Elsevier

Nutrition

Volume 30, Issues 11–12, November–December 2014, Pages 1287-1293
Nutrition

Applied nutritional investigation
Effects of DASH diet on lipid profiles and biomarkers of oxidative stress in overweight and obese women with polycystic ovary syndrome: A randomized clinical trial

https://doi.org/10.1016/j.nut.2014.03.008Get rights and content

Abstract

Objective

The aim of this study was to assess the effects of the Dietary Approaches to Stop Hypertension (DASH) diet on lipid profiles and biomarkers of oxidative stress in overweight and obese women with polycystic ovary syndrome (PCOS).

Methods

This randomized controlled clinical trial was conducted with 48 women diagnosed with PCOS. The women were randomly assigned to consume either the control (n = 24) or DASH diet (n = 24) for 8 wk. Both diets were designed to be calorie-restricted. Both diets consisted of 52% carbohydrates, 18% proteins, and 30% total fats. The DASH diet was designed to be rich in fruits, vegetables, whole grains, and low-fat dairy products and to be low in saturated fats, cholesterol, and refined grains. Fasting blood samples were taken at baseline and after 8-wk intervention to measure lipid profiles and biomarkers of oxidative stress including plasma total antioxidant capacity (TAC) and total glutathione (GSH).

Results

Adherence to the DASH diet, compared with the control diet, resulted in a significant decrease in weight (−4.4 versus −1.5 kg; P < 0.001) and body mass index (−1.7 versus −0.6 kg/m2; P < 0.001), decreased serum triglycerides (−10.0 versus +19.2 mg/dL; P interaction = 0.005) and very-low-density lipoprotein cholesterol levels (−2.0 versus +3.9 mg/dL; P interaction = 0.005). Increased concentrations of TAC (+98.6 versus −174.8 mmol/L; P interaction <0.001) and GSH (+66.4 versus −155.6 μmol/L; P interaction = 0.005) also were found in the DASH group compared with the control group.

Conclusion

Consumption of DASH diet for 8 wk led to a significant reduction in serum insulin, triglycerides and very-low-density lipoprotein cholesterol and a significant increase in TAC and GSH levels.

Introduction

Polycystic ovary syndrome (PCOS) is the most common endocrinopathy among reproductive-aged women [1], affecting 6% to 18% of female adults [2]. In Iran the estimated prevalence of this condition has been reported to be 7% based on the National Institutes of Health criteria, 15.2% according to the Rotterdam criteria, and 7.9% according to the Androgen Excess Society criteria [3]. Women with PCOS have androgen excess, insulin resistance, and variable amounts of estrogen exposure, all of which can result in increased lipid profiles and biomarkers of oxidative stress [4], [5]. Additionally, increased visceral fat and the reduction of adiponectin levels in PCOS would result in elevated lipid profiles [6], [7]. Decreased expression of peroxisome proliferator-activated receptor in women with PCOS also can result in dyslipidemia and increased biomarkers of oxidative stress [8]. PCOS is associated with infertility [9], increased risk for endometrial, breast, and ovarian cancers [10], and increased incidence of type 2 diabetes mellitus (T2DM) [11].

First-line treatment in the management of PCOS includes weight loss and lifestyle modifications with increased physical activity [12]. It has been reported that in obese women with PCOS, a 5% loss of body weight can improve hyperandrogenic features [13]. Furthermore, the use of oral contraceptive pills and metformin may help induce regular menses [14] and reduce hyperinsulinemia and ovarian androgens production in these women [15]. Recently, it has been suggested that low-carbohydrate, low-glycemic load, and high-protein diets might beneficially influence PCOS more than a conventional low-fat, high-carbohydrate diet [16], [17].Consumption of a low-glycemic diet in combination with medications has resulted in symptom relief in patients with PCOS [18]. However, adherence to a high-protein and low-glycemic diet for 12 wk did not influence lipid profiles among women with PCOS [19].

The Dietary Approaches to Stop Hypertension (DASH) eating plan is a low-glycemic index, low-energy dense diet that has been suggested for lowering blood pressure [20]; however, its beneficial effects also have been reported in T2DM [21], gestational diabetes mellitus (GDM), [22] and metabolic syndrome (MetS) [23]. Although the influence of some dietary components of the DASH diet, such as antioxidants [24], [25], magnesium [26], and dietary fiber, fruit, and vegetables [25], in PCOS has been assessed in previous studies, we are not aware of any studies examining the effects of the DASH diet on metabolic profiles and biomarkers of oxidative stress in patients with PCOS. High contents of dietary fiber, antioxidants, phytoestrogens, and isoflavones along with its low-glycemic index [21], [23] might help PCOS patients to control their increased levels of lipids and oxidative stress. Furthermore, adherence to the DASH diet has been associated with lower body fat [21], which could in turn result in lower testosterone levels [27], a key component in PCOS. The present study was, therefore, performed to investigate the effects of the DASH eating plan on lipid profiles and biomarkers of oxidative stress in overweight and obese women with PCOS.

Section snippets

Participants

This two-arm parallel, randomized controlled clinical trial (RCT) was carried out in Kashan, Iran, from January to May 2012. With the exception of the study dietitian (ZA), who provided the dietary education, all study personnel and participants were blinded to dietary assignment. Overweight or obese (body mass index [BMI] ≥ 25 kg/m2) women ages 18 to 40 y diagnosed with PCOS based on the Rotterdam criteria were recruited in this study. On the basis of sample-size formula suggested for RCTs [19]

Results

Among individuals in the control diet, three women were excluded (one was undergoing in vitro fertilization, one became pregnant, and one was using medications). Three women were also excluded from the DASH diet group (in vitro fertilization, use of medications, and health problems). Finally, 48 participants (24 in each arm) completed the study (Fig. 1).

Mean age of study participants was not statistically different between the two groups. Comparison of weight and BMI both at baseline and end of

Discussion

Adherence to the DASH eating pattern for 8 wk among overweight and obese women with PCOS had beneficial effects on weight, BMI, serum TGs, VLDL-C, insulin, plasma TAC, and total GSH levels compared with the control diet. However, the effects of the DASH eating pattern on serum TC, HDL-C, and LDL-C were not significantly different between the two groups.

To our knowledge, only a few studies have evaluated the beneficial effects of diet therapy on metabolic status in women with PCOS. According to

Conclusion

Consumption of the DASH diet for 8 wk in overweight and obese women with PCOS resulted in a significant decrease in weight, BMI, serum insulin, TGs, and VLDL-C levels as well as a significant increase in plasma TAC and total GSH levels. Given the high prevalence of PCOS and based on the findings of this study, we believe that the DASH diet could be recommended as a suitable diet for these patients to control abnormal metabolic profiles.

Acknowledgment

The authors acknowledge the staff of Naghavi and Shaheed Beheshti Gynecology Clinics (Kashan, Iran) for their assistance in this project.

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    The present study was supported by a grant (no. 9213) from the vice-chancellor for research, KUMS, Kashan, Iran. ZA conducted the study, carried out the statistical analyses, drafted the manuscript, and contributed to the interpretation of the findings. MS, ZT, HS, and S-SS contributed to the data collection and assisted in drafting the manuscript. AE contributed to the conception and design, advised on statistical analyses, and assisted in interpretation of the findings. None of the authors had any personal or financial conflict of interest. All authors approved the final version for submission.

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