荷兰研究人员在近日举行的北美放射学会年会上公布报告称，限制热量摄入可以改善Ⅱ型糖尿病患者的心脏功能。对这类患者而言，改变生活方式对心脏带的的益处可能比药物更大。

利用心脏核磁共振成像技术，荷兰莱顿大学的研究人员首先测量了15名Ⅱ型糖尿病患者的心脏功能、心包脂肪及身高体重指数。这些患者在随后的4个月内每天饮食仅含有500卡路里的热量，显著低于成年人每天应摄入的基本热量。4个月后，研究人员再次测量了上述指标。结果显示，这些患者的身高体重指数由平均35.3降为27.5，心包脂肪量由平均39毫升降为31毫升，Ｅ/Ａ比值（衡量心脏舒张功能的指标）由0.96提高至1.2。心包脂肪可以作为心脏病风险的指标之一，心包脂肪量越大，患心脏病的几率越大 。

原文：

Restricted Calorie Diet Improves Heart Function in Obese Patients With Diabetes

ScienceDaily (Nov. 28, 2011) - A low-calorie diet eliminates insulin dependence and leads to improved heart function in obese patients with type 2 diabetes, according to a study presented November 28 at the annual meeting of the Radiological Society of North America (RSNA).

"Lifestyle interventions may have more powerful beneficial cardiac effects than medication in these patients," said the study's lead author, Sebastiaan Hammer, M.D., Ph.D., from the Department of Radiology at Leiden University Medical Center in the Netherlands. "It is striking to see how a relatively simple intervention of a very low calorie diet effectively cures type 2 diabetes mellitus. Moreover, these effects are long term, illustrating the potential of this method."

Diabetes is a chronic illness in which there are high levels of glucose in the blood. According to the Centers for Disease Control and Prevention (CDC), diabetes affects 25.8 million people in the U.S., with 18.8 million diagnosed cases and an estimated seven million undiagnosed cases. Type 2 is the most common form of diabetes, representing 90 to 95 percent of diagnosed cases among adults.

Pericardial fat is a visceral fat compartment around the heart that can be detrimental to cardiac function, especially in people with metabolic disease. Dr. Hammer and colleagues set out to determine the long-term effects of initial weight loss induced by caloric restriction on pericardial fat and cardiac function in obese patients with type 2 diabetes.

Using cardiac MRI, the researchers analyzed cardiac function and pericardial fat in 15 patients -- including seven men and eight women -- with type 2 diabetes before and after four months of a diet consisting of 500 calories daily. Changes in body mass index (BMI) were also measured.

The results showed that caloric restriction resulted in a decrease in BMI from 35.3 to 27.5 over four months. Pericardial fat decreased from 39 milliliters (ml) to 31 ml, and E/A ratio, a measure of diastolic heart function, improved from 0.96 to 1.2.

After an additional 14 months of follow-up on a regular diet, BMI increased to 31.7, but pericardial fat only increased slightly to 32 ml. E/A ratio after follow-up was 1.06.

"Our results show that 16 weeks of caloric restriction improved heart function in these patients," Dr. Hammer said. "More importantly, despite regain of weight, these beneficial cardiovascular effects were persistent over the long term."

Dr. Hammer pointed out that these findings stress the importance of including imaging strategies in these types of therapy regimens.

"MRI clearly showed all the changes in fat compartments, structural changes in the heart and improvements in diastolic function, making it a very effective method of quantifying the effects of metabolic interventions," he said.

While these results are promising, not all patients are eligible for this type of therapy. Patients should consult with their doctors before embarking on any type of reduced calorie diet.

"It is of utmost importance to follow such a complicated intervention under strict medical supervision," Dr. Hammer said, "especially as patients may be able to stop all anti-diabetic therapy from Day 1."

Coauthors are Jan W. Smit, M.D., Ph.D., Johannes A. Romijn, M.D., Ph.D., Jacqueline Jonker, M.D., Marieke Snel, M.D., Albert De Roos, M.D., Hildo Lamb, M.D., and Rutger W. Van Der Meer, M.D.