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The good guts guide

Why probiotics and prebiotics are so beneficial to your digestive system

The average person carries around approximately 1.5kg gut bacteria and fungi, collectively known as the microbiome,” says Jill Bell of health store Well and Good in Midleton, Co Cork. “It’s reckoned that there are even more microbes than human cells in our bodies Bacteria are the most studied element of the microbiome, the ‘probiotics’ without which we wouldn’t survive. As well as our digestion and gut health, these bacteria can affect our immunity, mental health, allergies, vaginal health and fungal overgrowth, skin health, weight, the production of vitamins including B12 and K.”


“Probiotics are beneficial microbes that live in our gut whilst prebiotics are a source of food for probiotics,” says Lucy Kerr from health store The Good Earth in Kilkenny. “They help our good gut bacteria grow and flourish. Other benefits include to gut and digestive health, immune health, skin health and mental health. There are many different strains of probiotics and each has its own unique function for the body.”

“An imbalance of gut bacteria, known as dysbiosis, when the friendly gut bacteria are overruled by viruses, fungi or damaging bacteria (or antibiotics), frequently results in an upset tummy, diarrhoea or thrush and there are many brands of probiotics which are aimed specifically at righting the imbalance,” says Jill Bell. “These bind with harmful bacteria such as e coli, for example, or increasing vaginal bacteria. Some commercial probiotics are specifically designed to resist the effects of prescribed antibiotics, which is useful if a person is on medication.”

Probiotic foods

“Fermented foods that naturally contain probiotics include kombucha, sauerkraut, sourdough bread, miso and kefir, “says Lucy Kerr. Live yogurt, fermented and pickled vegetables like kimchi include probiotics, as do fermented soybean and barley malt, such as miso, and fermented drinks.

“We can affect our microbiome by accident or design,” says Jill Bell. “To support it, foods such as fermented products like sauerkraut, kefir, kombucha, unsweetened yogurts and high fibre wholegrains all help.”

Prebiotic foods

“Prebiotics are found in bananas, garlic, oats, onions, leeks, artichokes,” says Lucy Kerr. “For babies breastmilk is their first amazing source of probiotics and prebiotics.”

“Foods high in naturally-occurring prebiotics feed naturally-occurring friendly bacteria,” says Jill Bell. “These include artichokes, bananas, asparagus and apples.”

The prebiotic inulin is found in asparagus, artichoke, chicory, dandelion root and leeks. Other prebiotic foods include oat bran, whole nuts and seeds and dried fruit such as figs and dates. Prebiotics assist our good bacteria to produce specific metabolites that beneficially affect all areas of our health, from mood to immunity.


“The ‘biggie’ in our diets that damages our gut biome is refined sugar,” says Jill Bell. “Most women know that it also nourishes yeast overgrowth. Yeast feeds on sugar, and those of us who have felt the burning sensation of a UTI are well aware of the need to take a probiotic alongside antibiotics and avoid sugar-rich foods.”

Read the label

Ask your local health store staff for advice when choosing a probiotic supplement, and look for the genus, such as lactobicilis; and the species, for example acidophilus. Then look for a strain number under the name. For maintenance of gut health you need about two billion bacteria in a capsule at the time of expiry, and for longer term gut issues you need 20-30 billion.


“Supplements are a handy way of including pre and probiotics as it can be hard to achieve enough through or diet alone,” says Lucy Kerr. “When picking a probiotic look into what you will need it most for. The majority contain multiple strains, but some may contain only one or two strains for specific needs. For example, the strain l-planetarum is shown to help IBS sufferers.

“L reuteri protectis has been shown to reduce colic symptoms in babies. B breve is also another strain well studied in children. There are also many different strengths – sometimes we may need a higher strength such as when we have taken a course of antibiotics. Prebiotics may not be labelled as prebiotics on the label so look out for fos, gos and inulin which are prebiotics.”

Other natural helpers for gut health

  • Aloe vera – soothing and healing to the digestive tract.
  • Bone broths – contain a range of vitamins and minerals such as collagen, calcium and magnesium that help repair cells in the gut lining.
  • Centaurium tincture or camomile tea after meals – for acid reflux.
  • Chlorella –can increase the number of good bacteria in the gut.
  • Glutamine powder – healing for the digestive tract.
  • Herbal teas – chamomile, valerian or peppermint teas have antispasmodic properties. Ginger and fennel teas relieve gas and bloating.
  • Magnesium – from dark leafy greens, nuts and seeds, wholegrains, certain fish, avocados and bananas. Can help to relax the muscles in the intestine.
  • Slippery elm – good for heartburn and acid reflux.
  • Vitamin C – has a healing and cleansing effect in the gut so is good for constipation.
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