The association between sucrose and obesity has been extensively investigated and compelling evidence suggests that even small intakes of sucrose can significantly increase adipose tissue accumulation. Soft drinks that are sweetened with sugar are particularly harmful to health because they can supply a large quantity of fructose to a typical diet. However, equivalent isocaloric drinks devoid of fructose do not display the same detrimental effects. Fat accumulation in the skeletal muscle is thought to occur through consumption of high intakes of fructose. These fat droplets are thought to interfere with normal fatty acid signalling pathways and lead to insulin resistance. Fructose is also known to cause fat accumulation in the liver, with the eventual development of non-alcohol fatty liver disease. Because fructose is a component of the disaccharide sucrose, there is interest in the effects of sucrose on both muscle and liver fat accumulation.
For example, researchers1 have compared the effects of sucrose sweetened soft drinks with isocaloric skimmed milk, water or an artificially sweetened diet soft drink, on the ectopic fat disposition in overweight subjects. The sucrose sweetened and diet soft drinks were in the form of a cola drink, and all subjects consumed 1L/d for 6 months after being randomly assigned to their groups. The intramyocellular and intrahepatic fat accumulation was measured using 1H-magnetic resonance spectroscopy. The subjects in the sucrose sweetened soft drink group had significantly higher muscle and liver fat accumulation after 6 months compared to their baseline measurements than the other groups. Visceral fat, plasma triglycerides and total cholesterol was also elevated significantly in the sucrose soft drink group, compared to the other groups. Compared to the sucrose soft drink group, milk and diet cola consumption caused a 10-15% reduction in systolic blood pressure.
These results support previous findings, and show that as little as 6 month consumption of 1L/d of sucrose sweetened soft drink can cause visceral, muscular and hepatic fat accumulation, as well as detrimental changes to blood lipids. The increase in visceral fat following sucrose soft drink consumption, in pair-wise comparison, was +31% compared to milk, +23% compared to the diet soft drink and +24% compared with water. The detrimental effect on plasma lipoproteins were likely caused by the hepatic fat accumulation, as has been demonstrated previously. In addition, the muscle fat accumulation supports the role of fructose in insulin resistance and the development of the metabolic syndrome. Interestingly the total body weight did not differ between the groups. This may have been an artefact of the small sample size or suggest that the subjects who gained fat mass also lost lean tissue.
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