Postprandial Reflux-Indian Issues, Challenges, and Management with a focus on Sodium Alginate

Post-meal reflux, also known as postprandial reflux, refers to the regurgitation of stomach contents into the esophagus following a meal. (1). It is an indirect measure of lower oesophageal sphincter (LES) integrity and is one of the early steps leading to Gastroesophageal reflux disease (GERD) (2). Increased postprandial acid reflux is a distinguishing feature of GERD and is the main cause of patient-reported symptoms as the number of episodes of post-prandial GER increases by four to seven times (1). Symptomatic individuals exhibit abnormal postprandial reflux compared to normal individuals along with a defective LES (2). The present review focuses on postprandial reflux and its management with sodium alginate.

Risk Factors for Postprandial Reflux:

Lifestyle risk factors such as consumption of fatty meals, candy, chocolate, citrus juices, and carbonated beverages (3), tobacco use and alcohol consumption, increased body mass index, age, low socioeconomic status, connective tissue disorders, pregnancy, postprandial supination, and certain medications are some of the risk factors implicated in the reflux disease (4). Progressive deterioration of LES pressure and structural abnormalities in the sphincter also escalate postprandial reflux (2).

Post-prandial proximal gastric acid pocket (PPGAP): Pathophysiological Interaction in Post-Meal Reflux:

A phenomenon known as the postprandial proximal gastric acid pocket (PPGAP) manifests in both healthy individuals and those with GERD, characterized by an unbuffered, highly acidic region (pH<4) in the proximal stomach following a meal. This area, situated between distal (food-filled) and proximal (LES or distal esophagus) non-acidic segments, arises due to incomplete neutralization by ingested food, persisting for up to two hours postprandially with a pH as low as 1.6. GERD patients exhibit a more pronounced and extended PPGAP, with lower pH levels (pH 1.29 mean, pH peak 1.01) compared to healthy individuals (pH 2.03 mean, pH peak 1.67), suggesting its pivotal role as the source of acid reflux events.

Postprandially, gastric acidity diminishes due to food buffering effects; however, hydrophilic acid gastric juice tends to float atop hydrophobic fatty meals, maintaining an acidic layer. Contractions initiating distally in the stomach leave the proximal region relatively quiescent post-meal, facilitating PPGAP formation. PPGAP onset occurs earlier in GERD patients (14 minutes) compared to healthy participants (18 minutes) following a standardized meal. As gastric contents digest, PPGAP resolves, disappearing approximately 75 minutes post-meal in healthy individuals and 133 minutes in GERD patients. Notably, during PPGAP presence, proximal stomach, and refluxate pH levels drop below 4, underscoring its significance in acid reflux initiation. PPGAP represents a crucial element in GERD pathogenesis, potentially serving as a therapeutic target. Understanding its dynamics provides insights into GERD mechanisms and therapeutic avenues (5,6).

Guideline Directed Management of Post Meal Reflux- Overview:

Various guidelines have been proposed for the management of post-meal reflux in GERD. Some of them, encompassing both non-pharmacological and pharmacological interventions are summarised as follows:

• The American College of Gastroenterology Clinical Guidelines has recommended weight loss in overweight and obese patients, avoidance of meals within 2–3 hours of bedtime, cessation of tobacco use, avoidance of “trigger foods”, along with elevating head of the bed for nocturnal symptoms (7).
• The Indian Society of Gastroenterology and the Association of Physicians of India (ISG-API) advocate identifying triggers for reflux symptoms, weight reduction for obese/overweight patients, elevating the head end of bed to alleviate supine reflux, and avoiding lying down within 2 hours after a meal in GERD patients (8).

Beyond dietary and lifestyle modifications, pharmacological and surgical interventions have also been proposed. The Indian Society of Gastroenterology recommends proton pump inhibitors (PPIs) and histamine H2 receptor blockers to relieve reflux symptoms (9). Other pharmacological options include prokinetics, reflux inhibitors, acid pocket neutralizers, and mucosal protectors (10). Surgical interventions include endoscopic anti-reflux procedures as an effective alternative to long-term medical therapy.

Sodium Alginate: Clinically Relevant Importance in Post-Meal Reflux:

PPIs are used for the management and maintenance of GERD. However, they are associated with concerns like the possibility of long-term maintenance use, worsening of rebound symptoms post discontinuation, and refractoriness to the same. In such a scenario, alginates which are a well-established and effective treatment for GERD can be used as they form a physical protective barrier in the form of a gel raft when in contact with stomach acid, counteracting the PPGAP. It is a novel treatment strategy for tackling PPGAP associated with post-meal reflux (11).

