Diabetes Patients Reduce Visceral Fat, Using Exercise Alone

Lara C. Pullen, PhD

June 26, 2013

Patients with type 2 diabetes who followed a 6-month exercise program showed decreased hepatic triglyceride (TG) content, as well as decreased visceral abdominal and paracardial fat volume, as measured by magnetic resonance imaging. This suggests a possible reduction in cardiovascular risk as a result of the exercise regimen; however, the patients' cardiac function remained unchanged.

Jacqueline T. Jonker, MD, from Leiden University Medical Center in the Netherlands, and colleagues published the results of their prospective trial online June 25 in Radiology. They documented tissue-specific exercise-induced changes in body fat distribution in 12 patients.

"The major limitation of our study is the small number of patients. Patients acted as their own controls. Despite this small patient number, our data show statistically significant changes in fat distribution with exercise," the authors write.

The study included a 6-month training period with moderate-intensity exercise as well as a trekking expedition with prolonged moderate-intensity exercise. "Mean energy expenditure increased from 2965 kCal/day 6 ± 111 at day 0 to 3439 kCal/day 6 ± 152 at day 192 (P < .01)," the authors note. Mean exercise duration was increased in the trekking expedition compared with the training period. There were no dietary changes.

The authors hypothesized that both epicardial fat compartments and visceral abdominal fat compartments would be similarly affected by exercise. They found, however, that the exercise program correlated with decreased visceral abdominal fat (from 348 ± 57 mL to 219 ± 33 mL; P < .01) and paracardial fat (4.6 ± 0.9 mL to 3.7 ± 0.8 mL; P = .02), but it had no effect on epicardial fat volume. The results, the researchers say, suggest that epicardial fat may have a distinct response to exercise.

Patients began the study with a mean hepatic TG content of 6.8% ± 2.3%. Exercise decreased hepatic TG content to 4.6% ± 1.6% (P < .01). Although the mechanism behind the reduction was unclear, the authors propose that the liver adapts to changes in activity levels by upregulating distinct biochemical pathways for fat metabolism. Exercise did not change myocardial TG content.

Previous studies on the effects of exercise on intramyocellular lipid have offered conflicting results. "To our knowledge, only two studies have examined the effects of exercise on myocardial TG content. Twelve weeks of exercise decreased myocardial TG content in healthy obese patients, but it did not decrease myocardial TG content in patients with type 2 diabetes mellitus. Our study confirms and extends the latter result," the authors note.

Although there was improvement in exercise capacity (as determined by oxygen uptake), the authors measured no change in myocardial function after exercise training, as determined by systolic and diastolic blood pressure, heart rate, left ventricular mass, diastolic function, ejection fraction, cardiac output, and cardiac index.

In terms of clinical implication, the authors state that "[d]ietary interventions or substantial weight loss did not seem to be a requisite for beneficial reductions in visceral abdominal, paracardial, and hepatic fat volume in patients with type 2 diabetes mellitus."

The research was supported in part by the Bas van de Goor Foundation. The authors have disclosed no relevant financial relationships.

Radiology. Published online June 25, 2013.


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