Beet pigment (betacyanin) is renally excreted, and colors acidic urine pink to
deep red. Fourteen percent of normal persons develop visible beeturia after
ingesting beets, perhaps on a genetic basis (McKusick 10960).
However, when 100 g of small beets ("much more than anyone would eat from
free choice") were fed to patients with untreated iron deficiency anemia,1
80% developed beeturia. Of 15 similar patients who had already received iron, only
one developed beeturia, suggesting that betacyanin absorption, and hence
beeturia, occurs at times of "iron hunger." Consistent with this was the 46%
incidence of beeturia in pernicious anemia patients (augmented iron absorption
occurs in this disease during vitamin B12 treatment) and the 33% incidence in
non-anemic patients with both malabsorption and biopsy-proven jejunal
atrophy1 (the jejunum plays an important role in iron
It has been suggested that iron and betacyanin compete for an intestinal acceptor
substance, with iron the preferred ligand. Because beeturia can appear and
disappear in normals, at least some of the "baseline" 14% incidence may be due
to the fluctuating nature of iron absorption in normal people.1
Other effects of vegetables on the sensorium include the olfactory repercussions
of asparagus metabolites in urine (McKusick 10840) and the way artichokes
make water taste sweet to some individuals (McKusick 10832).
(l) Br Med J. 2:271-973 (1963). Study from Scotland.
(2) Annu Rev Med. 34: 55-68 (1983). Review of iron absorption.
Zebra Cards: An Aid to Obscure Diagnoses. JG Sotos. Philadephia: American College of Physicians, 1989. ISBN 0-943126-13-4. Copyright © 1989 American College of Physicians. All Rights Reserved. Phone: 1-800-523-1546.