Nutrition: dietary fibre: practice question

A PSM question in the style of the NEET PG paper. Answer it first, then read why the right option is right and why each of the others is wrong.

Try it

PSM · Nutrition: dietary fibre

Sample item

A man with hypercholesterolaemia is advised to increase soluble dietary fibre from oats, pulses and fruits. By which mechanism does this mainly help?

Original practice item, not a recalled exam question. Nothing here is recorded.

The answer and the reasoning

A. Binding bile acids and reducing cholesterol absorption

Soluble fibre binds bile acids in the gut and increases their faecal loss, so the liver uses more cholesterol to make new bile acids, which lowers serum LDL cholesterol. Fibre also slows glucose absorption and adds bulk to prevent constipation.

Option by option

  • A. Binding bile acids and reducing cholesterol absorption (correct)

    Correct. Soluble fibre binds bile acids and lowers LDL cholesterol.

  • B. Increasing hepatic VLDL secretion

    Fibre does not increase VLDL secretion, which would raise rather than lower lipids.

  • C. Inhibiting HMG-CoA reductase in the liver

    Inhibition of HMG-CoA reductase is the action of statins, not of fibre.

  • D. Raising insulin secretion

    Fibre slows glucose absorption but does not raise insulin secretion.

Source note: Original NextPrep sample item — pending expert review. This item is original practice material awaiting independent expert review, so confirm important facts in a standard textbook.

More PSM questions

Questions about this PSM question

What is the answer to this PSM question?

The best answer is A, Binding bile acids and reducing cholesterol absorption. Soluble fibre binds bile acids in the gut and increases their faecal loss, so the liver uses more cholesterol to make new bile acids, which lowers serum LDL cholesterol.

Why is "Increasing hepatic VLDL secretion" not the answer?

Fibre does not increase VLDL secretion, which would raise rather than lower lipids.

Why is "Inhibiting HMG-CoA reductase in the liver" not the answer?

Inhibition of HMG-CoA reductase is the action of statins, not of fibre.

Why is "Raising insulin secretion" not the answer?

Fibre slows glucose absorption but does not raise insulin secretion.

What concept does this question test?

It tests Nutrition: dietary fibre in PSM. Fibre also slows glucose absorption and adds bulk to prevent constipation.

How hard is this question?

We tag it as an application question: it asks you to use a fact on a patient or a finding. The tag is our own editorial judgement, not an official difficulty rating, so read the reason for every option, not only the answer.

How should I study Nutrition: dietary fibre?

Practise biostatistics with small calculations until sensitivity, predictive values and risk measures are automatic. Then use the flashcards and the other PSM questions on this site to test what stuck.

Is this a real NEET PG question?

No. It is an original practice item (editorial status: sample, version 1). NextPrep does not publish recalled or leaked questions, and independent faculty review of this item has not been completed yet, so confirm important facts in a standard textbook.