PROTEIN-REQUIREMENTS OF MARGINALLY NOURISHED LACTATING WOMEN

Few experimental data regarding protein requirements of lactating wome n are available. This study was designed to determine the protein requ irement of seven healthy lactating women from a poor Mexican community who were 2-6 mo postpartum and had a mean body mass index of 21.8 +/- 2 kg/m(2). Nitrogen balances were performed at intakes of 0.8, 1.0, a nd 1.2 g . kg body wt(-1) . d(-1) of a mixed protein diet (70% derived from vegetable sources). A balance at 1.2 g . kg body wt(-1) . d(-1) of a high-quality mixed protein (80% from animal sources) was the refe rence. The experimental diets were designed to resemble the habitual d iet in terms of energy and macronutrients. The balance responses to ni trogen intake were - 35.5 +/- 12.6, - 10.5 +/- 14.8, and 7.8 +/- 19.2 mg N . kg body wt(-l) . d(-1), respectively. Equilibrium balance was a ttained at 178.9 +/- 25.8 mg N (1.1 g protein . kg body wt(-l) . d(-1) ), close to current recommended dietary allowances, albeit the dietary protein was mostly from vegetable sources.