Although we eat food, our digestive system doesn’t absorb food – it absorbs nutrients. So our food has to broken down into amino acids from proteins, fatty acids from various fats, and simple sugars from carbohydrates, as well as vitamins, minerals and other essential nutrients.Your digestion is a complex network of organs that manages this process, breaking down food down into different compounds, and passing out what we don’t need as waste. The whole process takes on average one to three days.3
The part of the digestive tract known as the gut also contains trillions of various microorganisms, or beneficial bacteria, many of which help support our immune system.4 Plus, it has over 100,000 nerve cells and is closely linked to our emotions, which is why we may get butterflies or diarrhoea when we’re feeling nervous or stressed.5
Let’s take a close look at your digestion, from start to finish – quite literally.
What can go wrong? Rushing your meal or talking while you eat mean you can swallow air, leading to burping, bloating or flatulence.7
Keep it healthy. Friendly bacteria aren’t just beneficial for your gut – studies show they can be good for our dental health too.
Did you know? The average person produces one litre of saliva every day.8
What can go wrong? If stomach acid travels back up into your oesophagus, you can get heartburn: a burning sensation in your chest. Stress, obesity, smoking, and some foods and medicines can make heartburn more likely.10
Keep it healthy. Stopping smoking can help prevent heartburn and stomach ulcers, and reduce your risk of developing Crohn’s disease and gallstones, too.11
Did you know? Peristalsis is so powerful that food would reach your stomach even if you were eating upside down.12
What can go wrong? If the protective layer lining the inside of your stomach gets damaged, contact with stomach acid can result in an ulcer. This damage can be caused by the H.pylori bacteria or overuse of anti-inflammatory drugs such as ibuprofen.14
Keep it healthy. Avoid rushing your meals and maybe practice some yoga – research shows certain yoga postures can help support your gastrointestinal health, while exercise in general helps increase the friendly bacteria in your gut.
Did you know? Your stomach acid is strong enough to dissolve metal!15
What can go wrong? A lack of some enzymes can make it difficult to digest certain foods, causing food intolerances. Symptoms include stomach ache, bloating, flatulence and diarrhoea.17
Keep it healthy. Help rebalance the bacteria living in your gut by eating a high-fibre diet – aim for around 30g a day – and consider more fermented foods, such as sauerkraut, kefir or kombucha. If you don’t currently eat a lot of fibre, introduce it slowly by gradually increasing the amount every few days.
Did you know? The small intestine is an impressive six metres long.18
What can go wrong? A fatty diet with too many junk foods, or drinking too much alcohol can cause fat to build up in your liver, which significantly raises your risk of developing liver disease.20,21
Keep it healthy. Look after your liver by reducing your drinking and upping your intake of liver-supporting foods, such as broccoli.
Did you know? Your liver has more than 500 functions and is your body’s largest solid organ, weighing between 1.3kg and 1.8kg.22
What can go wrong? Not eating enough fibre can slow your digestion down, leading to constipation.24
Keep it healthy. Drink plenty of fluids, as this can reduce the risk of constipation.25 Keep your stress levels in check, too – stress hormones can contribute to digestive problems, such as diarrhoea.26
Did you know? Stools stay in the large intestine for an average of 33 hours in men and 47 hours in women.27
Sources1. NHS. Common digestive problems – and how to treat them 2. Salford Royal NHS Foundation Trust. The upper gastrointestinal tract 3. Stephanie Watson. Healthline. How long does it take to digest food? 4. Science Daily. Gut microbes closely linked to proper immune function, other health issues 5. Adam Hadhazy. Scientific American. Think twice: how the gut’s “second brain” influences mood and well-being 6. BBC Bitesize. What is digestion? 7. Mayo Clinic. Belching, intestinal gas and bloating: tips for reducing them 8. Mayo Clinic. How your digestive system works – slide 2
9. As above – slide 3.10. NHS. Heartburn and acid reflux 11. Love Your Gut. Lifestyle tips 12. Joseph Castro. Live Science. 11 surprising facts about the digestive system 13. Kim Ann Zimmermann. Live Science. Digestive system: facts, functions and diseases 14. NHS. Stomach ulcer – overview 15. Li PK, et al. In vitro effects of simulated gastric juice on swallowed metal objects: implications for practical management
16. As Source 1317. Christian Nordqvist. Medical News Today. What is a food intolerance?
18. As Source 13
19. As Source 8 – slide 5
23. As Source 8 – slide 724. NHS Inform. Causes of constipation 25. NHS Inform. Treating constipation
26. As Source 1127. Mayo Clinic. Digestion: How long does it take? 28. Love Your Gut. When to see a doctor