Now research has shown a big part of keeping the gut and its huge collection of bacteria healthy is fibre, especially a type of dietary fibre called resistant starch.
CSIRO, Australia’s national science agency, in its latest book CSIRO Gut Care Guide shares the latest findings on gut health.
In this extract their scientists explain the role of dietary fibre.
Since dietary fibres are not digested in the small intestine, they are available as a food source for the gut microbiome populations that abound in the large intestine.
Of the nutrients we consume, fibre has the biggest influence on the gut microbiome. A diverse range of dietary fibres creates a diverse and more resilient gut microbiome, leading to good gut health by building an environment less favourable to the growth of potentially harmful microbes, while also enhancing the immune system and the healthy functioning of the tissues and gut barrier.
A healthy gut environment is associated with a decreased risk of a range of diseases, including bowel cancer, type 2 diabetes and obesity.
Fibres are generally classified as soluble or insoluble. Soluble fibres come from nuts, seeds and legumes, oats, barley and psyllium husk, most vegetables and fruit while insoluble fibres also come from similar sources including wholegrain foods, green vegetables and unpeeled fruit.
Resistant starch is an insoluble fibre extensively fermented by the gut microbiome and it can be formed in the cooking of food such as potatoes which get a modest increase in the starch if cooked and chilled before eating.
Other sources are legumes, especially chickpeas, grains such as rye, buckwheat, oats and barley, under-ripe bananas and cooked and cooled starchy food including rice, pasta and beans.
How much fibre do we need?
The recommended total daily fibre intake in Australia and New Zealand is 25g for women and 30g for men. These amounts are considered adequate for maintaining gut function and laxation. However, to reduce the risk of chronic diseases, the National Health and Medical Research Council suggests a higher daily intake of 28g for women and 38g for men.
EATING TIPS
In summary, here are the key principles of the CSIRO Healthy Gut Diet:
• Eat at least 25-30g of total dietary fibre each day.
• Choose foods that are higher in resistant starch.
• Add high-fibre foods to your diet slowly.
• Drink plenty of water each day.
• Limit highly processed foods.
• Limit added salt and sugars.
• Minimise alcohol.
• Exercise regularly - this creates movement for the bowel.
Serves 4
800g chicken thigh fillets, skin and visible fat removed
2 Tbsp curry powder
2 tsp ground cumin
1 Tbsp extra virgin olive oil
2 Tbsp raw almonds, roughly chopped
300g sugar-snap peas, ends trimmed
2 bunches broccolini, halved lengthways
2 cups mint leaves
2 cups flat-leaf parsley leaves
2 cups coriander leaves
juice of ½ lime
2 Lebanese cucumbers, sliced into thin discs
Golden crispy rice
¾ cup (150g) basmati rice
¼ teaspoon ground turmeric
5 golden shallots, thinly sliced
2 Tbsp extra virgin olive oil
Method
To make the golden crispy rice, place the rice and turmeric in a saucepan, add 1 ½ cups (375ml) water and bring to the boil. Reduce the heat and simmer, covered, for 10 minutes. Remove and set aside, leaving the lid on for the rice to steam.
2. Meanwhile, place the chicken, curry powder and cumin in a large bowl and toss to coat the chicken evenly. Heat the olive oil in a large frying pan over medium-high heat, add the chicken and cook for 4-5 minutes each side until golden brown and cooked through. Remove to a plate and cover with foil to rest and keep warm.
3. To finish the golden crispy rice, add the shallot and olive oil to the same pan. Cook, stirring occasionally, for 5 minutes until softened and golden. Add the cooked rice and stir to combine, then press down on the rice with a spatula to flatten it. Cook for 6-7 minutes, without stirring, until a golden crust forms on the bottom. Using your spatula, flip big chunks of the rice over (it will break apart, but try to keep some sections stuck together), then push down into the pan for another 5 minutes until dark brown.
Remove and set aside for serving.
4. Return the frying pan to medium-high heat. Add the almonds, sugar-snap peas and broccolini and cook, tossing, for 3-5 minutes until the veges are tender.
5. Mix together the mint, parsley, coriander and lime juice in a bowl.
6. Divide the curried chicken, crispy rice and cucumber evenly among bowls, top with the veges and dressed herbs and serve.
