Digestion sits upstream of a lot of skin complaints, and stomach acid is the part of digestion people get wrong most often. This post covers what reflux is, why "too much acid" isn't the only story, what the evidence shows about long-term acid-blocking medicine, and which symptoms should send you to a doctor the same week rather than into a food diary.
The terrain version comes from Andra Sitoianu, who writes The Bioavailable Naturopath on Substack. She's a certified naturopath, and her Stomach Acid and GERD Guide maps six digestive patterns she works with, two of which carry a skin cue. The free preview runs through that map and her list of proton pump inhibitor tradeoffs; her blood work patterns sit behind her paywall, so they're not here.
I render fat and pour balms, so here's what this post can do. It can help you notice a pattern and take a better question to a clinician. It can't tell you what's wrong, and there's no acid supplement protocol below.
Where this comes from. This post draws on the public writing of Andra Sitoianu, The Bioavailable Naturopath, in particular The Stomach Acid / GERD Guide. We paraphrase her framing, add the general research, and link her posts so you can read her in her own words; her paid guides carry her full protocols. Educational content, not medical advice.
What reflux actually is
Start with the plumbing, because the mechanism explains most of the confusion. The National Institute of Diabetes and Digestive and Kidney Diseases describes reflux as stomach contents coming back up into the esophagus. A muscular valve at the bottom of the esophagus, helped by the diaphragm, normally keeps that from happening, and GERD can develop when the valve is weak or relaxes when it shouldn't.
The symptom list is broader than heartburn: regurgitation, chest pain, nausea, trouble swallowing, chronic cough and hoarseness all belong to it. So do the risk factors, which are unglamorous and mostly structural: excess weight, pregnancy, smoking, hiatal hernia and several classes of medicine.
Notice what the valve story does not say. The problem it describes is acid in the wrong compartment rather than too much of it. Those are different situations with different implications, and the difference is the whole argument of this post.
"Reflux is not always too much acid": her framing, labeled as hers
Andra calls reflux one of the most misunderstood and oversimplified digestive problems around, and her core position is that a lot of it runs on too little stomach acid rather than too much. Her mechanism: low hydrochloric acid slows digestion, slow digestion lets food ferment, fermentation makes gas, gas makes pressure, and pressure pushes stomach contents past a valve that was never designed to hold against it.
I want to flag that clearly. That chain is her naturopathic framing, not a finding from the gastroenterology literature, and the institutional page above says nothing about low acid or fermentation. It's a hypothesis with a mechanism attached, it's coherent, and it has not been demonstrated the way the valve story has. Hold it loosely.
What is well established is that stomach acid does real work. The NIH Office of Dietary Supplements notes that vitamin B12 has to be released from food protein by hydrochloric acid and gastric protease before your body can absorb it, and that atrophic gastritis, which affects 8 to 9% of adults aged 65 and over, reduces both intrinsic factor and stomach acid and therefore B12 absorption. So low acid is a real physiological state with real consequences. Whether it causes most reflux is a separate and unsettled question.
Her six patterns, and the two that carry a skin cue
Her guide sorts reflux into six patterns. I'm reproducing the shape of them because pattern recognition is genuinely useful when you're preparing for an appointment, with the caveat that these are her clinical observations rather than diagnostic categories.
| Her pattern | Cues she associates with it | Skin cue? |
|---|---|---|
| Low stomach acid | Bloating after protein meals, fatigue after eating, slow digestion, constipation | None she names |
| Helicobacter pylori | Reflux with upper stomach discomfort, bloating, nausea, burning ulcer pain | Yes: eczema on the hands |
| Gallbladder and bile flow | Reflux after fatty meals, nausea, bitter taste, right rib discomfort, constant burping | Yes: dry skin |
| Nervous system and stress | Reflux during anxiety, shallow breathing, tight chest, hoarseness | None she names |
| Microbial fermentation | Chronic gas and bloating, irregular stools, carbohydrate and fiber intolerance | None she names |
| Physical and structural | Hiatal hernia weakening the valve at the base of the esophagus | None she names |
Those two skin cues, hand eczema alongside H. pylori and dry skin alongside her bile pattern, are the only reason this is a skin post at all. They're her pattern observations from practice. They are not study findings, they have no numbers behind them, and plenty of other things cause dry skin and hand eczema. Notice them, write them down, don't act on them alone.
