Dietary Fructose Reduces Circulating Insulin and Leptin, Attenuates Postprandial Suppression of Ghrelin, and Increases Triglycerides in Women

Abstract

Previous studies indicate that leptin secretion is regulated by insulin-mediated glucose metabolism. Because fructose, unlike glucose, does not stimulate insulin secretion, we hypothesized that meals high in fructose would result in lower leptin concentrations than meals containing the same amount of glucose. Blood samples were collected every 30 -60 min for 24 h from 12 normal-weight women on 2 randomized days during which the subjects consumed three meals containing 55, 30, and 15% of total kilocalories as carbohydrate, fat, and protein, respectively, with 30% of kilocalories as either a fructose-sweetened [high fructose (HFr)] or glucose-sweetened [high glucose (HGl)] beverage. Meals were isocaloric in the two treatments. Postprandial glycemic excursions were reduced by 66 ؎ 12%, and insulin responses were 65 ؎ 5% lower (both P < 0.001) during HFr consumption. The area under the curve for leptin during the first 12 h (؊33 ؎ 7%; P < 0.005), the entire 24 h (؊21 ؎ 8%; P < 0.02), and the diurnal amplitude (peak ؊ nadir) (24 ؎ 6%; P < 0.0025) were reduced on the HFr day compared with the HGl day. In addition, circulating levels of the orexigenic gastroenteric hormone, ghrelin, were suppressed by approximately 30% 1-2 h after ingestion of each HGl meal (P < 0.01), but postprandial suppression of ghrelin was significantly less pronounced after HFr meals (P < 0.05 vs. HGl). Consumption of HFr meals produced a rapid and prolonged elevation of plasma triglycerides compared with the HGl day (P < 0.005). Because insulin and leptin, and possibly ghrelin, function as key signals to the central nervous system in the long-term regulation of energy balance, decreases of circulating insulin and leptin and increased ghrelin concentrations, as demonstrated in this study, could lead to increased caloric intake and ultimately contribute to weight gain and obesity during chronic consumption of diets high in

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 fact, fructose seems to be very poor in stimulating insulin secretion (Bray et al, 2004). In addition to lowered postprandial serum insulin concentration, fructose also seems to attenuate postprandial serum leptin and ghrelin concentrations (Teff et al, 2004). As serum insulin and leptin concentrations have a key role in the regulation of eating, this may explain why there were no differences in the feelings of hunger, satiety, fullness and desire to eat in this study.…”

“…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).…”

Anticipatory physiological regulation in feeding biology: Cephalic phase responses

“…This supports the hypothesis that a lower insulin response leads to increased food intake over the long term. However, unrestrained eaters showed no differences in either hunger scores or fat intake the following day (Teff et al, 2004), so there is variability among people in this response. Quite likely there are additional endocrine and metabolic signals that influence the response.…”

“…Insulin also has longer term, central effects on appetite that act to limit food intake (Porte et al, 2005). It is interesting that ingesting fructose produces a much less robust insulin response than does an isocaloric dose of glucose (Teff et al, 2004). Of course the absorption of fructose into cells is not insulin dependent, relying on GLUT5 as opposed to GLUT4 transporters.…”

Fructose and metabolic diseases: New findings, new questions

“…In patients with type 2 diabetes, the glucose and insulin responses to administration of 35 g of sucrose or HFCS were quite similar [50]. Based on the fact that fructose inhibits less ghrelin and increases less leptin than glucose [51], one may have hypothesized that HFCS would have a different effect than sucrose on these hormones and hence would have a lesser satiating effect. It was however documented that it was not the case, and that HFCS and sucrose produced similar leptin increases and ghrelin suppression in healthy female volunteers [52].…”