Mediterranean diet and psychological well-being intervention to reverse metabolic syndrome in Chile (CHILEMED trial)

Psychosocial status and lifestyle are key risk factors of non-communicable diseases (NCDs), which, in turn, are main drivers of healthcare costs and morbimortality worldwide, including Chile. Mediterranean diet (MedDiet) is one of the healthiest dietary patterns under study. However, its impact on high-risk conditions, such as metabolic syndrome (MetS), and NCDs outside the Mediterranean Basin remains mostly unexplored. Even though Central Chile has an environment, food production, and culinary traditions comparable to those present in Mediterranean countries, few studies -some with significant methodological limitations- have evaluated the effect of MedDiet on health and/or disease in Chilean subjects. Importantly, a Mediterranean lifestyle is a modus vivendi that integrates physical health with mental and social well-being. Psychological well-being (PWB) is associated with healthy behaviors, positive health outcomes, and longevity, thereby emerging as a novel healthcare goal. We report here an ongoing randomized controlled clinical trial in Chilean patients with MetS seeking to test whether (1) a PWB theory-based intervention facilitates induction to and increases long-term adherence to a locally adapted MedDiet, and (2) a MedDiet intervention -implemented alone or combined with well-being promotion- is more effective at reversing MetS compared to individuals following a low-fat diet without psychological support. The CHILEan MEDiterranean (CHILEMED) diet intervention study is a 1-year trial including patients with MetS living in Chile. Participants will be assigned randomly by a computer-generated random number sequence to one of the three intervention arms: a) low-fat diet as control group, b) MedDiet alone, and c) MedDiet plus well-being support. Patients will be followed-up by individual and/or group online nutritional sessions or phone cal as well as 6- and 12-month in-person re-assessment of medical history, medication use, food intake, PWB, anthropometrics/physical exam, and blood collection for laboratory analysis. The primary outcome of the trial will be the effect of the MedDiet -with or without PWB intervention- on overall reversal of MetS compared to low-fat diet alone. Based on a statistical superiority trial, expected impact, and patient loss, the estimated study sample is 339 subjects (113 individuals per arm in 3 equal-sized groups). Currently, we have enrolled 179 patients, predominantly women, evenly distributed by age (group means ranging from 45.7 to 48,9 years-old), 3/4 are obese with almost all of them showing abdominal obesity, 70% are hypertensive, whereas <10% exhibit diabetes. If findings turn out as expected (e.g., MedDiet -with or without PWB intervention- is better than the low-fat diet for reversion of MetS at 1-year follow-up), CHILEMED will provide further beneficial evidence of the MedDiet on NCD risk conditions beyond the Mediterranean region.