1Good morning, everyone, and welcome to the second lecture in our series on human nutrition.
2Today we turn to dietary fibre, a topic that researchers once dismissed as largely unimportant.
3For decades, textbooks claimed fibre simply passed through the body without offering any real benefit.
4Contrary to that older view, we now know gut bacteria ferment fibre into valuable compounds.
5The most important of these compounds are short chain fatty acids, especially one called butyrate.
6Butyrate was initially linked only to digestion, though further analysis revealed wider anti inflammatory effects.
7What I want to emphasize here is that not all fibre behaves in the same way.
8Soluble fibre dissolves in water, whereas insoluble fibre mainly speeds up the passage of food.
9Let me give you a concrete example: oats contain beta glucan, a soluble fibre that lowers cholesterol.
10Early trials suggested ten grams daily, but revised guidelines now recommend closer to thirty.
11It was not the quantity but the variety of plant foods that predicted a healthier microbiome.
12So, to conclude, eating many different plants each week matters more than obsessing over fibre totals.