Una nueva investigación relaciona el consumo de carne roja con un riesgo 22 % mayor de enfermedad cardíaca

El azúcar en la sangre, la inflamación general y los metabolitos relacionados con el microbioma, como el TMAO, parecen ser más cruciales para regular el riesgo de enfermedades cardíacas que la presión arterial o los niveles de colesterol.

¿Existe una relación entre consumir más carne, particularmente carne roja y procesada, y un mayor riesgo de enfermedad cardiovascular? Si es así, ¿por qué? Los efectos de los alimentos derivados de animales en la enfermedad cardiovascular aterosclerótica (ASCVD, por sus siglas en inglés) son muy discutidos a pesar de la extensa investigación, y aún se desconocen los mecanismos detrás de cualquier posible impacto de las proteínas animales. Comprender los efectos del consumo de carne es crucial para los adultos mayores, ya que corren un mayor riesgo de sufrir enfermedades cardíacas y pueden beneficiarse del consumo de proteínas para contrarrestar el deterioro de la masa muscular y la fuerza que conlleva el envejecimiento.

Los científicos han estudiado a lo largo de los años el vínculo entre las enfermedades cardíacas y las grasas saturadas, el colesterol dietético, el sodio, los nitritos e incluso la cocción a altas temperaturas, pero la evidencia de muchos de estos mecanismos no ha sido sólida. Los datos recientes apuntan a metabolitos específicos producidos por nuestras bacterias intestinales cuando consumimos carne como los posibles culpables subyacentes.

Un estudio reciente dirigido por científicos del Instituto de Investigación Lerner de la Clínica Cleveland y la Escuela de Ciencias y Políticas de Nutrición Friedman de la Universidad de Tufts cuantifica el riesgo de ASCVD asociado con el consumo de carne e identifica las vías biológicas subyacentes que pueden explicar este riesgo. El estudio de más de 4,000 hombres y mujeres mayores de 65 años en los Estados Unidos encontró que una mayor ingesta de carne está asociada con un mayor riesgo de ASCVD (riesgo 22 % más alto por cada 1.1 porción por día) y que los niveles elevados de tres metabolitos generaron por las bacterias intestinales de los nutrientes que prevalecen en la carne explican aproximadamente el 10% de este mayor riesgo. La carne roja se asoció con un mayor riesgo e interconexiones con metabolitos bacterianos intestinales, sin embargo, esto no se encontró para las aves, los huevos o el pescado.

La investigación, que fue publicada recientemente en la revista Arteriosclerosis, trombosis y biología vasculares el primero en examinar las conexiones entre los alimentos de origen animal y el riesgo de eventos de ASCVD, y la mediación de este riesgo por los compuestos generados por la microbiota intestinal, así como por las vías tradicionales de riesgo de ASCVD, como el colesterol en la sangre, la presión arterial y el azúcar en la sangre. .

La investigación se basó en años de datos del Estudio de Salud Cardiovascular (CHS) de los Institutos Nacionales de Salud (NIH), un estudio observacional a largo plazo de los factores de riesgo de enfermedad cardiovascular en estadounidenses de 65 años o más. Se midieron varios biomarcadores sanguíneos al inicio y nuevamente durante el seguimiento, incluidos los niveles de N-óxido de trimetilamina (TMAO) generado por el microbioma intestinal y dos de sus intermediarios clave, gamma-butirobetaína y crotonobetaína, derivados de L-carnitina, abundantes en carne roja.

Reflejos

• En esta cohorte comunitaria de hombres y mujeres mayores de EE. UU., las ingestas más altas de carne roja sin procesar, carne total (carne roja sin procesar más carne procesada) y alimentos de origen animal totales se asociaron prospectivamente con una mayor incidencia de ASCVD durante una mediana de seguimiento. de 12,5 años.
• Las asociaciones positivas con ASCVD fueron mediadas en parte (8-11 por ciento de exceso de riesgo) por[{” attribute=””>plasma levels of TMAO, gamma-butyrobetaine, and crotonobetaine.
• The higher risk of ASCVD associated with meat intake was also partially mediated by levels of blood glucose and insulin and, for processed meats, by systematic inflammation but not by blood pressure or blood cholesterol levels.
• Intakes of fish, poultry, and eggs were not significantly associated with ASCVD.

These findings help answer long-standing questions on mechanisms linking meats to the risk of cardiovascular diseases,” said the paper’s co-first author Meng Wang, a post-doctoral fellow at the Friedman School. “The interactions between red meat, our gut microbiome, and the bioactive metabolites they generate seem to be an important pathway for risk, which creates a new target for possible interventions to reduce heart disease.”

The 3,931 study subjects were followed for a median of 12.5 years, and their average age at baseline was 73. The study adjusted for established risk factors such as age, sex, race/ethnicity, education, smoking, physical activity, other dietary habits, and many additional risk factors.

