Latest / Common Sense Health / Why You Need Stomach Acid (And How Some Meds Can Damage It)
Transcript
- Stephen Thomas BSc. Hons: Hello. So welcome. the goal of this video series, it's a new series I'm doing, is to lift the hood on human biology and demystify the biochemistry and the physiology of the body. Well, don't turn off yet. I want to take the concepts that sound incredibly complicated on paper and break them down into simple universal language. So today I'm diving into a topic that sounds straightforward, but is actually an absolute marvel of everyday chemistry, and that's stomach energy. acid. And I'm going to look at what it actually is at an atomic level, how your body manages to produce stomach acid without destroying its own stomach and exactly why certain modern drugs are designed to switch that system off. Now that would be something like a proton pump inhibitor. Now to understand stomach acid we have to start with a definition that trips a lot of people up in chemistry class. If you open a textbook it will tell you that an acid Is a substance that donates a proton. At this point, we also need to understand what an atom is. So an atom tends to be the nucleus which has protons and neutrons and electrons whizzing round. But we won't go into that. We'll we'll carry on with the stomach acid. But if you look at the actual chemicals involved in stomach acid, the only thing you ever see mentioned is hydrogen. So is a proton just hydrogen? Well Yes, absolutely. A normal hydrogen atom is the simplest thing in the universe. It is just one single proton in the middle with this lone electron spinning around it. Now, when that hydrogen atom loses its electron, nothing is left behind except that bare proton. In chemistry, a hydrogen ion with a positive charge and a bare proton, they're the exact same thing. So When a strong acid like hydrochloric acid, which we write as HCL, donates a proton, it fundamentally transforms. Before any reaction happens, hydrochloric acid is a neutral molecule. When a hydrogen atom and a chloride atom are sharing a pair of electrons. Luckily there's a diagram to just explain this so simply. But when it acts as an acid, the chlorine atom essentially acts like a greedy partner. It takes Both of those shared electrons for itself and lets the hydrogen leave completely empty-handed. So the hydrogen walks away as a bare proton, and the leftover chlorine becomes a stable, negatively charged chloride ion. Don't worry about the ion bit. Let's concentrate on the stomach acid. Now, in chemistry, we call that leftover piece of a a conjugate base because hydrochloric acid gives up its proton so easily and the remaining chloride ion is perfectly happy on its own we classified that as a strong acid. Now you have probably been told that your stomach is full of hydrochloric acid which might make you picture a swimming pool of intact HCL molecules sloshing around inside you. But that is not actually what is happening. Your stomach lining does not contain Floating HCl molecules. Instead, your body creates the effect of stomach acid by using specialized cells called parietal cells to pump out bare protons and chloride ions completely separately. They only meet once they are already outside the cells and floating in your stomach fluid. This whole process relies on a beautiful chain of chemical equilibrium inside those parietal cells. Again, there's a diagram for that. The cells take water and carbon dioxide straight from your blood, and an enzyme called carbonic anhydrase forces them to combine into carbonic acid, which then naturally breaks apart into bicarbonate and those crucial hydrogen protons. The cell then has to do some incredibly heavy lifting. It uses a massive amount of cellular energy to drive a biological energy. Engine called the proton potassium pump. Now this pump acts like a security guard at a crowded venue, physically forcing the positive hydrogen protons up and out into the stomach cavity against an intense concentration gradient while pulling potassium ions back inside. Again, there's a diagram for this. So meanwhile, the cell pulls chloride ions out of your blood, originally sourced from the salt. flood your diet and shoots them through a completely separate channel to match those positive protons. The diagram makes that a lot simpler, doesn't it? Now because your body is constantly using up these ingredients, your stomach has to continuously top up the acid on demand. So when you smell or think about or swallow food, hormonal signals tell these proton pumps to get into gear. Now once the food moves out of the stomach and into the small intestine, your pancreas releases bicarbonate, which is a base, to neutralize the liquid, turning it back into harmless water and carbon dioxide to be reabsorbed. The chloride isn't wasted either, it gets sucked back through your intestinal walls into the bloodstream, and any excess is safely filtered out by your kidneys. But this does raise an obvious question. If stomach acid is a strong acid capable of dissolving metal and your stomach is made of protein, why doesn't the stomach digest itself? Well it survives by using a brilliant three-layer defense system. First, specialized cells secrete a thick, jelly-like mucus barrier that physically blocks the acid from touching the tissue. Second, those same cells pumped by carbonate directly into the bottom layer of that mucus. Creating sort of a chemical shield, and any stray acid trying to burn through gets instantly neutralized into water. And finally, because the environment is so incredibly harsh, the surface cells still take a beating, so your stomach lining completely replaces its entire inner surface layer every three