THE IMPORTANCE OF SITOSTEROL AND SITOSTEROLIN IN HUMAN AND ANIMAL NUTRITION

Sitosterol, the principal phytosterol in most higher plants and hence in plant-derived food products, is found in the serum and tissues of h ealthy humans in concentrations 800-1000 times less than the endogenou s cholesterol. The glucoside of sitosterol (sitosterolin) is present i n mammalian serum at even lower concentrations. In many animals, sitos terol and sitosterolin concentrations relative to cholesterol are cons iderably higher than in humans. Only plants can synthesise these compo unds and humans and animals obtain them from their diet. Even though t heir absorption efficiency is low (similar to 1/10 and similar to 1/50 for sitosterol and sitosterolin, respectively relative to cholesterol ), their apparent synergystic stimulatory effect on the immune system and prophylactic effect on a variety of diseases of civilisation indic ates their importance in human and animal nutrition. Since modern food processing tends to reduce their concentration in processed plant-foo d products, and eating habits also affect their consumption adversely, it is desirable to eat sufficient unrefined or unprocessed plant food s or resort to food supplements containing sitosterol and sitosterolin .