Adopting a low-calorie, green Mediterranean diet could reduce proximal aortic stiffness (PAS), which is a marker for vascular aging and a risk factor to reliably predict morbidity and mortality, new research concludes. In a study looking into the hypocaloric-green Mediterranean (hGreen-Mediterranean), hypocaloric-Mediterranean (hMediterranean) and healthy dietary guideline-directed diet (HDG), the hGreen-Mediterranean diet appeared to promote greater PAS reductions. The Israeli-based research team found that while all interventions were linked to lowering of PAS, the inclusion of plant-based polyphenols in the hGreen-Mediterranean diet may further reduce cardiometabolic risk. “A healthy lifestyle is a strong basis for improving cardiometabolic health,” said Iris Shai, RD, PhD, lead study researcher, from the Ben-Gurion University of the Negev in Israel, in a news release announcing the results. “We learned from the results of our experiment that the quality of the diet is crucial for mobilizing atherogenic adipose tissues, lowering cardiometabolic risk, and improving one's adiposity profile. Dietary polyphenols, substituting red meat with equivalent plant-based protein, show promise for improving various aspects of human health. “However, to date, no dietary strategies have been shown to impact vascular aging physiology," added Shai, who is also an adjunct professor from the Harvard School of Public Health in Boston and the senior author of a research letter reporting the findings. Lifestyle interventions on PAS The DIRECT PLUS study aimed to address the effects of distinct lifestyle interventions on PAS, a secondary outcome of the DIRECT-PLUS (Effects of Green-MED Diet Via the Gut-fat-brain Axis) trial. The study, published Monday online and in the April 18 issue of the Journal of the American College of Cardiology, enrolled 281 participants aged ≥30 years with abdominal obesity/dyslipidemia. These participants were age 51 ± 10.6 years with a body mass index of 31.3 ± 4.0 kg/m2 and were randomly assigned to either the hGreen-Mediterranean (n=94), hMediterranean (n=93) or HDG diets (n=94). The participants had valid baseline PAS measurements, where the baseline PAS (6.1 ± 2.7 m/s) was similar across intervention groups (P=0.20). All study groups were instructed to engage in physical activity. Both hMediterranean diets were similarly hypocaloric (men: 1,500-1,800 kcal/day; women: 1,200-1,400 kcal/day) and included 28 g/day of walnuts. The hGreen-Mediterranean dieters further consumed green tea (3 to 4 cups/day) and a Mankai (Wolffia globose) plant green shake (1 cup) as a meat substitute over 18 months. hGreen-Mediterranean and PAS effect Results revealed that all diet groups showed significant PAS reductions, with the HDG group recording a figure of 0.05 ln(m/s) (interquartile range [IQR]: 0.25 to 0.08 ln[m/s]). This represented a reduction of 4.8%. PAS reduction for the hMediterranean group was 0.08 ln(m/s) (IQR: 0.23 to 0.11 ln[m/s]). This represented a reduction of 7.3%. The hGreen-Mediterranean achieved a PAS reduction of 0.15 ln(m/s) (IQR: 0.31 to 0.02 ln[m/s]). This represented a reduction of 14.0%. (P < 0.05 for within-group changes). The group’s dieters had greater PAS reduction than HDG and hMediterranean dieters (P=0.003 and P=0.032, respectively; multivariable model). “Maintaining a healthy diet alone is associated with PAS regression,” said Gal Tsaban, MD, MPH, study team member, first author of the research letter and a cardiologist from Soroka University Medical Center in Beersheba, Israel, in the news release. “The Green-Mediterranean diet provides a 15% dramatic reduction in PAS, which is gained by making simple and feasible changes to your diet and lifestyle. The results of our study highlight, once again, that not all diets provide similar benefits and that the Green-Mediterranean diet may promote vascular health.” Study limitations and strengths In the research letter, the team noted some study limitations, including the sample population, which comprised mostly men and reflected the unique workplace where the study was performed. The team members also highlighted that during the MRI, they did not measure blood pressure, to which PAS may be sensitive. However, analyses were adjusted for baseline and changes in office mean arterial pressure. The DIRECT-PLUS study also had multiple endpoints; thus, this exploratory post hoc analysis may be sensitive to type I statistical error and should be considered hypothesis-generating by nature. “The study’s major strengths are the highly supervised conditions, the long intervention duration, the use of MRI that allows highly accurate estimation of PAS, the high retention rate, and the intervention-implementation feasibility in real life,” the team concluded. Source: Tsaban G, Shalev A, Katz A, et al. Effect of Lifestyle Modification and Green Mediterranean Diet on Proximal Aortic Stiffness. J Am Coll Cardiol. 2023;81:1659–1661 Image Credit: Hihitetlin – stock.adobe.com