In a study of the impact of weight loss on reversing heart damage from obesity, Johns Hopkins researchers found that poor heart function in young obese mice can be reversed when the animals lose weight from a low-calorie diet. However, older mice, who had been obese for a longer period of time, did not regain better heart function after they were on the same low-calorie diet.
“Our research indicates that the longer mice are obese, the greater the risk that their heart damage is irreversible,” says Majd AlGhatrif, M.D., the first author of the study and an assistant professor of medicine at the Johns Hopkins University School of Medicine.
“We don’t know whether the same principle would apply to humans as well, and if so, what the turning point would be. But the basic message is that losing weight sooner rather than later would be more beneficial,” says Lili Barouch, M.D., the senior author of the study and a cardiologist and assistant professor of medicine at the Johns Hopkins University School of Medicine. “It certainly warrants further study to see if the findings would be similar in people,” she says.
The results of the study, “Beneficial Cardiac Effects of Caloric Restriction are Lost with Age in a Murine Model of Obesity,” have been published online ahead print by the Journal of Cardiovascular Translational Research.
Barouch says it’s well-known that obesity increases the risk of cardiovascular disease in people, and some studies have shown that by cutting calories and losing weight, some of the detrimental effects of obesity on the heart can be reversed. But it has not been clear, she says,whether the duration of obesity in people—or their age— makes a difference in terms of the heart’s ability to recover.
To shed light on that issue, the researchers studied the effects of calorie restriction in two groups of mice, one young and one old. The younger mice were 2 months old (young adults in mice years), while the older mice studied were between 6 and 7 months old (similar to middle age).