FAO Nutrition Meetings 
    Report Series No. 48A 
    WHO/FOOD ADD/70.39


    The content of this document is the 
    result of the deliberations of the Joint 
    FAO/WHO Expert Committee on Food Additives 
    which met in Geneva, 24 June  -2 July 19701

    Food and Agriculture Organization of the United Nations
    World Health Organization


    1 Fourteenth report of the Joint FAO/WHO Expert Committee on Food
    Additives, FAO Nutrition Meetings Report Series in press; Wld Hlth
    Org. techn. Rep. Ser., in press.


    Biological data

    Biochemical aspects

         The incorporation of inorganic S35 into protein polysacarchides
    was used as a test system to determine the effects of sodium and
    calcium cyclamate on membrane processes. Normally over 98% of S goes
    into the macromolecule, less than 2% into S-containing amino-acids.
    This was unaffected by the addition of cyclamate (Wortman et al.,

         C14-labelled cyclamate was shown to have an average serum
    half-life of 8 hours in dogs and rats. 32% of plasma cyclamate is not
    protein bound. All tissues except the brain were shown to contain
    cyclamate. Milk levels of cyclamate in lactating dogs were higher than
    blood levels and amounted to 1% of the dose of cyclamate/1 milk
    (Sonders & Wiegand, 1968).

         C14-labelled orally given cyclamate was excreted in the urine
    and faeces of rats after 3 days as follows: 20-30% appeared in the
    urine, 70-80% in the faeces, 0% in the expired air. Urinary excretion
    of C14-material was higher in converters due to the additional
    excretion of C14-CHA (Lethco et al., 1969).

         Sodium or calcium cyclamate fed to female Holtzman rats at a dose
    level of 1 g/kg produced no hepatic microsomal enzyme induction as
    measured by the N-demethylase, O-demethylase and phosphorothioate
    detoxification activities. A 10:1 calcium cyclamate/calcium saccharin
    mixture produced a small increase in activity attributable to the
    saccharin (DuBois & Kinoshita, 1968).

    Cyclohexylamine (CHA) conversion


         Four groups of 35 male and 45 female rats were fed a 10:1 sodium
    cyclamate/sodium saccharin mixture at 0, 500, 1120 and 2500 mg/kg
    bodyweight per day for their lifespan. After 27 and 34 weeks
    examination of the urines from each dose level showed a greater
    percentage of converters at higher dose levels. Rats were either
    non-converters (less than 0.1% of daily cyclamate ingested excreted
    CHA in the urine), low converters (0.1-0.7% CHA of daily cyclamate
    ingested excreted in the urine) or high converters (1% or more CHA of
    daily cyclamate ingested excreted in the urine). Converting ability of
    rats appeared to vary from time to time (Oser et al., 1968). Rats
    pre-treated with water containing 0.5% calcium cyclamate were found to
    develop the ability to convert cyclamate into CHA.  Such pre-treated
    rats were given 14C-labelled cyclamate I.P. and unlabelled cyclamate
    orally. Gas-liquid chromatography and scintillation counting of the
    urine at 24 hours showed that 0.9% of the cyclamate giver I.P. was

    converted to CHA but about 38% of the cyclamate given orally was so
    converted. About 90% of the injected cyclamate was excreted in the
    urine at 24 hours compared with 58% of the cyclamate given orally.
    When pre-treated rats were taken off the cyclamate containing diet the
    ability to produce CHA from cyclamate fell to a low level (Renwick &
    Williams, 1969), Groups of Holtzman rats were fed calcium cyclamate at
    levels of 0 and 0.1% for 8 months. Twelve rats from each group were
    then intubated with 14C-cyclamate following which urine and faeces
    were collected for 5 days. None of the controls showed a conversion of
    the labelled cyclamate to CHA, dicyclohexylamine or
    hydroxycyclohexylamine. Seven of 11 cyclamate-fed rats converted
    cyclamate to CHA, the labelled CHA accounting for 12 to 25% of the
    total radioactivity seen in the urine. Traces of radioactive
    dicyclohexylamine were seen in 2 of the urine samples (Prosky &
    O'Dell, 1970).

