Dietary Glycemic Index, Glycemic Load, Cereal Fiber, and Plasma Adiponectin Concentration in Diabetic Men

Abstract

OBJECTIVE -Adiponectin may improve insulin sensitivity, reduce inflammation, and ameliorate glycemic control. However, few studies have evaluated dietary predictors of plasma adiponectin levels, especially among subjects with type 2 diabetes.RESEARCH DESIGN AND METHODS -To examine the associations of dietary glycemic load, glycemic index, and fibers with plasma adiponectin levels, we conducted a crosssectional analysis in 780 diabetic men from the Health Professionals' Follow-up Study. Dietary information was obtained in 1986, 1990, and 1994 using semiquantitative food-frequency questionnaires.RESULTS -After adjustment for age, BMI, smoking, alcohol consumption, physical activity, aspirin use, HbA 1c , history of hypertension or hypercholesterolemia, and fiber intake, dietary glycemic index and glycemic load were inversely associated with plasma adiponectin in a dosedependent fashion (P for trend ϭ 0.005 for glycemic index and 0.004 for glycemic load). Adiponectin levels were 13% lower in the highest quintile of dietary glycemic index than in the lowest quintile. For dietary glycemic load, adiponectin levels were 18% lower in the highest quintile than in the lowest. In contrast, high intake of cereal fiber was associated with increased plasma adiponectin levels, adjusting for lifestyle factors and dietary glycemic load (P for trend ϭ 0.003). Adiponectin levels were 19% higher in the highest quintile than in the lowest quintile. Higher magnesium intake was also associated with increased plasma adiponectin.CONCLUSIONS -Diets low in glycemic load and high in fiber may increase plasma adiponectin concentrations in diabetic patients. Diabetes Care 28:1022-1028, 2005D ietary glycemic index and load have been shown to predict risk of type 2 diabetes in healthy populations and also play a role in glycemic control among patients with diabetes (1-3). Meanwhile, several clinical studies have documented that a high-fiber diet substantially ameliorated metabolic abnormalities in diabetic patients by lowering fasting and postprandial levels of glucose and insulin and by improving blood lipids (4,5).The precise mechanism underlying the protective effects of glycemia-related dietary factors is not yet known. The fact that dietary glycemic measures and fiber intake may also affect body fat (6,7) gives rise to a hypothesis that the dietary effects may be in part mediated by adiposerelated pathways. It has been recognized that adipose tissue acts as an endocrine organ and plays pivotal roles in regulating whole-body metabolism by releasing bioactive molecules. Adiponectin is a newly identified adipose-secreted cytokine that presents at low plasma level in subjects with type 2 diabetes (8). Experimental and epidemiological studies have provided abundant evidence that adiponectin not only improves insulin sensitivity, but also has potent antiatherosclerotic effects (rev. in 9). Circulating adiponectin levels have been inversely associated with levels of fasting glucose and total-to-LDL cholesterol ratio and have been positively asso...

The effects of dietary fibre on C-reactive protein, an inflammation marker predicting cardiovascular disease

“…Ma et al (2006) observed an inverse association between the intake of total DF (separately for soluble and insoluble fibre) and CRP concentrations in both cross-sectional and longitudinal analyses but could not tease apart their effects because they are part of the same foods. Epidemiological (Salmeron et al, 1997;Schulze et al, 2004b) and experimental (Qi et al, 2005(Qi et al, , 2006) studies indicate a stronger inverse association of cereal fibre with type 2 diabetes, coronary heart disease and lower CRP concentrations than other types of fibre; however, the mechanisms are not clear.…”

“…Even in the short term (72 h), insoluble fibre (31.2 g) has been shown to improve wholebody insulin sensitivity in obese and overweight women (Weickert et al, 2006). In a cross-sectional analysis of 780 diabetic men, high glycaemic index and glycaemic load were associated with lower concentrations of plasma adiponectin (Qi et al, 2005) and positive associations between cereal fibre and plasma adiponectin were observed (Esposito et al, 2003b;Richter et al, 2004). In insulin-resistant states, insulin has a pro-inflammatory effect producing more cytokines (Fernandez-Real and Ricart, 2003).…”

Association between dietary fiber and markers of systemic inflammation in the Women's Health Initiative Observational Study

“…Secreted IL-6, intracellular IL-6, and IL-6 mRNA were found to be significantly increased with hyperglycemia (P < 0.001) [48]. In addition, Qi and colleagues found that diets high in fiber may increase plasma adiponectin concentrations in diabetic patients [49] and adiponectin has been found to have profound anti-inflammatory effects [50].…”

Magnesium intake and colorectal cancer risk in the Netherlands Cohort Study

“…As overweight is related to decreased insulin sensitivity (Fung et al, 2003), this may suggest that magnesium is inversely associated with colorectal cancer risk through improved insulin sensitivity. Recently, magnesium intake was found to be associated with increased levels of adiponectin, which may improve insulin sensitivity (Qi et al, 2005); adiponectin was inversely associated with colorectal cancer risk among men (Wei et al, 2005).…”