Sebastian Hammer, Marieke Snel, Hildo J. Lamb, Ingrid M. Jazet, Rutger W. van der Meer, Hanno Jijl, Edo A. Meinders, Johannes A. Romijn, Albert de Roos, Johannes W. A. Smit
Journal of the American College of Cardiology
Twelve obese patients with type 2 diabetes (average BMI: 35.6 kg/m2, average age: 48.3 years). All were treated with insulin, in some cases combined with oral glucose-lowering medications, with stable weight for the last three months prior to study start.
Obesity and type 2 diabetes are associated with accumulation of triglycerides in organs such as the heart, liver and pancreas. Some studies indicate that accumulation of triglycerides in the heart may have a negative impact on heart function. The study aims to evaluate the effect of a long-term low-calorie diet on myocardial lipid content in obese diabetic patients.
The study was divided into two phases, before and after a 16-week intervention with VLCD (Modifast, 450 kcal/day [in Sweden Modifast was a VLCD product up to the end of 2000, when it was upgraded to an LCD formulation by Impolin AB]).
Three weeks prior to study start, all oral glucose-lowering medications were discontinued, while insulin treatment was intensified. At the start of the VLCD period and throughout the intervention period, all glucose-lowering medications were completely discontinued, including insulin.
Results and discussion:
Caloric restriction reduced BMI from an average of 35.6 kg/m2 to 27.5 kg/m2 (p< 0.001). After 16 weeks, glycemic control had improved significantly and fasting blood sugars dropped from an average of 11.4 mmol/l at study start (despite high-dose insulin as a replacement for oral medications) to 6.7 mmol/l (p <0.001) after the 16-week diet replacement treatment period (without blood glucose-lowering treatment). HgbA1c dropped from 7.9 to 6.3 (p<0,006) and plasma levels of fatty acids (NEFA – non-esterified fatty acids) dropped from 0.92 mmol/l to 0.67 mmol/l (p<0,001).
Plasma levels of liver enzymes, total cholesterol, triglycerides, leptin and CRP also decreased significantly after 16 weeks of diet, while adiponectin levels increased.
After treatment, myocardial triglyceride content decreased significantly, from 0.88 to 0.64 (p < 0.019), while hepatic triglyceride content dropped from 21.2 to 3.0 (p<0.001). Systolic and diastolic blood pressure, as well as heart rate, dropped significantly during the period as a result of the substantial weight loss. In addition, cardiac output (CO) dropped significantly from 7,971 ml/min to 6,508 ml/min (p<0.001) and left ventricular mass (LV mass) dropped from 118 g/m2 to 99 g/m2 (p<0.001).
This study shows that long-term calorie restriction in obese type 2 diabetic patients decreases BMI and significantly improves glucose control. The data also show that triglyceride storage in these patients is flexible and responsive to calorie restriction. Both myocardial and hepatic triglyceride content decreased, while blood pressure, heart rate, lipid levels and insulin sensitivity etc. improved.