Meng H, et al. – Researchers compared the impacts of an isocaloric exchange of simple, refined, and unrefined carbohydrates on serum cardiometabolic risk indicators, adipose tissue inflammatory markers, and peripheral blood mononuclear cell (PBMC) fractional cholesterol efflux among postmenopausal women and men (n=11; aged 65±8 years; body mass index, 29.8±3.2 kg/m²; low-density lipoprotein [LDL] cholesterol level, ≥2.6 mmol/L). Elevated levels of fasting serum LDL and non–high-density lipoprotein (HDL) cholesterol levels were observed but had little impact on other cardiometabolic risk indicators in association with intake of diets enriched in refined vs simple or unrefined carbohydrate. Findings suggested that refined carbohydrate may have unique adverse effects on cardiometabolic risk indicators distinct from simple and unrefined carbohydrate.

Methods

• Using a randomized crossover design, participants were provided with diets (60% energy from total carbohydrate, 15% from protein, 25% from fat) for 4.5 weeks, with 2-week washout periods.
• An isocaloric exchange of simple, refined, or unrefined carbohydrate–containing foods was a variable component.
• Researchers measured serum lipoprotein, glucose, insulin, and inflammatory marker concentrations.
• Macrophage and inflammatory marker gene expression and ex vivo cytokine secretion by aspirating abdominal subcutaneous adipose tissue were evaluated.
• Isolated peripheral blood mononuclear cells were used to evaluate ex vivo fractional cholesterol efflux.

Results

• Refined vs simple or unrefined carbohydrate–enriched diets (P < 0.01) resulted in higher fasting serum LDL and non–HDL cholesterol concentrations.
• Between diets, other serum measures, ex vivo fractional cholesterol efflux and adipose tissue gene expression and ex vivo cytokine secretion, were found to be similar.