The Codex Alimentarius Commission of the Food and Agriculture Organization of the United Nations (FAO) and the World Health Organization (WHO) develops food standards, guidelines and related texts for protecting consumer health and ensuring fair trade practices globally. The major part of the world's population lives in more than 160 countries that are members of the Codex Alimentarius. The Codex Standard on Infant Formula was adopted in 1981 based on scientific knowledge available in the 1970s and is currently being revised. As part of this process, the Codex Committee on Nutrition and Foods for Special Dietary Uses asked the ESPGHAN Committee on Nutrition to initiate a consultation process with the international scientific community to provide a proposal on nutrient levels in infant formulae, based on scientific analysis and taking into account existing scientific reports on the subject. ESPGHAN accepted the request and, in collaboration with its sister societies in the Federation of International Societies on Pediatric Gastroenterology, Hepatology and Nutrition, invited highly qualified experts in the area of infant nutrition to form an International Expert Group (IEG) to review the issues raised. The group arrived at recommendations on the compositional requirements for a global infant formula standard which are reported here.

The gradual introduction of gluten-containing foods into the diet of infants while they are still being breast-fed reduces the risk of celiac disease in early childhood and probably also during the subsequent childhood period.

MFGM supplementation to infant formula narrows the gap in cognitive development between breastfed and formula-fed infants. Between 2 and 6 mo of age, formula-fed term infants have the capacity to upregulate their ingested volumes when the energy density of formula is reduced from 66 to 60 kcal/100 mL.

The celiac disease prevalence of 29/1000 (3%)-with two thirds of cases undiagnosed before screening-is 3-fold higher than the usually suggested prevalence of 1%. When these 12-year-olds were infants, the prevailing feeding practice was to introduce gluten abruptly, often without ongoing breast-feeding, which might have contributed to this unexpectedly high prevalence.

Following the feeding of a triacylglycerol-rich meal to healthy adult human beings, duodenal contents were aspirated for ex vivo chemical and physical-chemical analyses. The aspirates were collected during established lipid digestion and absorption into a "cocktail" of chemical inhibitors that rapidly inhibited ex vivo lipolysis. Following ultracentrifugation, the lipids separated into a floating oil layer, several interfacial layers, a "clear" or turbid "subphase", and a precipitated "pellet". By chemical and phase analyses, the floating layer was composed of oil-in-water emulsion particles with cores of triacylglycerol (TG), diacylglycerols (DG), and cholesteryl esters (CE) emulsified with a surface coat of partially ionized fatty acids (FA), monoacylglycerols (MG), diacylphosphatidylcholine (PL), and bile salts (BS). The interfacial layers contained similar emulsion particles dispersed among excess emulsifier which adopted a lamellar liquid-crystalline structure. Precipitated pellets were composed principally of emulsifying lipids, with smaller amounts of crystalline calcium soaps and BS. Relative lipid compositions of all but three subphases fell within a two-phase region of the condensed ternary phase diagram (Staggers et al., 1990, companion paper) where saturated mixed micelles composed of BS, FA "acid-soaps", MG, PL, cholesterol (Ch), and traces of DG (and TG) coexisted with unilamellar liquid-crystalline vesicles composed of the same lipids. Attempts to achieve clean separation of vesicles from micelles by repeat ultracentrifugation failed. Compared with the structure and sizes of lipid particles in equilibrated model systems (Staggers et al., 1990), quasielastic light scattering (QLS) analysis revealed that ex vivo micellar sizes (mean hydrodynamic radii, Rh) were similar (less than or equal to 40 A), whereas unilamellar vesicle sizes (Rh = 200-600 A) were appreciably smaller. Two-component QLS analysis of the subphases showed that much larger proportions of lipids were solubilized by micelles than were dispersed as unilamellar vesicles. When followed as functions of time, vesicles frequently dissolved spontaneously into mixed micelles, indicating that, in the nonequilibrium in vivo conditions, the constituent micellar phase was often unsaturated with lipids. These results are consistent with the hypothesis that, during hydrolysis of emulsified DG and TG by luminal lipases, unilamellar vesicles originate in lamellar liquid crystals that form at emulsion-water interfaces in the upper small intestine. In a BS-replete environment, unilamellar vesicles probably represent the primary dispersed product phase of human fat digestion and facilitate the dissolution of lipolytic products into unsaturated mixed micelles.(ABSTRACT TRUNCATED AT 400 WORDS)