A randomized-controlled clinical trial of high fructose diets from either Robinia honey or free fructose and glucose in healthy normal weight males

Abstract

Summary Background A high fructose diet causes hypertriglyceridemia and hepatic insulin resistance in humans, but it remains unknown whether refined sugars exert different effects than naturally occurring sugars present in honey. Aim To assess the metabolic effects of replacing 25% total energy from starch with honey or a pure fructose:glucose mixture. Methods Eight healthy male were studied while consuming a controlled weight-maintenance, low fructose diet (control, CTRL), or a isocaloric diet in which 25% complex carbohydrates were substituted with either honey (HON; fructose:glucose ratio = 1.7) or fructose:glucose mixture (FG) for eight days. On day 7, participants ingested a breakfast at 7:30 am, and a lunch at 12:00 pm, both corresponding to their ongoing experimental diet. On day 8, they had an oral glucose tolerance test (OGT) with dual glucose isotopes (oral 13C-, iv 6,6 2H2-glucose). Results On day 7, their postprandial glucose and insulin concentrations were lower with HON and FG than with CTRL but their plasma triglyceride concentrations and net substrate oxidation showed no difference. On day 8, there was no significant difference in glucose tolerance or postprandial suppression of glucose production between HON, FG and CTRL. Conclusions Consuming a diet containing 25% energy as honey or pure fructose–glucose slightly decreases postprandial blood glucose, but does not significantly increase postprandial plasma triglyceride, nor impair hepatic insulin sensitivity compared to an isocaloric starch diet.