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Aspartame ingestion and headaches: a randomized
crossover trial.
Van den Eeden SK, Koepsell TD, Longstreth WT Jr, van Belle G, Daling JR,
McKnight B.
Department of Epidemiology, School of Public Health and Community Medicine,
University of Washington, Seattle 98195.
To examine whether ingestion of aspartame is associated with headaches, we
conducted a double-blind crossover study using volunteers with self-identified
headaches after using aspartame. Of the 32 subjects randomized to receive
aspartame (approximately 30 mg/kg/d) and placebo in a two-treatment, four-period
crossover design, 18 completed the full protocol, seven completed part of the
protocol before withdrawing due to adverse effects, three withdrew for other
reasons, two were lost to follow-up, one was withdrawn due to noncompliance, and
one withdrew and gave no reason. Each experimental period was 7 days long.
Subjects reported headaches on 33% of the days during aspartame treatment,
compared with 24% on placebo treatment (p = 0.04). Subjects who were "very sure"
prior to the study that aspartame triggered some of their headaches reported
larger treatment differences (aspartame = 0.37 headache-days, placebo = 0.18
headache-days; p < 0.001) than subjects who were "somewhat sure" (aspartame =
0.29 headache-days, placebo = 0.22 headache-days; p = 0.51) or "not sure"
(aspartame = 0.33 headache-days, placebo = 0.39 headache-days; p = 0.51). There
was no significant treatment difference in the length or intensity of headaches
or in the occurrence of side effects associated with the headaches.
This experiment provides evidence that, among individuals with self-reported
headaches after ingestion of aspartame, a subset of this group report more
headaches when tested under controlled conditions. It appears that some people
are particularly susceptible to headaches caused by aspartame and may want to
limit their consumption.