Serves 4
160g mozzarella, grated
1 Tbsp capers, rinsed
150g hot-smoked salmon
1 Tbsp horseradish cream
2 cups (60g) watercress sprigs
3 Tbsp unsalted roasted almonds, roughly chopped
1 tsp extra virgin olive oil
lemon wedges, to serve (optional)
Buckwheat crepes
80g buckwheat flour
1 large free-range egg
2 tsp extra virgin olive oil
Method
To make the buckwheat crepe batter, place the flour in a large bowl, crack in the egg and add 1 cup (250 ml) water. Mix well to form a thin, smooth batter.
Set aside to rest for at least 1 hour, but preferably for 2 hours before cooking.
2. Heat ½ teaspoon olive oil in a large non-stick frying pan over medium heat. Pour in one-quarter of the batter and swirl the pan to cover the base, making a thin crepe. Place one-quarter of the mozzarella, capers and smoked salmon in the middle. Continue to cook for 4–6 minutes until the crepe is browned and crispy on the bottom and the cheese has melted.
3. Fold over the crepe and transfer to a plate. Cover to keep warm, then repeat with the remaining batter, mozzarella, capers and salmon to make four crepes.
4. Serve the crepes with the horseradish cream, watercress and almonds. Finish with a light drizzle of olive oil, a pinch of freshly ground black pepper and a lemon wedge for squeezing over, if you like.
Serves 8
½ head cauliflower, cut into florets
2 garlic cloves, skin on
2 tsp ground coriander
1 ½ Tbsp extra virgin olive oil
1 anchovy fillet
160g reduced-fat goat feta
½ cup (125g) reduced-fat natural yoghurt
1 cup (160g) cooked butter beans or drained and rinsed tinned butter beans
juice of ½ lemon
1 Tbsp unsalted walnuts, crushed
4 cups mixed raw sliced vegetables (snow peas, radish, celery, carrot, capsicum or cucumber), to serve
Seeded crackers
90g rolled oats
2 Tbsp flaxseeds
2 Tbsp pumpkin seeds (pepitas)
2 Tbsp sunflower seeds
2 Tbsp sesame seeds
1 ½ Tbsp poppy seeds
½ tsp fennel seeds, lightly crushed
2 Tbsp extra virgin olive oil
Method
1. Preheat the oven to 180degC (160degC fan-forced).
2. To make the crackers, place the oats in a food processor or blender and blitz into small (1-2 mm) pieces. Add the flaxseeds and pumpkin seeds and pulse a few times until the pumpkin seeds are roughly chopped. Tip into a bowl, add the remaining ingredients and ½ cup (125 ml) water and mix until well combined. If you need more water to bring the dough together, add it 1 tablespoon at a time. Set the mixture aside for 20 minutes to firm up.
3. Meanwhile, make a start on the cauliflower feta dip. Place the cauliflower florets and garlic cloves on a large baking tray, sprinkle over the coriander and 1 tablespoon olive oil and toss to coat. Spread out over the tray and bake for 25 minutes, until the florets are tender and golden brown on the edges.
Remove and set aside to cool, leaving the oven on for the crackers.
4. Place the cracker mixture between two sheets of baking paper. Using a rolling pin, roll it out to a 3-4mm thickness (don’t roll it too thin or the crackers will crumble when cooked). Remove the top layer of baking paper and slide the seed mix and bottom layer of paper on to a large baking tray.
5. Place in the oven and bake for 20 minutes, then remove and carefully flip the seed mixture over.
If it cracks in places, don’t worry - you’ll be breaking it into crackers anyway! Bake for another 10 minutes until golden brown. Remove from the oven and cool for 10 minutes, before breaking into crackers.
6. To finish the dip, place the cooled cauliflower in a food processor and squeeze in the flesh from the garlic cloves. Add the anchovy, feta, yoghurt, butter beans and lemon juice and blitz to form a smooth paste. For a smoother consistency, add a dash of water and blitz again.
7. Scoop into a serving bowl and sprinkle over the walnuts. Finish with the remaining olive oil and a good grinding of black pepper. Serve the dip with the crackers and vegetables.
