January 6, 2025, 4:31 pm | Read time: 6 minutes

Breakfast could be the key to a healthier heart – as long as it meets certain criteria. A new study from Spain found out which factors are important in the morning. FITBOOK nutrition expert Sophie Brünke presents the scientists’ findings.

What Was Studied?

The scientists explain that eating breakfast per se is associated with a lower risk of dying from cardiovascular disease. But how do different compositions of breakfast affect the risk of developing cardiovascular disease? The aim of the study was to identify a link between the choice of certain foods and heart health. The focus was on both the amount of calories and the combination of nutrients^.2

The study was part of the larger PREDIMED-Plus study, which investigated the effects of a Mediterranean diet and lifestyle changes on cardiovascular health. One of the aims was for the participants to lose weight. It is already known that a Mediterranean diet can protect the heart. It was recently voted the healthiest diet of 2024 by medical experts.

Breakfast Was Observed for Three Years

The researchers studied 383 participants between the ages of 55 and 75 who were overweight or obese and had metabolic syndrome. During the three-year study period, their eating habits were surveyed three times. This was done at the beginning, after 24 months, and after 36 months. For this purpose, the test subjects kept a detailed 3-day dietary protocol (two weekdays and one weekend day). Breakfast was defined as any morning food intake. This could be a traditional early breakfast but also a mid-morning snack. The research team analyzed the dietary data in terms of quantity, i.e., the percentage of calories consumed daily at breakfast, and nutritional quality using the Meal Balance Index. This score score evaluates meals based on nine nutritional components.

The scientists also collected data on the subjects’ weight, waist circumference, blood lipid levels, blood pressure, and diabetes markers– all risk factors for cardiovascular disease.

Meal Balance Index
The index evaluates a meal by the content of proteins, fats, fiber, potassium, calcium, and iron, as well as World Health Organization (WHO) recommendations for added sugars, saturated fats, and sodium. Each nutrient is given a score from 0 to 100, with potassium and saturated fat being weighted twice in the final calculation. The higher the score, the better the nutrient quality.

Evaluation of the Collected Data

The researchers categorized the participants based on their breakfasts. When analyzing the data, the participants were divided into three different groups in terms of energy content (quantitative):

• Group 1: Breakfast accounted for less than 20 percent of total energy
• Group 2: Breakfast accounted for 20 to 30 percent of total energy
• Group 3: Breakfast accounted for more than 30 percent of total energy

To assess the quality, the researchers divided the participants into a reference group, which had a low Meal Index Score (below the median, low quality), and an intervention group, which had a high Meal Index Score (above the median, high quality).

The Formula for the Ideal Breakfast to Protect the Heart

So, what does a heart-healthy breakfast look like? According to the authors of the study, the energy content lies in the golden mean. Participants who consumed 20 to 30 percent of their daily energy intake in the morning achieved better results with regard to several cardiovascular risk factors. A daily energy intake of 2000 calories corresponds to a breakfast of 400 to 600 calories. For example, their body weight developed more favorably over the course of the study than participants who ate more or less energy at breakfast. After 36 months, these participants had a two to 3.5 percent lower body mass index. They also had a two to four percent lower waist circumference. They were also able to improve their blood lipid levels. Triglyceride levels decreased by nine to 18 percent, and HDL cholesterol levels increased by four to 8.5 percent.

The results were also positive in terms of breakfast quality. Participants who ate a high-quality breakfast reduced their waist circumference by 1.5 percent. They also had a four percent lower triglyceride level and a three percent higher HDL cholesterol level. The study describes a high-quality breakfast as a meal that contains adequate amounts of protein, high-quality fats, fiber, and minerals such as potassium and iron while avoiding excessive added sugar and saturated fats. This could, for example, be a porridge consisting of oatmeal, nuts, fruit, and some quark as a topping.

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Limitations of the Study

Although the study is based on a large number of participants and extensive data, the authors also acknowledge some limitations. As this was an observational study, no direct cause-and-effect relationships can be proven; the study was only able to show correlations. In addition, all participants were older adults with metabolic syndrome, so the results may not apply to other population groups. As the data were obtained from self-reported food diaries, it cannot be ruled out that they may be incorrect. The study also took place as part of a larger study aimed at weight loss, among other things. Accordingly, the results could be different for people who are not actively trying to lose weight.

Nevertheless, the scientists are satisfied with their results. Karla-Alejandra Pérez-Vega, a researcher at the Hospital del Mar, concludes in a press release: “Promoting healthy breakfast habits can contribute to healthy aging by reducing the risk of metabolic syndrome and related chronic diseases and thus improving quality of life.”³