SN2 Palmitate is a structured

triglyceride A triglyceride (TG, triacylglycerol, TAG, or triacylglyceride) is an ester derived from glycerol and three fatty acids (from ''tri-'' and ''glyceride''). Triglycerides are the main constituents of body fat in humans and other vertebrates, as w ...

where

palmitic acid Palmitic acid (hexadecanoic acid in IUPAC nomenclature) is a fatty acid with a 16-carbon chain. It is the most common saturated fatty acid found in animals, plants and microorganisms.Gunstone, F. D., John L. Harwood, and Albert J. Dijkstra. The Li ...

is bonded to the middle position (sn-2) of the glycerol backbone. Structured triglycerides are achieved through an enzymatic process using vegetable oils. Current usage of structured triglycerides is mainly for infant formula providing a human milk fat substitute.

SN2 Palmitate in human milk

Fats in human breast milk provides about 50% of the energy needed for the development and growth of a newborn infant. About 98% of the fats provided by human milk are in the form of triglycerides, which themselves are molecules consisting of mixtures of three

fatty acids In chemistry, particularly in biochemistry, a fatty acid is a carboxylic acid with an aliphatic chain, which is either saturated or unsaturated. Most naturally occurring fatty acids have an unbranched chain of an even number of carbon atoms, f ...

bonded to sn-1, sn-2, and sn-3 positions of a glycerol backbone. The human

mammary gland A mammary gland is an exocrine gland in humans and other mammals that produces milk to feed young offspring. Mammals get their name from the Latin word ''mamma'', "breast". The mammary glands are arranged in organs such as the breasts in primat ...

provides the baby with a unique fat composition where the fatty acids arranged in specific combinations, different from the triglycerides in other human tissues and

plasma Plasma or plasm may refer to: Science * Plasma (physics), one of the four fundamental states of matter * Plasma (mineral), a green translucent silica mineral * Quark–gluon plasma, a state of matter in quantum chromodynamics Biology * Blood pla ...

,Breckenridge, W.C., L. Marai, and A. Kuksis, Triglyceride structure of human milk fat. Can J Biochem, 1969. 47(8): p. 761-9. or from common dietary fats and oils. Palmitic acid (C16:0) is the major

saturated fatty acid A saturated fat is a type of fat in which the fatty acid chains have all single bonds. A fat known as a glyceride is made of two kinds of smaller molecules: a short glycerol backbone and fatty acids that each contain a long linear or branched ch ...

in human milk, accounting for 17-25% of the total fatty acids, with over 70% of 16:0 is esterified at the milk triglyceride sn-2 position. The major unsaturated fatty acid in human milk is

oleic acid Oleic acid is a fatty acid that occurs naturally in various animal and vegetable fats and oils. It is an odorless, colorless oil, although commercial samples may be yellowish. In chemical terms, oleic acid is classified as a monounsaturated omega ...

(18:1n-9) and this is mostly esterified at the triglyceride sn-1,3 (outer) positions. The positioning of palmitic acid at the sn-2 position is conserved in all women, regardless of race or nutrition, unlike the general fatty acid profile of human milk.

SN2 Palmitate in infant formula

The development of the sn-2 Palmitate structured triglycerides enables the mimicking of both the composition as well as the structure of human milk fat.

Vegetable oil Vegetable oils, or vegetable fats, are oils extracted from seeds or from other parts of fruits. Like animal fats, vegetable fats are ''mixtures'' of triglycerides. Soybean oil, grape seed oil, and cocoa butter are examples of seed oils, or fat ...

s that are commonly used as source for infant formula fat have the opposite structure where the palmitic is located mainly at sn-1 and sn-3 positions. Enzymatic process on vegetable oils enables changing the position of palmitic acid to the sn-2 position.Carnielli, V.P., et al., Structural position and amount of palmitic acid in infant formulas: effects on fat, fatty acid, and mineral balance. J Pediatr Gastroenterol Nutr, 1996. 23(5): p. 553-60.Kennedy, K., et al., Double-blind, randomized trial of a synthetic triacylglycerol in formula-fed term infants: effects on stool biochemistry, stool characteristics, and bone mineralization. Am J Clin Nutr, 1999. 70(5): p. 920-7.Lopez-Lopez, A., et al., The influence of dietary palmitic acid triacylglyceride position on the fatty acid, calcium and magnesium contents of at term newborn faeces. Early Hum Dev, 2001. 65 Suppl: p. S83-94.Lucas, A., et al., Randomised controlled trial of a synthetic triglyceride milk formula for preterm infants. Arch Dis Child Fetal Neonatal Ed, 1997. 77(3): p. F178-84. Clinical studies in preterm and term infants, as well as preclinical animal model studies, show that enrichment of infant formula with sn-2 Palmitate results in increased fat absorption, reduced

calcium Calcium is a chemical element with the symbol Ca and atomic number 20. As an alkaline earth metal, calcium is a reactive metal that forms a dark oxide-nitride layer when exposed to air. Its physical and chemical properties are most similar to ...

soaps formation and stool hardness, increased calcium retention and larger skeletal mineral deposition.

