Study links red meat consumption to cardiovascular disease in older adults

Chemicals produced in the digestive tract by gut microbes after eating red meat may help explain some of the increased risk of heart disease (MCV) associated with the consumption of this food, according to a new study published in the scientific journal “Arteriosclerosis, Thrombosis, and Vascular Biology”.

Worldwide, cardiovascular disease is the leading cause of death. Although the risk of developing cardiovascular disease, including heart attack and stroke, increases with age, other risk factors are influenced by lifestyle.

The lifestyle and behaviors known to improve health cardiovascular include eating healthy foods, especially fruits and vegetables; regular physical activity; get enough sleep; maintaining a healthy weight; stop smoking; and control high blood pressure, high cholesterol and blood sugar.

“Most of the attention to red meat consumption and health has focused on levels of dietary saturated fat and blood cholesterol. Based on our findings, new interventions may be useful for treating interactions between red meat and the gut microbiota to help us find ways to reduce cardiovascular risk,” says study co-author Dr. Meng Wang, a postdoctoral researcher at the Friedman School of Nutrition Science and Policy at Tufts University in Boston.

Previous research has shown that certain metabolites (chemical by-products of food digestion) are associated with an increased risk of cardiovascular disease. One of these metabolites is el TMAO, trimethylamine N-oxideproduced by gut bacteria to digest red meat which contains high amounts of the chemical L-carnitine.

High levels of TMAO andn human blood may be associated with an increased risk of cardiovascular disease, chronic kidney disease, and type 2 diabetes. However, it is not known whether TMAO and related metabolites derived from L-carnitine may help explain the effects of red meat consumption on cardiovascular risk and the extent to which they may contribute to the cardiovascular risk associated with meat consumption.

To understand these questions, the researchers who conducted this study measured the levels of the metabolites in blood samples. They also examined whether blood sugar, inflammation, pressure blood pressure and blood cholesterol may explain the elevated cardiovascular risk associated with red meat consumption.

The study participants were almost 4,000 of 5,888 adults originally recruited between 1989 and 1990 for the US Heart Health Study. Participants selected for the present study were free of clinical cardiovascular disease at the time of enrollment.

The median age of participants at enrollment was 73, nearly two-thirds of participants were female, and 88% of participants identified as white. The median duration of participant follow-up was 12.5 years and up to 26 years in some cases.

Participants’ medical histories, lifestyle, health conditions, and sociodemographic characteristics, such as family income, education, and age, were assessed during follow-up appointments.

Various blood biomarkers were measured at the start of the study and again in 1996-1997. Fasting blood samples stored frozen at -80°C were tested for levels of various gut microbiomes associated with red meat consumption, such as TMAO, gamma-butyrobetaine and crotonobetaine.

Additionally, all study participants completed two validated food frequency questionnaires about their eating habits. usual dietary intakes, including intake of red meat, processed meat, fish, poultry, and eggs, at the start of the study and again between 1995 and 19996.

In the first questionnaire, participants indicated how often, on average, over the past 12 months they had consumed certain amounts of various foods, ranging from “never” to “almost every day or at least five times a weekbased on average portion size, which varied by food source.

In the second questionnaire, a frequency of ten categories of average intake over the last 12 months was selected, ranging fromnever or less than once a month” to “more than six servings a day», with defined standard portions.

For analysis, the researchers compared risk of cardiovascular disease in participants who ate different amounts of animal foods (i.e. red meat, processed meat, fish, chicken, and eggs).


They found that eating more meat, especially red meat and processed meat, was linked to a higher risk of atherosclerotic cardiovascular disease – a 22% increased risk for every 1.1 servings per day.

According to the authors, the increase in TMAO and metabolites the drugs found in the blood accounted for about a tenth of this elevated risk. They also noted that blood sugar and general pathways of inflammation may help explain the links between red meat consumption and cardiovascular disease.

Blood sugar and inflammation also appear to be more important in the link between red meat consumption and cardiovascular disease than pathways related to blood cholesterol or blood pressure. fish consumptionpoultry and eggs were not significantly associated with an increased risk of cardiovascular disease.

“Research is needed to better understand the potential health effects of L-carnitine and other substances found in red meat, such as heme iron, which has been linked to type 2 diabetes, rather than just focusing on saturated fat,” says Wang.

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