Friday, July 31, 2009

Low carb good for the circulation: Low fat BAD for circulation

Effects of dietary carbohydrate restriction vs low-fat diet on flow-mediated dilation


We previously reported that a carbohydrate-restricted diet (CRD) ameliorated many of the traditional markers associated with metabolic syndrome and cardiovascular risk compared with a low-fat diet (LFD). There remains concern how CRD affects vascular function because acute meals high in fat have been shown to impair endothelial function. Here, we extend our work and address these concerns by measuring fasting and postprandial vascular function in 40 overweight men and women with moderate hypertriacylglycerolemia who were randomly assigned to consume hypocaloric diets (∼1500 kcal) restricted in carbohydrate (percentage of carbohydrate-fat-protein = 12:59:28) or LFD (56:24:20). Flow-mediated dilation of the brachial artery was assessed before and after ingestion of a high-fat meal (908 kcal, 84% fat) at baseline and after 12 weeks. Compared with the LFD, the CRD resulted in a greater decrease in postprandial triacylglycerol (−47% vs −15%, P = .007), insulin (−51% vs −6%, P = .009), and lymphocyte (−12% vs −1%, P = .050) responses. Postprandial fatty acids were significantly increased by the CRD compared with the LFD (P = .033). Serum interleukin-6 increased significantly over the postprandial period; and the response was augmented in the CRD (46%) compared with the LFD (−13%) group (P = .038). After 12 weeks, peak flow-mediated dilation at 3 hours increased from 5.1% to 6.5% in the CRD group and decreased from 7.9% to 5.2% in the LFD group (P = .004). These findings show that a 12-week low-carbohydrate diet improves postprandial vascular function more than a LFD in individuals with atherogenic dyslipidemia.

Carbs trigger metabolic syndrome, or make it worse. But isn't fat bad for the blood vessels, clogging them up? Turns out, no, carbs do the most damage to the blood vessels. Recent research also shows that eating carbs make your veins brittle, and they lose the elasticity, like a rubber band that won't snap closed anymore. This is not good. Smoking does the same thing, and tinkers with the insulin system as well. Eating bread is like smoking, it's bad for you.

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