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

Objective: The aim of this study was to determine whether short-term adherence to the Mediterranean diet (MD) was associated with improved physiological function.

Methods: This was a single-center, cohort pilot study with 24 healthy, sedentary younger (18-35 y of age) and older (55-75 y of age) adults. Participants were advised to follow the MD for 4 wk. Baseline and post-intervention measurements were taken of weight, height, waist and hip circumference, blood pressure, and heart rate, as well as microvascular physiological assessments using laser Doppler flowmetry (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 nitric oxide 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 1 mo.

Conclusions: Improvements in physiological function were observed after a short-term dietary intervention based on the MD in a younger population. These were not statistically matched in an older group. Our findings suggest that different durations should be applied when designing dietary interventions in different age groups, with expectations in physiological improvement differing.