Twenty years of research validates mediterranean diet’s role in lowering hypertension risk
A landmark study published in the European Journal of Clinical Nutrition has shed light on the enduring benefits of the Mediterranean diet in preventing hypertension (HTN) over an extensive 20-year period. Conducted among a group of initially non-hypertensive adults, this research marks a significant step in understanding long-term dietary impacts on health.
Hypertension remains a critical challenge globally, significantly influencing the onset of heart diseases and strokes, predominantly in low- and middle-income nations. Despite advancements in medication that stabilise blood pressure, approximately 30% of adults still suffer from HTN, which escalates both the healthcare costs and mortality associated with cardiovascular diseases (CVD). Lifestyle changes such as adopting balanced diets, regular physical activity, and smoking cessation are crucial for managing and preventing HTN. Official health guidelines recommend diets rich in plant-based foods, healthy fats, and lean proteins while being low in sodium and alcohol. The Mediterranean diet, celebrated since the 1960s for its role in preventing chronic conditions and reducing CVD mortality, has lacked long-term concrete evidence of its efficacy in managing blood pressure, prompting further investigation.
The study in question, known as the ATTICA study, complies with the Declaration of Helsinki and explores CVD incidence among Greek adults. Beginning in 2001-2002 with 4,056 individuals from the Attica region invited to participate, 3,042 agreed, embarking on a two-decade-long health journey. Initial assessments involved detailed face-to-face interviews at homes or workplaces by trained health professionals, who collected extensive socio-demographic, clinical, and biochemical data. Key health measures included fasting blood samples for glucose, insulin, total cholesterol, and high sensitivity C-reactive protein levels, among others. Participants also underwent physical examinations to ensure no pre-existing CVD and to measure blood pressure. Lifestyle factors including diet, exercise, and smoking habits were meticulously recorded, using a validated food frequency questionnaire to evaluate adherence to the Mediterranean diet through the MedDietScore.
Throughout the 20-year study period, participant engagement was maintained through regular follow-ups, with the latest in 2022 assessing 2,169 of the original cohort. This follow-up re-evaluated their health outcomes, including HTN, diabetes, and CVD development, corroborating data through family reports and medical records for deceased participants.
Statistical analyses utilised advanced software to contrast initial and 10-year dietary patterns, identifying four distinct adherence trajectories to the Mediterranean diet. Techniques such as correlation coefficients, chi-squared tests, and logistic regression models were employed to ascertain the connection between dietary adherence and HTN risk, accounting for variables like age, sex, body mass index, lifestyle habits, and initial health status.
Findings revealed that at the start, participants averaged 41 years of age with a near-equal gender distribution and showed moderate adherence to the Mediterranean diet, scoring an average MedDietScore of 27.1. Physically, 63.1% were minimally active, and about half were classified as having overweight or obesity. Early medical evaluations noted a 35.3% prevalence of hypercholesterolemia and a 3.9% incidence of diabetes.
Analysis of initial data highlighted a strong negative correlation between adherence to the Mediterranean diet and both systolic and diastolic blood pressures, indicating that higher dietary adherence correlated with lower blood pressure levels. Over the study’s duration, 314 individuals developed hypertension, representing a 22.2% incidence rate. Those who developed HTN typically were older, predominantly male, had higher obesity rates, poorer cardiometabolic profiles, and greater tobacco use compared to those who remained free from HTN.
In-depth analysis demonstrated that participants with low initial MedDietScore faced significantly higher HTN development rates than those with medium or high adherence levels. Statistical evaluation confirmed that each point increase in MedDietScore at baseline correlated with a 7% decrease in HTN risk over 20 years, a relationship that persisted even after adjusting for demographic and lifestyle factors.
The study also examined changes in diet adherence from the start to the 10-year point, revealing varied patterns. Notably, participants consistently adherent to the Mediterranean diet showed a remarkably lower incidence of HTN, with a 46.5% reduced risk in the fully adjusted model, underscoring the diet’s protective effect against HTN when sustained over time.
