In a recent article published in the Food and Function Journal, researchers performed a cross-sectional study among 525 healthy volunteers who previously participated in nine clinical studies conducted between 2017 and 2021 at King's College London to understand the relationship between (poly)phenol consumption and cardiometabolic health.
Study: (Poly)phenol intake, plant-rich dietary patterns and cardiometabolic health: a cross-sectional study. Image Credit: DanijelaMaksimovic/Shutterstock.com
Type 2 diabetes (T2D) and cardiovascular diseases (CVDs) are the top two causes of death globally. Studies have estimated that of all modifiable risk factors, adopting a healthy diet could potentially prevent many CVD-related deaths.
In addition, diet quality improvement could reduce the incidence of CVDs by >80%, far more effectively than pharmacotherapies.
A recent meta-analysis showed that the higher the consumption of fruit and vegetable (up to 800g), the lower the risk of CVD. Indeed, healthy eating habits are critical determinants of good cardiometabolic health.
Contemporary nutritional studies focus on overall dietary patterns rather than the health benefits of a single nutritious food because people consume a diet that is a combination of multiple foods. For instance, plant-based diets, associated with a positive effect on cardiometabolic health, are high in fruits, vegetables, whole grains, nuts, etc.
Nutritionists have established multiple dietary score systems with varying scoring matrices, e.g., the Plant-based Diet Index (PDI). Other commonly used plant-rich dietary scoring systems are Mediterranean-DASH Intervention for Neurodegenerative Delay (MIND), Mediterranean Diet (MED), and Dietary Approaches to Stop Hypertension (DASH).
There is ample scientific evidence that dietary (poly)phenols promote cardiometabolic health, which, in turn, could decrease CVD mortality manifold. For instance, red wine and olive oil in the MED diet reduce blood pressure and improve serum lipid profile to benefit cardiometabolic health.
In addition, these natural plant compounds, abundant in vegetables, fruits, cocoa products, etc., reduce blood pressure (BP) and increase flow-mediated dilation (FMD).
Researchers postulate that they act by modulating nitric oxide (NO) to maintain the homeostasis of the vascular system, but their exact action mechanism is not yet comprehensible. Overall, there is a knowledge gap regarding the benefits of (poly)phenols on cardiometabolic health and their mechanism of action.
About the study
For the present analysis, researchers asked all consenting participants to complete a Food Frequency Questionnaire (FFQ) and cardiometabolic measurements.
Based on this data, the researchers estimated the (poly)phenol content of each food item listed in the FFQ using a home database created using the open-access Phenol–Explorer (PE) database, USDA database, and multiple published papers.
First, the team applied procyanidin data obtained by High-Performance Liquid Chromatography (HPLC). They used the processed yield factor from the PE database multiplied by the unprocessed raw food content to work out the (poly)phenol content of cooked processed foods.
Alternatively, they applied a factor of a similar food item. Next, the researchers computed (poly)phenol content in mg d−1 using the estimated food consumption multiplied by the corresponding (poly)phenol intake from the home database and divided by 100.
After the PE classified all (poly)phenols, they computed the total and subclasses of (poly)phenols and summed up all compounds within the group. Next, they used Spearman's correlation to test correlations between (poly)phenols.
The researchers used an all-encompassing cardiometabolic health marker panel to investigate how (poly)phenol intake mediated the benefits of plant-rich dietary patterns.
In addition, they used several other cardiometabolic health parameters, such as a 10-year Atherosclerotic Cardiovascular Disease (ASCVD) risk score, anthropometric, lipid profile, glucose metabolism, and vascular function.
The authors noted a positive correlation between (poly)phenols consumption and strictly following dietary scores, except for the unhealthy PDI (uPDI), which showed a negative correlation with (poly)phenol intake.
Correlations of (poly)phenol intake were substantial for healthy PDI (hPDI), and the correlations with proanthocyanidins and flavonols were also positive.
Of all dietary scores, DASH showed the strongest association with cardiometabolic health among all dietary scores investigated. However, DASH negatively correlated with diastolic BP, total, low-density, and non-high-density lipoprotein cholesterol.
While the MIND score showed a positive correlation with FMD, a higher intake of hydroxybenzoic acids, flavan-3-ols, flavonoids, flavan-3-ol monomers, and theaflavins showed a negative correlation with a 10-year ASCVD risk score.
Stilbenes, resveratrol, flavonols, flavones, isoflavones, and anthocyanins did not show any significant association with markers of cardiometabolic health, likely because their intake was low.
Conversely, higher flavanone intake was associated with higher adherence to plant-rich dietary patterns and favorable biomarkers of cardiometabolic risk.
Further, the authors identified flavanone intake as a partial mediator in the negative correlation between TC and DASH, Original MED (O-MED) scores, PDI, and hPDI scores.
In addition, flavanones showed a correlation with cardiometabolic markers, including fasting plasma glucose (FPG) and the Homeostasis Model Assessment (HOMA) of beta cell function.
The study results indicated that the beneficial relationship of plant-rich dietary patterns on cardiometabolic health might partially be driven by the (poly)phenols from the plant-rich food items within the habitual diet.
Nevertheless, higher (poly)phenol intake due to strictly following a plant-rich dietary pattern resulted in a more favorable cardiometabolic health profile, with flavanones being the top mediator of the beneficial effect on lipid profile.
Due to the collinearity between (poly)phenols and micronutrients, more research is warranted to understand the potential independent and synergistic effects of (poly)phenols on CVDs.
It could help find sustainable evidence to recommend a plant-rich diet to promote cardiometabolic health.