Physiology of triglycerides absorption

Triglyceride digestion by

endogenous Endogenous substances and processes are those that originate from within a living system such as an organism, tissue, or cell. In contrast, exogenous substances and processes are those that originate from outside of an organism. For example, es ...

lipases Lipase ( ) is a family of enzymes that catalyzes the hydrolysis of fats. Some lipases display broad substrate scope including esters of cholesterol, phospholipids, and of lipid-soluble vitamins and sphingomyelinases; however, these are usually tr ...

leads to

hydrolysis Hydrolysis (; ) is any chemical reaction in which a molecule of water breaks one or more chemical bonds. The term is used broadly for substitution reaction, substitution, elimination reaction, elimination, and solvation reactions in which water ...

of fatty acids from the triacylglyceride sn-1,3 positions, to release two fatty acids and one sn-2

monoglyceride Monoglycerides (also: acylglycerols or monoacylglycerols) are a class of glycerides which are composed of a molecule of glycerol linked to a fatty acid via an ester bond. As glycerol contains both primary and secondary alcohol groups two differen ...

into the intestinal lumen. The fatty acids configuration on the triglyceride has a major contribution to the efficacy of this nutrient absorption. While the unsaturated and short chain saturated free fatty acids are well absorbed regardless of their position, the absorption of free long chain saturated fatty acids, i.e. palmitic acid and longer, is relatively low. The main cause for this low absorption is their

melting point The melting point (or, rarely, liquefaction point) of a substance is the temperature at which it changes state from solid to liquid. At the melting point the solid and liquid phase exist in equilibrium. The melting point of a substance depends ...

above body temperature (~630 C), and thus high tendency to create complexes with dietary

minerals In geology and mineralogy, a mineral or mineral species is, broadly speaking, a solid chemical compound with a fairly well-defined chemical composition and a specific crystal structure that occurs naturally in pure form.John P. Rafferty, ed. (2 ...

, such as calcium or magnesium which are secreted into feces leading to loss of both fatty acids (energy) and calcium. These complexes, also known as fatty acids soaps, are insoluble and therefore indigestible and positively related to stool hardness.

Efficacy of SN2 Palmitate in infants

SN2 Palmitate and bone

Litmanovitz et al. applied the bone

speed of sound The speed of sound is the distance travelled per unit of time by a sound wave as it propagates through an elastic medium. At , the speed of sound in air is about , or one kilometre in or one mile in . It depends strongly on temperature as w ...

(SOS) ultrasound technology in a randomized, controlled, double-blind clinical study of bone parameters in term infants and showed that infants fed formula containing sn-2 Palmitate (INFAT®) had higher bone SOS compared to infants fed formula with standard vegetable oil blends at age of 12 weeks.Litmanovitz, I., et al., High Beta-palmitate formula and bone strength in term infants: a randomized, double-blind, controlled trial. Calcif Tissue Int. 92(1): p. 35-41. The bone SOS measures for infants fed the sn-2 Palmitate formula were also comparable to those of the group of breast-fed infants

SN2 Palmitate and Intestinal health

The intestinal

microflora Microbiota are the range of microorganisms that may be commensal, symbiotic, or pathogenic found in and on all multicellular organisms, including plants. Microbiota include bacteria, archaea, protists, fungi, and viruses, and have been found to ...

is an essential “organ” which serves numerous important functions, including protection against pathogens and modulation of inflammatory and

immune responses An immune response is a reaction which occurs within an organism for the purpose of defending against foreign invaders. These invaders include a wide variety of different microorganisms including viruses, bacteria, parasites, and fungi which could ...

, provision of metabolic intermediates and some vitamins, and regulation of intestinal epithelial proliferation and intestinal maturation. Yaron et al. showed that infants fed formula containing sn-2 Palmitate had higher numbers of

Lactobacilli The ''Lactobacillaceae'' are a family of lactic acid bacteria. It is the only family in the lactic acid bacteria which includes homofermentative and heterofermentative organisms; in the ''Lactobacillaceae,'' the pathway used for hexose fermentati ...

and

Bifidobacteria ''Bifidobacterium'' is a genus of gram-positive, nonmotile, often branched anaerobic bacteria. They are ubiquitous inhabitants of the gastrointestinal tract though strains have been isolated from the vagina and mouth ('' B. dentium'') of mamma ...

after 6 weeks of feeding than infants fed a control formula with standard vegetable oils.Yaron, S., et al., Effect of high beta-palmitate content in infant formula on the intestinal microbiota of term infants. J Pediatr Gastroenterol Nutr. 56(4): p. 376-81. Another recent experimental study published by Lu et al. has used the

MUC2 Mucin 2, oligomeric mucus gel-forming, also known as MUC2, is a protein that in humans is encoded by the ''MUC2'' gene. Function This gene encodes a member of the mucin protein family. The protein encoded by this gene, also called mucin 2, is sec ...

deficient mice to address the possible role of milk palmitic acid content and positioning in triglycerides on intestinal inflammation.

SN2 Palmitate and Infant behavior

"Stereo-specific positioning of fatty acids in human milk triglycerides involves preferential positioning of the saturated fatty acid palmitic acid (16:0) at the sn-2 position, rather than at the sn-1,3 positions, as is typical of human tissue and plasma lipids, and vegetable oils common in human diets." Early infant crying is considered to reflect basic, instinctive responses governed by neurochemical mechanisms similar to those that control feeding and drinking (i.e., spontaneous behaviors). Term infants fed formula with sn-2 Palmitate for the 12 weeks after birth demonstrated lower crying duration during the day and night compared to infants fed a standard vegetable oil

References

{{reflist Fatty acid esters Palmitate esters