INTERNATIONAL PROGRAMME ON CHEMICAL SAFETY
WORLD HEALTH ORGANIZATION
TOXICOLOGICAL EVALUATION OF SOME
FOOD COLOURS, EMULSIFIERS, STABILIZERS,
ANTI-CAKING AGENTS AND CERTAIN
FAO Nutrition Meetings Report Series
No. 46A WHO/FOOD ADD/70.36
The content of this document is the result of the deliberations of the
Joint FAO/WHO Expert Committee on Food Additives which met in Rome,
27 May - 4 June 19691
Food and Agriculture Organization of the United Nations
World Health Organization
1 Thirteenth 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.
This polysaccharide consists mainly of galacto mannans.
The digestibility of guar gum in rats fed 0.4 g/day was estimated to
be 76 per cent. (Booths et al., 1963). The rat can use guar gum as a
precursor for liver glycogen but at a much reduced efficiency (Krantz
et. al., 1948). Feeding chicks for four weeks on a diet containing
three per cent. cholesterol, three per cent. guar gum and three per
cent. cholesterol plus three per cent. guar gum reduced the serum
cholesterol levels, especially if both cholesterol and guar gum were
ingested. Liver cholesterol was only depressed if cholesterol and guar
gum were fed (Couch et al., 1966). The caloric value was determined in
groups of 10 rats fed for one week a 5 g basal diet supplemented with
either 1 g or 3 g corn starch or 1 g and 3 g guar gum. At 1 g level
guar gum was equivalent to corn starch but at the 3 g level there was
a lower equivalence. All animals had large intestines but normal
faeces (Warf, 1964).
No data available.
Rat. Five male rats were fed 0 and five per cent. guar gum for 91
days in their diet. No differences were observed between the two
groups in weight gain and food efficiency (Booths et al., 1963). Five
rats were fed a diet containing 0.5 per cent. guar gum and varying
amounts of water. Weight gain and protein efficiency increased with
higher water content (Keane et al., 1962).
Fifteen male and 15 female rats were fed a diet containing five per
cent,of guar flour. Thirty rats served as control. Animals were
sacrificed for autopsy studies at two to three month intervals. Seven
male and eight female animals remained at 50 weeks. The experiment was
continued, but the final report is not available to WHO. Up to 50
weeks, growth histopathology of liver and kidney were similar in the
treated and the control groups (Krantz, 1947).
Monkey. Two monkeys (no duration animals) received 1 g of guar flour
in their diet per day. Wellbeing, growth and haematology (RBC, WBC, HP
and urea N2) remained normal (Krantz, 1947).
Man. Five volunteers ingested 1 g of guar flour in a capsule per
day for 10 days without any apparent effect (Krantz, 1947).
Guar gum is consumed in some parts of the world as a component of guar
flour. When it comprises less than 15 per cent. of the diet it is
calorically equivalent to corn starch. The metabolic fate in animals
and man is not known. Only inadequate animal tests are available but
a long-term study in rats is in progress.
Level causing no toxicological effects in the rat
Five per cent. (= 50 000 ppm) in the diet equivalent to 2500 mg/kg
Estimate of acceptable daily intake for man
mg/kg body weight
Temporary acceptance 0-125
Further work required by June 1972
Metabolic studies in several species and an adequate 90-day study in a
non-rodent mammalian species.
Booths, A. N., Hendrickson, A. P. & De Eds, F. (1963) Toxic appl.
Pharmacd., 5, 478
Couch, L R., Bakski, Y. K. & Farr, F. M. (1966) VII International
Congress of Nutrition, Abstracts, p. 195
Keane, K. W. et al. (1962) J. Nutr., 77, 18
Krantz, J. C. (1947) Unpublished report by General Mills, Inc.
Krantz, J. C., Carr, C. J. & Farson, C. B. (1948) J. Amer. diet.
Ass., 24, 212
Wisconsin Alumni Research Foundation Lab. (1964) Unpublished report
No. 3110860/1 to Stein, Hall & Co.