Coffee, bean, roasted, ext.

Repeated dose toxicity: oral

Administrative data

Endpoint:

sub-chronic toxicity: oral

Type of information:

experimental study

Adequacy of study:

key study

Reliability:

2 (reliable with restrictions)

Rationale for reliability incl. deficiencies:

study well documented, meets generally accepted scientific principles, acceptable for assessment

Data source

Reference

Reference Type:

publication

Title:

The effect of brewed and instant coffee on reproduction and teratogenesis in the rat.

Author:

Nolen GA

Year:

1981

Bibliographic source:

Toxicology and Applied Pharmacology, 58, 171-183

Materials and methods

Test guideline

Qualifier:

no guideline available

Principles of method if other than guideline:

90-day subchronic study (growth to sexual maturity)

GLP compliance:

no

Limit test:

no

Test material

Test material information

Constituent 1

Reference substance name:

not applicable - High molecular weight constituents (Mwt > 719 g mol-1) such as polysaccharides, proteins and melanoidin polymers

Molecular formula:

not applicable - High molecular weight constituents (Mwt > 719 g mol-1) such as polysaccharides, proteins and melanoidin polymers

IUPAC Name:

not applicable - High molecular weight constituents (Mwt > 719 g mol-1) such as polysaccharides, proteins and melanoidin polymers

Constituent 2

Reference substance name:

not applicable - Inorganic constituents (including K, Mg and Ca) of Coffee, bean, roasted, ext.

Molecular formula:

not applicable - Inorganic constituents (including K, Mg and Ca) of Coffee, bean, roasted, ext.

IUPAC Name:

not applicable - Inorganic constituents (including K, Mg and Ca) of Coffee, bean, roasted, ext.

Constituent 3

Reference substance name:

Caffeine

EC Number:

200-362-1

EC Name:

Caffeine

Cas Number:

58-08-2

Molecular formula:

C8H10N4O2

IUPAC Name:

1,3,7-trimethyl-3,7-dihydro-1H-purine-2,6-dione

Constituent 4

Reference substance name:

1-methylpyridinio-3-carboxylate

EC Number:

208-620-5

EC Name:

1-methylpyridinio-3-carboxylate

Cas Number:

535-83-1

Molecular formula:

C7H7NO2

IUPAC Name:

1-methylpyridinium-3-carboxylate

Constituent 5

Reference substance name:

5-O-(3,4-dihydroxycinnamoyl)-L-quinic acid

EC Number:

206-325-6

EC Name:

5-O-(3,4-dihydroxycinnamoyl)-L-quinic acid

Cas Number:

327-97-9

Molecular formula:

C16H18O9

IUPAC Name:

3-{[3-(3,4-dihydroxyphenyl)acryloyl]oxy}-1,4,5-trihydroxycyclohexanecarboxylic acid

Specific details on test material used for the study:

SOURCE OF TEST MATERIAL
- Source and lot/batch No.of test material: Folgers instant coffee and ground vacuum coffee
- Expiration date of the lot/batch: not available
- Purity test date: not available

STABILITY AND STORAGE CONDITIONS OF TEST MATERIAL
- Storage condition of test material: not available
- Stability under test conditions: stable
- Solubility and stability of the test substance in the solvent/vehicle: soluble in water
- Reactivity of the test substance with the solvent/vehicle of the cell culture medium: not applicable

TREATMENT OF TEST MATERIAL PRIOR TO TESTING
- Treatment of test material prior to testing: the brewed coffee was prepared freshly each day of the study by brewing 648 g of ground coffee in 16’244 ml of water for 47 min. The instant coffee solutions were made by dissolving 14 g of instant coffee crystals in 1000 ml of water heated up to 150ºF (65.5ºC).
- Preliminary purification step (if any): none
- Final dilution of a dissolved solid, stock liquid or gel: not available
- Final preparation of a solid: not applicable

OTHER SPECIFICS: none

Test animals

Species:

rat

Strain:

Sprague-Dawley

Sex:

male/female

Details on test animals or test system and environmental conditions:

TEST ANIMALS
- Source: ARS/Sprague-Dawley, Inc. Madison, Wisconsin.
- Females (if applicable) nulliparous and non-pregnant: yes
- Age at study initiation: (P) 21-23 days
- Weight at study initiation: not available
- Fasting period before study: no
- Housing: individually in stainless-steel suspended wire cages with raised floors.
- Diet (e.g. ad libitum): Purina Laboratory Chow ad libitum
- Water (e.g. ad libitum): ad libitum during acclimation period
- Acclimation period: 3 days
ENVIRONMENTAL CONDITIONS
- Temperature: 23 ± 2°C
- Humidity: 50 ±10 %
- Air changes (per hr): not available
- Photoperiod (hrs dark / hrs light): 12-hour light and 12-hour dark cycle
IN-LIFE DATES: From: To: not available

Administration / exposure

Route of administration:

oral: drinking water

Vehicle:

water

Details on oral exposure:

The appropriate fluid was dispensed in clean calibrated bottles daily at about 10 AM and the consumption measured.

