Mediterranean diet may lower risk of heart diseases, diabetes

As noted in this study, cardiometabolic diseases include conditions like stroke, heart attack, and type 2 diabetes. Having two or more of these conditions is called cardiometabolic multimorbidity.

This research wanted to find if following the Mediterranean diet could decrease the risk for first cardiometabolic disease and cardiometabolic multimorbidity.

Researchers used participant data from the European Prospective Investigation of Cancer (EPIC)-Norfolk cohort study.

The research included 21,900 participants who did not have heart attack, stroke, or type 2 diabetes at baseline. Researchers measured participants’ adherence to the Mediterranean diet using two scores: pyramid-based Mediterranean diet score and median-based Mediterranean diet score.

The median follow-up time was 21.4 years, and researchers looked at the incidences of heart attack, stroke, type 2 diabetes, and death.

They accounted for covariates like age, education, family history of heart attack or stroke, particular medication use, and physical activity levels.

Throughout the study, 5,028 participants experienced one cardiometabolic disease, and 734 participants experienced cardiometabolic multimorbidity.

Overall, following the Mediterranean diet had a demonstrated benefit. Looking at both types of Mediterranean dietary scores, researchers found that following this dietary pattern was associated with a decreased risk for cardiometabolic multimorbidity for the 21.4-year follow-up.

Researchers next focused on how the Mediterranean diet affected transitioning from first cardiometabolic disease to cardiometabolic multimorbidity.

At the 10 and 15-year marks, the Mediterranean diet was associated with a decreased risk of this transition. Further analysis suggested that this observed risk reduction may be particularly related to first experiencing a heart attack or developing type 2 diabetes.

However, over the follow-up of more than 20 years, researchers did not find a statistically significant risk reduction for this transition associated with the Mediterranean diet.

The researchers also conducted some additional analyses to look at how social class may have played into risk association.

Non-manual workers appeared to reap the most benefit from following the Mediterranean diet over the median follow-up of just over 20 years.

This group saw a decreased risk for first cardiometabolic disease and a decreased risk for this first instance transitioning to cardiometabolic multimorbidity. In contrast, manual workers did not appear to have this decrease in transition risk.

Rigved Tadwalkar, MD, a board-certified consultative cardiologist and medical director of the Cardiac Rehabilitation Center at Providence Saint John’s Health Center in Santa Monica, CA, who was not involved in this research, shared his thoughts on the study’s findings with Medical News Today.

According to Tadwalkar, “the study provides strong evidence that adherence to the Mediterranean diet can significantly lower the risk of transitioning from a first cardiometabolic event, like a heart attack or stroke, to additional cardiometabolic conditions, like type 2 diabetes mellitus.”

Moreover, he noted:

“The finding that this association is more apparent in shorter follow-up periods [of] 10–15 years suggests that the protective effects of diet are most impactful in earlier stages of disease development. It also highlights how socioeconomic factors, including social class, may modify dietary impacts on health. Specifically, [it highlights] that diet quality and access to Mediterranean foods may be less accessible to some populations.”

It is also critical to understand the limitations of this research. For example, the data primarily focused on people of European heritage, which limits generalizability.

The participants were also adults aged 40 and older, so looking at younger demographics may be helpful in future research.

Researchers did not identify participants who had baseline chronic coronary syndromes, which could have ultimately led to an overestimation of the Mediterranean diet’s effects. They also did not differentiate between stroke subtypes.

The researchers only measured participants’ adherence to the Mediterranean at baseline, which could have further affected the results.

Moreover, participants also self-reported their dietary choices and adherence, which might not have matched their actual diets. Other information related to lifestyle was also self-reported. Additionally, the scoring methods to measure Mediterranean dietary adherence were not without error risk.

The researchers also acknowledged a few possible reasons why adherence to the Mediterranean diet appeared to have the most effect on the transition from first cardiometabolic disease to cardiometabolic multimorbidity at the 10 and 15-year follow-up periods.

For one, baseline dietary scores could decrease in accurately reporting diet quality over time. Thus, more research may be needed to look at the long-term effects of the Mediterranean diet on this health area.

They also noted a few reasons for the differences between manual and non-manual workers. For example, their research did not look at the specific types of food items, and participants with lower socioeconomic status could have had less variety and less nutritional food.

The results could also be due to the ways in which social class affected other risk factors, such as cardiometabolic disease management and access to preventive care.

Despite its limitations, the study points to a possible way people can take action to decrease their risk for cardiometabolic multimorbidity. There are also other steps people can take to reduce their risk of cardiovascular and metabolic conditions.

Christopher Berg, MD, a board-certified cardiologist at MemorialCare Heart and Vascular Institute at Orange Coast Medical Center in Fountain Valley, CA, who was not involved in this study, explained that “cardiometabolic multimorbidity is defined as an individual having two or more of the following cardiometabolic diseases: heart attack, stroke, or type 2 diabetes.”

“An easy and clear way that people can take to reduce the risk of heart attack, stroke, or type 2 diabetes is nicely summarized as the American Heart Association’s (AHA) ‘Life’s Essential 8‘,” he pointed out.

Berg summarized these recommendations, citing:

1. following a healthy diet, defined by the AHA as a Mediterranean diet, also including a recommendation to avoid or minimize highly processed or ultra-processed foods
2. engaging in physical activity, defined as more than 150 minutes/week of moderate-intensity exercise, such as walking at a brisk pace
3. stopping tobacco use
4. having a healthy amount and quality of sleep
5. maintaining a healthy weight
6. managing cholesterol levels
7. managing blood sugar
8. managing blood pressure.

People can work with their doctors and additional specialists towards these ends.

In addition, it may be important to address potential barriers to people adopting the Mediterranean diet so that more people can take advantage of this healthy dietary option.