Bacteria Friendly Foods (or BFF’s as I like to call them!) are essential for promoting a healthy gut microbiome. These kinds of foods are known as prebiotics and consist of non-digestible carbohydrates, or insoluble fibre, and soluble fibre. Both provide food for your gut microbes and also contribute to good health. Soluble fibre dissolves in the water in the GI tract and helps increase motility and soften stools. Insoluble fibre reaches the colon intact and is then fermented by the gut microbes, releasing beneficial by-products as a result.

Probiotics, on the other hand, are live bacteria and yeasts found in foods such as live yoghurt, kefir, sauerkraut, kimchi, kombucha, cheeses and other fermented foods. Probiotics are transient – in that they do not generally stay within the gut, but pass through, hopefully helping to reinoculate the microbiome with some of the beneficial bacteria necessary for health.

When probiotics are combined with prebiotics, such as is found in sauerkraut and kimchi, for example, it provides both the live bacteria (probiotic) plus the substrate (food – prebiotic) necessary to feed that bacteria, thus helping it to grow immediately. This combination is known as a synbiotic, because the two are working synergistically. Prebiotics help to increase beneficial bacteria such as Bifidobacteria, lactic acid bacteria and Lactobacillus amongst others.

The different types of fibre include:

Inulin – a polysaccharide – which is a natural water soluble carbohydrate found in plants. It is used by plants to store energy and can be found in root vegetables, or rhizomes, such as banana or plantain, chicory, dandelion leaves, garlic, onions and yam.

Galacto-oligosaccharides – these are foods that resist digestion breakdown and reach the colon intact. It is in the colon that the microbes ferment these foods, producing organic short-chain fatty acids (SCFAs), such as butyrate, acetate and proprionate. These SCFAs are absorbed into the bloodstream and help improve metabolic health. Galacto-oligosaccharides support the immune system by helping to increase healthy gut microbe numbers, which inhibits the growth of pathogens, and by producing antimicrobial substances as a result of fermentation. They also enable better absorption of vitamins and minerals.

Resistant starch is also carbohydrate that is resistant to digestion (as the name would suggest), meaning that our bodies do not absorb the nutrients but instead the gut microbes use these foods for energy for themselves and they also ferment them, producing the beneficial by-products listed above for us to use.

Resistant starch has different categories:

  • RS1 – indigestible starches found in seeds, legumes, whole grains
  • RS2 -inaccesible to enzymes due to starch conformation eg high amylose corn starch
  • RS3 – cooked and cooled in foods such as potatoes, rice, pasta
  • RS4 – chemically modified

Pectin is another polysaccharide found in non-woody parts of plants, and is often used as a gelling or thickening agent in products such as jam. Pectin is found in apples, gooseberries,oranges and other citrus fruits – particularly in the skins of these foods.

Adding extra fibrous and starchy foods can cause your digestive system to complain so it is important to increase gradually to avoid discomfort. Likewise with fermented foods – a little at a time is best to give your body time to adjust.

What are YOUR favourite BFFs?