Daily was hypothesized that PS themselves may
Daily consumption of foods with added PSin amounts of up to 2 g/day is equally effective in lowering plasma LDL-Clevels by up to 10%, and thus may reduce cardiovascular disease risk. At higherdaily intakes (9 g/day), the effects of plant stanols appear more pronounced (188).
Daily phytosterol intakes are overall below intakesrecommended for a meaningful LDL-cholesterol-lowering effect (189). Clear evidence that functional foodssupplemented with PS are safe and effective in the prevention of cardiovasculardiseases is as yet unavailable and individual studies show that they may evenbe harmful (190).As an example, due to the extremely elevated levels of phytosterols seen in therare genetic disorder phytosterolemia, which is associated with rapidlyprogressing CVD, it was hypothesized that PS themselves may be atherogenic (191).Therefore, additional studies are needed to confirm these results and examinesafety at higher doses.High dietary intakes ofPS, such as those consumed by vegans and vegetarians, are not recommended forcholesterol-lowering in pregnant women because the safety of their use duringpregnancy has not been fully established. A recently conducted study showed thatthe human placenta tends to limit the PS availability to the fetus.
It has beenreported free PS cross the human placenta more easily than PS ester (192).The discussion whether the type of food(food matrix) influences LDL-C lowering efficacy of plant sterol and stanolesters is still ongoing. Besides the type of fortified food with PS, thefrequency and the time of intake seems to be important as well (182).PS could be incorporated in diet not onlyto lower the cardiovascular disease risk, but also to potentially preventcancer development (193).
Itis indicated that phytosterol rich diets may reduce cancer risk by 20% (194).PS possess anti-cancer effect against cancer of the prostate, colon, lung,stomach, ovary and estrogen-dependent human breast cancer (195, 193). It has been speculated that PSinhibit the production of carcinogens, cancer-cell growth, invasion and metastasis,and promote apoptosis of cancerous cells. Phytosterol consumption may alsoincrease the activity of antioxidant enzymes and thereby reduce oxidativestress (193).Dietary intake of beta-sitosterol and stigmasterol were associated to lowerrisks of esophageal (196)and ovarian (197)cancers, respectively.
The anti-carcinogenic property of ?-sitosterol makes ita potential anti-cancer drug (198).
