The present in vitro experiment therefore suggests that dietary phytosterol intake sufficient to lower serum cholesterol may not have an estrogenic effect on the growth of estrogen-dependent breast cancer cells, but consumption of a diet high in phytosterols or dietary supplements may increase blood phytosterols enough ...

What are the side effects of phytosterols?

The current evidence suggests that phytosterol supplements are relatively safe and well-tolerated. 5 Side effects, if any, tend to be mild and may include constipation, nausea, upset stomach, heartburn, flatulence, and the discoloration of stools.

Do plant sterols increase estrogen levels?

Despite exerting an affinity for the ER, in rat models of PS exposure, β-sitosterol failed to increase uterine weight, a marker of estrogenic activity [82]. Likewise, plant stanols and stanol esters failed to stimulate estrogen responsive growth in MCF-7 cells [83].