FibreFiber · Dietary fibre

Fibre is plant carbohydrate that human digestive enzymes cannot break down. Soluble fibre forms a gel that slows digestion and helps lower cholesterol; insoluble fibre adds bulk and speeds transit. Most fibre-rich foods contain both.

It matters because it does several useful things at once: it feeds the gut bacteria that produce short-chain fatty acids, slows glucose absorption, increases satiety for very few calories, and shows consistent associations with lower cardiovascular and colorectal cancer risk across large cohort studies. A large series of systematic reviews put numbers on it: the highest fibre intakes were linked to 15 to 30% lower all-cause and cardiovascular mortality, with the benefit greatest between 25 and 29 g a day — well above what most people in Western countries actually eat.

In practice it comes from whole plants — pulses, oats, wholegrains, fruit, vegetables and nuts — rather than from supplements, which capture only part of the effect. Increasing it quickly causes bloating, so raising it gradually alongside more fluid is the comfortable route.

Sources

• Reynolds A, et al. Carbohydrate quality and human health: a series of systematic reviews and meta-analyses. Lancet 2019