INTERNATIONAL PROGRAMME ON CHEMICAL SAFETY
WORLD HEALTH ORGANIZATION
SAFETY EVALUATION OF CERTAIN
FOOD ADDITIVES AND CONTAMINANTS
WHO FOOD ADDITIVES SERIES 40
Prepared by:
The forty-ninth meeting of the Joint FAO/WHO Expert
Committee on Food Additives (JECFA)
World Health Organization, Geneva 1998
MALTITOL SYRUP
First draft prepared by
Ms. E. Vavasour
and
Dr. R. Rotter
Chemical Health Hazard Assessment Division
Bureau of Chemical Safety
Food Directorate, Health Protection Branch
Health Canada, Ottawa, Ontario, Canada
1. Explanation
2. Biological data
2.1 Biochemical aspects
2.2 Toxicological studies
2.2.1 Short-term toxicity studies
2.2.1.1 Rats
2.2.1.2 Dogs
2.2.3 Special studies on genotoxicity
3. Comments
4. Evaluation
5. References
1. EXPLANATION
The safety of hydrogenated glucose syrups (also referred to as
maltitol syrups) were evaluated at the twenty-fourth, twenty-seventh,
twenty-ninth, thirty-third and forty-first meetings of the Committee
(Annex 1, references 53, 62, 70, 83 and 107), such syrups are a
subgroup of the hydrogenated starch hydrolysates (HSHs) having a
composition which conforms to specifications designated at the
twenty-ninth meeting. These specifications require that the glucose
syrups used as starting materials have a glucose content of less than
8%, a maltose content greater than 50% and a maltotriose content not
greater than 25%, with the remainder being longer chain glucose
polymers. An ADI "not specified" has been allocated for maltitol
syrups that meet these specifications.
At the forty-sixth meeting of the Committee (Annex 1 reference
122), a review of the specifications for polyol ingredients was
undertaken. It recommended that a joint review of pertinent
toxicological data and specifications was required to support the use
of a broader range of starch hydrogenation products in maltitol syrup
than are currently permitted. By deletion of the specification tests
for hydrogenated saccharides other than maltitol, the theoretical
contents of any of these components in maltitol syrups (sorbitol,
maltotriitol and higher order polyols) could be as high as 49% and
maltitol content could vary from 50 to 98%. Maltitol and sorbitol have
already been evaluated and have been allocated ADIs "not specified".
This monograph addendum reviews the metabolic fate of HSH components
and considers the results of 90-day feeding studies employing two HSHs
that contain more than 49% hydrogenated polysaccharides.
2. BIOLOGICAL DATA
2.1 Biochemical aspects
A number of studies (published and unpublished) that have examined
the metabolic fate of maltitol and higher order polyols were reviewed.
In vitro and in vivo studies, including some utilizing human
intestinal mucosa, indicated that the available glucosidic linkages of
the higher-order polyols in HSH syrups covering a range of polyol
compositions were readily hydrolysed by digestive enzymes to glucose
and maltitol. The glucose units were absorbed in the upper intestine.
Hydrolysis of maltitol occurred more slowly. It was degraded primarily
in the jejunum, but also in the ileum and duodenum. In humans,
metabolism of maltitol was primarily through fermentation by the
intestinal flora. Some absorption of maltitol occurred, but it was
quickly excreted in the urine with little evidence of metabolism.
Human digestion of two HSH syrups (7:60:33 and 14:8:78) in
diabetic (Type I and Type II) and non-diabetic subjects indicated that
they were less glycaemic than glucose in all three test groups. This
was explained by decreased bioavailability of glucose from the HSHs
due to its the slower release in the gastrointestinal tract compared
with directly ingested glucose (Modderman, 1993).
2.2 Toxicological studies
2.2.1 Short-term toxicity studies
2.2.1.1 Rats
A 90-day oral toxicity study was conducted with Lycasin 65/63
(10.5% D-sorbitol, 7.5% maltitol, 25% tri- to hexasaccharide alcohols
and 57% higher-than-hexasaccharide alcohols; 10:8:82) with male and
female Charles River albino rats. Test material was included in
standard rat diets at levels of 0, 2, 5 or 15% (equal to 2.2, 6.2 and
15 g/kg bw per day for males and 2.6, 7.8 and 18 g/kw bw per day for
females) and fed to 15 rats/sex per dose. Each rat was weighed at the
start of the experiment and at weekly intervals thereafter. Feed
consumption was recorded for 5 individual animals/sex per dose each
week during the experiment. The rats were observed daily for signs of
abnormal behaviour or mortality. Blood and urine samples were
collected from 5 fasted rats/sex from the control and high-dose
Lycasin diet groups on days 45 and 84 of exposure (duration of fast
not stated). The blood samples were analysed for: haematocrit, red
blood cell count, haemoglobin, total and differential leukocyte
counts, blood urea nitrogen, serum alkaline phosphatase and serum
glutamic-pyruvic transaminase (alanine aminotransferase) activities
and fasted blood glucose. Urine samples were analysed for glucose,
albumin, microscopic elements, pH and specific gravity. At the end of
the experiment, all surviving animals were sacrificed and necropsied.
