INTERNATIONAL PROGRAMME ON CHEMICAL SAFETY
WORLD HEALTH ORGANIZATION
TOXICOLOGICAL EVALUATION OF SOME
FOOD COLOURS, EMULSIFIERS, STABILIZERS,
ANTI-CAKING AGENTS AND CERTAIN
OTHER SUBSTANCES
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.
STEAROYL LACTYLATE, CALCIUM SALT and STEAROYL LACTYLATE, SODIUM SALT
Biochemical aspects
In vitro tests with lipase showed ready hydrolysis into stearic and
lactic acid (Hodge, 1961). Rats fed the sodium or calcium salt
excreted only traces of lactate in the faecal fat showed good
utilization of the stearic acid moiety and of the calcium (Hodge,
1961).
Experiments comparing the metabolism of a mixture of 1 stearic acid
and C14 labelled lactic acid with stearoyl lactylate containing C14
in the lactic acid moiety, showed that 58 per cent. of the C14 in the
physical mixture was excreted in the first 24 hours as CO2 through
the lungs and 61 per cent. of the lactic acid moiety similarly. There
was no difference in C14 distribution and excretion in animals
receiving lactate in either form. Thus lactate derived from stearoyl
lactylate is metabolized normally after prompt and quantitative
release prior to absorption (Hodge, 1961).
Acute toxicity
Four out of eight rats given 30 g/kg body-weight stearoyl lactylate
acid died but all eight rats in each group given 20 g or 25 g/kg
body-weight survived. This is not a true LD50 estimation because much
unabsorbed material was found in the stomach of the dead animals
(Hodge, 1961).
Short-term studies
Rat. Calcium stearoyl lactylate was fed to groups of five male rats
at levels of 0.5 per cent., 2.0 per cent. and 12.5 per cent. in their
diet for 43 days. At the two per cent. level and 12.5 per cent. level
the relative liver weights were increased.
In a similar experiment on groups of 10 male and 10 female rats
calcium stearoyl lactylate was fed in the diet at levels of 0.5 per
cent., 5.0 per cent. and 12.5 per cent. for 98 days. Growth was
retarded at 5 per cent. and 12.5 per cent. and the relative weights of
liver, stomach, heart, spleen and brain were increased at 12.5 per
cent. No histological abnormalities were seen in kidneys, brain, lung,
spleen and liver, but at the 12.5 per cent. level lipogranulomata were
detected in the adipose tissue. No increase in stainable liver fat was
seen. Urinalysis and blood morphology were normal. Radiological
studies of femurs were normal indicating that the additional calcium
in the diet had no effect on body load (Hodge, 1961). Ten male rats
received five per cent. calcium stearoyl lactylate in their diet and
developed slightly greater relative liver weights. On the other hand,
20 male rats fed five per cent. sodium stearoyl lactylate showed no
difference in relative liver weight between test and control rats.
Twenty male rats received 5 per cent. sodium stearoyl lactylate for 28
days with 20 controls on stock diet. After 28 days the experimental
group was also returned to normal diet and observed for another three
months. Groups of five rats were sacrificed 32, 60, 90 and 140 days.
Relative liver weights were slightly higher in each test group except
in animals examined after 90 days (Hodge, 1961).
Further experiments were undertaken to elucidate the effect of
different levels of calcium stearoyl lactylate on relative liver
weights as well as the effect of the fat level of the diet ion
relative liver weights. The relative liver weights became normal when
rat's returned to stock diets. When diets contained physical mixtures
of stearic acid, lactic acid and calcium carbonate instead of calcium
stearoyl lactylate they produced comparable relative liver weights
Hodge, 1961).
Groups of 25 rats received diets containing 0 per cent., 0.1, 1.0 per
cent., 2 per cent., 3 per cent., 4 per cent., 5 per cent. and 7.5 per
cent. of calcium stearoyl lactylate. At the two highest levels there
was growth retardation with relative liver weight increase. Groups of
five male rats were given diets containing either 15 per cent. lard or
10 per cent lard + five per cent. calcium stearoyl lactylate for 30
days. The test group grew at a lower rate but relative liver weights
were less than in the controls. Groups of 10 rats received diets
containing five per cent. of calcium palmityl lactylate or calcium
oleyl lactylate for 30 days. All test groups grew slower and had
markedly raised relative liver weights compared with five per cent.
