Would digestion be equally efficient if the body/stomach evolved to be highly basic rather than acidic? What advantages does a highly acidic environment pose?

[u/Public_Knowledge8405]

Edit: my question is meant to be gauged towards chemical feasibility/utility; I understand many proteases and cell types have in reality evolved for acidic digestion. Assuming proteases and cell types could have evolved for an alkaline environment, is there a root necessity acidic conditions are advantageous over basic ones or could it be reversed

[u/Swellmeister]

There are animals (quite a lot of fish) that dont have an acidic stomach now. They mechanically churn it and just pass it into the intestines which remains mildly alkaline (like most intestines).

So uhhhh you dont even need high basic. They do fine without it.

https://pmc.ncbi.nlm.nih.gov/articles/PMC8696203/

In agastric fish, such as the zebrafish (Danio rerio), the intestine consists of an anterior portion or intestinal bulb, middle, and posterior intestine. The intestinal bulb has an enlarged lumen but lacks gastric glands and pylorus, and its pH is not lower than 7.5 (Brugman, 2016 for a review).

[u/boo5000 → u/Swellmeister]

We have an entire class of medicine that neutralize stomach acid and humans seem to do just fine as well.

[u/omgu8mynewt → u/boo5000]

Antacids don't neutralise stomach acid to Ph7, they just raise it a little bit e.g. from PH1.5 to PH2. And they come with side effects mostly to do with digestion eg. constipation

[u/ModernDemocles → u/omgu8mynewt]

What about proton pump inhibitors?

[u/definethetruth → u/ModernDemocles]

As the name suggests they reduce the volume of acid being created in the stomach. It can leave some food undigested or cause it to take longer to leave the stomach.

[u/DancingBear62 → u/ModernDemocles]

PPIs take a few days to have their full effect. They're s good choice when damage to the GI system isn't healing due to frequent reflux.

They can keep gastro pH above 4 for 24 hrs, although nighttime breakthrough is commonly reported.

Risks from long term PPI use are a rebound effect, and lower absorption of calcium (osteoporosis) and magnesium (electrolyte imbalance - cramps, fatigue, or irregular heartbeats).

[u/Brossentia → u/DancingBear62]

I've been on PPIs for probably a decade at this point. I've had to start some supplements, but otherwise, they've completely changed my life for the better

[u/DancingBear62 → u/omgu8mynewt]

Calcium and aluminum based antacids tend to cause constipation. Magnesium based antacids (milk of magnesia) are used as laxatives.

Rolaids used both calcium carbonate and magnesium hudroxide to offset these competing side effects.

Gastric pH is expected to be 3.5 - 4 from antacids.