An Evidence-Based Guide to Stomach Disorders: Helicobacter pylori, Probiotics, Reflux, and Zinc Carnosine

Stomach Disorders: An Evidence-Based Appraisal of Infection, Reflux, and Mucosal Protection

The conclusion in one sentence

Managing a stomach disorder begins with identifying its cause and the patient’s risks: appropriate screening, standard eradication regimens, and resistance-guided therapy are central to Helicobacter pylori care; probiotics and zinc carnosine have, at most, adjunctive or situation-specific roles; and neither food acid–base classifications nor oral D-lactic acid can replace clinical diagnosis and effective treatment. (PMID: 40912906)

Why Helicobacter pylori deserves attention

Helicobacter pylori infection is associated with gastric cancer risk. In asymptomatic adults, eradication therapy can reduce the risk of developing gastric cancer, and newer consensus guidance includes eradication as a gastric cancer prevention strategy. “No symptoms, no need to act” is therefore not a dependable general rule. (PMID: 41769464) (PMID: 40912906) Professor Lin has long advocated taking the infection seriously and eradicating it proactively; this core position is consistent with the current literature.

However, “treating a confirmed infection” and “indiscriminately screening everyone in every region” are not the same policy. The Kyoto consensus treats Helicobacter pylori infection as a disease that warrants management while emphasizing that policy must reflect conditions in each country. More recent guidelines likewise remain centered on risk stratification rather than placing everyone under one universal screening rule. (PMID: 27164026) (PMID: 40112834) Professor Lin’s proactive treatment stance, as presented through his discussion of the consensus, thus has a basis in the literature. Evidence remains incomplete, however, if that position is extended to mean that everyone aged 12 or older should undergo universal screening in every region.

Confirmation and follow-up remain necessary after eradication

Antibodies may develop after infection, but they should not be regarded as reliable, permanent protection. Documented reinfections support the conclusion that prior infection does not equal lifelong immunity, although case data cannot precisely represent everyone’s risk. (PMID: 27830066) Recurrence is generally uncommon after successful eradication; a cohort in a particular endemic region observed an annual recurrence rate of approximately 0.91%. (PMID: 30950407) More recent data estimate an annual rate of approximately 1.5%–5.0% and highlight the importance of intrafamilial transmission. This also shows why the older, broad estimate of approximately 2%–10% should not be directly conflated with an annual rate. (PMID: 41477431)

Treatment selection cannot be reduced to memorizing one fixed list of drugs. Antimicrobial resistance affects eradication success, and the literature supports tailoring treatment to susceptibility findings and individual circumstances. (PMID: 42316523) In practice, a healthcare professional should select the eradication regimen and use an appropriate method after treatment to confirm success. The disappearance of symptoms alone does not establish that the bacterium has been cleared.

Probiotics belong only in an adjunctive role

Professor Lin’s original article took a conservative position on probiotics, emphasizing that they cannot replace standard eradication drugs. That boundary remains valid. What has changed as the literature has been updated is that newer meta-analyses of randomized trials suggest probiotics may not only reduce treatment-related adverse effects but also modestly improve eradication rates. Even so, they are an add-on to standard therapy, and the certainty of the evidence remains low to very low. (PMID: 41574348) The defensible statement is therefore not that “probiotics cure Helicobacter pylori,” but that certain formulations may serve as adjuncts after medical assessment.

A reflux diet is not a choice between acid and alkali

PRAL and DAL can be used to estimate dietary acid load, but most research linking them to disease is associative, and the mechanisms remain unclear. It goes too far to say these tools have no research value, just as it goes too far to treat an association as proof of therapeutic causation. (PMID: 38282081) For esophageal or laryngopharyngeal reflux, dietary modification can form part of a broader intervention, but the available evidence summaries do not show that classifying foods as “acidic” or “alkaline” can predict how every food will affect every patient. (PMID: 39931559) Professor Lin’s objection to replacing individual symptom observation and clinical judgment with simplistic acid–base labels therefore has a reasonable basis.

As for claims that oral D-lactic acid supports digestion or improves gastroesophageal reflux, ECU’s targeted search found no clinical trials or systematic reviews supporting efficacy; the evidence must currently be judged insufficient. D-lactic acid and L-lactic acid should not be conflated. The former can arise in microbial metabolism or particular pathological states and has toxicological and diagnostic contexts. The mere presence of “lactic acid” in its name does not justify marketing it as a proven digestive-health therapy. (PMID: 32685468)

Zinc carnosine has uses—and safety boundaries

Zinc carnosine, also known as Polaprezinc, is supported by clinical trials and reviews for promoting gastric mucosal repair and treating gastric ulcers. In one multicenter trial, the endoscopically confirmed response rate was 81.48%, and efficacy was comparable to that of the approved drug rebamipide. (PMID: 35999163) (PMID: 35659631) A meta-analysis also found that adding it to Helicobacter pylori eradication therapy can improve eradication rates, but this does not mean that it can replace standard therapy on its own or guarantee a cure for every patient. (PMID: 36235778) As science has progressed, the evidence has become clearer than when Professor Lin cautiously described it as “seemingly effective.”

Regarding safety, clinical trials report rates of adverse events similar to those with an approved comparator drug. It is reasonable to describe zinc carnosine as generally well tolerated, but not as entirely risk-free. (PMID: 35999163) Copper-deficiency pancytopenia after use has been reported in a patient receiving maintenance hemodialysis, and case evidence also supports zinc–copper antagonism in which zinc supplementation causes copper deficiency. Patients in these circumstances should be especially cautious about unsupervised long-term supplementation. (PMID: 26948531) (PMID: 41539972)

Carnosine itself is a dipeptide composed of β-alanine and histidine. Reviews support roles in acid–base buffering, antioxidation, and metal chelation, among other effects; antiglycation properties are also documented, although its complete role in tissues remains under study. (PMID: 41894036) (PMID: 42076106) Biochemical plausibility does not establish that every commercial product can treat stomach disorders. Assessment must still return to the product’s composition, dose, indication, and clinical evidence.

Applying the evidence to everyday decisions

When dealing with stomach pain, reflux, or Helicobacter pylori, confirm the diagnosis before considering eradication, diet, or adjunctive products. Anyone with a confirmed infection should discuss eradication and antimicrobial resistance with a healthcare professional. Anyone considering probiotics should understand them as an adjunct that may reduce adverse effects or modestly improve eradication rates. Anyone considering zinc carnosine should verify the indication, other sources of zinc supplementation, and the status of any renal treatment. Claims that acid–base classification, a single microbial strain, or a single metabolite can by itself manage every kind of stomach disorder go beyond what the current evidence supports.