         The ability of rats to convert cyclamate to CHA can be
    transferred to non-converter rats either by bodily contact with
    converter rats for only 4 days or by contact with faeces from
    converters (Unilever Research Labs, 1970). Groups of 7 male and 7
    female rats were fed for 1 year on diets containing either sodium or
    calcium cyclamate at 0, 0.4%, 2% and 10% levels. 24 rats acted as
    controls. 53 oat of 53 rats became converters of which 25 excreted
    less than 0.1% of ingested cyclamate as ChA, 16 excreted 0.1-1.0% of
    ingested cyclamate as CHA and 12 excreted 2-38% of ingested cyclamate
    as CHA. A G-ve bacterial red was isolated from the faeces of converter
    rats that was capable of converting cyclamate to CHA in vitro but
    lost this ability after several passages. Generally it was not
    possible to obtain conversion of cyclamate to CHA by incubating
    intestinal contents from various gut levels with cyclamate (Lethco et
    al., 1969).

         The contents of the hind gut of rats pre-treated with cyclamate
    converted 0.8-3.5% of ingested cyclamate into CHA aerobically and
    0.4-2.5% anaerobically. Liver, kidney, spleen and blood from these
    rats failed to convert cyclamate to CHA (Renwick & Williams, 1969).

         Feeding antibiotics, e.g. neomycin, to converter rats inhibited
    the conversion of orally administered cyclamate to CHA. One rat which
    converted 14% of oral cyclamate and 1% of i.v. cyclamate to CHA lost
    this ability completely (Sonders, 1969).


         Dogs given orally 100 mg/kg bodyweight/day were found to convert
    up to 0.1% of the ingested cyclamate to CHA. The C14 of C14-labelled
    cyclamate took longer to clear from the body after prolonged
    consumption compared with clearance after a single dose. Incubation of
    C14-cyclamate with large and small gut contents produced 0.13-0.25%
    conversion of cyclamate to C14 CHA, possibly by Clostridium
    perfringens (Goldberg et al., 1968; 1969).


         Four pigs were shown to be able to convert orally fed cyclamate
    to CHA. When neomycin was given to 2 pigs conversion was completely
    inhibited. S.c. injection of cyclamate into 2 converter pigs for 8
    days produced no CHA. No cyclamate appeared in the faeces and the
    whole dose was excreted in the urine. Only anerobic incubation of
    intestinal contents from the large colon produced CHA from cyclamate
    hence this may be the probable site of conversion in the pig (Unilever
    Research Labs., 1970).


         Various subjects given 512 mg/day of cyclamate orally converted
    from 0-28% of the ingested cyclamate to CHA within 3-5 days after
    starting consumption. Other metabolites identified were cyclohexanone,
    cyclohexanol and N-hydroxy cyclohexylamine (Goldberg et al., 1968;
    1969). 40 volunteers showed 5 converters at about 0.8% of the dose and
    one subject converting 0.5% to CHA (Huntingdon Laboratories, 1967).
    Forty-nine children, aged 3 to 10, consumed 516 mg of cyclamate per
    day for 4 days. On the 4th day a 24-hour urine sample was collected
    and assayed for cyclamate and CHA. 4 of the 49 children excreted 3.4
    mg, 22 mg, 54 mg and trace amounts of CHA respectively. The incidence
    of converters among the children was similar to that seen in 138
    normal adults tested with cyclamate orally (Sanders et al., 1970).

