Title

Development of Mathematical Models to Assess the Effects of Carbohydrate Consumption and Fluctuations in Insulin on HDL Cholesterol

Date of Completion

January 2011

Keywords

Biology, Biostatistics|Health Sciences, Nutrition

Degree

Ph.D.

Abstract

Carbohydrate (CHO) consumption is believed to reduce high density lipoprotein (HDL) by increasing triglycerides (TG) and by increasing insulin. Thus, it is anticipated that there is an inverse relationship between CHO consumption and HDL that may be mathematically described to aid in the optimization of dietary interventions. The purpose of this work was to create a dataset to describe the relationship between HDL and CHO intake across a range of intakes in non-diabetic volunteers and to build a model that will describe the effect of changing macronutrient composition on circulating HDL. This work was then followed with a study of pharmacologically-induced changes in insulin and TG to describe the relationship between insulin/TG and HDL in type II diabetic subjects. Data from 11 dietary intervention trials were pooled, resulting in 1067 records of HDL at CHO-intakes spanning from 10 to 80.5% of daily energy intake. The inverse relationship between HDL and CHO consumption was fitted to a linear model. HDL was predicted to decrease at a rate of 0.0808 mg/dL per one percentage unit increase in CHO consumption. TG and concentrations of HDL at baseline were shown to significantly account for inter-individual variability around HDL when CHO intake was held constant. A second objective was to study the interrelationship between changes in insulin and TG in 265 type II diabetic subjects who received either placebo or a test drug believed to increase insulin sensitivity for 84 weeks. When HDL was modeled as a linear function of insulin, there was a predicted 0.0766 mmol/mL reduction in HDL following every one UIU/mL increase in insulin concentration. When TG were used to predict HDL concentrations, there was a predicted 0.0424 mmol/mL reduction in HDL following every one mmol/L increase in TG. These data suggest that HDL concentrations are decreased when CHO intake is increased. The inverse relationships between TG and insulin with HDL likely contribute to the effect of CHO intake on HDL. ^^