While men may lose more weight on low-carb diets, women see better improvements in artery flexibility, found a small University of Missouri/strong> study.
It's a finding that may help pre-diabetic women reduce their risk for heart disease through a low-carb diet. According to the US Centres for Disease Control and Prevention, an estimated 1 out of 3 adults in the US live with higher than normal blood sugar levels known as pre-diabetes.
"Previous research has shown that as women age, their blood vessels stiffen more so than men, putting them at an increased risk of heart disease," said Dr Elizabeth Parks, professor of nutrition and exercise physiology at MU. "Contrary to what you may think, you actually don't want stiff blood vessels. Rather, you want flexible vessels that expand slowly as the blood flows through them. Our study found that low-carb diets helped reduce the stiffness of arteries in women, which can, in turn, reduce their risk of developing serious heart conditions."
To illustrate this, Parks compares good vessels to be like a rubber hose and aging causing vessels to become stiff, similar to a plastic pipe. When you pour water through a rubber hose, the hose bends and flexes as the water makes its way through. When you pour water through a solid pipe, the water travels through the pipe quickly. In the human body, for good health, we want flexible, pliable, resilient arteries.
As part of the study, 20 middle-aged, pre-diabetic men and women were given carb-restricted meals provided by the MU Nutrition Centre for Health for two weeks and were supplied meal planning instructions for an additional two weeks. Over the four-week period, the men in the study lost 6.3% of their body weight, while women lost 4.4%. However, using an arterial stiffness measurement called pulse wave velocity, the women showed reduced blood flow speeds of 1 meter per second, while men showed no changes in blood flow speed.
"Vascular stiffness is a natural process of ageing that can be accelerated by obesity, insulin resistance and metabolic syndrome," said Parks, who also serves as associate director of the MU Clinical Research Centre. "Our study is the first to demonstrate that weight loss can reduce arterial stiffness in as little as four weeks and that dietary carbohydrate restriction may be an effective treatment for reducing aortic stiffness in women."
Abstract
Increased aortic stiffness, measured by carotid-to-femoral pulse wave velocity (PWV), is an independent predictor of cardiovascular disease (CVD) and past data have shown that low-fat and low-energy diets, fed for 8-24 wks lower PWV. The purpose of this study was to determine whether a reduction in PWV would be achieved by dietary carbohydrate (CHO) restriction, shown to bring about weight loss over a shorter timeframe. Men [n=10, age: 41.8 ± 3.2 y, BMI: 34.2 ± 1.0 kg/m2 (mean±SE)] and women (n=10, age: 38.6 ± 1.9 y, BMI: 33.5 ± 1.2 kg/m2) with characteristics of insulin resistance and the metabolic syndrome, consumed a structured, CHO-restricted diet (CRD) for 4 wks (energy deficit, 645 kcal/d). For the whole group, subjects lost 5.4 ± 0.5 % (P<0.001) of body weight and experienced significant reductions in blood pressure (6-8%), plasma insulin (34%) and triglycerides (34%). PWV was reduced by 6 ± 2% (7.1 ± 0.2 m/s to 6.7 ± 0.2 m/s, P=0.008) and surprisingly, in women, it fell significantly (from 7.2 ± 0.3 m/s to 6.3 ± 0.3 m/s, P=0.028), while no changes were observed in men (7.2 ± 0.3 vs 7.0 ± 0.3 m/s, P=0.144). This is the first study to demonstrate that weight loss can improve PWV in as little as 4 wks and that dietary CHO restriction may be an effective treatment for reducing aortic stiffness in women. Future studies are needed to establish the mechanisms by which dietary CHO restriction may confer more cardiovascular benefits to women compared to men.
Authors
Majid M Syed-Abdul, Qiong Hu, Miriam Jacome-Sosa, Jaume Padilla, Camila Manrique-Acevedo, Colette Heimowitz, Elizabeth J Parks
[link url="https://www.sciencedaily.com/releases/2018/07/180717112456.htm"]University of Missouri-Columbia material[/link]
[link url="http://www.nrcresearchpress.com/doi/10.1139/apnm-2018-0113#.W1Wmy_ZuJYc"]Applied Physiology, Nutrition and Metabolism abstract[/link]