Analytical verification of doses or concentrations:

yes

Details on analytical verification of doses or concentrations:

The brew solids were determined daily for each brew with Fuchs hydrometer and biweekly on a composite sample by reftactive index measurements.
These composite samples were also analyzed for pH, titratable acidity, and caffeine. Typical analyses showed brew solids of 0.90%, a caffeine level of 0.057%, pH 5.23 and titratable acidity of 13.65 ex-
pressed as milliliters of 0.1 N NaOH required to neu-tralize 1.5% solids in 100 ml of the coffee brew.

Duration of treatment / exposure:

Rats were exposed to coffee solutions during growth to maturity phase (91 days)

Frequency of treatment:

Daily

Doses / concentrations

Doses / concentrations 1

Dose / conc.:

25 other: %

Remarks:

brewed and instant coffee

Doses / concentrations 2

Dose / conc.:

50 other: %

Remarks:

brewed and instant coffee

Doses / concentrations 3

Dose / conc.:

100 other: %

Remarks:

brewed and instant coffee

No. of animals per sex per dose:

20 males and 30 females per group

Control animals:

yes

yes, concurrent vehicle

Details on study design:

Groups of animals were randomly assigned to the following treatments:
1) Distilled water
2) 100% brewed coffee
3) 50% brewed coffee
4) 25% brewed coffee
5) 100% instant coffee
6) 50% instant coffee
7) 25% instant coffee

Positive control:

none

Examinations

Observations and examinations performed and frequency:

CAGE SIDE OBSERVATIONS: no data

DETAILED CLINICAL OBSERVATIONS: No data

BODY WEIGHT: Yes
- Time schedule for examinations: weekly

WATER CONSUMPTION AND COMPOUND INTAKE (if drinking water study): Yes
- Time schedule for examinations: weekly food consumption and daily fluid consumption records
OTHER: During first 12 weeks of the study, 10 randomly selected rats of each sex per group were transferred to stainless-steel metabolism cages, where they stayed for 48 hours without feed. Their urine was collected for two consecutive 12-hour period. The total volume for 24 hours was measured and the second 12-hour collection was measured with Ames “Clinitest” strips for pH, sugar, ketones and total protein. Afterward the animals were returned to their regular cages.

OPHTHALMOSCOPIC EXAMINATION: No

HAEMATOLOGY: Yes
- Time schedule for collection of blood: 91 day
- Anaesthetic used for blood collection: animals were sacrificed
- Animals fasted: Not specified
- How many animals: 10 rats of each sex par testing group
- Parameters examined: WBC, RBC, hemoglobin, hematocrit, lymphocyte differencial count

CLINICAL CHEMISTRY: Not specified

URINALYSIS: Yes

IMMUNOLOGY: No

OTHER: none

Sacrifice and pathology:

After the end of the 91-day growth phase, 10 rats of each sex per group were randomly selected and sacrificed by excessive ether. The heart, liver, kidneys and gonads were removed and weighted; these and the following organs were removed, fixed in 10% neutral, buffered formalin, mounted in paraffin, sectioned, and stained with haematoxylin-eosin: lung, stomach, pancreas, jejunum, colon, mesenteric lymph node, urinary bladder, spleen, and brain. The slides were examined for histopathology.

Statistics:

The continuous data were analyzed by the analysis of variance, least significant difference test, Bartlett’s test for homogeneity, Wilcoxon’s rank sum test and t test for unequal variance. The discrete data were analyzed by X2.

Results and discussion

Results of examinations

Clinical signs:

not specified

Mortality:

mortality observed, non-treatment-related

Description (incidence):

Four rats died and four moribund were sacrificed during the study (thee males and five females). Five had severe pulmonary disease; one female given 25% brewed coffee died during parturition; one female given 25% instant coffee was sacrificed because of a mammary carcinoma and one male given 100% brewed coffee because of a nephroblastoma. These deaths and/or conditions were scattered through the test and control groups and were not related to the coffee treatments.

Body weight and weight changes:

effects observed, treatment-related

Description (incidence and severity):

During 91-day period, rats given either brewed or instant coffee solutions gained as much as or more weight than control rats given water. In fact, the three groups of female rats given brewed coffee solutions and the two groups of females given either the 100 or 50% instant coffee solutions, gained significantly more body weight than controls. All of the female rats given coffee more feed than the controls, while only the males given 50% brewed coffee or 50 and 25% instant coffee ate significantly more. The male rats fed 100% and 25% brewed coffee and 100% instant coffee solutions also ate more than controls although the difference was not statistically significant. Thus, in general, the rats that ate more, gained more weight, resulting in no significant differences in the feed efficiencies among groups of either sex.

