Low-calorie diets impair cardiac function, increase myocardial lipids
In patients with obesity who consumed a very low-calorie diet for 7 days, cardiac function declined and myocardial fat accumulated, according to an abstract presented at CMR 2018.
The diet also improved whole-body insulin sensitivity and hepatic fat, researchers reported.
“The metabolic improvements with a very low-calorie diet, such as a reduction in liver fat and reversal of diabetes, would be expected to improve heart function,” Jennifer J. Rayner, BMBCh, MRCP(UK), clinical research fellow at the Oxford Centre for Clinical Magnetic Resonance at University of Oxford in the United Kingdom, said in a press release. “Instead, heart function got worse in the first week before starting to improve.”
Researchers analyzed data from 21 patients with obesity (mean age, 52 years; 6 men; mean BMI, 37.1 kg/m2) who were on a very low-calorie diet for 8 weeks. Patients consumed between 600 kcal and 800 kcal daily.
Tests were conducted 1 week before, 1 week after and 8 weeks after the diet was initiated, which included an MRI for liver fat and abdominal visceral fat quantification, an echocardiogram to analyze diastolic function and spectroscopy to measure myocardial triglyceride content. Left ventricle structure and function were also reviewed.
At 7 days, visceral fat decreased by 11% (P = .005), total body fat fell by 6% (P < .001) and hepatic fat decreased by 42% (P < .001), whereas insulin resistance (P = .005), triglycerides (P < .01), fasting total cholesterol (P < .01) and glucose improved (P < .01).
Myocardial triglyceride content increased by 44% (P = .038) after 1 week, which led to reductions in systolic (P = .032) and diastolic function (P = .024). This increase was also associated with a change in LV ejection fraction (P = .05) and diastolic function (P = .058).
At 8 weeks, myocardial triglyceride content and cardiac function returned to normal as peripheral metabolic measurements improved from baseline.
“This suggests that although these diet programs are highly effective, they are likely to require careful monitoring in the early stages in individuals with cardiac disease,” Rayner and colleagues wrote. – by Darlene Dobkowski
Rayner JJ, et al. Abstract P084. Presented at: CMR 2018; Jan. 31-Feb. 3, 2018; Barcelona, Spain.
Disclosure s : The authors report no relevant financial disclosures.