A randomized, controlled trial on the effects of almonds on lipoprotein response to a higher carbohydrate, lower fat diet in men and women with abdominal adiposity

Abstract

Background: Almonds have been shown to lower LDL cholesterol but there is limited information regarding their effects on the dyslipidemia characterized by increased levels of very low density lipoproteins (VLDL) and small, dense low-density lipoprotein (LDL) particles that is associated with abdominal adiposity and high carbohydrate intake. The objective of the present study was to test whether substitution of almonds for other foods attenuates carbohydrate-induced increases in small, dense LDL in individuals with increased abdominal adiposity. Methods: This was a randomized cross-over study of three 3wk diets, separated by 2wk washouts: a higher-carbohydrate (CHO) reference diet (CHO high ), a higher-CHO diet with isocaloric substitution of 20% kcal (E) from almonds (CHO high + almonds ), and a lower-CHO reference diet (CHO low ) in 9 men and 15 women who were overweight or obese. The two CHO high diets contained 50% carbohydrate, 15% protein, 35% fat (6% saturated, 21% monounsaturated, 8% polyunsaturated), while the CHO low diet contained 25% carbohydrate, 28% protein, 47% fat (8% saturated, 28% monounsaturated, 8% polyunsaturated). Lipoprotein subfraction concentrations were measured by ion mobility. Results: Relative to the CHO low diet: 1) the CHO high + almonds diet significantly increased small, dense LDLIIIa (mean difference ± SE: 28.6 ± 10.4 nmol/L, P = 0.008), and reduced LDL-peak diameter (- 1.7 ± 0.6 Å, P = 0.008); 2) the CHO high diet significantly increased medium-sized LDLIIb (24.8 ± 11.4 nmol/L, P = 0.04) and large VLDL (3.7 ± 1.8 nmol/L, P = 0.05). Relative to CHO low , the effects of CHO high on LDLIIIa (17.7 ± 10.6 nmol/L) and LDL-peak diameter (- 1.1 ± 0.6 Å) were consistent with those of CHO high + almonds , and the effects of CHO high + almonds on LDLIIb (21.0 ± 11.2 nmol/L) and large VLDL (2.8 ± 1.8 nmol/L) were consistent with those of CHO high , but did not achieve statistical significance (P > 0.05). None of the variables examined showed a significant difference between the CHO high + almonds and CHO high diets (P > 0.05). Conclusion: Our analyses provided no evidence that deriving 20% E from almonds significantly modifies increases in levels of small, dense LDL or other plasma lipoprotein changes induced by a higher carbohydrate low saturated fat diet in individuals with increased abdominal adiposity. Trial registration: Clinicaltrials.gov NCT01792648.