Red meat consumption increases risk of cardiovascular disease, study says

A study published in the journal Arteriosclerosis, Thrombosis, and Vascular Biology earlier this month revealed that TMAO (trimethylamine n-oxide), a chemical generated in the gut during digestion of red meat, increases the risk of atherosclerotic disease by 20%.

Cardiovascular disease promotes the deposition of fatty plaques in arteries and vessels, which can lead to myocardial infarctions and stroke.

The work is the result of research carried out jointly by Tufts University, in the United States, and the Cleveland Clinic Lerner Research Institute.

The study included 3,931 American subjects over 65 years of age who were followed over 12.5 years. The researchers adjusted for established risk factors such as age, sex, race and ethnicity, education, smoking, physical activity, dietary habits, and others.

Approximately 10% of the disease risk is explained by increased levels of metabolites produced by intestinal bacteria from abundant nutrients in meat, one of which is TMAO.

The greater the amount of red meat, processed or not, is consumed, the danger increases. The proportion is 22% risk for every 1.1 servings consumed per day. However, intake of fish, poultry and eggs was not significantly associated with atherosclerotic cardiovascular disease.

“These findings help answer long-standing questions about the mechanisms that link meats to cardiovascular disease risk,” said one of the paper’s co-authors, Meng Wang, a postdoctoral fellow at Tufts University, in a note on the study.

However, for the nutrologist at HCor (Hospital do Coração), Thalita da Mata, it is necessary to view these results sparingly. “This study is observational. So, we have to be careful when drawing conclusions about it because it cannot prove any cause and no effect.”

The argument is supported by the article itself when it states that “further studies are needed to determine whether the results are generalizable across ages and nationalities”, as the research was based on years of data from the National Institutes of Health. , in Portuguese), focusing on elderly American individuals.

For the Brazilian experts interviewed by the report, the relationship raised by the research was already known, however, it was not known how it took place.

“These recommendations about improving the diet pattern were already known. But the mechanism that justifies these interventions and lifestyle changes is beginning to be discovered”, highlights the cardiologist at the Hospital Alemão Oswaldo Cruz, Leandro Costa.

The cardiologist, senior professor and researcher at InCor (Instituto do Coração, Hospital das Clínicas, Faculty of Medicine, USP), Protásio Lemos da Luz, ratifies. “The research adds one more piece of data to a concept we already have.”

Even so, da Mata affirms the relevance of the research. “This is a very important study because it has shown that higher intakes of animal protein, processed protein and proteins that contain high degrees of preservatives can be worse for our cardiovascular health as a result of the chemicals that are generated in our gastrointestinal tract.”

But after all, how much red meat should you eat for health maintenance? Incor researcher Lemos da Luz says that the amount depends on cardiovascular risk. That is, the dietary protocol must take into account factors such as family history of disease, changes in blood glucose and cholesterol and, finally, the presence of a cardiac event.

Other risks

The study also indicates that TMAO poses other health risks. Cardiologist Salete Nacif, from HCor, pointed out that the metabolite may be behind the higher incidence of diabetes and kidney disease.

In addition, an article published in the journal JAMA Network Open in May of this year pointed out that TMAO and related metabolites in older adults are associated with a higher risk of death, regardless of whether or not it is associated with cardiovascular disease.

Participants with the highest levels of TMAO had a 20-30% higher risk of death compared to those with the lowest levels.

The role of the intestine

The main actor in the production of TMAO is the intestine, whose health is “a topic that is rarely discussed”, according to nutritionist Thalita da Mata. “Our intestine is our second brain. It is a very important organ, because through it we have the modulation of several hormones and several substances. It is where we can degrade these bad substances. These studies show that our intestine is related to the all”.

“The intestinal microbiota is essential because it metabolizes everything we eat”, agrees Protásio Lemos da Cruz, who has been developing studies on the relationship between the intestine and cardiovascular health. “We are starting to study this. The intestinal flora is in the middle of the process that goes from ingestion, digestion and production of substances that go into the blood plasma.”

For cardiologist Leandro Costa, there is still a relationship between the proper functioning of the flora and the type of diet. “The change comes in the long run, not just at the expense of what you use, but the type of microbiota you select from the food choices you make.”

Also according to the cardiologist, individuals with a healthy diet and microbiota, when eating meat or processed foods, are better able to metabolize. “These exceptions are not going to bring about an increase in cardiovascular risk, but the rule,” he says.

In addition to eating a balanced diet and not consuming processed and processed foods, doctors’ guidelines for better intestinal health are: doing regular physical activity, controlling stress levels, quitting smoking, having an adequate amount of sleep every day. and make use of probiotics, if there is medical advice.