Protein and Breast Milk
I think it is reasonable to assume that early hominin infants, like those of modern hunter-gatherers, would have depended on breast milk for sustenance during the critical first year following birth, and very likely for some considerable time beyond (Kennedy 2005; Sellen 2007). If high-quality protein was the “nutrient among nutrients” underwriting the astounding encephalization that we see in our Plio-Pleistocene ancestors, one would expect that importance to be resoundingly reflected in the composition of human breast milk. This is patently not the case, however (Robson 2004; Sellen 2007). In fact, human breast milk is one the lowest-protein milks in the mammalian world, right along with the milks of the great apes and many other primates (Amen-Ra 2007:1149; Bell 1928; Ben Shaul 1962; Darragh and Moughan 1998; Davis et al. 1994; Goedhart and Bindels 1994; Hambraeus 1994; Hinde 1986; Jelliffe and Jelliffe 1978; Jenness 1985, 1986; Jenness and Sloan 1970; Lönnerdal 2003; Malacarne et al. 2002; McCullagh and Widdowson 1970; Milligan 2007; Milligan and Bazinet 2008; Milligan and Oftedal 2007; Milligan et al. 2008; Oftedal 1981, 1984; Oftedal and Iverson 1995; Patiño and Borda 1997; Power 2006; Power et al. 2002; Schmidt-Nielsen 1986; Siewert 2003:173). For example, according to Davis et al. (1994:1126):
Unable to display preview. Download preview PDF.