Human Nutrition and Digestion: Question 9
Syllabus 7.4
A patient has a disease that severely damages her pancreas, so that it can no longer release digestive enzymes. Her salivary glands, stomach and the wall of her small intestine all continue to function normally.
Which statement correctly describes the most direct effect of this disease on digestion in her small intestine?
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Worked solution
Step 1: Recall what the pancreas normally releases
The pancreas normally releases amylase, protease and lipase into the small intestine, where they continue the chemical digestion of starch, protein and fat.
Step 2: Work out the most direct effect of pancreatic damage
Lipase, the enzyme that digests fat into fatty acids and glycerol, is mainly produced by the pancreas. If the pancreas can no longer release its enzymes, very little lipase reaches the small intestine, so digestion of fat there is severely reduced. This is the most direct and serious effect of the disease.
Step 3: Rule out the other options
- B: the stomach also produces its own protease (pepsin), so protein digestion is reduced, not stopped completely, when the pancreas is damaged.
- C: the pancreas, not only the salivary glands, normally produces amylase; without pancreatic amylase, digestion of any starch that reaches the small intestine would also be reduced.
- D: bile is not a digestive enzyme. It only emulsifies fat into smaller droplets; it cannot chemically break down starch, protein or fat in place of the missing pancreatic enzymes.
Final answer
The disease severely reduces fat digestion in the small intestine, because lipase from the pancreas is no longer available, option A.