Consumption of cashew nuts does not influence blood lipids or other markers of cardiovascular disease in humans: A randomized controlled trial

Abstract

Background The US Food and Drug Administration (FDA) approved a qualified health claim for tree nuts and reduction of cardiovascular disease. However, cashews are excluded from that claim due to their content of saturated fats, which is predominantly stearic acid. Because stearic acid is neutral with respect to blood lipids, several studies have been conducted to test the effect of cashew nuts on blood lipids, and these studies have produced conflicting results. Objectives The aim of this study was to conduct a highly controlled intervention to determine the effect of cashews fed at the amount specified in the health claim on risk factors for cardiovascular disease. Methods A total of 42 adults participated in a controlled-feeding study conducted as a randomized crossover trial with 2 treatment phases. The volunteers were provided the same base diet in both treatment phases, with no additions during the control phase and with the addition of 1.5 servings (42 g) of cashews/d for the cashew nut phase. During the cashew nut phase, the amount of all foods was decreased proportionally to achieve isocaloric overall diets in the 2 phases. After 4 wk of intervention, assessments included blood lipids, blood pressure, central (aortic) pressure, augmentation index, blood glucose, endothelin, proprotein convertase subtilisin/kexin type 9 (PCSK9), adhesion molecules, and clotting and inflammatory factors. Results There were no significant differences in blood lipids, blood pressure, augmentation index, blood glucose, endothelin, adhesion molecules, or clotting factors in this weight-stable cohort. PCSK9 was significantly decreased after cashew consumption, although there was no change in LDL cholesterol. Conclusions Consumption of 1.5 servings of cashew nuts/d, the amount associated with the FDA qualified health claim for tree nuts and cardiovascular disease, did not positively or adversely affect any of the primary risk factors for cardiovascular disease. This trial was registered at clinicaltrials.gov as NCT02628171.