Why fibre is so good and healthy for the gut

Why fibre is important for the gut

Let's face it, fresh white bread or a colourful fruit smoothie both sound delicious, and even healthy. Unfortunately, what delights our taste buds doesn't bring much joy lower down. This is because these foods lack fibre, which is essential for the gut – even though the energy it provides is minimal. Our gut needs large amounts of indigestible fibre to stimulate its muscles, ensure trouble-free bowel movement and nourish its flora. A big bonus is that fibre contains hardly any calories and makes you feel full for longer.

How fibre affects the gut flora

Fibre could be described as food or a source of energy for our gut flora. Gut flora refers to the 100 million micro-organisms that colonise the gut. These are 90% bacteria, plus some viruses, yeasts, fungi and protozoa. Fibre therefore benefits the gut, as it nourishes the bacteria that mainly colonise the large intestine.

Which kind of fibre is par­ticularly good for our gut?

Generally speaking, the more varied our diet, the better it is for our gut inhabitants. An unbalanced diet can result in certain bacterial strains becoming dominant or even causing bacterial species to die off, leading to impaired digestion. However, if we supply our gut bacteria with plenty of different types of fibre, they will thrive.

Types of dietary fibre

A distinction can be made between 3 types of dietary fibre in particular:

1. Soluble fibre, which is broken down into small molecules by the gut bacteria through fermentation. These swell up into a kind of gel and bind water. Soluble fibre is found in foods like apples, carrots, garlic, asparagus, bananas, pulses, flaxseed and oats.
2. Insoluble fibre, which is largely excreted unchanged during bowel movements. This is found in foods like nuts, almonds, wholemeal cereals, oats, rye and fruit stones.
3. Resistant starch is formed in foods like potatoes, rice, pasta, pulses and cereals after being cooked and fully cooled down.

How fibre helps with constipation

Constipation or a lazy gut can be prevented by eating a high-fibre diet and drinking at least one and a half to two litres of water a day. This works for two reasons: firstly, fibre promotes regular bowel movements. Secondly, it ensures that the stool is soft. This is because, as mentioned earlier, fibre swells up in the gut and stores fluid, increasing the volume of the contents of the gut. The greater the mass that presses against the gut walls, the more the muscle layers are activated to “keep pressing” the food pulp. The swelling also ensures a softer stool consistency once the digestive process has reached its end.

Change to a high-fibre diet

If you have previously eaten a low-fibre diet and are changing your diet, try to do it step by step. The gut flora must first adapt to the new conditions, so it’s better to increase the amount of fibre gradually. And don’t forget to drink enough water!

Dietary fibre supplements

A whole range of dietary fibre supplements are available on the market, usually containing a single type of fibre in high concentrations. However, our gut flora is better served with unprocessed fibre-rich foods. These provide a wide variety of dietary fibres as well as other important ingredients and nutrients.

Fibre when taking medication

Fibre can slow down the absorption of certain medications such as paracetamol. For this reason, it’s advisable to consult your doctor or pharmacist first. The general advice is to take such medications on an empty stomach or about 2 hours after a high-fibre meal.

When should fibre be avoided?

Particular caution must be taken if you have acute, chronic inflammatory diseases or persistent diarrhoea, as a high-fibre diet can further irritate the gut. In this event, it's essential to consult a doctor.

Our gut flora is unique

Everyone’s gut flora is unique. How it develops from birth depends on various factors, including Caesarean section or spontaneous labour, breastfeeding or milk bottle feeding, the culture in which we grow up and the eating habits that shape us. For example, some bacteria thrive on seaweed from a sushi restaurant and others are more used to meat and sausage. Studies have also shown that the micro-organisms in the gut change when a person suffers from obesity, depression, malnutrition or chronic intestinal problems. Which leads to the conclusion that if we can use diet to counteract constipation, then we can also use it to counteract medical conditions like these.

Sources

• University Hospital Zurich
• Book: Vielkönner Ballaststoffe, Ibrahim Elmadfa
• Book: Gut: the Inside Story, Giulia Enders