Junk food diets increase heart risk, even when meat is cut out

Junk food diets increase heart risk, even when meat is cut out

A major new study shows that being vegetarian doesn't mean healthier. Only healthy, plant-based foods are tied to better heart health.

Study: Association of plant-based diets with subclinical cardiovascular disease in US adults, 1999-2004. Photo credit: 5PH/Shutterstock.com

In a study in theAmerican Journal of Pruventive Cardiology,Researchers at Johns Hopkins University recently analyzed a large-scale data set from a nationally representative sample of U.S. adults and highlighted the potential cardiovascular health benefits of consuming healthy plant-based foods.

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The scientific literature has widely documented the connection between healthy eating habits and cardiovascular health. Current dietary guidelines recommend consuming plant-based foods such as vegetables, fruits, legumes and whole grains for a healthy heart.

A healthy diet characterized by higher intake of plant foods and lower intake of animal foods is associated with a lower risk of cardiovascular disease. However, to accurately understand the impact of different dietary patterns on cardiovascular health, it is important to distinguish between healthy and less healthy plant-based foods.

The present study was designed to determine the effects of healthy and unhealthy plant-based foods on subclinical cardiovascular biomarkers in the general U.S. adult population.

The study

The study analyzed 7,708 participants in the National Health and Nutrition Examination Survey from 1999 to 2004.

Overall, the plant-based diet index, a healthy plant-based diet index, and the unhealthy plant-based diet index were calculated to distinguish between healthy and less healthy plant-based foods. For these indices, participants' consumption of different food groups was assessed in quintiles, with positive or reverse scoring based on whether the food group was considered healthy or unhealthy.

The influence of each plant nutritional index on three cardiac biomarkers, including cardiac troponin T, cardiac troponin I and N-terminal pro-B type natriuretic peptide, was evaluated.

Cardiac troponins are important biomarkers of myocardial damage and are used clinically to diagnose acute myocardial infarction. Subclinical elevations of these biomarkers can be observed in more than 50% of apparently healthy individuals.

On the other hand, N-terminal natriuretic peptide of type Pro-B is a diagnostic and prognostic biomarker for heart failure. It is released by ventricular heart cells in response to the stretching of the ventricular walls (heart chamber). These three biomarkers can be used to monitor the likelihood of cardiovascular disease in people without cardiovascular disease.

In this study population, 2% of adults had elevated cardiac troponin I, 6% had elevated cardiac troponin T, and 15% had elevated NT-Probnp.

Study results

The study found an inverse association between higher adherence to healthy plant-based foods and increased levels of cardiac troponin I in the US population. Compared to those with the lowest adherence, individuals with the highest adherence to healthy plant foods showed 49% lower odds of having elevated cardiac troponin I levels.

The study found a positive association between higher adherence and increased cardiac troponin I levels in relation to unhealthy plant foods. Individuals with higher adherence to unhealthy plant-based foods were 65% more likely to have elevated levels of cardiac troponin I compared to individuals with lower adherence.

Regarding other cardiac biomarkers tested (cardiac troponin T and N-terminal pro-B type natriuretic peptide), the study failed to find significant associations with healthy or unhealthy intake of plant foods.

Investigate significance

The study shows that higher consumption of healthy plant foods was associated with a reduced likelihood of having elevated levels of subclinical cardiac biomarkers. Conversely, higher consumption of unhealthy plant-based foods was associated with increased odds. The study also found that these associations remained significant after controlling for sociodemographic characteristics, lifestyle behaviors and health status. However, as with any observational study, the possibility of confounding cannot be ruled out.

The Dietary Approaches to Prevent High Blood Pressure (DASH) diet is one of the most commonly recommended diets for heart health. It is defined by increased intake of fruits and vegetables and limited intake of saturated fat, cholesterol, red meat, sweets and sugary drinks. Compared to a typical Western diet, the DASH diet significantly reduced cardiac troponin I levels.

Similar to the DASH diet, other healthy diets that emphasize plant-based foods have lower cardiac troponin I levels. These observations and the current study results are consistent with the idea that nutritional quality in plant-based diets is critical to heart health.

The study failed to find a significant association between plant-based food intake and cardiac biomarkers. This finding highlights the importance of distinguishing between healthy and unhealthy plant-based diets rather than focusing solely on the total amount of plant-based foods consumed.

The American Heart Association's current dietary guidelines recommend consuming healthy plant-based foods such as fruits and vegetables, whole grains, and plant proteins to promote cardiovascular health.

The observed heart health benefits may be attributed to specific characteristics of healthy plant-based diets, including high levels of dietary fiber, low saturated fats, and high antioxidants, which may not be present in all plant-based diets.

The study found no significant impact of healthy plant-based diets on the other two biomarkers tested, cardiac troponin T and N-terminal pro-B natriuretic peptide. Previous studies examining the association between diet quality and diet cardiac troponin-T levels have also found no clear association.

Existing evidence on the N-terminal pro-B-type natriuretic peptide shows that sodium intake is the main influencing factor, operating independently of dietary composition. This may explain why the study found no association between plant-based diet quality and NT-ProBNP.

The study considered several cardiac biomarkers and assessed their associations with healthy and unhealthy plant-based diets in a nationally representative sample of U.S. adults after controlling for several potential confounding factors such as sociodemographic characteristics, lifestyle behaviors, and health status. These considerations significantly improved the robustness of the study results.

However, the study used a 24-hour food recall to assess participants' dietary intake, which may potentially lead to misclassification and recall bias. Additionally, due to the cross-sectional design, the study cannot establish causality or determine the changes in cardiac biomarkers over time in response to plant-based diets.

Overall, the study results support that higher intakes of healthy plant-based diets are associated with improved cardiac biomarker profiles. This suggests that healthy plant-based diets may be valuable for promoting cardiovascular health at a population level.

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