Whole cow's milk: why, what and when?

Abstract

There are differences between at what age industrialized countries recommend that cow's milk can be introduced to infants. Most countries recommend waiting until 12 months of age, but according to recommendations from some countries (e.g. Canada, Sweden and Denmark) cow's milk can be introduced from 9 or 10 months. The main reason for delaying introduction is to prevent iron deficiency as cow's milk is a poor iron source. In one study mainly milk intake above 500 ml/day caused iron deficiency. Cow's milk has a very low content of linoleic acid (LA), but a more favorable LA/alpha-linolenic ratio, which is likely to be the reason why red blood cell docosahexaenoic acid (DHA) levels seem to be more favorable in infants drinking cow's milk compared to infants drinking infant formula that is not supplemented with DHA. It has been suggested that cow's milk intake can affect the later risk of obesity, blood pressure and linear growth, but the evidence is not convincing. There are also considerable differences in recommendations on at what age cow's milk with reduced fat intake can be introduced. The main consideration is that low-fat milk might limit energy intake and thereby growth, but the potential effects on development of early obesity should also be considered. Recommendations about the age for introduction of cow's milk should take into consideration traditions and feeding patterns in the population, especially the intake of iron and long-chain polyunsaturated fatty acids and should also give recommendations on the volume of milk.