         Of 141 volunteers given 0.5 g sodium cyclamate per day for 3 days
    some 25% converted more than 0.15% of the ingested cyclamate to CHA,
    The maximum observed conversion rate was 60%. No CHA was detected in
    100 people who did not ingest cyclamate. Converters given oral
    cyclamate start excreting cyclamate in the urine within 24 hours but
    CHA only after 24 hours. Peak excretion CHA occurs after 3-4 days. On
    withdrawal of oral cyclamate there is rapid fall in urinary cyclamate
    but CHA excretion does not fall until after 2 days. The percentage
    converted had a biological half life of 20 minutes and that of CHA was
    30 minutes. On. converter was used to demonstrate that CHA was not
    necessary to start off conversion of cyclamate. While the absolute
    amounts of urinary CHA excreted depend on the dose administered to
    man, the proportion converted decreased with increased amounts
    ingested. This was demonstrated in 3 volunteers. In 2 volunteers it
    was shown that giving antibiotics stops conversion to CHA by
    elimination of most of the intestinal bacterial flora (Unilever
    Research Labs, 1970). 4 male and 3 female subjects received 3 g sodium
    cyclamate in divided daily doses and 4 females received 1 g daily as a
    single dose for 14-42 days. All converted cyclamate to CHA and
    excreted on the average 2-8% of the ingested cyclamate as CHA in the
    urine and faeces. CHA excretion became approximately constant for each
    individual in the second week. A positive correlation was noted
    between frequency of constipation and increases in CHA excretion.
    Anaerobic incubation of cyclamate with faeces produced no CHA, all
    cyclamate being recovered unchanged. One converter excreted 154 mg
    CHA/day after ingestion of 1 g cyclamate and excreted 88% of the
    ingested cyclamate in his faeces and urine (Davis et al., 1969).

    Acute Toxicity


                              Animal    Route.    mg/kg       Reference

    Cyclamate-Saccharine      Mouse     oral      12800       Tremolières, 1964
    "                         "         "         21500       Mollet, 1966
    Extemp Prep               "         i.p.       4600       Tremolières, 1964
    Cyclamate-Saccharine      "         oral      17300            "
    Tabs (Abbott)
    Cyclamate-Saccharine      "         "        >25000            "
    Granules (Abbott)
    Cyclamate-Saccharine      Rat       "        >16500            "
    (90%:10%)                 "         i.p.       6500            "

         When the lipids in a standard diet were increased and
    intraperitoneal injections of saccharin were given in increasing doses
    to mice followed by a second injection 1 hour later of a fixed dose of
    cyclamate a considerable lowering of the toxicity of both products was
    noted (Tremolières, 1964).

         5 groups of 5 male mice were given subcutaneous injections of
    saccharin sodium, 0, 0.007, 0.07, 0.7 and 7 g/kg body-weight. A second
    injection of 7 g/kg sodium cyclamate was given to all groups 1 hour
    later. At first the mortality decreased gradually with increased doses
    of saccharin to reach the lowest point with the proportion of 90%:10%
    cyclamate/saccharin. After this the mortality increased sharply.

         5 further groups of 5 male mice were given sodium cyclamate 0,
    0.007, 0.07, 0.7 and 7 g/kg body-weight by subcutaneous injection. A
    second injection of sodium saccharin 7 g/kg was given to all groups 1
    hour later. Again the mortality was lowest with the proportion
    cyclamate/saccharin 90%:10%. (Tremolières, 1964).

    Special Studies

         Six rabbits received sodium cyclamate at 0.5% and 2% in drinking
    water for 4 weeks and the coagulation properties of their blood were
    examined. At the 2% level was there a reduction in the Quick value and
    factor VII. Another group of rabbits received 0.5% cyclamate in their
    drinking water while on an anticoagulant. This addition increased the
    anticoagulant effect (Gottinger et al., 1968). Tests to show the
    effect of cyclamate excreted in the faeces on faecal moisture revealed
    no correlation (Unilever Research Labs., 1970).

         Cyclamate administration to guinea-pigs has been shown to produce
    an allergic reaction of the delayed hypersensitivity type (Chung,

         Oral cyclamate appears to have a diabetogenic action as evidenced
    by blockage of the action of tolbutamide and chlorpropamide (Wisconsin
    Alumni Research Foundation, 1969). In another experiment however
    insulin has been shown to be more toxic in the presence of cyclamate
    (Fels Research Laboratory, 1969).

