INTERNATIONAL PROGRAMME ON CHEMICAL SAFETY
WORLD HEALTH ORGANIZATION
TOXICOLOGICAL EVALUATION OF SOME
FOOD COLOURS, ENZYMES, FLAVOUR
ENHANCERS, THICKENING AGENTS, AND
CERTAIN FOOD ADDITIVES
WHO FOOD ADDITIVES SERIES 6
The evaluations contained in this publication were prepared by the
Joint FAO/WHO Expert Committee on Food Additives which met in Rome,
4-13 June 19741
World Health Organization Geneva 1975
1 Eighteenth Report of the Joint FAO/WHO Expert Committee on
Food Additives, Wld Hlth Org. techn. Rep. Ser., 1974, No. 557.
FAO Nutrition Meetings Report Series, 1974, No. 54.
AMMONIUM SALTS OF PHOSPHATIDIC ACID
Explanation
These compounds have been evaluated for acceptable daily intake
by the Joint FAO/WHO Expert Committee on Food Additives (see Annex 1,
Refs Nos 20 and 34) in 1969 and 1973.
Since the previous evaluation additional data have become
available and are summarized and discussed in the following monograph.
The previously published monographs have been expanded and are
reproduced in their entirety below.
BIOLOGICAL DATA
BIOCHEMICAL ASPECTS
These compounds were readily absorbed from the rat
gastrointestinal tract in the presence of fats without changes in fat
absorption or gastrointestinal function (Frazer, 1954). No in vitro
haemolytic effect was seen with this product nor was it any stronger
than natural lecithin (Frazer, 1954). Incubation of the ammonium salt
of 32 P-phosphatidic acid with simulated gastric juice, homogenate of
intestinal mucosa, trypsin or chymotrypsin in vitro resulted
in the liberation of inorganic phosphate. The ammonium salt of 32
P-phosphatidic acid was given to eight male and seven female rats at a
level of 60-30 mg/kg bw. Urine and faeces were collected at intervals
of 1, 2, 4, 6, 7 and 24 h and at 10 and 16 days after administration
rats were killed for examination. Similarly, inorganic phosphate
labelled with 32 P was given to three male and three female rats by
intubation and rats were killed 1, 2 and 4 h after administration.
Many organs were examined for radioactivity. In addition,
incorporation of 32 P into phospholipids of tissues at various
intervals after dosing was determined. Percentage recoveries after 24
h were 91.4% males, 91.9% females, after 16 days 93.4% males, 98.1%
females. Thus 79% of the labelled material was excreted in the faeces
within 24 h while some 4% was eliminated in the urine. The remaining
17% were stored in bone and muscle as inorganic phosphate and
phosphate ester while the rest of the tissue contained oily traces
mostly in the phospholipid fraction. Comparison with uptake of
labelled inorganic phosphate showed similar distribution of the
phosphate to bone, muscle, liver, gut content and urine. The
radioactive phospholipid fraction present in the rat 4 h after
administration was found to be nearly identical whether 32 P was
administered as phosphatidic salt or as inorganic or thiotostate. The
radioactive phospholipid fraction in the liver of test rats was
chromatographically identical with the liver phospholipid of rats fed
32 P orthosphosphate. The observed tissued radioactivity is due to
breakdown into inorganic phosphate which enters the phosphate and
phospholipid pools. There was no evidence of storage in tissues of any
P containing moiety of the phosphatidic salt. The triglyceride moiety
was probably hydrolyzed and adsorbed by normal physiological routes
(Feuer, 1967).
TOXICOLOGICAL STUDIES
Special studies on reproduction
Rat
Groups of 10 male and 30 female weanling rats (Fo) were fed 0 or
6% compound for 13 weeks. After this time one male and three females
were mated for 21 days and date of mating established by vaginal
smears. All pregnant females were caged individually. An F1a
generation from 30 females was examined for litter parameters and
weaning performance and all young from 10 parental females were
autopsied, all weaned pups being autopsied on day 21. No effect was
seen on fertility, litter number, weaning performance or weight gain
of pups. Sex ratio was unaffected.
