First long-term study on Mediterranean diet’s effect on hypertension
According to the Centers for Disease Control and Prevention (CDC)Trusted Source , hypertension affects nearly half of all adults in the United States.
It occurs when someone’s blood pressure is 130/80 millimeters of mercury (mm Hg) or higher. When left untreatedTrusted Source , hypertension can lead to heart disease , stroke , and even kidney disease .
Some ways in which people can reduce or manage hypertension include making lifestyle changes, such as adjusting their diets and exercising more. Doctors often prescribe medications such as ACE inhibitors and beta-blockers to treat hypertension.
With dietary changes in mind, some diets — such as the Mediterranean diet — focus on consuming more plant-based foods. The Mediterranean diet promotes eating vegetables, fruits, nuts, seeds, whole grains, legumes, healthy oils, and moderate amounts of fish and seafood.
While the hallmarks of the diet should lead to a reduction in hypertension, up to now there have been no long-term studies on this subject.
This led researchers from the School of Health Sciences and Education at Harokopio University of Athens, in Greece, to conduct a study that lasted 20 years to see what benefits adhering to the Mediterranean diet can have.
The study began in 2002 and lasted through 2022. The researchers invited 4,056 people living in Greece to participate, and of that group, 3,042 signed up.
The average age of the participants at the beginning of the study was 41 years, with men making up 44% of the group and women making up 56%. One of the requirements for participating was that participants could not be hypertensive at the beginning of the study.
The researchers collected a variety of information on the participants at the beginning of the study. They made sure the participants did not have cardiovascular disease, checked glucose and cholesterol levels, checked their body weight and blood pressure, and conducted an interview to gauge their dietary and lifestyle habits.
To see how well the participants followed aspects of the Mediterranean diet at the beginning of the study, they assigned them a MedDietScore , scoring positively based on consuming the following food groups:
fruits
vegetables
whole grains
potatoes
legumes
fish
olive oil.
The participants received points based on these food groups. Higher scores indicated better adherence to the diet. Participants could lose points for consuming “non-Mediterranean” foods or food groups, including full-fat dairy products, poultry, and red meat.
Over the next 20 years, the researchers followed up with the participants to assess their MedDietScore, check their vitals, and look for the development of hypertension, high cholesterol , diabetes , and cardiovascular disease .
Mediterranean diet tied to lower hypertension risk
The researchers included 1,415 participants in their final sample. They found that participants who closely followed the Mediterranean diet had the lowest risk of developing hypertension.
Participants in the group who had the lowest MedDietScore – and therefore did more poorly at adhering to the diet – had hypertension rates of 35.5% at the end of the study. The middle group had a hypertension rate of 22.5%.
In comparison, the group with the highest MedDietScore, who adhered to the Mediterranean diet the best, had a hypertension incidence rate was 8.7%.
The scientists also analyzed what differences adhering to the Mediterranean diet had over time. Diet adherence in the study was measured using a longitudinal change in the MedDietScore from the initial assessment in 2002 to a follow-up in 2012.
The researchers were interested in seeing what difference sticking close to the diet consistently, rather than inconsistent adherence, might have.
According to the study paper, “[c]ompared to subjects who were consistently away from the Mediterranean diet, only those who were consistently close exhibited a 46.5% lower 20-year [hypertension] risk.”
Overall, the study results emphasize the importance of eating habits in reducing the risk of developing hypertension. It also shows that the Mediterranean diet can be instrumental in lowering hypertension risk.
What foods are best for cardiovascular health?
Cheng-Han Chen, MD , a board-certified interventional cardiologist and medical director of the Structural Heart Program at MemorialCare Saddleback Medical Center in Laguna Hills, CA, not involved in this research, spoke with Medical News Today about the study.
“In this long-term prospective study, stronger adherence to a Mediterranean diet was found to be associated with a lower incidence of developing hypertension,” noted Chen. “These results support the use of the Mediterranean diet as a heart-healthy eating pattern that can be beneficial to heart health.”
While Dr. Chen mentioned that a top strength if the study was how long it lasted, he also pointed out a key weakness.
“This study was conducted in a homogeneous population (specifically Greek adults), and it is not certain that the results would translate to a more diverse population,” he noted, implying that the findings may not apply to other populations.
Still, there is plenty of evidence to suggest that Mediterranean-type diets bring a variety of health benefits , so opting for this type of dietary pattern is likely to be a positive choice for wellbeing.
However, since some people may find sticking to the Mediterranean diet difficult, Chen said that incorporating at least some aspects of the Mediterranean diet could be beneficial to heart health.
Chen advised that:
“These include eating a diet rich in plant-based foods, healthier monounsaturated fats, lean meats, whole grains, beans, vegetables, and nuts. Foods to avoid are those that are highly processed, higher in saturated fat, and with high sodium.”
Do the findings apply to everyone?
John P. Higgins, MD , a sports cardiologist at McGovern Medical School at the University of Texas Health Science Center at Houston (UTHealth), also spoke with MNT about this study. Like Chen, he was not involved in this research.
“This study adds to the data that lowering blood pressure and preventing development of permanent high blood pressure is possible with a healthy diet,” commented Higgins. “In this case, the Mediterranean diet can reduce your risk of developing blood pressure.”
Like Chen, Higgins said that the study “needs to be reproduced in different populations” to ensure that the results are not only applicable to the Greek population.
The doctor also pointed out that some elements of the diet “improve vascular function – specifically, they boost production of nitric oxide (NO) from the blood vessel wall, which in turn results in vasodilation [the expansion of blood vessels].”
Some foods Higgins highlighted as heart-healthy include bananas, strawberries, and foods higher in polyphenols, such as dark chocolate, tea, and coffee.
Higgins also recommended that people concerned about heart health use a salt substitute when cooking.
“Switch out table salt or cooking salt (NaCl) with a salt substitute like Morton Salt Substitute (potassium chloride salt substitutes) — this not only has no sodium but also has potassium that can actually lower blood pressure,” he said.
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