Effect of Dietary Intervention on LDL-C and Lipoprotein Subclasses Distribution in Patients With Hypercholesterolemia

Overview

The primary aim of the present study was to elucidate the effect of a combination of functional foods on the low-density lipoprotein cholesterol (LDL-C) levels and on the distribution of the lipoprotein subclasses in subjects with hypercholesterolemia. To accomplish the latter, subjects that met the inclusion criteria and had mild hypercholesterolemia (Total cholesterol \>200mg/dL, and LDL-C \>130mg/dL \<190 mg/dL) were recruited for double-blind, parallel, controlled dietary intervention study. After two weeks of dietary standardization with an isocaloric diet, subjects were randomized and allocated to either placebo or a dietary portfolio treatment for two months. The secondary endpoints were the size of the different lipoprotein subclasses, total cholesterol levels, high density -lipoprotein cholesterol (HDL-C) levels, apolipoprotein B, triglycerides, total/HDL-C ratio, apolipoprotein B/apolipoprotein A ratio, and anthropometric measurements.

The present work took place at the Department of Physiology of Nutrition at the Instituto Nacional de Ciencias Medicas y Nutricion Salvador Zubiran (INCMNSZ). The study followed a randomized, controlled, double-blind, parallel design encompassing five visits. On the first visit, volunteers were screened for eligibility criteria. Subjects that met the inclusion criteria were then invited to a second visit. Herein, volunteers received a thorough explanation of the experimental maneuver, as well as the overall objectives of the study. Thereafter, subjects who agreed to participate signed a consent form. Upon agreement, assessment of habitual dietary intake and physical activity was obtained by 24-hour dietary recalls, food frequency questionnaire (FFQ), and by the International Physical Activity Questionnaire (IPAQ), respectively. Additionally, anthropometric measurements and blood samples were registered and collected. Then, volunteers underwent dietary standardization for two weeks with isocaloric diets (LSFD), which followed the National Cholesterol Education Program (NCEP) , Adult Treatment Panel III (ATP III) criteria. That is, 50-60% carbohydrates, 15% protein, 25-35% fat,\<7% saturated fat,≤ 200mg of dietary cholesterol, 20-35g of fiber, and 2000mg/d of sodium. On the third visit, subjects were randomly allocated to either LSFD plus placebo or an LSFD plus the dietary portfolio (DP). Of note, the prescribed diets were matched to the volunteers' habitual caloric intake -considering the energy provided by the placebo or DP- to avoid variability of the endpoint variables due to weight-loss. The DP and placebo provided 200kcal; the DP included 25g of soy protein, 14g of dehydrated nopal,14g of oats, 4g of chia seeds, 4g of inulin, and 0.15g of flavoring. The placebo consisted of 30g of calcium caseinate, 30g of maltodextrin, and 0.2g of flavoring. The organoleptic characteristics and packaging were similar between treatments. Subjects were instructed to consume two packets per day, preferably with breakfast and dinner. The content of each packet (30g of product) was dissolved in 250-300ml of water. Volunteers followed the given treatment for two consecutive months, during which two follow-up visits took place. Blood samples, anthropometric characteristics, and blood pressure were obtained in all visits. Compliance to diet, placebo, and DP was assessed with 24-hour dietary recalls, 3-day dietary records, and with the number of empty packets returned on the corresponding visits.