World Digestive Health Day: 29 May

Obesity: An ongoing pandemic

Healthwatch Dorset veteran volunteer blogger, Richie, will attempt to increase appreciation by focusing on some remarkable aspects of our digestive systems by taking you on a journey from the start to, well, not quite the end.

We produce around one to three pints of saliva every single day

Having spent much of lockdown salivating over the thought of a pint inside a pub, we’re finally allowed to enjoy that simple pleasure once again. So what better measurement to visualise the incredible amount of juice that your mouth produces on a daily basis! Alongside chewing, chemical digestion starts in the mouth with an enzyme called amylase that breaks down carbohydrates primarily. Saliva is the vehicle for amylase and it also re-mineralises teeth, restores soft tissues, and has defensive, antimicrobial properties.

Chewing induces greater saliva secretion so it’s a good idea to take your time munching rather than relying on a cool, foamy brew to wash things down.

Our stomachs contain corrosive acid

After swallowing, food typically takes under five seconds to reach the stomach. Stomach acid has a pH level around two and can therefore burn your skin like hydrochloric acid, and alongside other ingredients, that’s exactly what your stomach contains.

The high acidity unravels complex protein structures, it ‘denatures’ them, which makes them easier to break down into amino acid building blocks. It also serves to filter out harmful microbes before they can enter the bloodstream. You may have noticed that your stomach is rather good at containing such scary sounding chemicals though, and that’s largely thanks to a thick layer of mucus that protects the inner lining. The acid is neutralised upon leaving your stomach so that it doesn’t burn any holes elsewhere either!

Scientists measure the small intestine using racket-sport court size

Okay, not strictly true, but it is apparently the prevailing comparison when it comes to looking at the surface area of our gut. If spread out flat, it’s commonly claimed that our small intestine would cover the area of a tennis court, although more recently one group of scientists claimed that it’s probably more like one side of a badminton court.

Either way, it’s a large area all folded up inside us, and it’s certainly larger than a ping-pong table. Most nutrient absorption happens in our small intestine and for that reason its surface area is maximised by countless villi and micro-villi, think of hairs with micro-hairs sprouting off them. When I say countless it’s because there are an estimated 130 billion micro-villi in every square-inch, it’s like counting the individual threads in a carpet, just much smaller and much less accessible!

Our gut is home to 100,000,000,000,000 microscopic organisms

That’s one-hundred-trillion, or over 12,000 times the number of humans on the planet, inside every one of us. Our digestive tract is extremely hospitable to certain strains of bacteria, and our large intestine is their favourite hang-out. The literally big-name species that you may have seen on probiotic yogurt labels are ‘bifidobacterium-longum’ and ‘lactobacillus-paracasei,’ but there are many others at the party too.

They’re not parasites either, we give them a home, and they repay us by fulfilling a number of important functions such as vitamin synthesis, immune system regulation, and by breaking down foods that we could otherwise not absorb. There’s an emerging area of research that unpicks the interaction between gut bacteria and our mental health too, with conditions like irritable bowel syndrome highly correlated with depression for example.

Conclusion

It’s clear that there’s a lot of highly refined, marvellous machinery working away in the background to keep our digestive health in check, so I encourage you to browse the online resources and learn how to keep it well (olive) oiled. If you’re experiencing digestive abnormalities then seek out a local nutritionist, dietician, or talk to your doctor, because you may find that solving digestive issues has a positive knock-on effect for your general health and wellbeing too.