[Lactation performance in rural women with low bioavailability of nutrients from the regular diet].

Metabolizable energy (ME) and apparent nitrogen, fat and energy bioavailability from the habitual diet were measured in a group of lactating women from a Mexican rural community. Food intake was estimated in 40 women, age 24 +/- 3 y 3-5 m postpartum, body weight 48.7 +/- 5.4 kg and height 148 +/- 5 cm. Habitual diet was predominantly from vegetable sources based on maize (tortillas), beans, tomato, onion and chili. The daily intake was: 2224 +/- 336 kcal energy, 47.8 +/- 7.0 g protein, 44.7 +/- 11.3 fat and 408 +/- 70 g carbohydrates. Ten women were studied in balance conditions and consuming a controlled diet similar to their habitual diet. ME and apparent energy, nitrogen and fat availability were measured by metabolic balance. Milk output was measured by the test-weighing infant method and milk samples representative of 24-h were obtained for chemical analysis. Apparent digestibility of energy was 87 +/- 1.4%, from nitrogen 68.4 +/- 3.1% and 65.8 +/- 3.7 from fat. Measured ME was 1940 kcal/day. Metabolizable energy from the habitual diet by the marginally nourished lactating group was lower than the energy recommended allowance during lactation. Macronutrient's availability from the habitual diet was similar to that found in population with intake of predominantly vegetable diets and high dietary fiber content.