Small intestinal bacterial flora and folate status in gastrointestinal disease.

Serumfolate folate levels and the bacteriology of the small intestine were studied in 13 patients with jejunal diverticulosis, 29 patients with partial gastrectomy, and five patients with ileal disease. The mean serum folate level in the patients with partial gastrectomy (7.2 mmug/ml) was similar to that of control subjects but the mean level in the patients with jejunal diverticulosis (14.6 mmug/ml) was significantly higher than the mean level of the control group (8.0 mmug/ml). Five of the 13 patients with jejunal diverticulosis and two of the patients with partial gastrectomy had levels above the upper limit of the control group (> 16.6 mmug/ml), and five of six patients with jejunal diverticulosis studied excreted raised amounts of folate in the urine (> 13.2 mug in 24 hours). Serum folate in one of these patients with jejunal diverticulosis was identified chromatographically as 5-methyltetrahydrofolic acid. The mean serum folate level (9.0 mmug/ml) in the patients with partial gastrectomy who had Esch. coli in the jejunal aspirates was significantly higher than in those without Esch. coli present (mean 4.2 mmug/ml). It is suggested that in gastrointestinal disease jejunal bacteria may contribute to the serum folate level even though this remains in an accepted normal range. Some patients had low serum folate levels despite having a large number of Esch. coli in the jejunum. No evidence of malabsorption of folic acid was found in three such patients even though one had lactobacilli capable of consuming folate in the jejunum. No relationship was found between serum folate level and ileal bacteriology.