Health practitioners have been extolling the virtues of fibre-rich foods for decades. Dietary fibre is a nutrient that is important in regulating the digestion and eliminating waste.
Now researchers at the University of Michigan in the US have found another equally important reason to eat a diet high in fibre-rich foods. Dietary fibre, it appears, indirectly protects the intestinal wall, guarding against the invasion of unfriendly bacteria and pathogens.
The research, published in Cell, was carried out using specially-bred germ-free (“gnotobiotic”) mice which are born with no gut microbes of their own. The mice received a transplant of bacteria that normally grow in the human gut.
Three groups of mice were studied:
• one group of mice were fed a diet that contained 15 percent fibre
• another group were fed a fibre-free diet of processed foods
• a third group of mice were fed a diet high in prebiotic fibre of the type often found in health supplements and processed foods.
With no fibre to eat, the normally “friendly” bacteria began to eat the lining of the colon
The research revealed that in the mice fed a fibre-free diet, some of the normally helpful, “friendly” bacteria began to eat their way through the protective mucus layer that lines the wall of the colon, eroding it to such an extent that pathogenic bacteria were able to invade.
This was found to be the case even after just a few days of eating a fibre-free diet. It was also found to be the case in the mice fed the prebiotic fibre.
But where the host was fed a diet of fibre-rich foods, the protective mucus lining remained strong and impregnable.
When some of the mice were infected with a strain of pathogenic bacteria similar in effects to E.coli in humans, the fibre-free mice showed inflammation over a much greater area than the ones on a fibre-rich diet.
Eric Martens, PhD, who led the research, said: “The lesson we’re learning from studying the interaction of fiber, gut microbes and the intestinal barrier system is that if you don’t feed them, they can eat you.”
Read more about the research here.
Foods high in fibre:
Legumes – lentils, beans, peas, chick peas
Berries – raspberries, blackberries
Seeds – hemp seeds, linseeds/flaxseeds, chia seeds, pumpkin seeds, quinoa
Dried fruit – dates, figs
Vegetables – parsnips, brussel sprouts, broccoli, turnip
Wholegrains – oatmeal, wheat bran