Rats were remated to produce F1b generation which was observed
until day 21. Thirty females and 10 males of F1b were fed 0% or 6%
compound for 13 weeks, the remaining pups were autopsied. After 13
weeks selected F1b animals were mated to produce an F2a generation.
After a second remating for F2b seven control and eight treated F1b
females were examined on day 18 of pregnancy for implantations,
resorptions, corpora lutea and live fetuses. Fetuses were examined for
skeletal and organ abnormalities. The F2b generation was observed
until day 21 and examined. Again no abnormalities were seen in the
F2a or F2b generation nor were there any deleterious effects on
implantation. Only one abnormal fetus occurred in a control litter
(Brantom et al., 1972).
Acute toxicity
LD50
Animal Route mg/kg bw Reference
Rat Oral 5 000 Frazer, 1954
Rat l.m. 2 000 Frazer, 1954
Guinea-pig l.m. 2 000 Frazer, 1954
Rabbit Oral 5 000 Frazer, 1954
Dog Oral 2 000 Frazer, 1954
No abnormal pathological findings or behaviour patterns were seen
(Frazer, 1954).
Short-term studies
Rat
After twice-weekly intraperitoneal injections in rats of 2 g/kg
for five weeks, there was no deleterious effect on growth, relative
spleen weight, haematology or corpuscular fragility (Gaunt et al.,
1967).
Groups of 15 male and 15 female rats each received diets
containing 0%, 0.75%, 1.5%, 3.0% and 6.0% of the compound for 90 days.
No adverse effects were seen on appearance, growth, food consumption,
haematological indices, liver and kidney function, relative organ
weights and gross and histological appearance of the organs. Similar
results were obtained in rats given a dietary level of 6% soya
lecithins for 90 days except that a slight transient anaemia was seen
in females (Gaunt et al., 1967).
Groups of 50 rats each received 0%, 1% or 2.5% compound in their
diet for 45 weeks. No adverse effects were seen with regard to
mortality, weight gain, liver function, kidney function and
histopathology in test groups compared with controls (Frazer, 1954).
Long-term studies
Rat
Groups of 48 male and 48 female rats were fed in their diet 0, 2%
or 6% compound for two years. A similar group of rats was fed on a
diet containing 4% soya lecithin. These treatments had no adverse
effect on mortality, rate of body weight gain, haematology,
urinalysis, renal concentrating ability, serum biochemistry or tumour
incidence. Thyroid weight was increased in all treated groups but this
was found to be due to an increased parathyroid hyperplasia secondary
to spontaneous renal changes combined with an elevated intake of
phosphate. A slightly increased incidence of myocardial fibrosis was
also associated with the parathyroid hyperplasia. The incidence and
severity of other histopathological changes were not influenced by
feeding either compound (Brantom et al., 1972).
Comments:
The biochemical studies show that the ammonium salts of
phosphatidic acids break down into normal food constituents. The
available rat studies show this material to be non-toxic at the level
of 6% in the diet, the highest concentration tested. A long-term study
and reproduction studies on one species were also carried out which
showed no adverse effects.
EVALUATION
Level causing no toxicological effect
Rat: 6% (= 60 000 ppm) in the diet equivalent to 3000 mg/kg bw
Estimate of acceptable daily intake for man
0-30 mg/kg bw*
REFERENCES
Feuer, G. (1967) Fd. Cosmet. Toxicol., 5, 631
Frazer, A. C. (1954) Unpublished report dated July 1954
Gaunt, J. F., Grasso, P. & Gangolli, S. D. (1967) Fd. Cosmet.
Toxicol., 5, 623
Brantom, P. G. et al. (1972) BIBRA Report 4/1972
* The contribution from this compound to phosphate intake must be
included in the ADI for phosphate.