After surgery, all of the women were placed on a lower-calorie diet and an exercise program. One group, however, was also provided with regular doses of human growth hormone (somatropin, or Saizen).
Both groups lost similar amounts of weight. But after three months, the women on growth hormone in the months after the surgery lost four times less muscle mass than those in the control group, said Annamaria Colao, of the University Federico II of Naples, Italy, and her colleagues. And the growth hormone receivers lost a lot more fat mass.
The results are significant for the future health of obese women who undergo bariatric surgery because muscle is known to burn calories, contributing to yet more rapid and health-enhancing weight loss.
“The golden goal of every ideal weight-reducing intervention for obesity is to selectively lose body fat while retaining lean body mass,” the scientists wrote, a goal unachievable so far with any weight-loss method. Lower-calorie diets, standard for obese people after bariatric surgery, reduce not only body fat but also muscle. But loss of muscle is a problem for obese stomach-stapled patients “because of the serious complications associated with rapid and sustained weight loss.”
Significant additional pluses for the growth-hormone receivers were that insulin resistance, insulin sensitivity and HDL (“good”) cholesterol proportion improved (whereas those of the control group didn’t) and their arm and leg muscle mass fared better than the control group’s.
The researchers noted, however, that the high cost of growth hormone replacement therapy must be taken into account when deciding whether to prescribe it in post-bariatric surgery situations.