         Cyclamate has been shown to interfere with the intestinal
    absorption of lincomycin by competing for plasma protein absorption
    sites (Wagner, 1969). 14C-sodium, cyclamate infused into 2 rhesus
    monkeys during the last trimester of pregnancy traversed the placenta
    to the extent of about 29% while 14-CHA hydrochloride appeared to
    diffuse freely across the placenta (Pitkin et al., 1969). Placental
    transmission and foetal localization of radioactive cyclamate was
    studied in 5 patients at the time of therapeutic abortion and
    hysterectomy. Pregnancies were estimated to range from 68-93 days. A
    solution in distilled water of 14C-cyclamic acid together with
    nonradioactive sodium cyclamate to a total cyclamate concentration of
    2 g/ml (0.105 mg/ml radioactive) was sterilized and infused into the
    antecubital vein at constant rates. A volume of 50 ml was infused over
    a 1 hour period in 3 cases, over a 3 minute period in one case and 99
    ml were infused in 1 hour in one case. Maximum foetal blood values
    were found to be approximately one quarter of comparable maternal
    values. Amniotic levels were consistently low. Approximately 90% of
    the radioactivity was recovered in the maternal urine over a 72 hour
    period, 0.6% being recovered in the foetus in which it was widely
    distributed (Pitkin et al., 1970).

    Short-term studies


         A litter mate paired feeding study in rats at dietary levels of
    0, 0.5% 1% and 2% calcium cyclamate increased food consumption but
    showed no adverse effects on growth, skeletal development or
    gastrointestinal activity (Weinberg & Harrington, 1968).

         Groups of 20 male and 20 female weanling rats were fed 0, 0.05%
    and 0.5% sodium cyclamate for 3 months. No adverse effects were seen
    in terms of growth, food intake, haematology, chemistry and gross
    pathology (Loser, 1970).

         2 groups of 6 rats were fed on diets containing 0 or 1%
    cyclamate/saccharin (90:10%) mixture for 5 days, then subjected to
    partial hepatectomy (90%) and post operatively maintained for 48 hours
    on their respective diets. At autopsy on the 3rd day it was found that
    hepatic regeneration was markedly diminished (15%) with the
    cyclamate/saccharin mixture (Tremolières, 1964).

         A group of 8 male and 8 female rats were given 1 mg/kg of a 10:1
    cyclamate/saccharin mixture by gavage daily for 16 days. The control
    group consisted of 2 male and 2 female rats. The growth rate was the
    same in test and controls but the percentage weight gain was slightly
    higher in the control groups (Mollet, 1966).

         2 groups of 7 rats received 0 or 2% cyclamate/saccharin (90%:10%)
    mixture for 5 weeks. Growth rate was only slightly lower in the test
    group. In 3 test rats focal hepatic necrosis and congestive renal
    lesions were found. (Tremolières, 1964).

         2 groups 16 male and 16 female rats were given a 10:1
    cyclamate/saccharin mixture in their diet at levels of 0.5% or 2%. The
    control group consisted of 8 male and 8 female rats. After 16 weeks
    50% of the animals in each group were sacrificed and the rest
    continued on the same diet. Only 3 rats receiving the 0.5% level and 4
    rats receiving the 2% level died during the experiment. No significant
    effect of the test substance was noted on growth rate, food
    consumption or haematology. Histological examination of the stomach,
    liver, kidneys, gonads, spleen and pancreas revealed no alterations
    (Mollet, 1966).


