Effect of a Moderate Fat Diet With and Without Avocados on Lipoprotein Particle Number, Size and Subclasses in Overweight and Obese Adults: A Randomized, Controlled Trial

BACKGROUND Avocados are a nutrient-dense source of monounsaturated fatty acids (MUFA) that can be used to replace saturated fatty acids (SFA) in a diet to lower low density lipoprotein cholesterol (LDL-C). Well-controlled studies are lacking on the effect of avocado consumption on cardiovascular disease (CVD) risk factors. METHODS AND RESULTS A randomized, crossover, controlled feeding trial was conducted with 45 overweight or obese participants with baseline LDL-C in the 25th to 90th percentile. Three cholesterol-lowering diets (6% to 7% SFA) were fed (5 weeks each): a lower-fat diet (LF: 24% fat); 2 moderate-fat diets (34% fat) provided similar foods and were matched for macronutrients and fatty acids: the avocado diet (AV) included one fresh Hass avocado (136 g) per day, and the moderate-fat diet (MF) mainly used high oleic acid oils to match the fatty acid content of one avocado. Compared with baseline, the reduction in LDL-C and non-high-density lipoprotein (HDL) cholesterol on the AV diet (-13.5 mg/dL, -14.6 mg/dL) was greater (P<0.05) than the MF (-8.3 mg/dL, -8.7 mg/dL) and LF (-7.4 mg/dL, -4.8 mg/dL) diets. Furthermore, only the AV diet significantly decreased LDL particle number (LDL-P, -80.1 nmol/L, P=0.0001), small dense LDL cholesterol (LDL(3+4), -4.1 mg/dL, P=0.04), and the ratio of LDL/HDL (-6.6%, P<0.0001) from baseline. CONCLUSIONS Inclusion of one avocado per day as part of a moderate-fat, cholesterol-lowering diet has additional LDL-C, LDL-P, and non-HDL-C lowering effects, especially for small, dense LDL. Our results demonstrate that avocados have beneficial effects on cardio-metabolic risk factors that extend beyond their heart-healthy fatty acid profile. CLINICAL TRIAL REGISTRATION URL http://www.clinicaltrials.gov. Unique identifier: NCT01235832.