Water consumption and compound intake (if drinking water study):

effects observed, treatment-related

Description (incidence and severity):

The rats given either brewed or instant coffees at full strength (100%) drank significantly less than controls from the very beginning of the study. However, the rats given 50 or 25% solutions drank more than controls. Among the males, the difference was statistically significant only for the group fed the 25% dilution of brewed coffee, but among the females the differences were significant for the groups fed the two dilutions (50 and 25%) of both coffees.
The male rats ingested less caffeine per unit body weight than the females because of their larger size and of course, the rats given the instant coffee ingested less caffeine than those given brewed coffee.

Ophthalmological findings:

not examined

Haematological findings:

no effects observed

Description (incidence and severity):

Hematological characteristics did not exhibit patterns indicative of a treatment-related effect.

Clinical biochemistry findings:

not specified

Urinalysis findings:

effects observed, treatment-related

Description (incidence and severity):

The dicreased fluid intake of the rats given full-strength coffees resulted in a decreased urnary output with s concomitant increase in urinary protein. Otherwise the urinary characteristics measured were within the normal range of the rat and did not exhibit a dose-resonse relationship.

Behaviour (functional findings):

not examined

Immunological findings:

not examined

Organ weight findings including organ / body weight ratios:

effects observed, treatment-related

Description (incidence and severity):

At the end of 91-day growth period, among the males, the kidneys of the rats given both full-strength coffees were enlarged (based on both absolute and relative weights). The only other statistical difference among males was in the weight of the hearts of rats given 50% instant coffee, but this appeared to be without biological significance. Among the females, both the liver and the kidneys were heavier in all rats given brewed coffee, although the relative weights (ratios) were significantly higher only in the rats given the full-strength solution. Both the absolute and relative weights of these two organs were increased in the females given either 100 or 50% solutions of instant coffee. However, there were no clear patterns of dose-responses.

Significant differences also occurred in the heart weights of females given 50% brewed coffee and 100 or 50% instant coffee, as well as in the ovary/body weight ratio of rats given 25% instant coffee. These differences can be dismissed, since there is no dose-response, and they appear to be within normal limits.

Although there was liver and kidney enlargement in the females and kidney enlargement in males, no histopathology related to the ingestion of the coffees was discerned in any of the tissues examined in either males of females. The liver and kidney enlargement appeared to be adaptive hyperthophy.

Gross pathological findings:

no effects observed

Neuropathological findings:

not examined

Histopathological findings: non-neoplastic:

no effects observed

Description (incidence and severity):

No histopathology associated with the coffee treatments was observed in either sex.

Histopathological findings: neoplastic:

no effects observed

Effect levels

1

Key result

Dose descriptor:

NOAEL

Effect level:

25 other: %

Based on:

test mat.

Remarks:

Brewed/instant coffee

Sex:

male/female

Basis for effect level:

organ weights and organ / body weight ratios

2

Key result

Dose descriptor:

NOAEL

Effect level:

20 mg/kg bw/day (nominal)

Based on:

other: caffeine

Sex:

male/female

Basis for effect level:

organ weights and organ / body weight ratios

Target system / organ toxicity

Key result

Critical effects observed:

no

Applicant's summary and conclusion

Conclusions:

In a 91-day study in rats receiving high doses of brewed and instant coffee, the NOAEL for both male and female rats was 25% brewed and instant coffee dilutions, which was equivalent to 20 mg/kg body weight per day of caffeine.

Executive summary:

In a 91-day study, female and male rats received brewed or instant coffee as 100, 50, or 25% solutions instead of their drinking water. For the brewed coffee, this represented approximately 80, 40 or 20 mg/kg body weight per day of caffeine with slightly lower doses for the 3 solutions of instant coffee. Control animals received water.

The replacement of the rats’ drinking water with the coffee solutions exposed animals to very high doses of coffee and caffeine, albeit distributed throughout most of the day in small increments. This consumption was equivalent to up to 50-60 cups per day in the human.

At the end of 91-day period, male rats receiving both full-strength coffees had enlarged kidneys.

The only other statistical difference among males was in the weight of the hearts of rats given 50% instant coffee, but this appeared to be without biological significance. In females receiving either 100 or 50% solutions of instant coffee, the absolute and relative weights of liver and kidneys were increased; however, there were no clear patterns of dose-responses.

Although there was liver and kidney enlargement in the females and kidney enlargement in males receiving higher doses of coffees, no histopathology related to the ingestion of the coffees was discerned in any of the tissues examined in either males of females. The liver and kidney enlargement appeared to be adaptive hyperthophy.

The NOAEL for both male and female rats was 25% brewed and instant coffee dilutions, which was equivalent to 20 mg/kg body weight per day of caffeine.