If the liquids we drink end up in the stomach, how does our stomach acid not get thinned down by the constant flow of liquid?



If the liquids we drink end up in the stomach, how does our stomach acid not get thinned down by the constant flow of liquid?

In: Biology

Because stomach acid is many thousands of times stronger than water, so you really can’t consume enough water with a meal to cause any meaningful change in pH. The stomach can also secrete a lot of it to keep up with depletion.

If you’re consuming water alone, it won’t matter anyway. The acid already in the stomach will just pass through with the water into the small intestine where it’s neutralized and reabsorbed.

It does get diluted, but the stomach walls just add more concentrated acid back in. Even if you weren’t drinking anything, purely solid food is mixed with the acidic liquid-y contents of the stomach and sent on to the small intestine together, so you “lose” acid over time regardless. The stomach would lose its function very, very quickly if it couldn’t maintain its contents’ proper acidity.

It does thin down, it gets replaced though.

However if your body can’t keep up or keeps up too much you end up with indigestion or gastric reflux aka heart burn.

It was also once though stomach ulcers where caused by over production of stomach acid, but was actually caused by a bacteria.

In short, proton pumps! The cells lining the stomach contains many proton pumps which can actively sense their environment (say fluctuations in ph) which then respond by increasing the export of H+ ions and eventually restoring the proper ph.

Edit: export not influx

I always wondered where my stomach was finding chlorine to make the hydrochloric acid, but of course where else but salt!

I have a kooky friend who swears alkaline water is healthy because it “helps the liver remove toxins.” I told her I assumed alkaline water simply neutralizes in the stomach. Is that true? What happens to alkaline water in the stomach?

The stomach just produces more acid. When we eat or drink, it does dilute, which is why people with stomach ulcers get some relief when eating.

It does. Have you ever had a heartburn? Or gastritis? All these things happen when acidity of our stomach is not in balance and often it can happen when drinking too much fluid that doesn’t have minerals. Specially if you don’t eat enough.

So if you feel sick and don’t eat properly / enough, and you drink too much water, your stomach acids get messed up so they don’t stay down and instead they rise up (even to your throat).

That is why when people puke they drink rehydration drinks, so they can replace minerals and electrolytes. That is also why people take probiotics when they use antibiotics.

Basically our stomachs are most important organ after brain and heart because if your stomach gets messed up it messes almost every other system and organ in our body. You feel weak, your vision blurs, your skin gets horrible, your heart has to work twice as hard, your brain gets foggy, your kidneys and liver have to work double shift, you may experience vertigo, Merniere disease and tinnitus. And it takes almost as long to recuperate after stomach issues as it takes to recover from other serious conditions.

Off: i speak from personal experience where it took me almost 3 months to get my body to normal state after bad gastritis episode, and because of which I thoroughly researched gastritis and stomachs and everything about them

What happens to the acids we lose? Do we just redigest them?

How does our stomach even make acid? I don’t want to hijack the thread but still wondering.

The first thing to realize is that it takes quite a lot of liquid to lower your stomach acid however it can create a problem if the stomach is not able to work the way it’s designed.

The solution is quite elegant and is based on the shape of your stomach. When your stomach is empty it is shaped similarly to a banana. To be able to expand many times its size to accommodate a big meal, there are deep folds which run the length of the stomach. When you drink a liquid, it spreads out quickly and runs into the deep crevices. This keeps the liquid separate from the solids and allows the liquids to be absorbed almost immediately. Only a few things can be absorbed this way: directly through the stomach wall; water, some sugars in solution, alcohol, some other smaller molecules that are in solution such as medications.

When you eat something with very little moisture, your stomach will need to add fluids to the contents so that the acidity can mix in thoroughly. Your stomach will not use the water you just drank directly but will take the fluid from your bloodstream to create the acidic juices.

Some problems that stop this system from working are:

Very cold liquids will slow down or even stop all stomach processes until the contents are warmed up by your bodies heat.

If your stomach is overfull then there will be no folds left to accommodate the fluids and they will sit on top and take much longer to absorb through a relatively small area of stomach wall that they are exposed to.

A few other interesting points:
The stomach does not usually reabsorb its own acid and the top of the stomach(where most water is absorbed) has less acidity than the bottom. Food is mixed with your stomach acid in the order that it is eaten. The first bite reaches your stomach’s exit first. This sphincter has special cells called parietal cells which register the acidity of the contents and will not open the gates until proper acidity is reached. Fibrous and water filled veggies take less stomach acid to reach the correct pH than dense proteins and concentrated fats. So a big steak can sit for a long time(around 2 hours) and block the passage of a salad sitting on top which would only take 20 minutes to go through if it was first. If the salad sits long enough without getting fully acidified, it will start to ferment and create burping and upward pressure. This will be increased when lying down and may cause stomach contents to be forced up the esophagus causing acid reflux.

The stomach itself does not get digested by the stomach acid due to a mucus lining that protects the stomach lining. Although this lining is very resistant to strong acid for short periods, even a weak acid can erode it over a long period. When stomach contents do not get thoroughly acidified, the parietal cells will not let the food through and it sits there long enough to erode the mucus lining. Many ulcers are caused this way- paradoxically from too little acid!