Impaired Glucose Tolerance in Healthy Men Treated with St. John's Wort.
The purpose of this study was to examine whether the over-the-counter herbal medicinal plant St. John's wort affects glucose tolerance in healthy men. To do this, we included 10 healthy men who were examined by a 2-hr oral glucose tolerance test on three occasions: A: baseline; B: after 21 days of treatment with St. John's wort; and C: at least 6 weeks after the last capsule of St. John's wort was ingested. Plasma glucose, serum insulin and C-peptide levels were measured during an oral glucose tolerance test and used for estimation of area under the concentration-time curve (AUC) as well as indices of insulin sensitivity and insulin secretion. We found that treatment with St. John's wort increased total and incremental glucose AUC and 2-hr plasma glucose levels. Surprisingly, this effect was sustained and even further increased 6 weeks after the last capsule of St. John's wort was taken. No effect on indices of insulin sensitivity was seen, but indices of insulin secretion were reduced even after adjustment for insulin sensitivity. In conclusion, this study indicates that long-term treatment with St. John's wort may impair glucose tolerance by reducing insulin secretion in young, healthy men. The unregulated use of this over-the-counter drug might be a risk factor for impaired glucose tolerance and type 2 diabetes.
Clinical Pharmacology, Department of Public Health, University of Southern Denmark, Odense, Denmark.
Tore Bjerregaard
TB
Stage
Clinical Pharmacology, Department of Public Health, University of Southern Denmark, Odense, Denmark.|Department of Clinical Chemistry and Pharmacology, Odense University Hospital, Odense, Denmark.
Per
P
Damkier
Clinical Pharmacology, Department of Public Health, University of Southern Denmark, Odense, Denmark.|Department of Clinical Chemistry and Pharmacology, Odense University Hospital, Odense, Denmark.
Mette Marie Hougaard
MM
Christensen
Department of Psychiatry, Odense University Hospital, Unit of Svendborg, Svendborg, Denmark.
Lene Buch-Krogh
LB
Nielsen
Department of Endocrinology, Odense University Hospital, Odense, Denmark.
Kurt
K
Højlund
Clinical Pharmacology, Department of Public Health, University of Southern Denmark, Odense, Denmark.
Kim
K
Brøsen
D000293:Adolescent; D000328:Adult; D015415:Biomarkers / Q000097:blood; D001786:Blood Glucose / Q000378:metabolism; D015992:Body Mass Index; D002096:C-Peptide / Q000097:blood; D004305:Dose-Response Relationship, Drug; D018149:Glucose Intolerance / Q000097:blood / Q000139:chemically induced*; D006442:Glycated Hemoglobin / Q000378:metabolism; D006801:Humans; D020902:Hypericum / Q000009:adverse effects* / Q000737:chemistry; D007328:Insulin / Q000097:blood / Q000378:metabolism; D007333:Insulin Resistance; D000078790:Insulin Secretion; D008297:Male; D010946:Plants, Medicinal / Q000009:adverse effects* / Q000737:chemistry; D018401:Sample Size; D055815:Young Adult
D015415:Biomarkers; D001786:Blood Glucose; D002096:C-Peptide; D006442:Glycated Hemoglobin; D007328:Insulin