From fermented foods to low FODMAP eating - how you can improve your gut health
Unlike the usual food trends that promise you'll lose a few pounds in a matter of weeks, gut bacteria has been scientifically proven to seriously impact your overall health and well-being. Here, Aoife Carrigy reports on how, from fermented foods to low FODMAP eating, our menus are now being led by our gut instincts
The state of your gut wasn't always considered polite conversation. These days everyone seems to be talking about it. What's more, scientists are dedicating considerable time and resources to thinking about it - and our diets are being increasingly influenced by it. Fermented foods such as kimchi are, quite literally, the dish of the day, thanks to the boost they give to our digestive systems. And 2017 looks set to be the year that low FODMAP eating, which eliminates hard-to-digest foods, takes hold.
And the conversation is not limited to those who experience digestive problems - whether they be sensitive to gluten or allergens, irritable bowel syndrome (IBS) or debilitating conditions like Crohn's or coeliac diseases. We're starting to realise that our gut health plays an important role in our overall physical and mental health and well-being, and that diet is crucial.
"As our understanding shifts towards a greater appreciation of the human being as a composite organism," writes Dearbhla Reynolds in the introduction to her recent book on fermentation, The Cultured Club, "it would appear there is a lot happening within our guts, which are home to the trillions of micro-organisms called the microbiota and the two million genes they carry, called the microbiome."
Reynolds continues that: "Scientific studies are revealing that the microbial ecosystem living in us and on us needs careful consideration, and how we address it is hugely influenced by diet, one forkful at a time. We are literally on the frontier of a new medical understanding."
Meals dictated by medical research may sound too far-fetched for even Heston Blumenthal, but experts argue that it's only through properly understanding our bodies' needs that we can feed them correctly to maximise both energy and nutrition.
"The science is exploding in the area," says Paula Mee, a State-registered dietitian and co-author with Lorraine Maher of the upcoming cookbook, Gut Feeling: Delicious Low FODMAP Recipes to Soothe the Symptoms of a Sensitive Stomach.
"We now know that there are 10 times more bacterial cells in the intestine than there are human cells in our body," Mee says. "That means there are 100 times more bacterial genes than human genes. We have approximately 2kg of these bacteria in our gut, and we're now beginning to understand what they do."
What they do is complex, Mee explains, but includes helping our bodies to extract energy from food, to digest protein, and to create some essential vitamins. They also regulate our bowel movements and have an impact on stool consistency.
Of course, not all bacteria are created equally. These good bacteria are our friends, helping to keep the bad bacteria - or pathogens - in check. They do so in a number of ways. "They produce natural antibiotics to prevent growth of pathogens, and they also adhere to the gut wall, so they crowd out harmful bacteria," Mee says. "They also compete with harmful bacteria for food, so that if they're consuming a lot of what is available in the gut, the good bacteria grow and thrive at the expense of the not-so-good pathogens."
Research is showing that our gut reflects changes in our overall mental and physical health, and our microbiome changes when the rest of our body is unwell.
"We know that the microbiome changes as we age," Mee says, explaining that the beneficial bacterial appear to weaken, "but it also is influenced by our diet and stress levels."
Our time-poor lifestyle and the processed convenience foods we are increasingly relying upon is having an impact on our gut and the microbiomes growing in it.
"What we see is that alterations in gut bacteria are increasingly being linked to variations in health, including things like obesity. We know that people who are obese have a different microbiome than those people who are a normal weight for height. And there are changes linked to inflammatory conditions as well, and inflammation underpins a lot of disease."
We know that there is a direct knock-on effect in that what we eat influences what grows in our gut and what we grow in the gut influences our immune system, and our overall health. Research is now showing that the gut and the brain influence one another.
"Harvard has done some interesting research looking at people who have negative thoughts, a negative pre-disposition, or are under stress, and can actually see symptoms manifest in the bowels because of their thoughts and the feelings created around that," Mee says. "And likewise, what we eat also affects the microflora and in turn has an effect on our mood and our brain health as well."
