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

Authors: Baer, David; Novotny, Janet

Submitted to: The American Journal of Clinical Nutrition
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 8/16/2018
Publication Date: 2/8/2019
Citation: Baer, D.J., Novotny, J. 2019. Consumption of cashew nuts does not influence blood lipids or other markers of cardiovascular disease in humans: a randomized controlled trial. American Journal of Clinical Nutrition. 109:269-275. https://doi.org/10.1093/ajcn/nqy242.
DOI: https://doi.org/10.1093/ajcn/nqy242

Interpretive Summary: The U.S. Food and Drug Administration 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. Since stearic acid has been shown to neither increase nor decrease cholesterol levels, several studies have been conducted to test the effect of cashew nuts on blood lipids, and these studies have produced conflicting results. The objective 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. Forty-two adults participated in a controlled feeding study. The volunteers consumed a base diet during one study phase, and the same base diet with added cashews during the other study phase, ensuring that the caloric intake was the same during both phases. After 4 weeks of each diet, volunteers were assessed by a panel of cardiovascular disease risk factors. Despite the wide range of risk factors tested, cashew nut consumption had no effect on the primary risk factors (cholesterol, blood pressure, CRP). Other secondary risk factors were also unaffected. One measure of cholesterol metabolism was improved, and one inflammation molecule had a slightly unfavorable change. Overall, 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. These results will be used by scientists and health professionals.

Technical Abstract: 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. 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. 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. 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. 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.