Reported side effects associated with plant sterols include diarrhea, nausea, heartburn or indigestion, and constipation, states eMedTV. Erectile dysfunction and other sexual side effects have also been observed in connection to plant sterols.
Plant sterols are naturally-occurring substances present in small amounts in many grains, vegetables, fruits, nuts and seeds, according to WebMD. These substances have properties causing them to significantly lower cholesterol levels by preventing cholesterol from being absorbed into the bloodstream as it passes through the digestive system. Manufacturers of food products frequently add plant sterols to items such as margarine, cereal, orange juice and granola bars.
Experts from the American Dietetic Association recommend that ingesting plant sterols from natural food sources is preferable to obtaining them through food additives or dietary supplements, according to WebMD. The heterogeneous combination of nutrients occurring naturally in whole foods is thought to offer more benefits than those found fortified foods or supplements.
Most people tolerate plant sterols agreeably and with few or no side effects, reports eMedTV. If a dietary supplement or product containing plant sterols also contains other dietary supplements, herbs or medications the possibility of serious side effects increases. Inactive ingredients in such products also have the potential to cause allergic reactions and other adverse side effects.