         Two adult guinea-pigs received for 103-120 days in their drinking
    water 0.5% sodium cyclamate, 2% (= 1200 mg/kg) sodium cyclamate or
    0.3% sodium chloride. The water intake of the 2% test group was 30
    ml/24 hours and the other 2 test groups were also kept at 30 ml fluid
    intake/24 hours. Dead animals were replaced at once by fresh
    guinea-pigs from stock. There was an apparent increase in mortality
    and 20% decrease in body-weight at the 2% level. Histology of the
    liver of 4 animals at both levels showed "reduced protoplasmic
    content", vacuolization and occasional scattered focal necrosis. At
    the 0.5% level there was less evidence of these hepatic lesions.
    Histology of controls was apparently normal. The serum lactic
    dehydrogenase and SGOT levels were raised at the 2% level but the
    serum alkaline phosphatase level was normal. No changes were seen at
    the 0.5% level (Gottinger et al., 1968). A continuation of this
    experiment in female guinea-pigs kept for 64 days at 27, cyclamate in
    their drinking water, 95 days at 0.5% cyclamate and 126 days at 0.3%
    sodium chloride showed a loss in average body-weight of 36%, 37% and
    23.4% respectively and a two-fold mortality in the 0.5% cyclamate
    group compared with 0.3% saline (Hellauer, 1968).


         Oral administration of high doses of calcium cyclamate produced
    myocardial degenerative lesions and coronary artery sclerosis when
    compared with other calcium salts (Bajusz, 1969).


         30 adults took a 10:1 cyclamate/saccharin mixture (C:S) 6.4 g/day
    for 12 months. Transient diarrhoea was noted in 5 subjects (Radding,
    1967). For 6 weeks 32 adults took a C:S mixture 1.5 g/day increasing
    to 7 g/day (7 days). At 7 g increased stool weight and softness was
    noted (Olson, 1955). 184 children and adolescents took C:S mixture
    1.0-1.5 g per 30 lb weight for 3 months and 6 months respectively,
    There were some reports of soft light colour stools (Freese et al.,
    1964). 20 adults with functional gastrointestinal conditions took 5
    g/day C:S mixture for 10 weeks. Improvement in constipation was noted
    (Batterman, 1966) 42 adult diabetics took C:S mixture 1.1 g/day for 6
    months followed by 3.2 g/day for a further 6 months. No significant
    changes in laboratory tests or physical status were noted (Stern,

    Reproduction and teratogenicity studies


         Groups of 2-4 mice with control groups of 3 mice were given
    single intragastric doses of sodium cyclamate at various stages of
    pregnancy as follows: 62.5 mg on day 4-5, 125 mg on day 4-5 and 6-7,
    250 mg on day 6-7 and 8-10 and 500 mg on day 6-7 and 8-10. The uteri
    were removed on the eighteenth day, opened and the foetuses assessed
    and absorption sites counted. No abnormalities were detected following
    any administrations on days 8-10 but in all other instances the
    majority of embryos had either been resorbed or appeared dead and
    showed delayed development compared with controls. The foetal LD50
    was calculated to be 180 mg/kg body-weight (Tanaka, 1964a; 1964b). In
    embryo toxicity studies, groups of 10-20 mice were given single
    intragastric doses of 5 and 10 g/kg of sodium cyclamate on days 5, 7
    and 9 of pregnancy. The fetuses were delivered by caesarian section on
    day 18. Foetal LD50 was found to be greater than 10.0 g/kg (Lorke,
    1969). Groups of 10 mice were given intragastric doses of calcium
    cyclamate of 86, 173, 346, 692 mg/kg sodium cyclamate of 62, 125, 250,
    500 mg/kg and calcium cyclamate/sodium saccharin, 10:1 of 83, 166,
    333, 667 mg/kg. Controls were 100 sham treated mice. Doses were given
    on day 4, 6 and 9 of gestation. The foetuses were delivered by
    caesarian section on day 18. Foetal swellings, implantation sites,
    foetus numbers and viability were determined. Gross examination was
    made for foetal growth and external evidence of terata, presence of
    the latter being looked for additionally by serial sectioning and
    clearing and alizerin staining. No cyclamate or cyclamate/saccharin
    induced effects were seen (Industrial Bio-test Lab. Inc, 1967).

