Elsevier

Nutrition

Volume 26, Issue 4, April 2010, Pages 399-404
Nutrition

Applied nutritional investigation
Effect of pistachio diet on lipid parameters, endothelial function, inflammation, and oxidative status: A prospective study

https://doi.org/10.1016/j.nut.2009.05.023Get rights and content

Abstract

Objective

Recent studies have suggested that nuts have favorable effects beyond lipid lowering. We aimed to investigate effect of the Antep pistachio (Pistacia vera L.) on blood glucose, lipid parameters, endothelial function, inflammation, and oxidation in healthy young men living in a controlled environment.

Methods

A Mediterranean diet was administered to normolipidemic 32 healthy young men (mean age 22 y, range 21–24) for 4 wk. After 4 wk, participants continued to receive the Mediterranean diet but pistachio was added for 4 wk by replacing the monounsaturated fat content constituting ≈20% of daily caloric intake. Fasting blood samples and brachial endothelial function measurements were performed at baseline and after each diet.

Results

Compared with the Mediterranean diet, the pistachio diet decreased glucose (P < 0.001, −8.8 ± 8.5%), low-density lipoprotein (P < 0.001, −23.2 ± 11.9%), total cholesterol (P < 0.001, −21.2 ± 9.9%), and triacylglycerol (P = 0.008, −13.8 ± 33.8%) significantly and high-density lipoprotein (P = 0.069, −3.1 ± 11.7%) non-significantly. Total cholesterol/high-density lipoprotein and low-density lipoprotein/high-density lipoprotein ratios decreased significantly (P < 0.001 for both). The pistachio diet significantly improved endothelium-dependent vasodilation (P = 0.002, 30% relative increase), decreased serum interleukin-6, total oxidant status, lipid hydroperoxide, and malondialdehyde and increased superoxide dismutase (P < 0.001 for all), whereas there was no significant change in C-reactive protein and tumor necrosis factor-α levels.

Conclusion

In this trial, we demonstrated that a pistachio diet improved blood glucose level, endothelial function, and some indices of inflammation and oxidative status in healthy young men. These findings are in accordance with the idea that nuts, in particular pistachio nuts, have favorable effects beyond lipid lowering that deserve to be evaluated with prospective follow-up studies.

Introduction

Epidemiologic studies have shown that frequent nut consumption decreases the risk of coronary heart disease (CHD). Compared with people who consumed nuts less than one time per week, people who ate nuts at least five times per week showed a 50% reduction in risk [1], [2], [3], [4]. Nuts are rich in monounsaturated fatty acid (MUFA) and polyunsaturated fatty acid (PUFA), which are known to have favorable effects on the lipid profile [5]. However, the potential benefits of the nuts on decreasing CHD are not limited to their effects on lipid parameters. Nuts are also a good source of dietary fiber, vitamins, micronutrients, antioxidants, amino acids (e.g., arginine), and plant stenols [5].

The majority of the nut studies were performed with walnuts, almonds, and peanuts. Thus far, to our knowledge, only three studies have been conducted in humans investigating the effects of pistachio nuts, which were performed as outpatient dietary intervention trials [6], [7], [8]. Investigators are more focused on the favorable effects of nuts beyond their effects on lipid parameters. Endothelial dysfunction is an early key event in the atherosclerotic process that predicts future CHD development [9], [10]. Endothelial function measurement can be non-invasively performed. A recent study has demonstrated that substituting walnuts for MUFA in a Mediterranean diet improved endothelium-dependent vasodilation (EDV) in hypercholesterolemic subjects as a measurement of endothelial function [11]. Like the walnut, the pistachio is a good source of l-arginine, which is a precursor of endogenous vasodilator nitric oxide. To our knowledge, there are as yet no data regarding the effect of a pistachio diet on endothelial function.

Inflammation and oxidation play an important role in the pathogenesis and progression of CHD. Some studies have shown that nuts have favorable effects on inflammation and oxidative status; however, our knowledge about the impact of pistachios on inflammatory and oxidative balance is limited. In this study we therefore investigated the effect of an Antep pistachio (Pistacia vera L.) diet on lipid parameters, endothelial function, inflammation, and oxidative status in healthy young men living in a controlled environment, which has not been studied previously.

Section snippets

Study population

To our knowledge, previous nut studies were organized as outpatient dietary modification studies. Although all of the previously published studies have reported good compliance of the participants to the administered diet, we believe that subjects living in a controlled environment would provide a better sample population in a dietary intervention study. After providing the required legal permissions, we performed the study in the vocational police education school of Gaziantep, Turkey. In the

Results

Of the 33 participants initially included into the study, 1 subject had to undergo a urologic operation; therefore, 32 subjects (mean age 22 y, range 21–24) completed the protocol. Table 3 presents body weight, blood pressure, glucose, and lipid parameters of the participants at baseline and at the end of each diet. Body weight and blood pressure of the participants remained unchanged during the study. Compared with the Mediterranean diet, the pistachio diet caused significant decreases in

Discussion

In this 8-wk dietary intervention trial, we demonstrated that a pistachio diet had favorable effects on glucose level, lipid parameters, endothelial function, and some indices of inflammation and oxidative status in healthy young men.

Most of the nut studies were performed with walnuts, almonds, and peanuts. Thus far, to our knowledge, only three studies have been conducted in humans investigating the effects of pistachio nuts, which were performed as outpatient dietary intervention trials [6],

Acknowledgments

The authors thank the subjects for participating and co-operating during the study period. They also appreciate the help of the administration of vocational police education school of Gaziantep and the Gaziantep police department. They appreciate the help of Nilgun Dogruer Kalkanci from the Pistachio Investigation Institute, Gaziantep, for providing the data about the Antep pistachio (Pistacia vera L.).

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    Financial support of the present study was provided by the Pistachio Investigation Group of the Gaziantep Chamber of Commerce.

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