title: Long-term intake of saccharin decreases post-absortive energy expenditure at rest and is associated to greater weight gain relative to sucrose in wistar rats.
abstract: BACKGROUND
  Non-nutritive sweeteners (NNS) have been associated with increased prevalence of obesity. In previous studies, we demonstrated that saccharin could induce an increase in weight gain either when compared to sucrose or to a non-sweetened control at a similar total caloric intake. These data raised the hypothesis that reduced energy expenditure (EE) could be a potential mechanism explaining greater weight gain with saccharin use in rats. The aim of the present study was to compare long-term energy expenditure at rest between rats using saccharin or sucrose and correlate it with weight gain. ﻿.
  
  
  METHODS
  In the present study, we examine the potential impact of saccharin compared to sucrose in the EE of Wistar rats. In a controlled experiment of 17 weeks, 24 Wistar rats were divided into 2 groups: saccharin-sweetened yogurt (SAC) or sucrose-sweetened yogurt (SUC), plus a free chow diet. Only rats that consumed at least 70% of the offered yogurt were included. EE (kcal/day) was determined at rest through open circuit indirect calorimetry system in the early post-absorptive period with determinations of both VO2consumption and CO2production. Measurements were evaluated at baseline, 5 and 12 weeks of dietary intervention. Weight gain, caloric intake (from yogurt, from chow and total) were determined weekly.
  
  
  RESULTS
  Body weight and EE were similar between groups at baseline: (p= .35) and (p= .67) respectively. At the end of the study, SAC increased total weight gain significantly more in relation to SUC (p= .03). Cumulative total caloric intake (yogurt plus chow) was similar between groups during the whole period (p= .54). At 12 weeks, the EE was smaller in SAC compared to SUC (p= .009). Considering both groups, there was a strong negative correlation between total weight gain and change in EE observed [r(20) = -.61,p= .003]. However, when analyzing the groups separately we found that SUC maintained this inverse correlation [r(8) = -.68,p= .03], while SAC did not [r(10) = -.33,p= .29].
  
  
  CONCLUSIONS
  These data support the hypothesis that long-term use of saccharin may blunt post-absorptive EE at rest in Wistar rats, which is related to weight gain. On the other hand, long-term sucrose intake can increase energy expenditure in rats. This effect combined can explain, at least partially, the weight gain increases associated to saccharin in relation to sucrose in these animals.
authors.affiliation: Programa de Pós-Graduação em Medicina: Ciências Médicas, Universidade Federal do Rio Grande do Sul-UFRGS, Rua Ramiro Barcelos, n° 2400, CEP 90035-003, Bairro Rio Branco, Porto Alegre, RS Brazil.
authors.forename: Denise Entrudo
authors.initials: DE
authors.lastname: Pinto
authors.affiliation: Programa de Pós-Graduação em Medicina: Ciências Médicas, Universidade Federal do Rio Grande do Sul-UFRGS, Rua Ramiro Barcelos, n° 2400, CEP 90035-003, Bairro Rio Branco, Porto Alegre, RS Brazil.
authors.forename: Kelly Carraro
authors.initials: KC
authors.lastname: Foletto
authors.affiliation: Laboratório de Fisiologia Experimental, Universidade Federal de Ciências da Saúde de Porto Alegre-UFCSPA, Rua Sarmento Leite, n° 245, CEP 90050-170, Bairro Centro, Porto Alegre, RS Brazil.
authors.forename: Ramiro Barcos
authors.initials: RB
authors.lastname: Nunes
authors.affiliation: Laboratório de Fisiologia Experimental, Universidade Federal de Ciências da Saúde de Porto Alegre-UFCSPA, Rua Sarmento Leite, n° 245, CEP 90050-170, Bairro Centro, Porto Alegre, RS Brazil.
authors.forename: Pedro Dal
authors.initials: PD
authors.lastname: Lago
authors.affiliation: Programa de Pós-Graduação em Medicina: Ciências Médicas, Universidade Federal do Rio Grande do Sul-UFRGS, Rua Ramiro Barcelos, n° 2400, CEP 90035-003, Bairro Rio Branco, Porto Alegre, RS Brazil.|Serviço de Medicina Interna, Hospital de Clínicas de Porto Alegre-Universidade Federal do Rio Grande do Sul, Rua Ramiro Barcelos, n° 2350, CEP 90035-903, Bairro Rio Branco, Porto Alegre, RS Brazil.
authors.forename: Marcello Casaccia
authors.initials: MC
authors.lastname: Bertoluci
keywords: Energy expenditure; Non-nutritive sweeteners; Oxygen consumption; Saccharin; Sucrose; Weight gain