Metabolic Changes after Jejuno-Ileal Bypass for Obesity

Abstract

Metabolic parameters were studied in 6 patients before and for 18 months after jejunoileal bypass for obesity. The postoperative changes in plasma concentration of amino acids were characterized by a decrease in essential amino acids, while the non-essential amino acids were unchanged or elevated, indicating a state of protein-caloric malnutrition. The pattern of fatty acids in serum the first year after operation: an unchanged sum of unsaturated and saturated fatty acids accompanied by a significant fall in linoleic acid and a corresponding increase in oleic acid, showed that even during this period the patients were in a state of essential fatty acid deficiency. The oral glucose tolerance test and the levels of serum immunoreactive insulin activity indicated a general improvement in glucose tolerance and a normalization of preoperative hyperinsulinism. A 40-50% reduction was found both in serum triglycerides and cholesterol levels. Serum iron was reduced by approximately 30%, whereas TIBC levels remained unchanged. The Schilling test showed a significant fall in vitamin B₁₂ absorption postoperatively with subnormal values at 6 and 12 months. Vitamin B₁₂ in serum dropped, but remained within the normal range, suggesting that the preservation of 25 cm of distal ileum is sufficient to secure adequate absorption of vitamin B₁₂. Folic acid levels in serum fell after the bypass, demanding supplementation in 5 of the 6 patients at 6 months postoperatively.

Key-words:

• Amino acids
• fatty acids/serum
• glucose tolerance
• obesity
• shunt operation.