How does plant fiber help lower blood lipids? A breakdown of soluble and insoluble fiber.

Foods rich in dietary fiber are recommended: Dietary fiber is generally divided into two main categories: soluble and insoluble. Soluble dietary fiber includes cellulose and non-cellulose polysaccharides (also known as hemicellulose). It is mainly found in vegetables, fruits, legumes, oat bran (sugar), corn husks, agar, pectin, seaweed gum, etc. Insoluble dietary fiber mainly constitutes lignin in plants.

Many experiments have shown that soluble dietary fiber has excellent water absorption. After entering the intestines, it swells upon contact with water, increasing stool volume, promoting intestinal peristalsis, and promoting the excretion of cholesterol in feces. It can bind with bile acids or other lipids, reducing cholesterol absorption and lipoprotein synthesis, thereby accelerating the clearance of low-density lipoprotein cholesterol. However, insoluble dietary fiber is hardly digested and absorbed in the intestines, instead forming an insoluble complex—lignin-cellulose—thereby also affecting cholesterol absorption and promoting excretion. Therefore, both soluble and insoluble dietary fiber have a role in regulating blood lipids, but soluble fiber has a stronger effect than insoluble fiber. A study of 43 patients with hyperlipidemia followed a lipid-lowering diet for two months, then administered soluble and insoluble dietary fiber for 16 weeks. The results showed that the two types of fiber reduced serum total cholesterol and LDL cholesterol by an average of 4.9% and 48%, respectively, with the most significant lipid-lowering effect observed in the fourth week. Furthermore, the reduction in serum total cholesterol was more pronounced in men than in women. However, the effects of the two types of fiber on serum HDL cholesterol remained largely unchanged. Moreover, it was demonstrated that even after serum total cholesterol had returned to normal levels, soluble dietary fiber continued to significantly lower serum total cholesterol.

This study clearly demonstrates that dietary fiber has a good lipid-lowering effect. Therefore, both patients with hyperlipidemia and healthy individuals should be encouraged to consume foods rich in dietary fiber. Patients with hyperlipidemia, in particular, should consume more of these foods to prevent and treat hyperlipidemia.

While dietary fiber can lower serum total cholesterol and LDL cholesterol, excessive consumption should be avoided, as it can cause bloating and increased bowel movements.