Safety evaluation of certain food additives - ipcs inchem

124 PHYTOSTEROLS, PHYTOSTANOLS AND THEIR ESTERS
attributable to the consumption of phytosterol esters. Relevant haematological
findings (statistically significantly different from control, Student’s t-test, two-sided,
1% or 5% level) consisted of a slight reduction in platelet number (at 1.6% and
3.2% in males and in all dose groups in females) and a slightly reduced prothrombin
time (males: at 3.2% only; females: in all dose groups). Eosinophils were
slightly reduced in the two highest dose groups; neutrophils and lymphocytes
were slightly reduced in the highest dose group in males, but not in females.
Statistically significant findings in clinical chemistry consisted of increases in serum
activity of alkaline phosphatase (males: at 8.1% [337 International Units (IU)/l versus
234 IU/l in controls]; females: from 1.6% [166 IU/l versus 130 IU/l in controls]),
alanine aminotransferase (males: from 1.6% [51.2 IU/l versus 40.7 IU/l in controls];
females: from 3.2% [39.9 IU/l versus 30.0 IU/l in controls]) and some other changes
in the highest dose groups. There were neither macroscopic findings at necropsy
nor histological findings attributable to treatment with phytosterol esters (Horner,
1997; Hepburn et al., 1999). Based on the low degree of the changes and the
absence of any histopathological changes, the Committee concluded that these
findings were not of toxicological significance. Therefore, the no-observed-effect
level (NOEL) in this study was 8.1% phytosterol esters in the diet, equal to a dose
of 3.9 g phytosterol/kg bw per day for male rats.
Another 90-day dietary study was performed with mixtures of phytosterol
esters and phytosterol oxidation products according to United Kingdom and
Organisation for Economic Co-operation and Development (OECD) GLP requirements
and in compliance with OECD Test Guideline 408. Five groups of Wistar rats
(20 animals per dose and sex) were fed diets containing mixtures of phytosterol
esters (PE) with a phytosterol oxide concentrate (POC) at the following
concentrations: (I) 0, (II) 5.67% PE + 0.2% POC, (III) 5.67% PE + 0.6% POC,
(IV) 5.67% PE + 1.6% POC or (V) 5.67% PE only (PE control). To obtain the
phytosterol oxide concentrate, phytosterol esters were heated in the presence of
oxygen to produce a phytosterol oxide concentrate containing approximately 31%
phytosterol oxides and 19% free sterols (not further specified). The remaining 50%
consisted of unknown compounds. Throughout the study, clinical observations,
body weights, and food and water consumption were monitored. Investigations
comprised neurobehavioural testing, ophthalmoscopic examination, clinical
pathology, a renal concentrating test, gross necropsy and determination of organ
weights (adrenal gland, brain, epididymides, heart, kidney, liver, spleen, testes,
thymus, thyroid and uterus) and histopathology of a broad range of tissues. No
treatment-related clinical observations and no statistical differences in body weights
or neurobehavioural testing results were observed. Haematology revealed possible
treatment-related changes in several parameters (e.g. red blood cell count,
thrombocyte count, prothrombin time), which did not follow a clear dose–response
relationship and were partly present also in the phytosterol ester control. Alkaline
phosphatase was elevated in groups II–V. Liver weights of female rats were
increased in group IV only. No consistent macroscopic or histopathological
observations attributable to treatment were found (Lea et al., 2004). The Committee
noted that it is difficult to assess whether the observations made are attributable to
the phytosterol ester part of the applied mixture or to the oxides.