For decades, the health benefits of a Mediterranean diet have been well documented and well known. Now, a new study published in the journal Heart has revealed the even more extensive benefits of what is known as a green Mediterranean diet (‘green Med’), which contains higher proportions of plant matter and even less red meat or poultry.
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The results of the study hint that the green Med diet may be effective at lowering the risk of diabetes, heart disease, and stroke in those who consume this diet, or in men, at least. The impact of this diet is thought to be linked to the higher level of polyphenols, or 'healthy' fats, associated with the green Med diet.
Investigating the impact of a ‘greener’ Mediterranean diet
The study’s researchers aimed to investigate the health benefits of the greener version of the Mediterranean diet. To do this, they recruited 294 individuals who were classed as both sedentary and moderately obese (with a BMI of at least 31) and allocated them into three dietary groups.
Group one was given guidance on how to increase their physical activity as well as how to eat a generally healthy diet. Group two received the same guidance on physical activity and also received advice on how to follow a traditional Mediterranean (calorie-restricted to 1500-1800 kcal/day for men and 1200-1400 kcal/ day for women).
The diet that group two consumed was low in simple carbohydrates, high in vegetables, and substituted red meat with fish and poultry. Group three also received advice on physical activity as well as advice on following the green Med diet. This consisted of higher levels of plant matter, none/limited red or processed meat, and a portion of walnuts. Green teas and Wola globosa were also incorporated into this diet.
The participants followed their physical activity and diet guidance for six months. Following this, the team analyzed the impact of the separate interventions on the groups’ weight loss and their cardiovascular and metabolic risk factors.
The study’s results revealed that participants consuming either type of Mediterranean diet lost more weight than the group that did not. In addition, researchers found that participants’ waist circumference, known to be a key indicator of numerous health issues, was reduced by an average of 8.6 cm in those consuming the green Med diet, greater than the 6.8cm average shrinkage measured in those consuming the Mediterranean diet and the 4.3 cm average waist circumference reduction of those consuming the healthy diet.
Further to this, the results show that those in the green Med group demonstrated the largest falls in 'bad' low-density cholesterol. Data also showed that cardiovascular and metabolic risk factors improved greatly in the green Med group, showing better improvements than any other group. The team witnessed significant reductions in diastolic blood pressure, insulin resistance, and the C-reactive protein, all indicators of poor health.
The changes in these risk factors in the green Med group equated to almost a two-fold reduction in the 10-year Framingham Risk Score, a measure constructed to predict how likely an individual is to suffer heart disease over the following decade.
While the study’s participants were mainly men and therefore the results cannot be generalized across genders, the study’s results are significant and warrant further research to determine the impact of the green Med diet on various cohorts and health indicators.
Restricting meat consumption for a healthier life?
The team’s authors state that "Education and encouragement to follow a green Med dietary pattern in conjunction with physical activity has the potential to be a major contributor to public health as it may improve the balancing of cardiovascular risk factors, eventually preventing cardiovascular morbidity and mortality.” Suggesting the key role of the green Med diet, alongside exercise, in preventing key causes of mortality.
Tsaban G, Yaskolka Meir A, Rinott E, et al, The effect of green Mediterranean diet on cardiometabolic risk; a randomised controlled trial, Heart Published Online First: 23 November 2020. doi: 10.1136/heartjnl-2020-317802