Abstract-Evidence suggests that obesity may raise blood pressure (BP) through oxidative stress-sensitive mechanisms and that the Dietary Approaches to Stop Hypertension combination diet (DASH-CD) may decrease BP by enhancing antioxidant capacity. To address this question, 12 obese patients with high-normal-to-stage 1 hypertension (hypertensives) and 12 lean normotensives were studied on their usual diets and after following the DASH-CD and a low-antioxidant diet in random sequence for 4 weeks each. Acute oxidative stress was induced by a 4-hour infusion of intralipid and heparin. Ferric-reducing activity of plasma (FRAP) and plasma F 2 -isoprostanes were measured as biomarkers of antioxidant capacity and oxidative stress, respectively. BP was lower in obese hypertensives on the DASH-CD than on the usual and low-antioxidant diets (Ϫ8.1Ϯ1.5/Ϫ7.4Ϯ1.6 mm Hg, PϽ0.05). BP did not change significantly in lean normotensives after 4 weeks on the DASH-CD but tended to rise on the low-antioxidant diet. FRAP on usual diets was higher in lean subjects than in obese subjects. FRAP increased in obese but not lean volunteers on the DASH-CD compared with usual diet, and the group difference disappeared. F 2 -isoprostanes increased from baseline during intralipid and heparin in both groups on the low-antioxidant diet but not in obese hypertensives on the DASH-CD. Among free-living obese hypertensives, the DASH-CD raises antioxidant capacity, lowers BP, and reduces oxidative stress induced by acute hyperlipidemia. The findings are consistent with evidence that elevated BP in obese subjects may reflect an imbalance between antioxidant capacity and oxidative stress that is improved by the DASH-CD. Key Words: obesity Ⅲ insulin resistance Ⅲ fatty acids Ⅲ F 2 -isoprostanes Ⅲ oxidative stress Ⅲ antioxidants P atients with high-normal blood pressure (BP) and hypertension are more obese and insulin resistant than are normotensives. Reduced antioxidant capacity and oxidative stress represent a potential mechanism linking obesity with insulin resistance, elevated BP, and cardiovascular disease. 1-10 For example, acutely raising lipids with a short-term infusion of intralipid and heparin, which mimics and/or exacerbates the dyslipidemia seen with insulin resistance, increases BP and raises F 2 -isoprostanes, a biomarker of oxidative stress. 11,12 Moreover, in experimental models, increasing oxidative stress with a long-term low-dose infusion of angiotensin and reducing antioxidant capacity by depletion of glutathione produce severe hypertension. 2,13 In these models, BP declines when antioxidant defenses are augmented by providing either superoxide dismutase 13,14 or vitamins C and E. 13 Vitamin C also lowers BP in humans, which implicates a role for antioxidant capacity in human hypertension. 15 In the Dietary Approaches to Stop Hypertension (DASH) Study, a diet rich in fruits and vegetables, either with or without low-fat dairy products, reduced BP significantly more in hypertensives than in normotensives. 16 Both diets are rich in a varie...

BackgroundObstructive Sleep Apnea (OSA) is tightly linked to some components of Metabolic Syndrome (MetS). However, most of the evidence evaluated individual components of the MetS or patients with a diagnosis of OSA that were referred for sleep studies due to sleep complaints. Therefore, it is not clear whether OSA exacerbates the metabolic abnormalities in a representative sample of patients with MetS.Methodology/Principal FindingsWe studied 152 consecutive patients (age 48±9 years, body mass index 32.3±3.4 Kg/m2) newly diagnosed with MetS (Adult Treatment Panel III). All participants underwent standard polysomnography irrespective of sleep complaints, and laboratory measurements (glucose, lipid profile, uric acid and C-reactive protein). The prevalence of OSA (apnea-hypopnea index ≥15 events per hour of sleep) was 60.5%. Patients with OSA exhibited significantly higher levels of blood pressure, glucose, triglycerides, cholesterol, LDL, cholesterol/HDL ratio, triglycerides/HDL ratio, uric acid and C-reactive protein than patients without OSA. OSA was independently associated with 2 MetS criteria: triglycerides: OR: 3.26 (1.47–7.21) and glucose: OR: 2.31 (1.12–4.80). OSA was also independently associated with increased cholesterol/HDL ratio: OR: 2.38 (1.08–5.24), uric acid: OR: 4.19 (1.70–10.35) and C-reactive protein: OR: 6.10 (2.64–14.11). Indices of sleep apnea severity, apnea-hypopnea index and minimum oxygen saturation, were independently associated with increased levels of triglycerides, glucose as well as cholesterol/HDL ratio, uric acid and C-reactive protein. Excessive daytime sleepiness had no effect on the metabolic and inflammatory parameters.Conclusions/SignificanceUnrecognized OSA is common in consecutive patients with MetS. OSA may contribute to metabolic dysregulation and systemic inflammation in patients with MetS, regardless of symptoms of daytime sleepiness.

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