Monounsaturated Fat–Rich Diet Prevents Central Body Fat Distribution and Decreases Postprandial Adiponectin Expression Induced by a Carbohydrate-Rich Diet in Insulin-Resistant Subjects

Abstract

OBJECTIVE -Central obesity is associated with insulin resistance through factors that are not fully understood. We studied the effects of three different isocaloric diets on body fat distribution, insulin sensitivity, and peripheral adiponectin gene expression. RESEARCH DESIGN AND METHODS-Eleven volunteers, offspring of obese type 2 diabetic patients with abdominal fat deposition, were studied. These subjects were considered insulin resistant as indicated by Matsuda index values Ͻ4 after an oral glucose tolerance test, and they maintained A1C Ͻ6.5% without therapeutic intervention. All subjects underwent three dietary periods of 28 days each in a crossover design: 1) diet enriched in saturated fat (SAT), 2) diet rich in monounsaturated fat (MUFA) (Mediterranean diet), and 3) diet rich in carbohydrates (CHOs).RESULTS -Weight, body composition, and resting energy expenditure remained unchanged during the three sequential dietary periods. Using dual-energy X-ray absorptiometry we observed that when patients were fed a CHO-enriched diet, their fat mass was redistributed toward the abdominal depot, whereas periphery fat accumulation decreased compared with isocaloric MUFA-rich and high-SAT diets (ANOVA P Ͻ 0.05). Changes in fat deposition were associated with decreased postprandial mRNA adiponectin levels in peripheral adipose tissue and lower insulin sensitivity index values from a frequently sampled insulin-assisted intravenous glucose tolerance test in patients fed a CHO-rich diet compared with a MUFA-rich diet (ANOVA P Ͻ 0.05).CONCLUSIONS -An isocaloric MUFA-rich diet prevents central fat redistribution and the postprandial decrease in peripheral adiponectin gene expression and insulin resistance induced by a CHO-rich diet in insulin-resistant subjects. Diabetes Care 30:1717-1723, 2007A positive energy balance, which leads to obesity, is associated with insulin resistance and an increased risk of type 2 diabetes. According to our studies in rodents, adipose tissue expandability seems to be a key determinant linking obesity and its associated complications (1,2). Expansion of the intra-abdominal depot has been associated with increased insulin resistance, as well as with an increased incidence of fatty liver and ␤-cell failure (3,4).The factors that regulate body fat distribution are not well understood. We hypothesize that the specific macronutrient composition of the diet may be an important environmental factor that controls nutrient partitioning to specific adipose tissue depots (5). It is now well established that adipose tissue is not simply an energy storage organ but is, in fact, the "largest" endocrine gland controlling energy homeostasis (6). It is conceivable that specific diet composition may directly influence the molecular events that govern gene expression in adipocytes (7), adipokine production, and adipocyte lipid and glucose metabolism (8).Adiponectin adipocyte-secreted adipokine plays an important role in modulating insulin sensitivity and concentrations of circulating plasma glucose and noneste...

Acute Effects of Dietary Fat on Inflammatory Markers and Gene Expression in First-Degree Relatives of Type 2 Diabetes Patients

“…Several previous studies have shown a decrease in leptin in response to mixed and high-fat meals in healthy individuals [12], but not in subjects with T2D [37]. Our results contrast to a longer-term study where lower plasma leptin responses to a test meal were observed in 11 REL after 3 weeks on a MUFA-rich diet versus a SFArich diet [38]. While others found decreased baseline and insulin-stimulated LEP expression in the main site of leptin synthesis (adipose tissue) in male REL [23], we only found differences in muscle.…”

Long-term effects of increased dietary polyunsaturated fat from walnuts on metabolic parameters in type II diabetes

“…Animal model research suggests that dietary PUFA may protect against obesity through mechanisms linked to fat deposition and hormonal regulatory systems (Wang et al, 2002). Human studies show that energy deficits alone do not change body fat distribution (Redman et al, 2007), but this is not the case with fat modification (Summers et al, 2002;Panigiagua et al, 2007). Dietary fat can influence the expression of genes associated with body weight regulatory systems (Summers et al, 2002;Wang et al, 2002).…”

Regular intake of high-oleic peanuts improves fat oxidation and body composition in overweight/obese men pursuing a energy-restricted diet

“…Moreover, after following a MUFA enriched-diet with a mix of olive oil and nuts for 4-weeks, a significant reduction in body weight and fatness was observed in overweight and obese man (38). Furthermore, although an olive oilenriched diet did not change body weight and fatness of the obese individuals, it prevented central body fat distribution leading to an improvement in insulin sensitivity (39). When two MUFA-enriched diets within a 6-months weight reduction program were compared (olive oil versus rapeseed), no significant difference between then was verified, yet, both were effective in reducing body weight, fat mass, and waist circumference with an increment in lean mass (40).…”