to five days. It sheds the old cells and seals any microscopic gaps before the acid can leak through. Now, when this system fails. Often due to a bacterial infection or the overuse of certain painkillers, the acid breaks through and forms a painful ulcer. One bacterium that has famously learned how to defeat this acid shield is Helicobacter pylori, often called H. pylori. It cannot actually survive inside raw stomach acid, so it uses a genius two step survival trick. First, it produces an enzyme called urease, which grabs a neutral waste chemical in your stomach called urea and breaks it down into ammonia. Because ammonia is a strong base, it forms a literal chemical space suit or cloud of neutralized liquid around the bacterium. Protected by this cloud, the bacterium uses its spinning tail-like hairs to swim rapidly through the acid pool. Until it reaches the thick mucus barrier, then it burrows deep inside that safe neutral mucus layer and attaches to the stomach wall. Over time, its chemical byproducts damage the mucus, leaving the stomach wall exposed to its own acid, which is how it causes ulcers. Now this brings us to modern medicine and how we treat conditions like severe acid reflux or ulcers. We have developed three main types of drugs. And you can think of your stomach acid like a leaking tap or force as I say in America. The first type is an acids or anti acids as we say in England, and they're things like Tums or Renny. These don't stop acid production at all. They just mop up the puddle. They are basic chemicals that you swallow, which mix directly with the liquid acid already sitting in your stomach, neutralizing it and into water and salt actually within minutes. They provide instant relief but they only last for about an hour. Now the second type is an H2 blocker, and these turn the force it or tap handle to slow down the flow. That's what they do. They work by blocking histamine actually, which is one of the key chemical signals telling your stomach cells to start making acid. They take about fifteen to thirty minutes to kick in, but they can slow down acid production for up to twelve hours. Now the final most powerful type is a proton pump inhibitor or PPIs. These completely shut off the main water valve. so when you take a PPI, it travels through your bloodstream into your stomach cells. The highly acidic environment inside the cell activates the drug, turning it into a chemical sort of sticky trap that permanently binds to the proton pump engines. And it damages the pumps so they can never fire again. Because the shutdown is permanent, your body has to physically build brand new proton pumps from scratch to start making acid again, which is why a single pill can suppress stomach acid for over 24 hours. Now, while PPIs are incredibly effective for short term healing, shutting off your stomach acid for months or years Comes with some significant biological consequences. Now remember, stomach acid has two vital jobs, absorbing nutrients and killing dangerous invaders. Without enough acid, your body struggles to dissolve and absorb calcium, which significantly increases the long-term risk of osteoporosis and bone fractures. It also prevents your body from cutting vitamin B12 away from food proteins and This leads to severe fatigue and nerve issues over time, and it can even impair magnesium absorption. Furthermore, turning off your stomach's natural acid shield leaves you vulnerable to infections. Harmful bacteria that you accidentally swallow can survive the journey, leading to chronic gut infections like C. diff or migrating up the throat during sleep to cause respiratory infections like pneumonia. So prolonged use is Has even been linked to chronic kidney stress. Plus, if you stop taking PPIs cold turkey after a long period, your stomach cells often panic and temporarily flood your system with a massive rebound wave of acid, causing intense heartburn. So ultimately, stomach acid isn't a design flaw or a mistake your body is making. It is a finely tuned, highly energetic chemical system essential for your survival. While blocking it with medication is a literal lifesaver for treating sort of severe tissue damage or ulcers, doing so long term changes our internal chemistry in ways that ripple across the entire body. Anyway, hopefully that was helpful. Thank you for watching and I hope this sort of demystifies the incredible chemistry that's happening inside your stomach every single day. If you're interested in more videos like this, don't forget to subscribe. Hit the notification bell so every time I post something new you get told. It's free to do and it really helps my channel. If you really like the content, please drop a like by pressing the like button or even putting a comment down in the comment section below, which I do read by the way, and I'll read every single one if I can. It's just me. There's no one doing fancy pants editing or doing any admin for me. If you want any improvements, if you didn't think the diagrams were clear enough, if you thought it was a little bit s science is still and you want it even simpler then drop that comment. If it wasn't scientific enough, then that's fine too. Now with these videos I will be producing a student handout sort of PDF. And if you're interested in that, just drop a comment to say that you'd like that. And I will set up a system to make it very easy to get those resources. Anyway, thank you for watching. Hope you enjoyed it and if you're suffering from acid reflux, if you've got a PPI problem If this resonates with you because you've had any issues, I'd love to hear your story as well. Anyway, thanks for watching and I'll see you on the next one. I'll be back.