Helicobacter pylori, and the nickel connection
H. pylori deserves its own paragraph because it can be tested for and treated, and because the mechanism connects this post to the one above it in the series. Andra's account is that it makes ammonia, neutralizes acid locally, and impairs digestion downstream.
The chemistry is well described. de Reuse and colleagues, 2013, show that nickel is a virulence determinant for the organism because two of its enzymes need it, and urease alone holds 24 nickel ions per active complex. Urease splits urea into ammonia and carbamate, which buffer the bacterium's internal pH and let it survive stomach acid. Mice fed nickel-deficient chow showed a colonization defect.
That last sentence is the one people run too far with. It's mouse dietary work. Nothing there shows that eating less nickel does anything to H. pylori in a person, and the way you find out whether you have it is a test your doctor orders, not a symptom list. The dental and dietary nickel side of this is in the mouth as skin upstream.
The PPI conversation, with the parts that have evidence
Proton pump inhibitors are effective medicines and millions of people need them. Andra publishes a long list of long-term tradeoffs, and to her credit she hedges the weaker items with the word "possible" and flags the dementia item as observational, which is fairer than most lists of this kind. Here's the shorter version: the items I can put a citation on.
| Concern | What the evidence actually says |
|---|---|
| Small intestinal bacterial overgrowth | Su and colleagues, 2018, pooled 19 articles and 7,055 people and found an odds ratio of 1.71. They call it a moderate increase in risk and describe the field as controversial with conflicting results |
| Vitamin B12 | The NIH fact sheet states that PPIs and H2 blockers can interfere with B12 absorption from food by slowing the release of gastric acid, and can lead to deficiency. It does not quantify how often that becomes clinically significant |
| Magnesium | The FDA warning covers prescription PPIs taken long term, typically more than a year, and notes that in 25% of reported cases supplements did not correct the low magnesium and the drug had to be stopped |
| Her other items | Iron, calcium, fracture risk, gut infections, microbiome changes, raised gastrin, kidney and dementia associations. These are hers, and I'm leaving them attributed rather than dressed up with citations I don't have |
None of that is a reason to stop a prescribed medicine, and I want to say that plainly because this is exactly the corner of the internet where people do. A moderate association in pooled observational data is a reason for a conversation at your next appointment. It isn't proof that a drug caused anything in your case, and reflux left untreated has its own consequences.
Warm meals, and where the skin part actually lives
Andra's practical bridge out of this guide is her Eat Your Hydration idea: warm, mineral-rich, salted liquids like broths and soups rather than cold water alone, on the theory that a cold start asks more of a sluggish digestive system. That's her framing and a food tradition, not a trial result, and it's also harmless, cheap and pleasant. If that's the one thing you take from this post, I'd call it a good trade. The longer version is in eat your hydration.
As for skin: the route from digestion to skin runs through the gut, and the review literature there is careful. Salem and colleagues, 2018, describe gut dysbiosis increasing intestinal permeability, letting bacterial metabolites reach the circulation and feeding systemic inflammation that shows up in acne, atopic dermatitis and psoriasis. They establish association and mechanism rather than causation, and they never mention reflux. The full picture is in the gut-skin axis, which also handles the SIBO evidence properly, and the rosacea version is in rosacea through a terrain lens.
Red flags: when reflux is not a terrain question
Andra's preview doesn't publish a red flag list, and a reflux post needs one, so here's the institutional version. Per the NIDDK, see a doctor for chest pain, loss of appetite, persistent vomiting, trouble or pain swallowing, unexplained weight loss, or any sign of bleeding: vomit containing blood or looking like coffee grounds, or stool that's bloody or black and tarry.
Those are not "track it for a month" symptoms. They're "call this week" symptoms, and chest pain in particular has causes that have nothing to do with your stomach. The same rule applies on the skin side: anything severe, scarring, infected, suddenly worsening or involving your eyes belongs with a licensed clinician now. This post can name a condition. Diagnosing one is a clinician's job, and no balm does that work.
