Bamboozled by gut health lingo and what it all means? Our gut health glossary, written by dietitian Laura Tilt, will help you make sense of those frequently used gut health words and phrases.
A is for apple cider vinegar Ok, we’re starting with a cheeky one, because despite the hype around ACV and gut health, there’s actually no scientific evidence to support the claim that apple cider vinegar has positive effects on the gut or digestive issues. It’s not a booster for stomach acid (which is much stronger and sufficient by itself), but it can damage your tooth enamel, so this is one ingredient best left for your salad dressing.
B is for Bacteria, single celled microbes (tiny, living organisms), which are classified according to their shape - for example balls, rods, or spirals. They’re too small to be seen by the naked eye, but they live on us, in us and around us, and play an important role in maintaining our environments. The large majority of bacteria are beneficial or harmless - less than 1% of bacteria are the type that can cause infection and disease. In the gut, bacteria carry out many important jobs, including supporting the immune system and keeping the lining of your gut healthy.
C is for Constipation, described as having less than 3 bowel movements (poos) per week, or poos which are hard, lumpy, and difficult to pass. There can be lots of reasons for constipation including medications and underlying health conditions, but a lack of fibre or not drinking enough fluid can be contributing factors. Usually, a change in diet and fluid can help, but speak to your G.P. if you notice a change in your poo which lasts longer than a couple of weeks.
D is for Digestion One of the main functions of your gut, digestion is the process of breaking down food into nutrients that can be absorbed and used by the body. It starts in the mouth and is continued by your stomach and small intestine. Each year, your gut is responsible for digesting around 907 kilos of food. Thank you, gut!
E is for Enzymes Enzymes are specialised proteins that cause or accelerate a process in the body. In the gut, digestive enzymes are needed to help break down food, so that nutrients can be absorbed. They’re produced in your saliva, and by the stomach and pancreas. Unless you have lactose intolerance or a condition affecting your pancreas, there’s no scientific evidence to suggest that supplemental digestive enzymes are beneficial or necessary.
F is for Fibre, a type of carbohydrate found in fruits, vegetables, wholegrains, nuts, seeds, and pulses. Fibre is not broken down in the upper part of the gut, but lands in the large intestine where it feeds and fuels your gut microbes, and helps bulk out your poop, making it easier to pass. In short, it’s the most important nutrient you can eat for your gut health.
G is for Gut-Brain Axis, a phrase which describes how your brain and gut communicate with each other. Your brain and gut are physically connected by a nerve known as the vagus nerve, but we also know that gut microbes can send messages to the brain too, which may influence mood and behaviour. The gut-brain axis explains why stress and anxiety can be felt by the gut, which is why taking care of your mental health is a positive thing for your gut too.
H is for Heartburn, a sensation of burning in the chest area, which is caused by stomach acid flowing back up from the stomach into the oesophagus (or food pipe). Heartburn can be triggered by smoking, drinking lots of alcohol, and pregnancy hormones, but some people find large meals eaten late at night and certain foods (spicy foods, citrus, and caffeine) can be triggers too. If you’re experiencing heartburn on a regular basis, see your G.P. to check there’s no underlying cause
I is for Irritable Bowel Syndrome, a condition which affects how the gut moves and functions, causing symptoms like tummy pain and a change in bowel habits. It’s thought to affect about 1 in 7 people and is more common in women than men. It’s not completely clear what causes IBS, but research suggests it’s a combination of factors which include genetics, stress, previous gut infections, altered motility (movement) antibiotics, disrupted communication between the brain and the gut, and hypersensitivity in the gut wall.
J is for Jejunum, the middle part of the small intestine. This is where most nutrients are absorbed. If we were to zoom into the walls of the jejunum, we would see they look a bit like a shag pile carpet. This is because they are covered in finger-like tissues called villi, which increase surface area and whisk nutrients into the bloodstream. By the time food has moved through the jejunum, around 90% of the available nutrients have been absorbed.
K is for Kefir, a fermented milk drink thought to originate from the Caucasus and Tibet. It’s similar to yoghurt, with a slightly fizzy, sour taste. It’s made using beneficial strains of yeasts and lactic acid bacteria, which are thought to have the potential to colonise the gut, although more research is needed to determine their effects on the microbiome. Happily, it's well tolerated by those with lactose malabsorption as the bacteria break down the lactose in the milk during fermentation, clever huh?
L is for Large Intestine also known as the colon, is situated underneath your small intestine, and ends at the rectum. It’s about 1.5 metres long and is responsible for reabsorbing water and electrolytes from the residue of your food and forming and propelling your poop towards the exit of your gut. It’s also home to the majority of microbes in your gut.
