Abstract
Plant-based foods are natural sources including vegetables, fruits, cereals and legumes. These foods consist of various types of nutrients in which carbohydrate is the basic component. However, some plant-based diets contain carbohydrates in the form of fiber. The fiber is usually a nondigestible polysaccharide that is not digested in the human body. It is present in the form of soluble or insoluble in different part of foods like peel, bran, pulp and grain. Pectin, beta-glucan, mucilage, psyllium, resistant starch and inulin are soluble fiber, and cellulose, hemicellulose and lignin are insoluble fiber attained from plant foods. The major function enhances immunity by creating gastrointestinal barrier, mucus production, immune cell activity and IgA level. Previous evidences showed that peoples with strong immunity have fewer chances of viral disease. A recent viral disease named COVID-19 spread in the world and millions of peoples died due to this viral disease. Coronavirus mostly attacks humans that suffer with weak immune system. It is due chronic diseases like diabetes and CVD (cardiovascular disease). The current review shows that fiber-containing plant-based foods boost immunity and aid human against COVID-19. The therapeutic role of fiber in the human body is to control the risk of hypertension and diabetes because a high-fiber diet has the ability to lower cholesterol, blood pressure and blood sugar. Fibers aid in GIT (gastrointestinal tract) and prevent constipation because it absorbs water and adds bulk to stool.