The composition of human milk serves as a valuable reference for improving infant formula. However, human milk contains living cells, hormones, active enzymes, immunoglobulins and components with unique molecular structures that cannot be replicated in infant formula. Unlike human milk, infant formula must remain stable on the shelf for up to thirty-six (36) months. These fundamental differences between human milk and infant formula often mandate differences in the composition to achieve similar clinical outcome.
The study of human milk components has stimulated many investigations into what constituents may be added to an improved infant formula. Greater knowledge of the composition of human milk affords the opportunity to design infant formulas that arc closer in composition to human milk. However, it becomes increasingly apparent that infant formula can never exactly duplicate human milk. Many constituents in human milk are bioactive and because of synergies among these components, there is little reason to believe that the same compound would have the same bioactivity in infant formula. The likelihood of this possibility is further diminished when the impact of heat treatment for sterilization and long-term storage of the formula is considered. The present invention is based, in part, on the concept of providing a formula which matches the performance of breast milk in stool consistency parameters without attempting to duplicate exactly the delicate balance of human milk components.
The composition of human milk differs appreciably from that of other species and much attention has been paid to the various components. Several investigators have reported on the nucleotide content of milk from humans (Janas, L M et al: The Nucleotide Profile of Human Milk. Pediatr. Res. 16:659-662(1982) and Gil et al.: Acid-soluble Nucleotides of Human Milk at Different Stages of Lactation. Journal of Dairy Research (1982), 49, 301-307). Numerous publications have also discussed various lipid, oil or fat blends for use in an artificial nutritional for human infants. As the result of investigations regarding the use of nucleotides in infant formula, the inventors of the present application discovered that a particular blend of oils resulted in infant stool patterns that are similar to those of the breast fed infant.
Formula tolerance is generally assessed by gastrointestinal symptoms (e.g., emesis, stool patterns and gas) as well as behavioral characteristics (e.g., acceptance of formula, fussing and crying). Concerns regarding poor tolerance are frequently reported as a reason for formula switching within the first two months of life. (Forsythe BWC, McCarthy P L, Leventhal J M: Problems of early infancy, formula changes, and mother's beliefs about their infants. J. Pediatr. 1985; 106:1012-1017). Stool patterns are known to differ between formula-fed and breast-fed infants, (Weaver L T, Ewing G. Taylor, L C: The Bowel Habit of Milk-Fed Infants. J. Pediatr. Gastroenterol Nutr. 1988; 7:568-571), as well as between infants fed various formulas (Hyams, J S, Treem W R, Etienne N L, et al.: Effect of infant formula on stool characteristics of young infants. Pediatrics 19951 50:54).
The Hyams et al. publication, supra, also reports that certain infant formulas typically cause a significantly greater percentage of firm stools compared to the breast-fed infant which may be perceived by the parent or care giver as unacceptable. This publication also indicated that milk-based, iron-fortified formulas resulted in a significantly lower percentage of watery stools. S. J. Fomon in Nutrition of Normal Infants (L. Craven ed.) Mosby: St. Louis, Mo., at page 250 states that "Many physicians appear to be convinced that infants fed iron-fortified formulas are prone to fussiness . . . and constipation." It is this problem and/or perception that the present invention addresses. Quinlan et al. in Pediatr Gastroenteral Nutr., Vol. 20, No. 1 (1995) concludes that "Constipation" and "hard stools" are associated with formula feeding of both term and pre-term infants and, in the latter, can lead to life threatening complications."
Numerous investigators have reported that fatty acid profiles similar to human milk are important to the human infant. Representative of those numerous publications are: 1) Gil et al., changes in the Fatty acid Profiles of Plasma Lipid Fractions Induced by Dietary Nucleotides in Infants Born at Term, Eur. J. of C. Nutrition, (1988) 42, 473-481; 2) E.P. 0129,990; 3) E.P. 0376,628; 4) U.S. Pat. No. 4,670,285; 5) U.S. Pat. No. 3,231,385; 6) U.S. Pat. No. 4,544,559; 7) U.S. Pat. No. 4,758,553; and 8) U.S. Pat. No. 4,994,442. These investigators have failed to discover that a blend of lipid sources, which is essentially free of palmitic acid which may comprise a blend of high oleic safflower oil, soy oil and coconut oil, is beneficial in overcoming certain shortcomings associated with infant formula.