         5 groups of 10 pregnant mice over 6 weeks were administered 0,
    83, 166, 333 and 667 mg/kg body-weight of a 10:1 calcium
    cyclamate/sodium saccharin mixture on gestation days 4, 6 and 9. All
    animals were sacrificed on gestation day 18. The test material did not
    significantly increase the incidence of foetal resorption and no
    teratogenic effect could be related to treatment (Kennedy & Arnold,


         20-23 female rats were dosed orally each day, from 6-15 day of
    pregnancy, with the sodium cyclamate 50 mg/kg, 100 g/kg 250 g/kg.
    These were compared with tap water (20 ml/kg) and saccharin and
    sucrose as additional controls as well as 363 untreated controls. Dams
    were autopsied on the 21st day of pregnancy. There were no significant
    differences between any treated and control groups as regards litter
    size, resorption rate and mean foetus eight. No abnormal incidence of
    malformation was noted (Bein et al., 1967; Fritz. & Hess, 1968).

         3 groups of 25 female rats were given by gavage a 10:1 sodium
    cyclamate/ sodium saccharin mixture at levels of 0, 500, 2500
    mg/kg/day based on their pre-pregnant weight from the 6th through the
    16th day of gestation. No adverse responses were found regarding
    behaviour, appearance, survival and reproduction. At 500 mg one dam
    produced a malformed pup and another dam had 6 pups with absent lumbar
    vertebrae. These changes are probably not attributable to the test
    material as none occurred at 2500 mg/kg (Abbott, 1968).


         Groups of 10 pregnant rabbits were given 50, 100 and 250 mg/kg of
    sodium cyclamate or 5, 10 and 25 mg/kg of saccharin intragastrically
    on days 6-18 of pregnancy. Pregnancies were terminated on day 29 by
    caesarian section. Implantation sites, resorption sites and corpora
    lutae were counted and foetuses were examined for evidence of visceral
    or skeletal anomalies. No evidence of teratogenic or embryotoxic
    effects were seen (Klotzche, 1969). Forty pregnant rabbits received
    2500 mg/kg of sodium cyclamate/sodium saccharin (10:1) mixture by
    gavage from days 6 through 18 of pregnancies. Thirty-eight pregnant
    controls received water. Delivery was by caesarian section on day 29.
    No effects attributable to the C:S mixture were seen in terms of
    implantation and resorption sites live and dead foetuses, foetal
    survival and terata (US Food and Drug Research Laboratories, 1969).

         3 groups of 15 pregnant rabbits were given orally doses of 0, 500
    and 2500 mg/kg of a 10:1 cyclamate/saccharin mixture once daily during
    the 6th to 18th days of pregnancy. No teratogenic potential was noted.
    One out of 61 pups from the high dosage level group showed
    malformation of cranial structures, herniated abdomen and only one
    kidney. The mean number of live pups in the treated groups in this
    study was equal to or greater than that found in the control groups
    (Oser, 1968).

         Because of 1 malformed pup the experiment was repeated using 84
    pregnant rabbits dosed intragastrically with 2500 mg/kg of 10:1
    cyclamate/saccharin mixture once daily from 6th to 18th day of
    pregnancy. No adverse effects were noted on the number of implantation
    sites or live foetuses, resorption sites or dead foetuses in the test
    group. No unusual malformations attributable to treatment were seen.
    There was no evidence of teratogenesis (Oser, 1969).


         Groups of 2 male and 4 female dogs were given a sodium cyclamate:
    sodium saccharin (10:1) mixture (C:S) at 0, 0.5, - and 1.5 g/kg/day
    for 2 years. No significant changes were seen in terms of growth, food
    consumption, behaviour, appearance, haematology, biochemistry,
    ophthalmological findings, endocrine function, hepatic biopsy,
    reproductive performance, gross observation for terata and gross and
    microscopic appearance of the major organs. A first litter obtained
    from these animals and fed at similar levels for one year showed no
    effects from the C:S mixture in terms of growth, food consumption,
    haematology, biochemistry, endocrine function, ophthalmological
    findings and gross and microscopic appearance of major organs. A
    second litter was observed for periods ranging from 2 to 6 months
    beyond weaning, receiving the C:S mixture at parental dosage levels.
    In these animals growth, haematology, biochemistry, and gross and
    microscopic findings were compared to control (Industrial Bio-test
    Lab. Inc., 1968).

