efsa-opinion-chromium-food-drinking-water

Chromium in food and drinking water
In a former opinion (EFSA, 2008b), the EFSA Scientific Panel on Food Additives Flavourings,
Processing Aids and Materials in Contact with Food (AFC Panel) referred to a study provided by a
petitioner reporting an animal study, designed to determine the absorption of radioactive chromium
from a chromium amino acid chelate (composition not specified by the petitioner in the application) in
comparison to the absorption of chromium from inorganic trivalent chromium chloride. In this study
two groups of rats were slightly anesthetised and then intragastrically intubated with equal amounts of
chromium as either 51 CrCl 3 or the 51 Cr-amino acid chelate. Blood was drawn at 1-hour intervals for
3 hours and the radioactivity of equal volumes (100 μL) were measured for corrected disintegration
counts per minute. Data show that the absorption of chromium nearly doubled when supplied as
chromium amino acid chelate, in comparison to inorganic chromic(III) chloride.
A review article by Lukaski (1999) summarised two articles on the absorption of chromium and stated
that amino acids when chelating the dietary chromium prevent precipitation within the alkaline milieu
of the small intestine. Similarly, nicotinic acid when administered with trivalent chromium may
enhance absorption.
In the intestine of black ducks, administration of saline solutions of chromium potassium sulphate
(KCr(SO 4 ) 2 ) and chromium trioxide (CrO 3 ) resulted in chromium absorption about 1.5 to 2.0 times
greater than observed with solutions of chromium nitrate (Cr(NO 3 ) 3 ) and the organic salt,
2,4-pentanedione chromium (Cr(C 5 H 7 O 3 ) 3 ) (Eastin et al., 1980). Small differences in the absorption of
Cr(III) between the inorganic salts chromium chloride and chromium nitrate, and the organic salt
chromium picolinate, have been reported, using an in vitro model of the rat jejunum, with a more
efficient absorption of the organic form in comparison to the inorganic salts (Gammelgaard et al.,
1999).
No increase in the absorption of trivalent chromium ( 51 CrCl 3 ) was observed following intraduodenal
or intrajejunal administration in comparison to oral administration in humans and rats (Donaldson and
Barreras, 1966).
The absorption rate of trivalent chromium from chromium polynicotinate, chromium nicotinateglycinate
and chromium picolinate was several times higher than that from chromium chloride, as
indirectly estimated from urinary excretion of chromium in human volunteers (DiSilvestro and Dy,
2007).
Trivalent chromium in the form of propionate or amino acid chelates are also suggested to have a
higher absorption rate than inorganic Cr(III) compounds (Ohh and Lee, 2005).
Other studies reported that oral absorption of Cr(III) complexed with an organic ligand was also very
low and not higher than the absorption of inorganic forms of Cr(III) (Gonzalez-Vergara et al., 1981;
Anderson et al., 1996).
Many dietary factors affect the absorption of Cr(III) and the absorption efficiency of trivalent
chromium salts depends largely on the nutritional status of the animal as well as the nature of the
anion making up the trivalent chromium salt (MacKenzie et al., 1959; O’Flaherty, 1996). Starch,
simple sugars, ascorbic acid, oxalate, nicotinic acid and organic acids were shown to increase the
absorption rate of Cr(III) (Chen et al., 1973; Kozlovsky et al., 1986; Urberg and Zemel, 1987; Seaborn
and Stoecker, 1989; Dowling et al., 1989, 1990; Offenbacher, 1994; Samanta et al., 2008).
Carbohydrate intake has been shown to influence chromium urinary excretion and tissue
concentrations (Lamson and Plaza, 2002). Some amino acids and histamine were reported to result in
a higher chromium absorption rate (Mertz et al., 1965). It has been hypothesized that amino acids act
as chromium ligands, resulting in rapid diffusion of chromium complexes of low molecular weight
(Dowling et al., 1990).
Habitual consumption of acetylsalicylic acid derivatives enhanced chromium absorption (Davis et al.,
1995), while higher phytate, calcium, manganese, titanium, zinc, vanadium and iron inhibited
chromium absorption (Mertz, 1970; Chen et al., 1973; Hill, 1975).
In rats co-administration of 51 CrCl 3 with phytate and with oxalate significantly decreased and markedly
increased, respectively, chromium absorption (Nelson et al., 1973). Experiments with rats given
EFSA Journal 2014;12(3):3595 63