Ascorbic acid absorption in patients with systemic sclerosis.
OBJECTIVE
To investigate whether reduced circulating levels of ascorbic acid in patients with systemic sclerosis (SSc) are a result of malabsorption.


METHODS
Eight patients with SSc, but with no evidence of bacterial overgrowth, and 8 healthy controls were recruited. On the first day of study, each subject was given orally an aliquot of [14C] ascorbic acid, which was then "flushed out" by oral intake of unlabeled ascorbic acid for the following 7 days. Plasma samples were collected at specified intervals and urine was collected continuously over the 8 day study period. [14C] content of plasma and urine were measured by scintillation counting. For each subject, a plasma [14C] decay curve was drawn. Each subject's ascorbic acid absorption was assessed using the area under the curve (AUC) and the apparent renal clearance (CLr[app]). Ascorbic acid intake was assessed using dietary history and food composition tables.


RESULTS
There were no differences in the dietary intake of vitamin C (p = 0.16) and body mass indices (p = 0.91) between patients and controls. The plasma [14C] AUC and CLr(app) were similar between patients and controls [AUC patient mean (standard deviation, SD) = 37.1 (6.8), AUC control mean (SD) = 38.6 (9.9), p = 0.74; CLr(app) patient mean (SD) = 0.57 (0.24), CLr(app) control mean (SD) = 0.47 (0.27), p = 0.45].


CONCLUSIONS
There was no evidence of impaired absorption of ascorbic acid in patients with SSc without bacterial overgrowth compared to healthy controls.
Teh
L S
LS
Rheumatic Diseases Centre, Radioisotope Department, University of Manchester, UK.
Johns
C W
CW
Shaffer
J L
JL
Booth
E J
EJ
Aarons
L
L
Bennett
R J
RJ
Herrick
A L
AL
Jayson
M I
MI
D000042:Absorption; D000328:Adult; D001205:Ascorbic Acid / Q000097:blood / Q000493:pharmacokinetics* / Q000652:urine; D015992:Body Mass Index; D002250:Carbon Radioisotopes; D005260:Female; D005769:Gastrointestinal Motility; D006801:Humans; D007422:Intestines / Q000382:microbiology; D008286:Malabsorption Syndromes / Q000378:metabolism / Q000382:microbiology; D008297:Male; D008875:Middle Aged; D012595:Scleroderma, Systemic / Q000378:metabolism* / Q000382:microbiology
D002250:Carbon Radioisotopes; D001205:Ascorbic Acid