Phytosterols and phytostanols and the hallmarks of cancer: a
meta-analysis of pre-clinical animal models
Abstract
Background and Purpose Phytosterols and phytostanols are natural
products present in vegetable oils, nuts, and seeds, or added to
consumer food products and intake is inversely associated with incidence
and prognosis of several cancers. Randomised cancer prevention trials in
humans are unfeasible due to time and cost yet the cellular processes
and signalling cascades that underpin anti-cancer effects of these
phytochemicals have been explored extensively in vitro and in
preclinical in vivo models. Experimental Approach Here we have performed
an original systematic review, meta-analysis, and qualitative
interpretation of literature published up to June 2020. MEDLINE, Scopus,
and hand-searching identified 408 unique records that were screen
leading to 32 original articles that had investigated the effects of
phytosterols or phytostanols on cancer biology in preclinical models.
Data was extracted from 22 publications for meta-analysis. Key Results
Phytosterols were most commonly studied and found to reduce primary and
metastatic tumour burden in all cancer sites evaluated. Expression of
pAKT, and markers of metastasis, angiogenesis, and proliferation were
consistently reduced in breast and colorectal cancer. Very high dose
treatment (not easily achievable through diet or supplementation in
humans) was associated with adverse events including poor gut health and
intestinal adenoma development. Conclusion and Implications Phytosterols
and phytostanols are already clinically recommended for cardio-vascular
disease risk reduction, and represent promising anti-cancer agents that
could be delivered in clinic and to the general population at low cost,
with a well understood safety profile, and now with a robust
understanding of mechanism-of-action.