Energetic consequences of mild Giardia intestinalis infestation in Mexican children.

This study explored the effects of mild infestation with Giardia on energy intake and expenditure at rest and in activity in an urban Mexican population. Ten boys aged 6-10 y living in low-income sectors in northwest Mexico who had Giardia infestation were recruited. Energy intake, basal metabolic rate (BMR), and total free-living expenditure (TEE) measured by the doubly labeled water method were determined for 7 d during both infestation and after treatment. There was no significant difference in recorded energy intake between the two periods (7.76 and 7.70 MJ/d; P = 0.847). BMR showed no significant change in response to treatment; values were 4.79 and 4.86 MJ/d (P = 0.03). The mean TEE increased by almost 1 MJ/d in the Giardia-free period. This increase was observed in 8 of the 10 subjects; however, the overall change was not statistically significant (P = 0.08).

Basal metabolic rate and body fatness of adult men in northern Mexico.

To investigate the possibility that overprediction of basal metabolic rate (BMR) of tropical populations is related to differences in fatness between tropical and temperate populations, 32 Mexican men aged 18-40 years underwent measurements of BMR and body fat content. The men were divided into four body mass index (BMI) groups (< 20, 20-25, 25-30 and 30-40). The mean weight was 78 (range 52-119) kg and the mean height was 1.75 (range 1.61-1.89) m. BMR was measured in the subjects after an overnight stay in a residential unit by a Deltatrac ventilated hood indirect calorimetry system. Body fat content was determined by 2H2O dilution. The relationship between BMR and body weight was analysed by linear regression and the equations derived were compared to the values predicted using the FAO/WHO/UNU (1985) equations. The FAO/WHO/UNU equations overestimated measured BMR by 9.8%, 9.6%, 7.8% and 5.5% in the four groups. The overall difference was 8.2%, which was statistically significant (P < 0.001). The intercepts of the two equations were significantly different (P < 0.001) by 532 kJ/day, but there was no significant difference between the slopes of the two regression equations. There was no significant difference between BMR/kg fat-free mass in the four BMI groups. The results therefore do not support the possibility that the overprediction of BMR in tropical populations by international prediction equations based on body weight is accounted for by differences in fatness between tropical and temperate populations.

[Effect of ripening and drying on pro-vitamin A carotenoid content in pepper (Capsicum annuum var. Anaheim)]. / Efecto de la maduración y el secado en el contenido de carotenoides pro-vitamina A en chile (Capsicum annuum var. Anaheim).

The content of the principal carotenes with biological activity (alpha-, beta, gamma-carotene and beta-criptoxantine) in green pepper (Capsicum annuum var. Anaheim) was determined in order to investigate the vitamin A content during the traditional process of ripening and drying. The analytical technique used was high pressure liquid chromatography (HPLC) with a Novapack C18 column and acetonitrile/methanol/tetrahydrofuran (58V:35V:7V) as a mobile phase. The results showed differences in vitamin A activity of 7.2 +/- 0.8, 51.1 +/- 2.4 and 55.3 +/- 1.2 micrograms of RE/g dry matter for immature, mature and dry pepper fruit respectively (p < 0.05). Approximately 95% of total activity was due to beta-carotene being synthesized faster than the other carotenes under study during the ripening process. Total vitamin A activity reached its highest value at 14 days after harvest (2738.8 +/- 128.6 micrograms RE/100 g of edible portion), with a decrease in activity with time.