calcium stearoyl lactylate. Kidney weights were normal for all groups
and histological examination of liver, kidneys and fatty tissues
revealed no abnormalities in any of these groups (Hodge, 1961),
The appearance of lipogranulomata and the increased relative liver
weight are related to the excessive intake of abnormal proportions of
long-chain fatty acids. The balance between saturated and unsaturated
fats (S:U ratio) in the human diet is about 0.6 if the diet contains
30 - 40 per cent. fat. Rats fed diets containing 35 - 50 per cent.
saturated fatty acid products (palmitic acid, stearic acid,
ethylstearate, monoglycerides and acetylated monoglycerides of
hydrogenated lard) develop localized fat necrosis with formation of
lipogranul omata. The condition is preventable by simultaneous feeding
of cornoil and reversible by a return to normal diet (Cox & De Eds,
1958; Herting & Crain, 1958; Ambrose et al., 1958).
Groups of five rats were maintained for periods up to six months on
diets containing varying levels of calcium stearyl dilactylate (3 per
cent. - 25 per cent.) and stearoyl lactylic acid (8 per cent. - 22 per
cent.). The total fat content was 20 per cent. The outcome depended
on the S:U ratio. The added fats were chosen to give ratios from 0.6
to 4.4. Growth was depressed with increasing percentage of calcium
stearoyl lactylate at 16 per cent. and higher levels and with 14 per
cent, and above, for the acid. Mortality was high at levels of 20 per
cent. and above. Relative liver weights were normal at S:U ratios of
0.6 (17 per cent. fat + 3 per cent. calcium stearoyl lactylate or 17
per cent. fat + 2.6 stearoyl lactylic acid) but rose with higher
ratios. Lipogranulomata appeared at ratio values beyond 1.4. The
iodine number of depot fats reflected the variation in S:U ratio of
the diet. Restoration to the basal ration containing 20 per cent. fat
caused disappearance of lipogranulomata in four - six months. No
histopathological abnormalities were seen (Hodge et al., 1964). In a
repeat experiment with 40 male and 40 female rats fed 25 per cent.
calcium stearoyl lactylate or 118 per cent. stearoyl lactylic acid in
their diet, all animals developed severe lipogranulomata with high
mortality. Recovery was rapid if animals were placed on basal diet
containing 20 per cent. fat (half cornoil, half lard). Growth rate
recovered and any deaths occurring were unrelated to the diet (Hodge,
1961).
Dog. One male and three female beagles were fed a diet containing
7.5 per cent. calcium stearoyl lactylate; another group of one male
and three females acted as controls. After two years no noteworthy
differences were observed between the two groups. Urinalysis and
haematological findings remained normal. No gross or microscopic
tissue changes were found attributable to administration of calcium
stearoyl lactylate. Liver weights were within normal range; nor did
the livers differ in moisture, protein, lipids, ash or glycogen. Other
organ weights were also normal. No adverse effects were observed in
one dog receiving sodium stearoyl lactylate in his diet for one month
at a level of 7.5 per cent., then increased to 12.5 per cent. for two
weeks and to 15 per cent. for another month. No changes occurred in
the blood; organ weights and the microscopic appearance of the tissues
were normal (Hodge, 1961).
Long-term studies
None available.
Comments
The metabolism of these substances has been studied satisfactorily.
Despite the absence of long-term feeding studies it is possible to
proceed with their evaluation. Extensive short-term studies in rats
have shown that at levels below two per cent. in the diet there is no
effect on growth or relative liver weight. The dog appears to be a
less sensitive species. It would be desirable to carry out metabolic
studies in man to ascertain species differences.
EVALUATION
Level causing no toxicological effect in the rat.
0.5 per cent. (= 5000 ppm) in the diet equivalent to 250 mg/kg body-
weight per day.
Estimate of acceptable daily intake for man
mg/kg body-weight
Temporary acceptance 0 - 2.5
Further work required by June 1972
See specification Ref. 19, Annex 1.
REFERENCES
Ambrose, A. M., Robbins, D. J. & Cox, A. J. (1958) Fd Res., 23, 536
Cox, A. J. & De Eds, F. (1958) Amer. J. Path., 34, 263
Herting, D. C. & Crain, R. C. (1958) Proc. Soc. exp. Biol. (N.Y.),
98, 347
Hodge, H. C., Maynard, E. A., Downs, W. L. & Panner, B. (1964)
Toxic. appl. Pharmac., 6, 350
Hodge, H. C. (1961) Unpublished report to the C. J. Patterson Co.
submitted by Markel, Hill & Byerley, 1969