         4 groups of 2 male and 4 female beagles were given 0, 0.5, 1 and
    1.5 g/kg body-weight of a (10:1) sodium cyclamate:sodium saccharin
    mixture for 2 years. The first and second litters received the same
    dosage as their parents. No effect was noted in any generation on
    blood chemistry, urine analysis or organ function. Reproduction
    parameters including mating ability and gestation were normal; liver
    biopsies, gross and microscopic pathology did not reveal any test
    related lesions. There were no significant differences between test
    and control animals in the first generation with regard to growth,
    haematology, urology, organ function and pathology. The second litters
    were also unaffected. No congenital malformations were observed in any
    of the offspring (Jackson, 1968; Blockus et al., 1968).

    Chick embryo

         Calcium cyclamate and cyclamic acid were inoculated into fresh
    fertile eggs either directly into the yolk or through the air cell at
    0 and 96 hours of incubation. Decreased viability of embryos and a
    high incidence of malformations were found at a dose level of 10 ppm
    per egg when compared with sugar inoculation (Verrett, 1969). Similar
    experiments using "doses equivalent to 18 g/day in man" produced
    characteristic deformities in the embryos (Ghiani & Accame, 1969).

    Special teratogenicity study


         Rabbit embryos collected 30 hours post coitum in situ or in
    vitro from superovulated mature doses were placed in a treatment
    media containing a 10:1 sodium cyclamate:sodium saccharin mixture at
    concentrations of 0, 3, 6 and 8 mg/ml. There was no effect on cleavage
    in vitro or subsequent development of the same embryos in vivo
    (Manor & Szymanski, 1968).

    Mutagenicity studies

         Cyclamate produced no chromosomal alterations in microbial cell
    cultures and using a host-mediated assay with the S-typhimurium
    cyclamate had no effect.

         High levels of cyclamate have been found to cause breaks in
    chromosomes of human leucocytes cultured in vitro (Stone et al.,
    1969; Staltz et al., 1970).

         Groups of 2 male and 2 female humans established as converters of
    cyclamate to CHA and a similarly constituted group established as
    nonconverters received 70 mg/kg of sodium cyclamate daily for 4 days.
    A third control group received no cyclamate. Chromosome analyses were
    performed on peripheral leucocyte cultures prior to and immediately
    following the cyclamate ingestion. The frequency of chromosome
    abnormalities in all 12 subjects prior to cyclamate was 0-4% with a
    mean of 1.6% (based on counts of 100 metaphase cells per subject) and
    after 4 days of treatment 0-4% with a mean of 1.8% (Abbott Labs.,

    Long-term studies


         Sodium cyclamate was given in drinking water ad libitum to
    groups of 30 day old mice. Cyclamate intake was estimated at 20-25
    mg/mouse/day. Four mouse strains were used: C3H -40 males and 40
    females, RIII -60 males, XVII/G -60 females, F1(C3H × RIII) -80
    males. In each group half of the animals served as controls. Animals
    dying prior to the appearance of a tumor in each group were not
    considered in the evaluation. Average survival times for the animals
    considered in the various groups ranged from 430 days to 667 days. In
    the C3H and RIII strains no effects in terms of tumour numbers or
    onset were seen. For the XVII/G strain tumor genic a greater number
    multiple pulmonary tumours were seen. In the F1 (hybrid) strain the
    hepatoma incidence was increased (Rudali et al., 1969).

         Groups of 100 female Swiss mice were fed diets containing 0 and
    5% sodium cyclamate for 18 months. At the start of the feeding 50 mice
    in each group received intragastrically a single dose of 50 micrograms
    of 3,4-benzopyrene in 0.2 ml of polyethylene glycol 400 (PEG) the
    other 50 receiving PEG alone. Results did not indicate that the
    feeding of cyclamate was associated with an increase in tumours either
    arising in the G.I. tract or tumours at other sites, nor was there any
    evidence of carcinogenicity or effects upon mortality (Roe et al.,

         Implantation of cholesterol pellets containing 20% sodium
    cyclamate into the urinary bladder have produced an increased number
    of tumours in mice after 16 months. (Bryan & Ertürk, 1970).

