Aspartame pharmacokinetics - the effect of ageing.
Aspartame is an intense sweetener which is increasingly used in the UK. It is registered at an acceptable daily intake (ADI) of 40 mg/kg, although there are no previous data relating to the metabolism of aspartame in older people. Twelve young and 12 elderly volunteers each received a single dose of approximately 40 mg/kg of aspartame. Baseline concentrations of phenylalanine (the main metabolite of aspartame) rose after ingestion with a significantly higher maximum concentration (Cmax) (81.3 vs. 63.3 micromol/1, p<0.01) and area under the plasma concentration-time curve extrapolated to infinity AUC 9(0-infinity)(518.7 vs. 353.5 micromol . h/l, p<0.01) in the elderly group. The higher concentrations reflected a significant fall in volume of distribution (V) from 2.03 to 1.59 1/kg (p <0.05) and clearance (CL) from 7.3 to 4.9 ml/min/kg (p <0.005) in the elderly group. The greater effect on CL than on V resulted in a small but non-significant rise in elimination half life (3.5 to 3.9 hours). The sizes of the differences were modest implying that there is no need on pharmacokinetic grounds for a change in the ADI for older people.
Puthrasingam
S
S
Department of Health Care of the Elderly, King's College School of Medicine and Dentistry, Dulwich Hospital, E. Dulwich Grove, London E22 8PT, UK.
Heybroek
W M
WM
Johnston
A
A
Maskrey
V
V
Swift
C G
CG
Turner
P
P
Abrams
S M
SM
Jackson
S H
SH
D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D000375:Aging / Q000097:blood*; D001218:Aspartame / Q000008:administration & dosage / Q000493:pharmacokinetics*; D005260:Female; D006801:Humans; D008297:Male; D008657:Metabolic Clearance Rate / Q000502:physiology; D010649:Phenylalanine / Q000097:blood; D010865:Pilot Projects; D012016:Reference Values
D010649:Phenylalanine; D001218:Aspartame