What a balm has to do with any of this
Only the outside of your skin, and I'd rather say that than stretch. A jar that sits in a metal mailbox through an August afternoon arrives as liquid, and the obvious read is that it spoiled. It didn't. Tallow melts near body temperature and re-sets fine, and a night on a cool shelf brings it back to a solid block. The obvious explanation and the correct one were different things. "Too much acid" is the same kind of guess.
What a balm does is slow water loss from the outside of your skin, which is worth something if your face is dry and tight while you sort out the rest. It doesn't reach your stomach, your bile, your microbiome or your medication. The long version of what tallow is and isn't sits in the tallow for skin guide.
Questions we hear
Is my reflux caused by low stomach acid?
It might be part of the picture and nobody can tell you from a symptom list. The mainstream description of GERD is about a weak or inappropriately relaxing valve rather than acid volume, and the low-acid chain is a naturopathic framing with a mechanism rather than a demonstrated cause. If you want to know, that's a testing conversation with a clinician.
Should I take betaine HCl or digestive bitters?
I'm not going to give you a protocol for that, and the NIH fact sheet on B12 that covers stomach acid endorses no acid supplement. Taking acid on top of an ulcer or an inflamed stomach lining is a bad idea, and you can't rule either of those out from your kitchen.
Do proton pump inhibitors cause SIBO?
The pooled data shows an association: 19 articles and 7,055 people gave an odds ratio of 1.71, which the authors describe as a moderate increase in risk in a field they call controversial. That's a reason to ask your prescriber whether you still need the medicine at the dose you're on, not a reason to stop it yourself.
Why does my skin get dry when my digestion is off?
Plenty of reasons, most of them boring: less appetite, less fluid, less fat in the diet, poorer sleep, and the age or medication factors that often travel with digestive trouble. Andra associates dry skin with her bile flow pattern specifically, and that's a pattern observation from her practice rather than a study finding.
Can eczema on my hands mean Helicobacter pylori?
It's one of her pattern cues, and it is not a diagnostic sign. H. pylori is found with a breath, stool or endoscopic test, all of which are ordinary and available, so if the question is live for you the answer is to get tested rather than to infer.
Does a balm help with digestion-related skin changes?
It helps with the feel of dry, tight skin while something else is being worked out, and that's the whole of it. No topical reaches digestion, and nothing on the outside of your skin changes what your stomach is doing.
Go deeper
The hub is Skin Terrain 101 and the orientation piece is skin is downstream. Upstream of this one is the mouth as skin upstream; downstream is the gut-skin axis, which carries the SIBO evidence in full. The food and fluid side is in eat your hydration, the flushing side in mast cells and histamine, and the condition this map was built around in rosacea through a terrain lens.
Sources
- Andra Sitoianu, The Bioavailable Naturopath (2026). The Stomach Acid / GERD Guide. Substack. Her six patterns, the two skin cues and her PPI list; her blood work patterns are paywalled.
- Andra Sitoianu, The Bioavailable Naturopath (2026). The Rosacea Guide. Substack. Her low stomach acid lane in a skin context.
- National Institute of Diabetes and Digestive and Kidney Diseases. Symptoms and Causes of GER and GERD. NIDDK.
- Su T, Lai S, Lee A, He X, Chen S (2018). Meta-analysis: proton pump inhibitors moderately increase the risk of small intestinal bacterial overgrowth. Journal of Gastroenterology 53:27.
- National Institutes of Health Office of Dietary Supplements (2025). Vitamin B12: Fact Sheet for Health Professionals. NIH ODS.
- National Institutes of Health Office of Dietary Supplements (2026). Magnesium: Fact Sheet for Health Professionals. NIH ODS.
- de Reuse H, Vinella D, Cavazza C (2013). Common themes and unique proteins for the uptake and trafficking of nickel, a metal essential for the virulence of Helicobacter pylori. Frontiers in Cellular and Infection Microbiology 3:94.
- Salem I, Ramser A, Isham N, Ghannoum MA (2018). The Gut Microbiome as a Major Regulator of the Gut-Skin Axis. Frontiers in Microbiology 9:1459.
Brian is the founder of Craft Tallow, a small-batch tallow skincare line shipped from Cottonwood Heights, Utah, built on 100% grass-fed suet. Questions? Reply to any email from us; it lands with him.