Rates of whole body protein synthesis and breakdown increase with the severity of inflammatory bowel disease.

Rates of whole body protein synthesis and breakdown were estimated in 19 undernourished patients with inflammatory bowel disease from the cumulative nine hour excretion of urinary 15NH3 after intravenous injection of 15N glycine. Thirty six studies were made during constant nutrient input either parenterally by 3 litre bag technique (29 studies), or enterally by nasogastric infusion of protein containing liquid feeds (four studies), or by diet kitchen prepared food eaten at two hourly intervals (three studies). Mean daily intakes were 50.7 kcal and 0.29 g nitrogen/kg body weight. Synthesis and break down rates correlated significantly with disease activity as judged by erythrocyte sedimentation rate and by ranking by an observer unaware of the turnover results. Rates for synthesis and breakdown by this method were about 2.1 and 1.7 g protein/kg/24 h respectively for ESR 10 increasing to 4.0 and 3.3 for ESR 100.