The following organs from all animals were weighed: liver, kidneys,
spleen, testes/ovaries, heart and brain. Histological examinations
were performed on 37 tissues/organs (including the adrenal glands and
caecum) from 10 rats/sex fed the control and high-dose Lycasin diets.
No animals died as a result of treatment and there were no effects
of treatment on body weight gain, food consumption, haematological,
clinical chemistry or urinary parameters, organ weights or
histopathogy. The results of this experiment suggest that Lycasin
65/63 was not toxic in rats under the test conditions used. The NOEL
was the highest dose tested, 15% of the diet. This experiment was
conducted by Industrial BIO-TEST Laboratories, Inc. in 1969, prior to
the implementation of GLP. It was audited in 1982 by an independent
auditor and concluded to be substantially accurate. However, many of
the raw data were not available for examination (Industrial BIO-TEST
Laboratories, Inc., 1969a).
Male and female OFA rats (derived from Sprague Dawley rats) were
randomized into 4 treatment groups (20 rats/sex per dose) and fed
diets containing 0, 1.25, 2.5 or 5% hydrogenated dextrin (0:0:100)
(equal to 0, 1.0, 2.0 or 4.0 g/kg bw per day for males and 0, 1.4, 2.8
or 5.2 g/kg bw per day for females) for 13 weeks. The rats were housed
two per cage according to sex. At first exposure, the male rats
weighed an average of 192 g and the females weighed 157 g. The animals
were examined at the start of the experiment and they were observed
daily. Body weight was recorded once each week and feed and water
consumption were noted twice weekly. Ophthalmological examinations
were conducted on all animals after 4 weeks of exposure and at
sacrifice. Under anaesthesia, blood samples were collected from fasted
animals from the orbital sinus after 4 weeks of exposure and from the
vena cava prior to sacrifice. Urine samples were collected after 4
weeks of exposure and on the day of sacrifice. All blood samples were
analysed for cholesterol, triglycerides, glucose, total protein,
aspartate aminotransferase (ASAT), alanine animotransferase (ALAT),
alkaline phosphatase, gamma-glutamyl transferase, urea, creatinine,
sodium, potassium, chloride, magnesium, calcium, inorganic phosphorus
and uric acid. The blood samples collected prior to sacrifice were
also analysed for prothrombin time, cephaline activated time,
cholinesterase activity, albumin, total bilirubin, lactase
dehydrogenase and amylase. All urine samples were analysed for the
following: total protein, glucose, urea, uric acid, sodium, potassium,
creatine, chloride, volume, pH, nitrite, ketone bodies, urobilinogen,
bilirubin and blood. At the end of the experiment, all animals were
sacrificed and necropsied. The following organs were weighed:
encephalon, thymus, heart, liver, spleen, kidneys, adrenal glands,
caecum and testes/ovaries. Histological examination of 36
organs/tissues including adrenal glands and caecum were performed.
Only tissues from the control and high dose groups were examined.
No treatment-related effects were observed on animal health,
weight gain, food or water consumption, no eye abnormalities were
detected and no mortalities occurred during the experiment. No
abnormalities were seen at necropsy and there were no
treatment-related differences in organ weights. Some statistically
significant differences were seen in several blood parameters, but
they were only observed at one time point and in one sex. Many of the
parameters were still within normal ranges and none of the effects
were dose-related. Consequently, these differences were not considered
to be of toxicological significance. The data suggest that
hydrogenated dextrin was not toxic in rats up to the highest dose
tested, 5% of the diet (Roquette Frčres Biology and Toxicology
Department, 1995).
2.2.1.2 Dogs
Pure-bred male (6.7-11.5 kg bw) and female beagle dogs (5.3-9.2 kg
bw), 6.0-6.5 months old, were assigned to 4 treatment groups (4
dogs/sex per dose). The dogs were fed diets containing 0, 2, 5 or 15%
Lycasin 65/63 (10:8:82) (equal to 0, 5, 14 and 43 g/kg bw per day,
respectively) for 90 days. All dogs of the same sex were housed
together according to treatment group. In addition to feeding the
Lycasin-containing food, each dog had unrestricted access to untreated
diet for an addition 3 hours per day. The Lycasin was from the same
lot used in the IBT study on rats described above. The dogs were
observed daily for signs of toxicity. Individual body weight and a
pen-based average food consumption were recorded weekly. Blood samples
were collected on days 0, 42 and 90 of the experiment, and urine
samples were collected on days 0, 42 and 84. Haematological analysis
of the blood samples included determination of haematocrit,
haemoglobin, red blood cells and total and differential white blood
cells. Clinical chemistry analyses of the blood samples were also
conducted to determine blood urea nitrogen, serum alkaline
phosphatase, serum glutamic-oxaloacetic transaminase (aspartate
aminotransferase), serum glutamic-pyruvic transaminase (alanine
aminotransferase) and serum glucose. The urine samples were analysed
for albumin, glucose, pH and microscopic elements. All animals were
sacrificed on day 91 of the experiment and subjected to necropsy. The
following organs/tissues were weighed: liver, lungs, kidneys, heart,
brain, pituitary, spleen, ovary/testes, adrenals and thyroid. Samples
of 30 organs/tissues were removed and prepared for histological
examination.
