Study shows calorie restriction keeps heart young
Researchers in Italy and the United States have discovered that people who consume fewer calories in order to live longer have hearts that function more like those of people who are 20 years younger. The findings of the study are presented in the journal Aging Cell. Researchers from Washington University School of Medicine in St. Louis in the United States and Istituto Superiore di Sanità in Rome, Italy identified that a key measure of the heart's capacity to adapt to physical activity, stress, sleep and other elements that impact the rate at which a heart pumps blood doesn't decline nearly as rapidly in people who restrict how many calories they consume for around seven years, compared with the hearts of those who do not limit their caloric intake. 'This is really striking because in studying changes in heart rate variability, we are looking at a measurement that tells us a lot about the way the autonomic nervous system affects the heart,' says Dr Luigi Fontana, a researcher at both the Washington University School of Medicine and the Istituto Superiore di Sanità, and senior author of the study. 'And that system is involved not only in heart function, but in digestion, breathing rate and many other involuntary actions. We would hypothesise that better heart rate variability may be a sign that all these other functions are working better, too.' For this study, the team hooked portable heart monitors to 22 subjects who not only limited their caloric intake by 30 % but who also ate healthily. Each subject was just over 51 years old. To get their results, the researchers also assessed 20 people, also around 51 years old, who followed the typical Western diet. Their results show that the heart rate of the test group was considerably lower than that of the control group. The test subjects also had greater heart rate variability over their 'Western' diet counterparts. 'Higher heart rate variability means the heart can adjust to changing needs more readily,' says lead author Dr Phyllis K. Stein of the Washington University School of Medicine. 'Heart rate variability declines with age as our cardiovascular systems become less flexible, and poor heart rate variability is associated with a higher risk of cardiovascular death.' Dr Stein goes on to say that the study sought to determine whether humans who restrict calories have a similar adaptation in heart rate variability as those found in studies evaluating calorie-restricted animals. 'The idea was to learn, first of all, whether humans on calorie restriction, like the calorie-restricted animals that have been studied, have a similar adaptation in heart rate variability,' adds Dr Fontana. 'The answer is yes. We also looked at normal levels of heart rate variability among people at different ages, and we found that those who practice calorie restriction have hearts that look and function like they are years younger.' While the data is still fresh, the team postulates that eating healthily while restricting calories results in significant change in people. 'In many of our studies, we have found that a number of metabolic and physiologic changes that occur in calorie-restricted animals also occur in people who practice calorie restriction,' Dr Fontana explains, adding that because heart rate variability is better in people who consumer fewer calories, their cardiovascular systems are flexible too. 'But we can't be absolutely positive that the practice of calorie restriction is solely responsible for the flexibility of the cardiovascular system,' Dr Stein says. 'People who practice calorie restriction tend to be very healthy in other areas of life, too, so I'm pretty sure they don't say to themselves, 'Okay, I'll restrict my calorie intake to lengthen my life, but I'm still going to smoke two packs a day.' These people are very motivated, and they tend to engage in a large number of very healthy behaviours.'For more information, please visit: Washington University School of Medicine: http://medschool.wustl.edu/ Istituto Superiore di Sanità http://www.iss.it/ Aging Cell: http://onlinelibrary.wiley.com/journal/10.1111/(ISSN)1474-9726
Countries
Italy, United States