and potassium bicarbonate.9 This formula, called Leibig's Soluble Infant Food, was added to heated cow's milk. It was the first commercial baby food to be sold in the United States. It sold for $1 per bottle in 1869.9

It was in 1869 that Nestlй's Infant Food, made with malt, cow's milk, sugar and wheat flour became available in the United States.4 Its price was $.50 per bottle in 1870.4,9 Nestlй's formula not only contrasted Leibig's Food in terms of price but also was only diluted with water. Because it did not require cow's milk to prepare like Leibig's, it became the first complete artificial formula to be available in this country.4,9

Over the next twenty years, several cow's milk modifier formulas were introduced. In the 1897 Sears catalogue, there were at least eight brands of commercial infant foods.9 These formulas, despite their wide spread availability, had only modest sales due to the fact that they were expensive in comparison to cow's milk.

It was 1929 when the first soy based infant formula was introduced by Mead Johnson Company.33 This innovation was in response to those babies with allergies to cow's milk.3

During the 1900's scientists were focused on trying to make advances in creating a more "humanized" formula. Nutrition scientists began focusing on trying to modify carbohydrate, fat, and protein. Vitamins and minerals were also added or balanced. The goal was to make infant formula more closely resemble that of human milk. For example, polyunsaturated vegetable fats were used to replace much of the saturated fats of cow's milk. 19

Research in 1912 by E. Mead Johnson, founder of the Mead Johnson Company, produced a cow's milk additive called Dextri-Maltose. Dextri-Maltose, based on the malt oligosaccharides (oligosaccharide: any carbohydrate with a few units of simple sugar) used in Europe, was a specialty carbohydrate product as well as the first clinically supported, physician recommended infant formula in the United States.3,19 It was used by hospitals and in homes for sixty years.3

The protein content and quality of formula were a consideration from the 1930's on.27 Early estimates of breast milk protein levels were higher than now known. In addition, it was believed that cow milk protein was greatly inferior to breast milk; a belief that led to very high levels of protein in original formulas (3.3-4.0 g/100kcal). Protein concentrations were lowered as a result; current protein levels in formula average 2.07g/100kcal.3,4,5

Based on recognition that human milk contains a predominance of whey proteins, while in cow's milk, caseins are higher, formula with a whey:casein ratio similar to human milk were introduced in 1962.27 The protein quality was changed by replacing some of the casein of cow's milk with whey (whey is the watery part of milk that is separated from the coagulated part or curd).19

More recent changes to infant formulas were the adding of taurine in