Effects of one serving of mixed nuts on serum lipids, insulin resistance and inflammatory markers in patients with the metabolic syndrome☆
Received 14 April 2009; received in revised form 23 June 2009; accepted 12 August 2009. published online 23 December 2009. Corrected Proof
Abstract
Background and aims
Knowledge of the effect of nut consumption on metabolic syndrome (MetS) components is limited. We assessed the effects of nut intake on adiposity, serum lipids, insulin resistance, and inflammatory biomarkers in patients with MetS.
Methods and results
In a randomized, parallel-group, 12-week feeding trial, 50 patients with MetS were given recommendations for a healthy diet with or without supplementation with 30g/day of raw nuts (15g walnuts, 7.5g almonds and 7.5g hazelnuts) (Nut and Control diet groups, respectively). Adiposity measures, serum lipids, insulin, Homeostasis Model Assessment (HOMA), interleukin-6 (IL-6) and other inflammatory biomarkers, and 48-h fecal fat were determined basally and at study's completion. Moderate weight loss, decreased adiposity, and lower blood pressure occurred similarly after both diets. The Control, but not the Nut diet, was associated with significant (P<0.05) reduction of LDL-cholesterol, with mean changes of −0.36 versus −0.13mmol/L, respectively (between-group differences, P=0.154). The Nut diet reduced fasting insulin by 2.60μU/mL (95% CI, −4.62 to −0.59) and HOMA-insulin resistance by 0.72 (−1.28 to −0.16) (P<0.05 versus Control diet; both). Among inflammatory markers, the Nut diet resulted in changes of median plasma IL-6 of −1.1ng/L (−2.7 to −0.1; P=0.035 versus Control diet), but adjustment for weight loss attenuated the significance of the association. Stool fat decreased with the Control diet and slightly increased with the Nut diet (P<0.05 for between-group differences).
Conclusion
Patients with MetS show decreased lipid responsiveness but improved insulin sensitivity after daily intake of 30g of mixed nuts.
aHuman Nutrition Unit, Hospital Universitari Sant Joan de Reus, IISPV, Rovira i Virgili University, Reus, Spain
bLipid Clinic, Endocrinology and Nutrition Service, Institut d'Investigacions Biomèdiques August Pi Sunyer (IDIBAPS), Hospital Clínic, Barcelona, Spain
cCIBER Fisiopatología de la Obesidad y Nutrición (CIBEROBN), Instituto de Salud Carlos III (ISCIII), Spain
dÀrea Bàsica de Salut Reus-1, Institut Català de la Salut, Reus, Spain
Corresponding author at: Human Nutrition Unit, Department of Biochemistry and Biotechnology, Faculty of Medicine and Health Sciences, Rovira i Virgili University, Sant Llorenç 21, 43201 Reus, Spain. Tel.: +34 977 759312; fax: +34 977 759322.
☆ Support for research: Supported by grants from the Spanish Ministry of Education and Science (CICYT-AGL2005-03605), Spanish Ministry of Health (RTIC RD06/0045) and the International Nut Council. The nuts used in the study were donated by Borges S.A., Reus, Spain. None of the funding sources played a role in the design, collection, analysis or interpretation of the data or in the decision to submit the manuscript for publication. Patricia López-Uriarte is a recipient of a predoctoral fellowship from the Generalitat de Catalunya's Ministry of Universities, Research and the Information Society and the European Social Funds.
ABSTRACT
g/day of raw nuts (15