“Interestingly, we identified three major pathways that help explain the links between red and processed meat and cardiovascular disease—microbiome-related metabolites like TMAO, blood glucose levels, and general inflammation—and each of these appeared more important than pathways related to blood cholesterol or blood pressure,” said co-senior author, Dariush Mozaffarian, dean for policy at the Friedman School. “This suggests that, when choosing animal-source foods, it’s less important to focus on differences in total fat, saturated fat, or cholesterol, and more important to better understand the health effects of other components in these foods, like L-carnitine and heme iron.”

By leveraging extensive clinical and dietary data among a large elderly community, the research “links the gut microbial TMAO pathway to animal source foods and heightened atherosclerotic cardiovascular disease risks,” said co-senior author Stanley L. Hazen, section head of preventive cardiology and rehabilitation at Cleveland Clinic. “The study also argues for dietary efforts as a means of reducing that risk, since dietary interventions can significantly lower TMAO.”

More study is needed to determine if the findings are generalizable across ages and nationalities. The authors also noted that while microbiome biomarkers were directly measured in the blood, study participants’ dietary habits were self-reported, and study findings are observational and cannot prove cause-and-effect.

Ahmed Hasan, a medical officer and program director in the Atherothrombosis & Coronary Artery Disease Branch at the National Heart, Lung, and Blood Institute, part of the NIH, agrees. “While more studies are needed, the current reports provide a potential new target for preventing or treating heart disease in a subgroup of people who consume excessive amounts of red meat,” said Hasan, who was not a part of the study.

For now, consumers are encouraged to follow current recommendations for a heart-healthy lifestyle, including adopting a healthy diet that is rich in vegetables, fruits, whole grains, and other heart-healthy foods, NHLBI’s Hasan said. Other heart-healthy lifestyle changes also include aiming for a healthy weight, managing stress, managing blood pressure, getting more exercise, getting adequate sleep, and quitting smoking, he added.

Higher Levels of TMAO, Related Metabolites Linked to Higher Risk of Death

The ATVB study is part of an ongoing collaboration among scientists at the Friedman School and Cleveland Clinic to uncover the role that the gut microbiome plays in human health, especially cardiovascular health. In a paper in JAMA Network Open in May, many of the same researchers reported that TMAO and related metabolites in older adults are positively associated with a higher risk of death whether deaths were related to cardiovascular disease or another disease. Participants with the highest levels of plasma TMAO and its biomarkers had a 20 to 30 percent higher risk of death than those with the lowest levels.

This study included more than 5,000 participants from the CHS. Findings were notable because there have been few studies on TMAO and the risk of death in the general population; previous research typically looked at clinical patients with underlying conditions such as diabetes, kidney disease, and heart disease. While identified risk factors are concerning, the good news is that TMAO levels are potentially modifiable. “Now that we know more about the severity of risks associated with TMAO, we can explore effective approaches to change these levels in the body,” said the paper’s co-first author, Amanda Fretts of the University of Washington Department of Epidemiology.

References: “Dietary Meat, Trimethylamine N-Oxide-Related Metabolites, and Incident Cardiovascular Disease Among Older Adults: The Cardiovascular Health Study” by Meng Wang, Zeneng Wang, Yujin Lee, Heidi T.M. Lai, Marcia C. de Oliveira Otto, Rozenn N. Lemaitre, Amanda Fretts, Nona Sotoodehnia, Matthew Budoff, Joseph A. DiDonato, Barbara McKnight, W.H. Wilson Tang, Bruce M. Psaty, David S. Siscovick, Stanley L. Hazen and Dariush Mozaffarian, 1 August 2022, Arteriosclerosis Thrombosis and Vascular Biology.
DOI: 10.1161/ATVBAHA.121.316533

“Association of Trimethylamine N-Oxide and Metabolites With Mortality in Older Adults” by Amanda M. Fretts, Ph.D., MPH, Stanley L. Hazen, MD, Ph.D., Paul Jensen, Ph.D., MPH, Matthew Budoff, MD, Colleen M. Sitlani, Ph.D., Meng Wang, Ph.D., Marcia C. de Oliveira Otto, Ph.D., Joseph A. DiDonato, Ph.D., Yujin Lee, Ph.D., Bruce M. Psaty, MD, Ph.D., David S. Siscovick, MD, MPH, Nona Sotoodehnia, MD, MPH, W. H. Wilson Tang, MD, Heidi Lai, Ph.D., Rozenn N. Lemaitre, Ph.D., MPH and Dariush Mozaffarian, MD, Ph.D., 20  May 2022, JAMA Network Open.
DOI: 10.1001/jamanetworkopen.2022.13242

The study was funded by the National Heart, Lung, and Blood Institute. 

Both the ATVB and JAMA Network Open studies support the importance of the microbiome and specific metabolites to human health, with the ATVB paper specifically linking the gut microbiome with meat intake, and impacts on heart health.