Fibre – Not Just for Constipation
The importance of fibre for digestive health has been known about for some time. Increasing fibre intake through including plenty of fruit and vegetables and wholegrains in the diet are part of the suggested lifestyle changes, including increasing fluid intake and physical activity, for the effective management of constipation. As many are aware, constipation is a widespread problem in the elderly, and lifestyle changes may sometimes be an alternative to the huge number of laxatives prescribed. Having adequate fibre in the diet has interestingly also been associated with lower risk of heart disease, diabetes and weight gain.
More fibre – an unlikely treatment for asthma?
Now, a recent publication in the journal Nature Medicine suggests that increased fibre in the diet may also be important in asthma. The team of scientists at the University of Lausanne showed, in an animal study, that a high-fibre diet could reduce inflammation in the lungs. The researchers looked at the effect of different levels of dietary fibre on mice exposed to house dust mites, a common trigger for asthma symptoms in humans.
They found that mice on a high-fibre diet produced increased levels of short chain fatty acids. These can act as signals to the immune system potentially making the lungs more resistant to irritation. Bacteria naturally present in the gut can convert the soluble fibre found, for example, in fruit and vegetables, to short chain fatty acids. The researchers found that mice fed on a low-fibre diet had stronger allergic reactions than mice fed on a higher fibre diet, which seemed to confer some protection against allergic inflammation on the lung.
The authors argue that a dietary shift away from high fibre containing foods to more processed foods, may have some relationship with the increased prevalence of allergic asthma seen in developed countries. However, this is the authors’ interpretation of a trend, and does not yet have robust scientific evidence to support it.
So far it’s only in mice
It is early days; animal studies can never be directly translated to humans but show interesting areas for further investigation. In any case, eating more fruit and vegetables and fibre are firm recommendations for healthy eating. Latest surveys, for example, show that only 11% of boys and 8% of girls aged 11-18 years, 31% of adults and 37% of older adults met the “5-a-day” fruit and veg recommendation. Fibre intake in the population currently averages 14g rather than the recommended 18g per day.
Find out more about simple ways of increasing fibre in the diet on BNF website
*All information is correct at the time of publishing