The findings further add to the food’s poor image with its links to cardiovascular disease, Alzheimer’s disease and colon cancer established. The discovery of a metabolic pathway in this study also provides a stronger association between red meat and heart disease.
According to the European Society of Cardiology, 15 million people are living with heart failure in Europe, and it is one of the few cardiovascular conditions whose prevalence continues to rise.
The researchers, led by Dr Toru Suzuki from the University of Leicester's Department of Cardiovascular Sciences and PI within the Leicester Cardiovascular BRU, gathered plasma samples from approximately 1,000 acute heart failure patients admitted to University Hospitals of Leicester NHS
The researchers were interested in trimethylamine N-oxide (TMAO) and the levels found in subject samples. Red meat 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.
Here researchers measured and recorded TMAO levels. Next they looked at the metabolites linked with in-hospital mortality, all-cause mortality, and a composite of death or re-hospitalisation due to heart failure within one year.
The researchers found that acute heart failure patients with elevated levels of TMAO had poorer health outcomes.
The results also indicated that patients with acute heart failure showed higher levels of the oxidised metabolite TMAO than those who died or were re-hospitalized within the first year.
Heart failure patients already have a high hospital readmission rate. A 2012 study published in Circulation found around half of patients readmitted to hospital within six months of discharge.
"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,” said Dr Suzuki.
"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.
Past TMAO investigations
The study is the first to investigate levels of TMAO levels and its link to acute heart failure patients. The findings also suggest a strong association between circulating levels of the metabolite formed from this process with prognosis of acute heart failure.
Previous studies appear to confirm this. A study in 2014, observed high TMAO levels in patients with heart failure and elevated TMAO levels signified higher long-term mortality risk independent of traditional risk factors.
Likewise another study pointed towards using the serum levels of TMAO as a marker of cardiovascular risk in the future.
Published online ahead of print, doi:10.1136/heartjnl-2015-308826
“Trimethylamine N-oxide and prognosis in acute heart failure.”
Authors: Toru Suzuki, Liam M Heaney, Sanjay S Bhandari, Donald J L Jones, Leong L Ng