Does eating a high-fibre diet help against constipation as you get older?

Eating more fibre does not help everyone against constipation, including as you age. In people with persistent constipation that has no clear cause, researchers sometimes observed the opposite: those who stopped eating large amounts of high-fibre food had fewer symptoms, went to the toilet more often, and felt less bloated. Those who continued eating a high-fibre diet experienced no improvement. In more severe forms of constipation, extra fibre can even make symptoms worse.

At the same time, three large cohort studies involving nearly 96,000 people with an average age above sixty show something remarkable: those who ate the most Mediterranean or plant-based diet had a 16 to 20% lower chance of developing constipation. Vegetables and nuts emerged as the most protective components. A Western dietary pattern or a diet high in pro-inflammatory foods increased the risk of constipation by 22 to 24%. Notably, this association was not purely linked to the total amount of fibre consumed; it is about the overall dietary pattern.

The distinction is therefore important: a Mediterranean or plant-based dietary pattern appears to work preventively, whereas targeted fibre supplementation as a remedy for existing constipation yields mixed results. Guidelines for older adults do mention high-fibre foods and fibre supplements (such as psyllium fibres) as a first step, but emphasise that these should be introduced gradually because of side effects such as gas and bloating. It works for some people, but certainly not for everyone.

Physical activity also plays a role: less physical activity is associated with more symptoms, and rehabilitation programmes focused on movement appear to help. In older adults, multiple factors often play a role simultaneously, such as medication use and reduced intestinal motility. If you have suffered from constipation for a long time and adjusting your diet does not help, it is wise to discuss this with your doctor, as extra fibre can in some cases also worsen symptoms.