Nutrition in the second year of life. Effects of different milk compositions on dietary intakes, growth and metabolism

Abstract: In the diet for young children, whole cow´s milk is the major contributor of calories, protein and saturated fat, but it supplies little iron and polyunsaturated fat. Although several recommendations exist for the composition of formula, recommendations for the composition of milk for young children are lacking. We investigated if milk with modified fat-, protein-, and iron content aimed at young children could be advantageous to whole cow´s milk. Therefore, children were fed one of four different milk diets: standard fat cow´s milk; low fat cow´s milk or iron fortified, protein reduced cow´s milk with either 50% or 100% vegetable fat. From 12 to 18 months of age, dietary intakes, growth and indices of fat-, protein-, and iron metabolism were compared between the groups. We found similar energy intakes and growth in all groups despite differences in energy content in the milk used. Children given iron fortified, protein reduced milk with 50 or 100% vegetable fat had saturated fat intake around 12 % of energy; polyunsaturated fat intake around 6% of energy, both verified in plasma fatty acid contributions; recommended iron intake and protein intake closer to recommendations. Children fed low fat milk had fat intakes below 30% of energy. Further, children fed whole cow´s milk showed saturated fat intakes of around 19% of energy, signs of weaker development of iron stores and indices of protein metabolism indicating unnecessarily high protein intakes. The differences in intakes of polyunsaturated fat had no major effect on plasma long-chain polyunsaturated fatty acid contributions. We found that a reduction of saturated fat intake and recommended protein and iron intake is difficult to achieve without modifications in the fat, protein and iron compositions of whole cow´s milk. Therefore, we propose that a recommendation of fat quality composition and protein and iron content in milk for young children should be developed.