Body weight gain in male and female dogs receiving the low and mid
doses of Lycasin was lower than in the control animals. The mean
weekly feed consumption was also 14 and 12% lower in the low- and
mid-dose female dogs, respectively. The authors of the report
attributed this to problems with behavioural incompatibility in these
groups rather than an effect of treatment. This is supported by the
lack of dose relationship for these effects. All haematological and
blood chemistry parameters measured were similar across the treatment
groups. No treatment-related lesions or differences in organ weights
were noted. The results of this experiment indicated that Lycasin
65/63 was not toxic in Beagle dogs under the test conditions used.
This experiment was conducted by Industrial BIO-TEST Laboratories
prior to the implementation of GLP. A 1982 audit of the data concluded
that the conclusions of the study were supported by the data. However,
no summary data were supplied with the study and statistics were not
performed (Industrial BIO-TEST Laboratories, Inc., 1969b).
2.2.3 Special studies on genotoxicity
The results of studies on the genotoxicity of hydrogenated dextrin
are presented in Table 1.
Table 1. Results of tests for the genotoxicity of hydrogenated dextrin
End-point Test object Concentration of Results Reference
hydrogenated dextrin
(µg/plate)
Reverse mutation S. typhimurium 50-5000 Negative1 Institute Pasteur
TA98, TA100, TA1535, de Lille (1995)
TA1537
E. coli 50-5000 Negative1 Institute Pasteur
WP2pKM101, de Lille (1995)
WP2urvA.pKM101
1 In the presence and absence of S9 metabolic activation.
3. COMMENTS
The results of metabolic studies in rats and humans indicated that
the higher-order polyol components in HSHs of differing composition
were efficiently hydrolysed in the gastrointestinal tract to glucose
and a small amount of maltitol. Maltitol was hydrolysed less readily
by endogenous enzymes and a considerable portion undergoes
fermentation in the lower gastrointestinal tract. The small amount
that is absorbed is quickly excreted unchanged in the urine.
Animal studies with maltitol syrups composed of up to 41% higher
order polyols were reviewed at the twenty-ninth meeting of the
Committee (Annex 1, reference 70). The toxic potential of two
materials that contain more than 49% of the hydrogenated
polysaccharides, the first containing 10% sorbitol, 8% maltitol and
82% higher-order polyols and the second containing 100% hydrogenated
dextrin, were evaluated in animal feeding studies, and the mutagenic
potential of hydrogenated dextrin was also examined in bacterial
assays. Ingestion of up to 5.2 g hydrogenated dextrin/kg bw per day
for 13 weeks did not result in any treatment-related effects in rats.
No treatment-related toxicity was seen in rats or dogs fed Lycasin
65/63 up to dose levels of 18 and 43 g/kg bw per day, respectively,
for 90 days. Hydrogenated dextrin was not mutagenic in either
S. typhimurium or E. coli bacteria strains in the absence or
presence of rat S9 activation.
4. EVALUATION
On the basis of the above considerations, the Committee confirmed
the previous ADI "not specified" and concluded that it could be
applied to substances meeting the revised specifications.
5. REFERENCES
Industrial BIO-TEST Laboratories, Inc. (1969a) Ninety-day subacute
oral toxicity of Lycasin. Albino rats - BTL-68-25. Unpublished report
No. B6874 from Industrial Bio-Test, dated April 16, 1969 (Submitted to
WHO by Roquette Frčres, Lestrem, France; validated by Booz, Allen and
Hamilton Inc.).
Industrial BIO-TEST Laboratories, Inc. (1969b) Ninety-day subacute
oral toxicity of Lycasin in Beagle dogs - BTL-68-25. Unpublished
report No. C6875 from Industrial Bio-Test, dated May 7, 1969
(Submitted to WHO by Roquette Frčres, Lestrem, France; validated by
Booz, Allen and Hamilton Inc.).
Institute Pasteur de Lille (1995) Mutagenicity test on bacteria
(Salmonella typhimurium his- and Esherichia coli trp-) using
B.N. Ames technique with hydrogenated dextrin. Unpublished report No.
IPL-R 95-0305 from Institute Pasteur de Lille, France, dated March
21, 1995 (Submitted to WHO by Roquette Frčres, Lestrem, France).
Modderman, J.P. (1993) Safety assessment of hydrogenated starch
hydrolysates. Regul. Toxicol. Pharmacol., 18: 80-114.
Roquette Frčres Biology and Toxicology Department (1995) Subchronic
toxicity (13 weeks) by the oral route of Lab 2204 in rats. Unpublished
report No.95041 from Roquette Frčres Biology and Toxicology
Department, dated September 12, 1995 (Submitted to WHO by Roquette
Frčres, Lestrem, France).