Journal Name:
Obesity
Article Title:
Postprandial Cytokine Concentrations and Meal Composition in Obese and Lean Women.
Date Written:
2008
Volume:
16
Number:
NA
Page:
2046
Author(s):
Manning, P.J.; Sutherland, W.H.; McGrath, M.M.; de Jong, S.A; Walker, R.J.; Williams, M.J.
Article:
Dietary saturated fat impairs insulin action and glucose metabolism (9), whereas dietary unsaturated fats have the opposite effect (10). Saturated fat induces inflammation with increased expression and/or secretion of IL-6 or TNF-α in cultured adipocytes, muscle cells, and adipose tissue macrophages. ALA has anti-inflammatory activity and inhibits expression and secretion of IL-6 from cultured human monocytes. There is evidence that ingestion of fatty meals may acutely modulate circulating concentrations of adipokines and insulin resistance. In obese subjects, plasma IL-6 concentrations increase during 2–4 h after a liquid meal rich in saturated and monounsaturated fats. However, the effect of obesity and the type of fat in the meal on postprandial adipokine concentrations is not yet clearly defined. There is evidence that intake of carbohydrate and fiber also modulates inflammation. A meal high in both carbohydrate and fiber decreases while a meal high in carbohydrate and low in fiber does not alter plasma concentrations of the proinflammatory cytokine IL-18 appreciably. Few studies have investigated the acute effect of meals rich in different types of fatty acids and rich in low glycemic index (GI) high fiber cereals on postprandial adipokine levels in obese individuals.
The aim of this study was to compare the acute effect of (i) meals rich in saturated fat, oleic acid, and alpha-linolenic acid and (ii) meals rich in starch and fiber on markers of inflammation and oxidative stress in obese and lean women. In a crossover study, 15 abdominally obese women (age, 54 +/- 9 years; BMI, 37.3 +/- 5.5 kg/m2) and 14 lean women (age, 53 +/- 10 years; BMI, 22.9 +/- 1.9 kg/m2) consumed meals rich in cream (CR), olive oil (OL), canola oil (CAN), potato (POT), and All-Bran (BRAN) in random order. Blood samples were collected before and up to 6 h after the meals and plasma interleukin-6 (IL-6), IL-8, tumor necrosis factor-alpha (TNF-alpha), lipid peroxides (LPOs), free-fatty acids (FFAs), insulin, glucose, and cortisol were measured.
Plasma IL-6 decreased significantly 1 h after the meals then increased significantly above baseline at 4 h and 6 h in obese women and at 6 h in lean women. The incremental area under the curve (iAUC) for IL-6 was significantly higher in obese compared with lean women and was significantly lower following the high fiber BRAN meal compared with a POT meal. Waist circumference and cortisol AUC were significant determinants of the magnitude of 6 h changes in plasma IL-6 after the meals.
A substantial increase in plasma IL-6 concentrations during 4 h after a liquid meal rich in saturated and monounsaturated fats and a prolonged postprandial inflammatory response after a high-fat, high-carbohydrate meal in obese individuals was noted. Here obesity enhances the postprandial increase in plasma IL-6 in women irrespective of the type or content of fat in the meal and that meals rich in fiber attenuate this increase in IL-6. Further, the magnitude of the postprandial increase in plasma IL-6 was similar after meals rich in saturated fatty acids, oleic acid, and α-linolenic acid.
These findings suggest that the postprandial response of plasma IL-6 concentrations may be influenced by the type of carbohydrate in the meal, central adiposity, and circulating cortisol concentrations in women. The authors suggest that further studies are required to clarify the physiological impact of exaggerated postprandial increases in plasma IL-6 in obese women.
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