Question 13
Why does cellulose still matter in the human diet, even though it has no nutritional value?
The right answer is the one marked above.
The human digestive system cannot digest cellulose at all, so it supplies no nutrients. It earns its place by helping to prevent constipation — this is the fibre in food.
Cellulose is found in plant cell walls and in the fibres running through a plant. Same building unit as starch — glucose — but joined in a way human enzymes cannot break.