It may be some time before we fully understand the extent of the influence of our microbiome on our overall health. But we are beginning to understand the role of certain foods in either supporting or disrupting a well-balanced gut.
Some foods can be hard to digest and can contribute to an imbalance of gut health. Based on research done by dietitians and gastroentrologists at the Monash University, the low FODMAP diet has been developed as an evidence-based intervention for people who have IBS - which is one in five of us.
"Symptoms of irritable bowel would range from distension to abdominal pain, cramping, a lot of wind, and things like alterations in the bowel movements," Mee explains, continuing that the low FODMAP diet provides relief from symptoms in up to 75pc of patients with IBS.
The name 'FODMAP' is an acronym for Fermentable Oligosaccharides, Disaccharides, Monosaccharides and Polyols, which are complex types of molecules found in certain foods. Examples include every day foods like wheat, onions, garlic, milk, and yoghurt.
"In some cases these can be poorly digested in the small intestine of people who have IBS," says Mee, "and they end up travelling along the digestive tract further down into the large intestine, where the natural bacteria that grows there starts to consume and interact with them and produce gas and other symptoms."
When implemented in consultation with a dietitian, the diet works by excluding all FODMAPs before re-introducing various food groups to discover which foods are aggravating symptoms for that individual.
You don't have to have full-blown IBS to experience the effect of these trigger foods, Mee adds. Many people will experience bloating or other low-level symptoms without ever seeking medical help. Mee's new cookbook Gut Feeling - one of many low FODMAP books to hit shelves this spring - is designed to help those on the diet to navigate around these trigger foods and towards their alternatives.
The book may also be of interest to those who suspect they may have symptoms of an irritable bowel, but who don't yet have a diagnosis. But Mee stresses that major long-term changes to any diet should always be done in consultation with health professionals. "Some of the FODMAPs are surprisingly healthy foods, for example peas, beans and lentils which are probiotics and feed the good bacteria."
Avoiding these food groups can be a useful way to control symptoms in the short term, but in the long term it could be problematic unless the diet is accordingly balanced, which is where the dietitian comes in.
Conversely, some foods actively support our digestive system. Fermented foods are full of good bacteria, says Reynolds, and are rich in digestive enzymes that can help in the efficient processing of food and absorption of its nutrients. In a couple of years, fermented foods have gone from fringe trend for the culinarily curious, to mainstream choice, both for complexity of flavour and as a dietary tool. We're starting to realise that the age-old skill of fermenting food was more than simply a way to prolong the shelf life of fresh produce to last through the leaner months: these foods also served to keep us in good internal shape.
"Including a diverse daily serving of fermented foods," Reynolds writes, "can enhance immune system response, decrease irritation of the bowels, give you a healthy glow, provide digestive ease, give respiratory ease, decrease incidences of allergies and sensitivities, reduce sugar cravings, lessen incidence of bacterial infection, and contribute to a continual feeling of satisfaction, increased energy, better mood, mental clarity and a general all-round feeling of well-being."
With those kinds of benefits, it seems that the conversation about our gut health is certainly one worth having.
The most talked-about food of the moment, kimchi (top right) is a traditional Korean side-dish. A pungent dish with a spicy kick, it's made from fermented vegetables, most usually cabbage, and is something of an acquired taste.
A sparkling drink made by fermenting black, or more usually, green tea (centre right). A popular one to make at home, but strict hygiene conditions must be observed to prevent potentially harmful contamination.
Made by fermenting soy beans, salt and a gut-friendly fungus, miso paste is a staple of Japanese cooking. High in protein and available in different strengths and flavours, it can be used in countless ways to add big flavour to everyday cooking.
A dairy milk drink, kefir is made by adding a live culture of yeast and bacteria to milk and leaving it to ferment. With a tart taste, it's low in lactose and high in calcium and good bacteria.
More fermented cabbage, this time owing its origins to Germany. Once considered to be not much more than the punchline to a joke in Ireland, sauerkraut (above) is now popping up on menus all over the country, alongside picked vegetables (main photo, above) of all kinds.