UK scientists have linked the consumption of any form of red meat – such as beef, lamb and pork – with a decline in heart function.
The researchers, who studied nearly 20,000 individuals, found that greater intake of red and processed meat was linked with a decline in three different measures of heart health.
Processed meats – such as sausages, salami and cured bacon – are meats that have been preserved by smoking or salting, curing or adding chemical preservatives.
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.
Red meat consumption has already been linked to heart disease – the world’s biggest killer.
Burger lovers could consider switching to the many plant-based alternatives that now line supermarket shelves – which are also better for the environment.
Bad news for burger lovers: An observational study of nearly 20,000 individuals has found that greater intake of red and processed meat is associated with worse heart function
HEART DISEASE: THE WORLD’S BIGGEST KILLER
The world’s biggest killer is ischaemic heart disease, responsible for 16 per cent of the world’s total deaths.
Since 2000, the largest increase in deaths has been for this disease, rising by more than 2 million to 8.9 million deaths in 2019.
Stroke and chronic obstructive pulmonary disease are the 2nd and 3rd leading causes of death, responsible for approximately 11 per cent and 6 per cent of total deaths respectively.
Only last month did another team of researchers from Canada link cardiovascular disease events, like heart attack and stroke, with processed meat consumption.
A 2018 study, meanwhile, found regular consumption of red meat can raise levels of a cardiovascular disease-causing chemical more than 10 times.
The organic compound – TMAO (trimethylamine N-oxide) – is produced in the gut during digestion.
‘Previous studies have shown links between greater red meat consumption and increased risk of heart attacks or dying from heart disease,’ said study author Dr Zahra Raisi-Estabragh of Queen Mary University of London.
‘For the first time, we examined the relationships between meat consumption and imaging measures of heart health.
‘This may help us to understand the mechanisms underlying the previously observed connections with cardiovascular disease.’
The study included 19,408 participants of the UK Biobank – a long-term study investigating the contribution of genes and the environment to the development of health problems.
The researchers examined associations of self-reported intake of red and processed meat with heart anatomy and function.
Cardiovascular disease (CVD) is a general term for conditions affecting the heart or blood vessels. CVD events include heart disease and stroke. All heart diseases are cardiovascular diseases, but not all cardiovascular diseases are heart disease
THE THREE HEART MEASURES
1. Cardiovascular magnetic resonance (CMR) assessments of heart function used in clinical practice such as volume of the ventricles and measures of the pumping function of the ventricles
2. 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)
3. Elasticity of the blood vessels (stretchy arteries are healthier)
Three types of heart measures were analysed – one of which was the elasticity of the blood vessels, which is a sign of good health.
The analysis was adjusted for other factors that might influence the association, 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 researchers found that greater intake of red and processed meat was associated with declined measures of heart health across all measures studied.
Specifically, individuals with higher meat intake had smaller ventricles, poorer heart function and stiffer arteries – all markers of worse cardiovascular health.
As a comparison, 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.
‘The findings support prior observations linking red and processed meat consumption with heart disease and provide unique insights into links with heart and vascular structure and function,’ said Dr Raisi-Estabragh.
Interestingly, the links between the three heart health measures and meat intake were only partially explained by high blood pressure, high cholesterol, diabetes and obesity.
‘It has been suggested that these factors could be the reason for the observed relationship between meat and heart disease,’ said Dr Raisi-Estabragh.
‘For example, it is possible that greater red meat intake leads to raised blood cholesterol and this in turn causes heart disease.
‘Our study suggests that these four factors do play a role in the links between meat intake and heart health, but they are not the full story.’
Dr Raisi-Estabragh noted that the study did not look into alternative mechanisms, and admitted that it did not establish casualty – that red meat causes a decline in heart function.
‘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,’ Dr Raisi-Estabragh said.
The research is being presented at ESC Preventive Cardiology 2021, an online scientific congress of the European Society of Cardiology (ESC), which runs from Thursday to Saturday this week.
SHOULD YOU CUT BACK ON RED MEAT? WHAT THE EVIDENCE SAYS
Meat is a good source of protein, vitamins and minerals in the diet.
The Department of Health advises that we eat no more than 70g (cooked weight) of red and processed meat a day, which is the average daily consumption in the UK.
This is mainly because there is a link between bowel cancer and red meat, such as beef and lamb, and processed meat, such as sausages and bacon.
A 2011 report called Iron and Health from the Scientific Advisory Committee on Nutrition (SACN) assessed evidence on the link between bowel cancer and iron – meat is the main source of iron.
SACN concluded that eating a lot of red and processed meat probably increases the risk of bowel cancer, and advised accordingly.
The American Institute for Cancer Research advises we consume no more than three portions of red meat a week and urges us to ‘avoid’ processed meats.
Processed meat often contains nitrogen-based preservatives that stop it going off while being transported or stored.
These preservatives have been linked to both bowel and stomach cancer.
When red meat is digested, the pigment haem gets broken down in our gut to form chemicals called N-nitroso compounds.
These compounds have been found to damage the DNA of cells that line our digestive tract, which could trigger cancer.
Our body may also react to this damage by making cells divide more rapidly to replace those that are lost.
This ‘extra’ cell division may increase the risk of cancer.
Cancer Research UK says three chemicals in meat are linked to bowel cancer because they damage cells in the gut.
Red and processed meat has also been linked to type 2 diabetes.
This may be due to the preservatives used or the meats’ higher levels of saturated fat than chicken and fish.
However, researchers in Canada, Spain and Poland cast a shadow over eating advice adopted by health organisations around the world in November 2019.
In a landmark paper, the academics analysed past studies of how eating meat affected the health of more than four million people.
The research, published in the journal Annals of Internal Medicine, found no evidence that eating beef, pork and lamb could increase the rates of heart disease, cancer, stroke or type 2 diabetes – despite fears.