Olle Hernell

Human Milk K-casein and Inhibition of Helicobacter pylori Adhesion to Human Gastric Mucosa

Summary: Readily digested caseins, which account for almost half of the protein content in human milk, are important as nutritional protein for breast-fed infants. It has also been advocated that part of the antimicrobial activity of human milk resides in the caseins, most likely the glycosylated K-casein. To explore this possibility, we purified K-casein from human milk to homogeneity by a two-step size-exclusion chromatography procedure. Purified human K-casein, in contrast to K-casein purified from bovine milk, effectively inhibited the cell lineage-specific adhesion of fluoroisothiocyanate-labeled Helicobacter pylori to human gastric surface mucous cells. The inhibitory activity was abolished by metaperiodate oxidation and considerably reduced by preincubation with α-L- fucosidase but not with α-N-acetylneuraminidase or endo-β-galactosidase. These results strongly support the view that fucose containing carbohydrate moieties of human K-casein are important for inhibition of H. pylori adhesion and, thus, infection. They also suggest that breastfeeding may protect from infection by H. pylori during early life and that species-specific glycosylation patterns, as illustrated by human and bovine K-casein, partly determine both the narrow host spectrum of this human gastric pathogen and the capacity to resist infection.

Total energy expenditure and physical activity level in healthy young Swedish children 9 or 14 months of age

Objectives: To measure total energy expenditure (TEE) and total body water (TBW) in healthy Swedish children 9 or 14 months of age. To compare their TEE with current recommendations for energy intake. To define their body composition and relate this to energy expenditure.Design: Children were investigated at 9 or 14 months. The following variables were measured: TEE and TBW (by the doubly labelled water method), weight and length. Total body fat (TBF), sleeping metabolic rate, activity energy expenditure and physical activity level (PAL) were calculated.Subjects: Thirty infants 9 months of age and 29 children 14 months of age.Results: TEE was 323±38, 322±29, 313±23 and 331±28 kJ/kg/day in 9-month-old girls, 9-month-old boys, 14-month-old girls and 14-month-old boys, respectively. At 9 months of age girls and boys contained 29.6±4.8 and 29.7±4.5% TBF, respectively. At 14 months the corresponding figures were 29.1±4.3 and 28.2±4.3%. There was a significant negative relationship between PAL and %TBF (r=−0.81, P<0.001, n=59).Conclusions: Measured TEE plus calculated energy cost of growth confirm previous estimates that the physiological energy requirements of children 9 and 14 months of age are 15–20% lower than current recommendations for energy intake. One possible interpretation of the relationship between PAL and %TBF is that children with a high TBF content are less physically active than children with less TBF. However, this relationship needs further studies.