There has been increasing reports concerning several physiological responses, such as lowering of plasma cholesterol levels, modification of glycemic response, improving large bowel function, and lowering nutrients availability. According to recent evidences, most isolated fibers that are water soluble will lower plasma cholesterol in humans and animals. These include pectins, psyllium, and various gums such as guar gum, locust bean gum and modified celluloses such as carboxymethylcellulose. Consumption of fiber-rich sources containing water-soluble fibers, such as oat bran, barley (sources of β-glucan fiber), legumes, and vegetables, usually results in a lowering plasma cholesterol. In this review, I will describe two different meta-analysises and some mechanisms of these action including its effects on cholesterol synthesis rates, VLDL secretion rates, LDL turnover rates and susceptibility of LDL to oxidation.