Fructose, weight gain, and the insulin resistance syndrome,,

Abstract

This review explores whether fructose consumption might be a contributing factor to the development of obesity and the accompanying metabolic abnormalities observed in the insulin resistance syndrome. The per capita disappearance data for fructose from the combined consumption of sucrose and high-fructose corn syrup have increased by 26%, from 64 g/d in 1970 to 81 g/d in 1997. Both plasma insulin and leptin act in the central nervous system in the long-term regulation of energy homeostasis. Because fructose does not stimulate insulin secretion from pancreatic beta cells, the consumption of foods and beverages containing fructose produces smaller postprandial insulin excursions than does consumption of glucose-containing carbohydrate. Because leptin production is regulated by insulin responses to meals, fructose consumption also reduces circulating leptin concentrations. The combined effects of lowered circulating leptin and insulin in individuals who consume diets that are high in dietary fructose could therefore increase the likelihood of weight gain and its associated metabolic sequelae. In addition, fructose, compared with glucose, is preferentially metabolized to lipid in the liver. Fructose consumption induces insulin resistance, impaired glucose tolerance, hyperinsulinemia, hypertriacylglycerolemia, and hypertension in animal models. The data in humans are less clear. Although there are existing data on the metabolic and endocrine effects of dietary fructose that suggest that increased consumption of fructose may be detrimental in terms of body weight and adiposity and the metabolic indexes associated with the insulin resistance syndrome, much more research is needed to fully understand the metabolic effect of dietary fructose in humans.

Impact of sugar beet pectin and polydextrose on fasting and postprandial glycemia and fasting concentrations of serum total and lipoprotein lipids in middle-aged subjects with abnormal glucose metabolism

“…In animal studies, increased intake of fructose has been found to cause insulin resistance or worsen existing insulin resistance (Blakely et al, 1981). In humans, the metabolic effect of increased fructose intake is not clear (Elliott et al, 2002). Hallfrisch et al (1983) have found that a diet containing 15% of energy as fructose has detrimental effects on glucose metabolism both in normal and hyperinsulinemic men.…”

“…A confounding factor in the present study might have been the relatively high fructose intake per day. High fructose intake has been reported to lower circulating insulin concentrations (Elliott et al, 2002;Teff et al, 2004). In fact, fructose seems to be very poor in stimulating insulin secretion (Bray et al, 2004).…”

Coenzyme Q10 supplementation lowers hepatic oxidative stress and inflammation associated with diet-induced obesity in mice

“…We did not found any inducement of the expression of key enzymes involved in lipogenesis since HFF treatment did not increased FAS. However, the observed increase in the expression of DGAT2 -an enzyme which catalyses the final step of TG synthesis-could also be implicated in hepatic lipid accumulation, together with the fact that fructose is an excellent lipogenic substrate [12,41]. HF plus fructose diet induces a shift from microvesicular towards macrovesicular lipid storage as analysed by histology.…”

“…Those metabolic disturbances have been associated with i.e. hypertriglyceridemia and steatosis, linked to an increased de novo lipogenesis [12,13], modification of the activity of enzymes involved in hepatic glucose metabolism and glucose uptake pathways [14,15] and activation of NADPH oxidase pathway [11].…”

Dietary determinants of subclinical inflammation, dyslipidemia and components of the metabolic syndrome in overweight children: a review

“…131,132 In western Europe, unlike in the United States, high fructose corn syrup is not a commonly used sweetener. Thus, the origin of most free dietary fructose is fruits and vegetables and overall fructose intakes are lower than in the United States.…”