Plant sterols: functional lipids in immune function and inflammation?

Plant sterols are naturally occurring food components that are well known for their serum LDL-C-lowering ability. Recently, a new area of research into these components was initiated, as there are indications that plant sterols might enhance immune function and have anti-inflammatory effects. Plant sterols appear to evoke a Th1 response, which might be beneficial in conditions characterized by decreased Th1 responses (e.g., HIV) or increased Th2 activity (e.g., allergy). In addition, decreased edema and concentrations of proinflammatory cytokines in mice have been reported. Although in humans effects on immune function seem promising, effects on inflammatory markers are far from consistent. Altogether, there is enough reason to initiate long-term, well-controlled intervention studies, specifically designed to examine the effects of plant sterol supplementation on immune function and markers of inflammation.