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.
Riboflavin is essential for all animals and many micro-organisms.
Riboflavin-5-phosphate is the prosthetic group of flavoproteins
involved in general cell metabolism as hydrogen acceptors. The
recommended daily dietary allowance1 (U.S. Food and Nutrition Board,
1968). The recommended therapeutic doses for treatment or prevention
of riboflavin deficiency are:
1968 BP and 1963 BPC 1965 USP XVII
Therapeutic dose 5-10 mg/day 10-15 mg/day
Prophylactic dose 1-4 mg/day 2 mg/day
Crystalline riboflavine was recovered from the bladder and ureters of
rats a few hours after i.v. injection of a saturated solution in
saline. Nephrectomized rats accumulated injected riboflavin in the
small intestine through excretion from the jejunal mucosa. The large
intestine destroyed riboflavin (Selye, 1943). Normal man excretes
unchanged riboflavin in faeces and urine (Axelrod et al., 1941).2
Human deficiency is indicated by adult urinary excretion of less than
10 µg/6 hours (Harrison et al., 1962). The total amount absorbed by
man never exceeds 15 - 20 mg per day.
1 For man is about 1.5 mg/day (pregnant women 1.8 mg/day, lactating
women 2.0 mg/day).
2 The urinary recovery after oral administration to fasted normal
humans decreased with higher doses, but administration immediately
after breakfast resulted in a constant per cent of urinary recovery
independent of dose (Levy & Jusko, 1966).
Compound Animal Route LD50 Reference
Riboflavin mouse i.p. > 340 Kuhn & Boulanger, 1936
rat oral3 >10 000 Unna & Greslin, 1942
s.c. 5 000 Unna & Greslin, 1942
i.p. 560 Unna & Groslin, 1942
dog oral > 2 000 Unna & Greslin, 1942
riboflavinate rat oral >10 000 Unna & Greslin, 1942
s.c. 790 Unna & Greslin, 1942
i.p. 560 Unna & Greslin, 1942
3 Oral > 10 000, Pellmont, 1962; i.v. 50 -100, Pellmont, 1962.
The high oral LD50 in rats is probably due to poor absorption from
the gastro-intestinal tract and the low solubility of riboflavin.
Parenteral administration of 0.6 g/kg body-weight leads to renal
obstruction of pelvis and collecting tubules crystals of riboflavin
with death from renal failure and weight less. Toxicity is similar to
pyridoxine or pantothenic acid (Unna & Greslin, 1942).
Rat. 10 mg/day fed to male and female rats over 20 weeks after
weaning in 3 successive generations produced no apparent adverse
effect on growth and reproduction. No pathological changes were
observed (Unna & Greslin, 1942).
Dog. Four dogs fed 25 mg/kg body-weight/day for, 5 months showed no
adverse effects or pathological changes (Unna & Greslin, 1942).
Animals fed high doses of riboflavin show no toxic effects. There are
numerous biochemical studies and a vast amount of clinical and
nutritional data on riboflavin. It is reasonable to use this
information for evaluation.
Level causing no toxicological effect in the rat
50 mg/kg body-weight per day.
Estimate of acceptable daily intake for man
0 - 0.5
Axelrod, A. E., Spies, T. D. & Elvehjem, C. A. & Axelrod, V. (1941)
J. clin. Invest., 20, 229
British Pharmaceutical Codex 1963
British Pharmacopoeia 1968
Emmerie, A. (1938) Acta. brev. neerl. Physiol., 8, 116
Food & Nutrition Board (1968) Publication 1694, National Academy of
Science N.R.C., Washington, D.C.
Harrison, T. R. (1962) Principles of Internal Medicine, 4th edn.,
537, McGraw-Hill, N.Y., Toronto & London
Khun, R. & Boulanger, P. (1936) Hoppe-Seylers Z. physiol. Chem.,241,
Koschara, W. (1935) Hoppe-Seylers Z. physiol. Chem., 232, 101
Levy, G. & Jusko, W. J. (1966) J. Pharm. Sci 55, 285
Pellmont (1962) Handbuch der allgemeinen Pathologie Band 11, pp.
984, Springer Verlag, Berlin
Selye, H. (1943) J. Nutr., 25, 137
United States Pharmacopoeia, seventeenth revision, 1965
Unna, K. & Greslin, J. G. (1942) J. Pharmacol. exp. Ther., 76, 75