Heart disease and red meat correlation may not be about saturated fat
The nutrient L-carnitine, which is found in red meat and used as a dietary supplement, is associated with cardiovascular disease in people and causes cardiovascular disease in mice, according to a new study by US researchers.
The results of the study, published today in the Advanced Online version of the journal ‘Nature Medicine’, point to L-carnitine, rather than saturated fat and cholesterol, as explaining the link between consumption of red meat and cardiovascular disease.
The research suggests that the bacterial gut flora that forms in meat eaters to properly digest the l-carnitine in red meat is then changed by the liver into a chemical that damages the arteries supplying the heart and brain. This damage to the arteries increases the risk of stroke and heart disease.
“The same has been known for some time about choline, which is found in lecithin (a fatty substance used as a food additive and dietary supplement). It is increasingly evident that neither carnitine nor choline may be safe as nutrient supplements, and that the safest way to obtain them from the diet is from a varied plant-based diet,” said Mark Wahlqvist, Emeritus Professor of Medicine at Monash University and Past President of the International Union of Nutritional Sciences.
But other Australian experts have also suggested that the outcome of the research for dietary advice is more complicated than it might initially seem.
“These results add further support to previous substantial research showing that excessive meat consumption is associated with increased risk of a range of chronic diseases,” said Shawn Somerset, Associate Professor of Public Health at the Australian Catholic University.
“[But] Meat is an excellent dietary source of iron and a range of other minerals and there are some Australians with insufficient intakes of these nutrients. The public health challenge continues to centre around developing strategies to prevent deficiencies in these nutrients whilst avoiding the adverse consequences of excessive meat consumption,” said Professor Somerset.
Professor Garry Jenkins, Director of the Baker IDI Heart and Diabetes Institute, points out that carnitine is needed by the body to help oxidise fat.
“While this paper makes some clever observation, the overall evidence that red meat is harmful is not consistent with a broader body of evidence. Some studies have shown a moderate adverse effect, others only with processed meats and other have shown no risk associated with red meat,” said Professor Jenkins.