Physiological effects of a short-term lifestyle intervention based on the Mediterranean diet: comparison between older and younger healthy, sedentary adults

Objective: To determine whether short-term adherence to the Mediterranean Diet (MD) is associated with improved physiological function. Research Methods and Procedures: This was a single-centre, cohort pilot study. Twenty-four healthy, sedentary younger (18-35 years) and older (55-75 years) adults took part. Participants were advised and supported to follow the Mediterranean diet for 4 weeks. We took baseline and post-intervention measurements of weight, height, waist and hip circumference, blood pressure, heart rate, as well as microvascular physiological assessments using laser Doppler Fluximetry (LDF) at rest as well as transcutaneous oxygen pressure (TcPO2) during a sub-maximal exercise assessment. Results: We identified statistically-significant improvements in axon-mediated microvascular vasodilation (2.24 (±0.56) to 3.14 (±0.84), P =0.03) and endothelial-mediated NO synthesis (2.59 (±0.67) to 3.32 (±0.87), P =0.022) in the younger group. Despite the intervention not including an exercise element, the rate of perceived exertion was reduced in both groups (p<0.001), after following the MD for a month. Conclusions: Improvements in physiological function were observed following a short-term dietary intervention based on the MD in a younger population. These were not matched in a senior group. Our findings suggest that different durations should be applied when designing dietary interventions in different age-groups, with expectations in physiological improvements differing. Keywords: Mediterranean diet, LDF, Oxygen tension, cardiovascular disease, blood pressure.