         4 groups of 35 male and 45 female rats were given a 10:1 sodium
    cyclamate/sodium, saccharin mixture (C:S) at dosage levels of 0, 500,
    1120 and 2500 mg/kg/day. At the 79th week each group was divided and
    in addition to the C:S mixture the rats in 3 subgroups were dosed as
    follows with cyclohexylamine until animals reached 2 years.

              C:S Mixture                   Cyclohexylamine
              500 mg/kg      +              25 mg/kg

              1120 mg/kg     +              56 mg/kg

              2500 mg/kg     +              125 mg/kg

    The other subgroups continued with their original C:S dosage. The
    subgroups contained equal numbers of converters and non-converters.

         The only physical sign seen in these test animals was occasional
    soft stools or diarrhoea occurring primarily in male rats in the high
    dosage group. Growth and food intake were similar in the control and
    test animals. Haemograms and urine analyses performed at periodic
    intervals revealed no adverse responses.

         Bladder tumours were seen only at the 2500 mg/kg level between
    the 78th and 105th week. Almost all, except for 1, occurred in male
    converters. Out of 25 male controls 1 developed a papilloma. Out of 25
    male test animals 2 developed papillomata and 5 developed carcinomata.
    Out of 35 test females 1 developed a carcinoma (Price et al., 1969).

         6 groups of male and female Osborne-Mendal rats were fed diets
    containing 0.4%, 2% and 10% sodium or calcium cyclamates. Preliminary
    histopathological evaluation of only the bladders of rats autopsied at
    88 and 101 weeks indicate bladder effects in the animals fed cyclamate
    as compared to controls. These effects were largely evident in the
    animals autopsied at 88 weeks. They suggest a possible carcinogenic
    effect, the calcium salt apparently being more potent. These findings
    are tentative pending a complete evaluation (US Food and Drug
    Administration, 1970).

         Groups of 12 female and 6 male rats received 0, 0.8%, 1.6% and 3%
    sodium cyclamate in their diet over 3 generations showed some
    disturbance of oestrus and depression of growth as well as increased
    mortality in the second generation and some testicular degeneration
    (Ferrando et al., 1968).

    Observations in man

         Photoallergic dermatitis has been reported as a delayed reaction
    to UV light in a patient taking 3600 mg calcium cyclamate per day. The
    reaction was verified by testing with pure cyclamate and saccharin
    separately (Lamberg, 1967). Pruritus, urticaria and other disorders
    have been reported after ingestion of cyclamate (Feingold, 1968).

         Groups of 8 men were given 0, 5, 10 and 18 g/day of sodium
    cyclamate. Seven on the highest dose level develop a severe persistent
    diarrhoea but the eighth tolerated this intake for 62 days. Some
    persistent diarrhoea also occurred at 10 g/day in two men but none at
    5 g/day (Wills et al., 1968).

         In a continuation of studies previously described (Zollner &
    Schnelle, 1969), patients suffering from liver and kidney disease were
    continued on sodium cyclamate at dosage levels of 5 g/day and 2 g/day.
    Patients receiving 2 g/day were observed over an average time of 21
    months, those receiving 5 g/day were observed over 23 months in the
    case of kidney patients and 30 months in the case of liver patients,
    there being 10 of each type. Results of clinical biochemistry and
    function tests did not in general show any deleterious effects on
    renal or hepatic function nor were effects on the course of the
    diseases seen (Zollner & Pieper, 1970). Epidemiologic study of the
    incidence rates for bladder cancer indicates a gradual increase. While
    epidemiological features of this neoplasm may be attributable to
    cigarette smoking, an effect due to artificial sweeteners may be
    undetectable because of the short observation time (Burbank &
    Fraumeni, 1970).

    See Also:
       Toxicological Abbreviations