By Jenny Tschiesche BSc(Hons) Dip(ION) FdSc BANT

Prebiotics and where to find them in everyday foods

Our interest in gut health and what it can do for us has grown at a rapid pace in the past decade. Now words like probiotics and prebiotics are used commonly. There has been a lot of interest in particular in the introduction (or should I say reintroduction) of fermented foods, known as probiotic foods, into our diet in order to boost bacterial diversity in the gut. However, hiding in plain sight and probably in the healthiest diets all along have been prebiotic foods. They just were not referred to as prebiotics and therefore we might not have known about the contribution they make to the growth of beneficial gut bacteria.

In order to be clear on the differentiation; probiotic foods provide bacteria strains; prebiotic foods provide the fuel to help those strains and those already present in your gut to thrive. Whilst some of the most easily accessed prebiotics come from the sorts of foods that we have always considered healthy what may perhaps surprise you is the discovery of the role of resistant starch as a prebiotic which has put some previously less favoured carbohydrates back on the healthy eating agenda too. Let’s find out which everyday foods can be considered prebiotics:

Broccoli, Cauliflower, Brussels sprouts, Rocket and Kale these are known as cruciferous vegetables. These vegetables provide vitamins, minerals, and fibre in abundance, but also contain sulphur-containing metabolites, known as glucosinolates. Bacteria in the gastrointestinal tract break glucosinolates down releasing bioactive compounds that play an anti-inflammatory role.

Beans, Peas and Lentils - are high in fibre, protein, B vitamins, and folate. The high fibre content provides an ideal food source for the healthy gut bacteria, which break down the carbohydrates into component parts, including short-chain fatty acids that our body uses for many important functions, including boosting our immune response.

Onion, Garlic, Leeks, Spring Onions, Shallots and Chives – these are all members of the allium family. Allium vegetables are high in beneficial organo-sulphur compounds, which is what makes them anti-inflammatory, anti-cancer, and protective against cardiovascular disease. They are a great source of inulin which is a prebiotic fibre. Garlic is also a source of allicin, which is naturally antimicrobial and can therefore improve the likelihood of optimal bacterial balance in the gut.

Bananas - The fibrous quality of bananas helps to soothe the gut membrane, but these natural fibres also promote good bacteria growth. Slightly underripe bananas are a source of resistant starch which is known to provide a prebiotic fuel source for probiotic bacteria.

Blueberries - the fibre in blueberries have been shown to enhance the digestive flora. Furthermore, they are one of the highest antioxidant foods available. Particularly rich in polyphenols, which have shown to have neuro-protective, anti-inflammatory, and anti-aging properties.

Cooked and Cooled Starches e.g., pasta, rice, potatoes. The resistant starch created by cooking and cooling these starches, even if you subsequently reheat them, benefits the gut by producing butyrate as a result of fermentation in the gut. Butyrate is the preferred energy source of the cells lining the colon and it also plays several roles in increasing metabolism and decreasing inflammation.