Humans cannot digest cellulose as the digestive system of humans do not have cellulase, the enzyme which digests the cellulose. Cellulose is composed of long chains of polymeric polysaccharide carbohydrate. Cellulose is the main constituent of the cell in most plants and it is used in the manufacture of plant based products such as paper, textiles and organic pharmaceuticals.
[ihc-hide-content ihc_mb_type=”show” ihc_mb_who=”2,3″ ihc_mb_template=”1″ ]Herbivorous animals digest cellulose and hemicellulose in two steps. First is mechanical digestion and second is enzymatic digestion.The strong fibres of the cellulose are broken up mechanically by the strong
mouth parts of animals called mandibles and the gastric mills that they
have in their stomachs. As humans lack this gastric mills there is no chance
of mechanical digestion of the cellulose. For instance, a cow has more than one stomach and it chews the food by ruminating thoroughly.
The next level of digestion is enzymatic digestion where the food is digested by enzymatic action. Animals have symbiotic bacteria in their intestinal tract. These bacteria possess cellulase and other enzymes that are required for the digestion.
The process of digestion is not completely understood but it is hypothesised that this bacteria is responsible for the digestion of cellulose on animals.
Although cellulose is not digestible by humans, it is taken in the form of plant foods. Foods such as leafy vegetables and fruits add cellulose to give the ‘fibre’ to the diet.
Nutritionists and dieticians identify cellulose to be the useful part of food that keeps the move through the digestive tract efficiently. It is also believed that fibre rich diet can lower the risk of colon cancer.
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