“Other good gut health foods, particularly when it comes to promoting a healthy gut lining, include pumpkin, sweet potatoes, squash, nuts and also chicken stock, as the collagen promotes strong gut lining,” adds Llewellyn-Waters.
Other nutrients vital for optimal gut health which deserve a mention are:
- Wild fish such as wild salmon, avocados, nuts and olive oil which are rich in healthy fats, anti-inflammatory and gut healing.
- Black beans improve gut barrier function and also increase the number of beneficial gut bacteria.
- Antioxidant-rich foods. Most fruits, vegetables and herbs contain antioxidants such as vitamin C, vitamin E, lutein, beta-carotene, flavonoids and lycopene. Blueberries, green leafy vegetables, onion, oregano, turmeric, cumin, basil, ginger, cayenne pepper, dark chocolate (70 per cent minimum cocoa solids), green and white tea are other excellent sources.
- Zinc-rich foods. Zinc is an important mineral for a healthy gut. Researchers from King’s College London have found an association between low zinc intake and inflammatory bowel disease – although if taking zinc supplements, it’s important not to exceed recommended levels. Good natural sources include: poultry, seafood, legumes, lentils and dairy products like cheese and milk.
“A diet high in ultra-processed foods, and low in plant-based fibre, is bad for your gut,” explains Dr Kinross. “We don’t yet fully understand the precise mechanisms that make ultra-processed foods so damaging to gut health but it seems that they might directly damage the lining of the gut which is where a lot of our immune system sits.”
However, poor diet is just one driver behind the loss of the diverse ecosystems we need for a healthy microbiome.
“Misuse of antibiotics, drugs and medicines are also key,” says Dr Kinross. “Pollutants play an important part, so does smoking and drinking too much alcohol.”
The way we eat – not just what we eat – also counts. “Having takeaways, eating alone instead of preparing foods yourself with your hands is not good for gut health,” says Dr Kinross.
“Sharing meals and eating with friends and family is an important way of maintaining these microbe communities within us. We need other people’s microbes as it ensures that we have diversity and resilience within our own microbiome. It’s a way of seeding it with preferential or helpful microbes; it’s exactly the opposite of catching a cold,” says Dr Kinross.
“Having physical interaction is important, simply because when we prepare food, by touch, by holding cutlery or mixing food with our hands, the microbes from our skin and hands are ultimately transferred. Eating socially, also means you are more likely to have physical contact – shake hands, hug someone or kiss them. This will also share microbes irrespective of diet.
Family sizes are shrinking, real world networks are shrinking, elderly people are isolated – all these things are creating what I would describe as an internal climate crisis – the mass extinction of microbes that we need inside us for optimal health.”
- Ultra-processed foods – such as sausage, bacon, pies, biscuits, ice cream. There is much more to learn in order to understand why ultra-processed foods are damaging to gut health, but one theory is that they contain substances – chemical additives and preservatives – that impair microbial life in our gut and create inflammation. Another theory is that the sugars in ultra-processed foods cause harmful bacteria to bloom.
- Fried foods. These tend to be high in harmful fats that could damage the gut microbiome and lead to inflammation.
- Red meat. Research suggests that a diet high in red or processed meat carry a 30 or 40 per cent increased risk of bowel cancer, respectively. A likely cause is the chemicals either naturally found in meat, added during processing or produced when cooking.
Shared meals: “Sharing foods, preparing them yourself and eating them with friends and family is an important way of sharing microbes,” says Dr Kinross. “Our gut microbes are dependent on us being social.
There’s also evidence that eating home-cooked meals as a family improves dietary intake, creates healthier eating habits in young people and reduces obesity in later life.
Prioritise sleep: “The microbes in our gut fluctuate with our circadian rhythms,” says Dr Kinross. “We know that the gut microbiome of night shift workers is very different to those who work regular hours, even when you take into account confounding variables like different diet and nutrition.”
One hypothesis is that sleep deprivation triggers pro-inflammatory changes in the gut microbiome. Research suggests that irregular sleep patterns – even when sleep patterns vary by as little as 90 minutes – are associated with unfavourable alterations in gut microbiome composition.
Regular exercise: “Exercise improves gut health in a number of ways,” notes Dr Kinross. “It improves the profusion of blood flow, regulates appetite and eating patterns and also changes the microbes in the gut.” Both moderate and intense exercise are associated with positive changes in microbiome composition. By allowing more oxygen to reach the bloodstream, exercise creates an environment for good bacteria to flourish. It also reduces the time it takes for food to move through the digestive tract, enabling the gut microbiome to function more efficiently.
Manage stress: “One of the most interesting aspects of the gut is its deep connections with the brain,” says Dr Kinross. “Having good mental health can improve your gut health and having good gut health can improve your mental health – it’s a two way conversation.”
There are many pathways connecting the two. “The first is the immune system. Your gut is such an important determinant of how your immune system functions and 15 per cent of the cells within your brain are immune cells. They talk to each other.”
In addition are well established hormone pathways as well as the vagus nerve, the direct ‘super highway’ that links them. “It seems that bugs in the gut send signals to the brain but equally, when the brain is unhappy – when we’re stressed, anxious, depressed, it can communicate directly with the bugs in the gut and change gut ecology.” Research shows that stress can lead to gastrointestinal disorders such as IBS, ulcers and reflux.
