UK Biobank imaging investigation finds link between meat and heart disease

16 Apr 2021 --- Red and processed meat is associated with worse heart function, according to an observational study of nearly 20,000 people. The UK investigation included imaging measures of heart health, which the researchers say progresses the understanding of the mechanisms behind previously observed connections with cardiovascular disease (CVD).

“Our findings, interpreted in conjunction with other existing evidence, are informative for public health and policy decisions,” study author Dr. Zahra Raisi-Estabragh of Queen Mary University of London tells NutritionInsight.

She points out that examining how meat intake may influence different aspects of cardiovascular health can help us better understand its health effects.

“This was an observational study and causation cannot be assumed. But in general, it seems sensible to limit intake of red and processed meat for heart health reasons,” Raisi-Estabragh states.

The findings suggest that on a population level, greater red and processed meat intake is associated with poorer heart health across all parameters studied.

The associations between imaging measures of heart health and meat intake were only partially explained by high blood pressure, high cholesterol, diabetes and obesity. The researchers also tested the relationships between heart imaging measures and intake of oily fish, which has previously been linked with better heart health. They found that as the amount of oily fish consumption rose, heart function improved and arteries were stretchier.

A host of heart measures
The investigation, which is being presented at European Society of Cardiology’s online scientific congress, included 19,408 participants of the UK Biobank. The researchers examined associations of self-reported intake of red and processed meat with heart anatomy and function.

They then analyzed three types of heart measures:

• Cardiovascular magnetic resonance (CMR) assessments of heart function: Used in clinical practice, these measure volume of the ventricles and the pumping function of the ventricles.
• Novel CMR radiomics: Used in research to extract detailed information from heart images such as shape and texture, which indicates health of the heart muscle.
• Elasticity of blood vessels: Stretchy arteries are healthier.

It was revealed that individuals with higher meat intake had smaller ventricles, poorer heart function and stiffer arteries – all markers of worse cardiovascular health.

The analysis was adjusted for other factors that might influence the relationship, including age, sex, deprivation, education, smoking, alcohol, exercise, high blood pressure, high cholesterol, diabetes and body mass index (BMI) as a measure of obesity.The UK Biobank cohort incorporates information about health and lifestyle of over half a million participants from across the country.

Building on previous studies
Raisi-Estabragh acknowledges that previous studies had linked greater consumption of red and processed meat to poorer clinical cardiovascular outcomes, for example, higher risk of having a heart attack or of dying from heart disease.

“However, the biological mechanisms underlying these relationships are not well understood. Furthermore, the impact of meat intake on more direct measures of heart health, such as structure and function of the heart and blood vessels, has not been previously studied in large cohorts,” she adds.

The study tested the influence of factors like diabetes, high blood pressure, high cholesterol and obesity on the various measures of heart health. Raisi-Estabragh found that although these factors were of some importance, they did not provide a full explanation.

“Therefore, more research is needed to understand alternative disease mechanisms – like the influence of the gut microbiome – in mediating these observed relationships,” she adds.

However, she notes that there is some evidence that red meat alters the gut microbiome, leading to higher levels of certain metabolites in the blood, which have in turn been linked to greater risk of heart disease.”

Room for nuance
These findings are unlikely to put a lid on the debate raging around the health of meat. Commenting on the study, Ian Givens, director of the Institute for Food, Nutrition and Health at the University of Reading, points out that processed meat is likely to pose more of a risk than red meat.

“There is also a very large range of products that fall into the processed meat category, and they vary between countries. Indeed, even red meat is variable as it includes pork, which is not very red,” he adds.

However, Raisi-Estabragh’s team found that, in general, associations were consistent across the different meat types.

Additionally, a US study funded by the Beef Checkoff found that a Mediterranean diet combined with small portions of lean beef helped lower risk factors for developing heart disease, such as LDL cholesterol.

“When you create a healthy diet built on fruits, vegetables and other plant-based foods, it leaves room for moderate amounts of other foods like lean beef,” says Jennifer Fleming, a study co-author and assistant teaching professor of nutrition at Penn State.

She argues that there are still important nutrients in beef that consumers can benefit from by eating lean cuts.

By Katherine Durrell

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