By Chukwuma Muanya
Patients with acute heart failure often have high levels of the metabolite trimethylamine N-oxide (TMAO)- of which red meat is a major dietary source- according to researchers from the University of Leicester, United Kingdom (UK).
Red meat, which has been reported to be associated with cardiovascular disease, is a source of L-carnitine, which is broken down by gut bacteria to form TMAO.
In previous studies, TMAO has been associated with mortality risk in chronic heart failure but this association in acute heart failure is still unknown.
The team, led by Professor Toru Suzuki from the University of Leicester’s Department of Cardiovascular Sciences and PI within the Leicester Cardiovascular BRU, measured circulating TMAO levels in approximately 1,000 patients admitted to University Hospitals of Leicester NHS Trust with acute heart failure.
The study, published in the journal Heart, was the first to investigate association of TMAO levels in acute heart failure patients, a condition associated with high mortality and morbidity — and suggests involvement of the gut microbiota and diet in outcomes of acute heart failure.
This study shows an association between circulating levels of a metabolite of this process with prognosis of acute heart failure.
Suzuki said: “Patients with acute heart failure showed higher levels of the oxidised metabolite TMAO in those that died or had a repeat admission to hospital with heart failure within the first year.
“Our study shows that higher levels of TMAO, a metabolite of carnitine derived from red meat, is associated with poorer outcomes associated with acute heart failure, one of the main diseases of the heart.
“This metabolic pathway provides a possible link between how red meat is associated with heart disease.”
Meanwhile, experts have warned that junk food is addictive, and gorging on the guilty pleasure triggers the urge to binge eat.
Highly-calorific fast food floods the brain’s reward system with the feel-good chemical, dopamine.
The hormonal surge makes people want more and more.
In experiments feeding mice plenty of sweetened high-fat food for 24 hours increased the levels of dopamine in their brains, and led them to eat more.
But, when the hormone insulin with injected into the pleasure centre of their brains – a central area known as the ventral tegmental area – researchers noted a drop in appetite.
It is believed the findings published in Proceedings of the National Academy of Sciences could also apply to humans – and could lead to a new way of combating the obesity epidemic.
Dr. Stephanie Borgland, of Calgary University in Canada, said: “In an environment rich with easily accessible, low-cost, palatable food, this plasticity may be a significant driver of overeating.”
She said: “These data indicate mice have increased food approach behaviours and consumption two days after the 24-hour access to the sugary and fatty food.”
Dopamine acts on regions of the brain that regulate movement, emotion, motivation and feelings of pleasure. When activated at normal levels this system rewards our natural behaviours.
But overstimulating the system produces euphoric effects which produces an urge to repeat it.
Borgland said: “In an environment with easy access to highly palatable and energy-dense food, food-related cues drive food-seeking regardless of satiety – an effect that can lead to obesity.
“Priming effects of food-related advertising and consumption of palatable food can drive food intake. However, the mechanism by which this effect occurs, and whether these priming effects last days after consumption, is unknown.
“Here we demonstrate short-term consumption of palatable food can prime future food approach behaviours and food intake.”
But she said insulin – a hormone that controls blood sugar levels and helps you feel full after eating – can reduce food consumption.
Borgland said: “Targeting this circuit with brain delivered insulin may provide a strategy to suppress food cravings.”
Previous research has shown fatty or sugary foods can be as addictive as cocaine.
– The Guardian
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