Oral Contraceptive Pill Alters Acute Dietary Protein-Induced Thermogenesis in Young Women.

OBJECTIVE: There is much interest in the role of dietary protein for weight control. However, there remains a need to characterize individual determinants of the thermogenic effects of protein. This study aimed to investigate the influence of menstrual cycle phase and the combined, monophasic oral contraceptive pill on the thermogenic response to a standardized high-protein (HP) versus normal-protein (NP) meal. METHODS: Following an overnight fast, resting energy expenditure (EE) was measured in 16 healthy young women (8 taking and 8 not taking the pill) and 8 men for 30 minutes pre ingestion and 3 hours post ingestion of a NP (11%) or HP (24%) meal. RESULTS: There was no effect of menstrual phase or contraceptive pill use on fasting EE or NP response. However, HP increased EE significantly more than NP in women not taking the oral contraceptive pill and in men, but not in women taking the pill. CONCLUSIONS: This study shows an absence of the greater thermic effect of HP versus NP in women taking the oral contraceptive pill and has important implications regarding the effectiveness of HP for body weight regulation in women. With current obesity treatment/prevention strategies remaining largely ineffective, understanding the relationship between oral contraceptive pill use and protein-induced thermogenesis may enable the successful recalibration of existing dietary recommendations.

Development of insulin antibodies and changes in titers over a long-term period in patients with type 2 diabetes.

BACKGROUND: Recently, insulin analogs have become widely used for the treatment of diabetes. The aim of this study was to determine differences in the antigenicity of insulin analogs and long-term changes in titers in patients with type 2 diabetes. METHODS: Insulin antibodies were examined using polyethylene glycol and protein G methods in 381 patients with type 2 diabetes. RESULTS: Insulin antibodies were detected in 48 of 118 patients (40.7%) who used insulin, and insulin glargine and aspart were more antigenic. Insulin antibodies were unexpectedly found in seven of 263 patients (2.7%) who had never used insulin. Serum insulin concentrations in patients with insulin antibodies were significantly higher than those without them. Two years after the initial evaluation, insulin antibodies were still positive in 92.7% of patients who used insulin; while, they disappeared in all patients who had never used insulin. A patient who stopped insulin injections 6years ago was found to be positive for insulin antibodies at the first evaluation as well as 2years later. CONCLUSIONS: Insulin glargine and aspart induced insulin antibodies more frequently, and insulin antibodies remained in patients for a long time. Insulin antibodies should be suspected even in patients not currently on insulin therapy.