The Effects of a Mediterranean-style, Low-glycemic-load, Diet on Lipoprotein Metabolism, Inflammation, and Mononuclear Cell Gene Expression in Women Classified with Metabolic Syndrome

Date of Completion

January 2011

Keywords

Women's Studies|Health Sciences, Nutrition|Health Sciences, Public Health

Degree

Ph.D.

Abstract

Metabolic syndrome (MetS) is a constellation of abnormalities characterized by abdominal obesity, hyperglycemia, elevated blood pressure (BP), high plasma triglycerides (TG), and low HDL cholesterol (HDL-C). This clustering of characteristics in individuals places them at a higher risk for cardiovascular disease (CVD) and type 2 diabetes. Environmental factors, especially diet, can modulate MetS parameters, and as MetS prevalence increases, there is a need for effective dietary intervention options. The purpose of this project was to assess the impact of a Mediterranean-style diet alone, or supplemented with a medical food containing soy isoflavones and plant sterols, on MetS parameters, lipoprotein metabolism, inflammation, and gene expression. ^ Eighty-nine women, ages 20-75 years, body mass index (BMI) 25-40 kg/m 2, were recruited from three sites. Inclusion criteria were TG ≥ 150 mg/dL, LDL-C ≥ 100 mg/dL, plus two additional characteristics of MetS, according to ATP-III criteria. Following a 2-arm randomized design, participants were allocated to the medical food (MF) group or the control group. Women followed dietary instructions for 12 weeks, and 3-day food records were collected every 2 weeks. Anthropometric measurements and blood were collected at baseline, week 8 and week 12.^ Following the intervention, both groups had reductions in carbohydrate and fat intake as a percentage of total energy; however, protein intake increased. Similar decreases were observed in both groups for weight, BMI, waist circumference (WC), TG, and BP (p < 0.05). Moreover, LDL-C, large VLDL, small LDL, oxLDL, Lp (a), and apo B decreased significantly in both groups (p < 0.01), but reductions in apo B were greater in the MF group (p < 0.025). Both groups had favorable decreases in insulin and insulin resistance, as measured by HOMA (p < 0.0001). Additionally, plasma levels of leptin and TNF-α decreased significantly in both groups (p < 0.0001).^ Mononuclear cell mRNA expression of HMG-CoA reductase decreased in a sub-group of women (p < 0.001), and this decrease was correlated with measured reductions in insulin (r = 0.450, p < 0.05).^ A Mediterranean-style dietary pattern favorably affected MetS parameters, lipoprotein metabolism, and inflammation; addition of a medical food further improved apo B levels. ^

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