M is for Microbiome - meaning all the microorganisms in a particular environment. In the case of the gut microbiome, it’s all the microbes (and their genetic material) that live in the gut. These microbes harvest energy from food, produce compounds which keep the gut lining healthy and even help programme the immune system, which is why we can think of the gut microbiome as a virtual organ.
N is for Nature - spending time in the natural environment seems to be a good thing so far as your gut health is concerned. Not only can spending time in nature reduce stress levels but living near green space has been associated with a higher diversity of gut microbes, particularly in early life. There’s also some research to suggest that gardening can have a positive effect on the gut microbiome. Time to sign up for an allotment?
O is for Oesophagus - otherwise known as your food pipe! It’s a muscular tube about the length of a ruler and connects your throat with your stomach. It’s coated with special cells to protect it from sharp or crunchy foods and covered in a sticky mucus which helps food move through smoothly. Once you swallow, it takes about 5–8 seconds for food to reach your stomach via the oesophagus.
P is for Probiotic - probiotics are described as live microbes, which, when consumed in large enough quantities, have a positive effect on health. They don’t tend to colonise our gut, but instead can impact the gut microbiome as they travel through.
Q is for Queensland Heeler - forgive us, the letter Q is a tricky one :) A Queensland heeler is a breed of dog, so this relates to pets. Studies suggest that early-life exposure to household pets can influence the gut microbiome in positive ways that may impact the risk of developing conditions like asthma. A good reason to get a furry friend at home or take a friend’s pooch for a regular walk.
R is for Resistant Starch, a type of carbohydrate which ‘resists’ digestion in the gut, and instead acts as a prebiotic. Prebiotics are food for the beneficial microbes that live in our gut. They are consumed by our gut microbes and can have a positive impact on the gut environment. Research even suggests they might even have positive impacts on bone health, as they promote calcium absorption. Foods rich in resistant starch include beans and lentils, greenish bananas, oats, cooked and cooled potatoes and pasta (think pasta and potato salads!).
S is for Stools - another name for poo! The Bristol Stool Chart shows the consistency and look of 7 different types of stools, which provide clues about what’s going on in your gut. Stool types 1 and 2 are pellet-shaped, which can indicate constipation. At the other end of the scale, types 6 and 7 are looser and contain more liquid, a sign that they have moved quickly through the gut, giving the large intestine little time to reabsorb the water. A ‘normal’ poop is around type 3-4, a smooth sausage shape which is pain free to pass. If you notice a change in your poop which lasts more than a week or two, chat with your G.P.
T is for Transit Time - the length of time it takes from food to go from entry to exit! On average, it takes about 24-40 hours for the movement of food from mouth to bottom. Most of this time is spent in the colon or large intestine.
U is for Unique - each of us have a unique gut microbiome, which is shaped from birth. As yet, there’s no consensus as to what constitutes a healthy microbiome - it’s likely there’s a broad variation, but one thing scientists agree on is the importance of a diverse gut microbiome, because it means our microbes are more capable and resilient. One way to support this is through diet - eating a diverse range of plant foods and plenty of fibre.
V is for Vagus Nerve This long wandering nerve connects your brain and gut. It helps to stimulate muscle contractions, facilitating the movement of food through the gut but it also sends messages from your gut microbes to your brain. Think of it like an information superhighway between brain and gut.
W is for Wind We might feel embarrassed about farting, but wind is a normal healthy side effect of your gut microbes doing their thing. So, what’s a ‘normal’ amount of wind? One study of healthy volunteers found that the average body relieves itself of around 700ml of gas a day - primarily carbon dioxide and hydrogen, which is mostly generated in the large intestine by microbes. This equates to around 14-25 farts a day, which shouldn’t cause problems, although people with gut hypersensitivity (which is common in IBS) may be more sensitive to the sensations of gas. If your wind is really bad smelling or you find yourself feeling bloated over a prolonged period, chat with your G.P.
Y is for Yoghurt Made using lactic acid-producing bacteria (LAB) yoghurt is a fermented food. We’re still learning how fermented foods affect the gut, but several studies have linked fermented milk products like yoghurt with positive effects on gut health. Choose live yoghurt if you want one which still contains active cultures.
Z is for Zzzzz - and by that we mean sleep. Like most aspects of health, gut microbes seem to be influenced by sleep - with good quality sleep being associated with greater microbial diversity. We’re still learning more about this relationship but adopting habits to help you sleep well (avoiding alcohol before bed, limiting caffeine to the morning, dimming the lights an hour before you hit the hay and turning off your phone) is a smart thing to do.