Sex‐dependent effects of a low carbohydrate diet‐induced weight loss on aortic stiffness
Authors: Abdul Majid Mufaqam Syed , Hu Qiong , Padilla Jaume , Manrique Camila M , Heimowitz Colette , Le Nhan , Bingham Kimberlee , Parks Elizabeth Jane 
Published: November 2023

Increased arterial stiffness, measured by aortic pulse wave velocity (PWV), is an independent predictor of cardiovascular disease (CVD) and past data suggest that at any given age, obese and insulin‐resistant women are at greater risk for arterial stiffness than men. Weight loss is associated with improvements in arterial stiffness, yet, whether a sexual dimorphism exists for these improvements is not known. The purpose of this study was to determine the changes in arterial stiffness due to significant weight loss in premenopausal women and men.

METHODS

Non‐obese, men (n=10, age: 41±11y, BMI: 34.8±2.4 kg/m2) and premenopausal women (n=10, age: 38±6y, BMI: 33.5±3.8 kg/m2) with characteristics of metabolic syndrome volunteered for a commercial, short‐term, structured weight‐loss program for 4 weeks. Subjects received all foods for the first 2 weeks which included Atkin's products (frozen dinners, bars and shakes), and some freshly‐prepared meals (total fat was 54±4% of energy (%E), protein, 28±2 %E, and CHO 14±1 %E; fiber intake, 26±8 g/d) and resulted in an energy deficit of 1198 ± 655 kcal/d. To mirror the manner in which the program would be used commercially, all subjects were fed the same food, regardless of sex or body size. For the next 2 weeks, subjects prepared their own meals with the goal of achieving a similar food intake. Plasma metabolites and hormones were measured via biochemical assays pre‐ and post‐weight loss.

RESULTS

Both women and men lost a significant amount of weight, although as expected, a sex difference was observed (P=0.002) with women exhibiting less weight loss (−4.5±0.7%, P=0.0002) compared to men (−6.6±0.5%, P<0.0001). Similarly, the reduction in waist circumference was smaller for women (−3.8±1.0 cm, P=0.004) than men (−7.3±1.2 cm, P=0.0002). For the group as a whole, significant changes were observed for plasma glucose (−5±3%, P<0.0001), insulin (−23±6, P<0.002), total cholesterol (−12.5±2.8%, P<0.0001), TG (−27.9±64%, P=0.0001), FFA (+44.3±9.1%, P=0.0001), and ketones (+44.3±9.1%, P=0.0001), with women and men responding the same. By contrast, HDLc and LDLc where significantly reduced in women (P=0.001 and P=0.005, respectively) but not in men. Surprising, aortic PWV was significantly reduced in women (P=0.028, pre: 7.2±0.3 m/s vs. post: 6.3±0.3 m/s) while no change was observed in men (P=0.144, pre: 7.2±0.3 m/s vs. post: 7.0±0.3 m/s). Aortic systolic blood pressure (BP) dropped equally in both women and men (−4.1±1.5% for the group as a whole, P=0.008), as did aortic diastolic BP (−5.9±1.7%, P=0.001) with no effect of sex observed (P>0.24).

CONCLUSIONS

Given that obese and insulin‐resistant women are at increased risk for CVD compared to men, and that increased arterial stiffness is an independent predictor of CVD, these data suggest that weight loss occurring through dietary restriction of sugars may be a particularly effective treatment for reducing CVD risk in women with metabolic syndrome. Future studies will investigate the interaction between dietary carbohydrate intake and sex hormone actions on arterial stiffness in men and women.

Support or Funding Information

Atkins Nutritionals Inc.