Unique Mechanism of Action of Sodium Alginate:

Alginate-based pharmaceutical formulations have been efficaciously employed in treating GERD with a rapid onset of symptom relief. They comprise linear copolymers of 1,4-linked β-D-mannuronic acid (M) and 5-epimer α-L-guluronic acid (G). The most effective formulations contain sodium (Na) alginate, Na bicarbonate (HCO3), and calcium (Ca) carbonate (CO3). Upon exposure to gastric acidity, these components combine to form a cohesive, buoyant alginate raft. This raft acts by suppressing reflux, capping the acid pocket, and mitigating postprandial acid reflux, thereby alleviating heartburn and GERD symptoms. Alginates exert their effects by suppressing gastric reflux, preventing postprandial reflux, inhibiting pepsin and bile acids, and providing topical protection (12)

Recommendations on Alginates:

The Indian Society of Gastroenterology has provided a management algorithm using therapies including alginates for confirmed reflux in GERD (9). The Southeast Asian consensus statements and recommendations mentioned alginates as the first-line treatment for mild-to-moderate GERD and as adjunctive therapy when GERD symptoms are partially responsive to PPIs (13).

Alginates are the first-line agents for treating acid reflux in GERD during pregnancy (7). Alginate-antacid combinations are an effective treatment for reflux-like symptoms and are considered safe in pregnancy and breastfeeding as per an International evidence-based consensus published in 2024.(14)

Sodium Alginate in Post Meal Reflux: Review of Literature:

Sodium alginate -Rapid Onset of Action Around Three Minutes: A crossover study was conducted to analyse the efficacy and the onset of action of a single dose of sodium alginate-containing formulation low dose and sodium alginate-containing formulation high dose in patients (n=52) with heartburn of moderate intensity and GERD. The primary sensation of a cooling (soothing) effect after using a single low-dose alginate has been reported in 65.7 seconds (on average) and 66.1 seconds with a high-dose alginate. Fourty three (82.7%) patients with heartburn have described the effects of both medications as "instant" cooling effects. Heartburn was relieved in 3.3 minutes in all patients after a single dose of low-dose alginate and 3.6 minutes in 51 (98.1%) patients who received high-dose alginate. This study concluded that the onset of action of sodium alginate starts around 3 minutes.

Alginate-antacid Combination Better than Only Antacid: A comparative study evaluated the efficacy of an alginate-antacid combination against an equivalent-strength antacid lacking alginate in managing postprandial acid reflux among GERD patients. Fourteen participants underwent two 3.5-hour high-resolution manometry/pH-impedance studies, consuming either an alginate-antacid combination or only an antacid with ~18 mmol/L acid-neutralizing capacity. Parameters assessed included distal esophageal acid exposure, reflux event frequency, proximal reflux extent, pH of refluxate, reflux mechanism, and reflux symptoms. The results revealed significantly reduced distal esophageal acid exposure and higher refluxate pH in the 30–150 min postprandial period with an alginate-antacid combination compared to the antacid. Thus, the study concluded that an alginate-antacid combination exhibited superior efficacy in controlling postprandial esophageal acid exposure relative to an alginate-free antacid. (16).

Sodium Alginate Effective Stomach Barrier Based Treatment: A systematic review of evidence-based medicine evaluated the efficacy of sodium alginate solutions in alleviating postprandial symptoms among adult GERD patients. Incorporating two randomized controlled trials and one controlled case series, comparisons were made against placebo, proton pump inhibitors, and H2 receptor antagonists. Sodium alginate administration led to a significant reduction in esophageal symptom incidence, decreased symptom severity at two and six months post-alginates treatment, and notable alleviation of acid taste sensation. These findings indicated that alginate suspensions, offer a non-systemic, barrier-based therapeutic approach for GERD management, highlighting sodium alginate solutions' safety, efficacy, and tolerability in adults aged 18 years and older (17).

Take-home Points:

• Postprandial reflux is an early indicator of LES integrity and can predispose to the development of GERD.
• The PPGAP is a significant phenomenon in both healthy individuals and those with GERD, characterized by a highly acidic region in the proximal stomach after a meal, and is a potential therapeutic target in post-meal reflux management associated with GERD.
• Lifestyle modifications and addressing risk factors are crucial in managing postprandial reflux, with sodium alginate emerging as a useful treatment option.
• Alginate-based formulations form a buoyant alginate raft in the stomach, suppressing reflux, capping the acid pocket, and mitigating postprandial acid reflux.
• Alginates can be the first-line treatment for mild-to-moderate GERD and also as adjunctive therapy when GERD symptoms are partially responsive to PPIs.
• Alginates are considered the first-line agents for acid reflux treatment in GERD during pregnancy as per recommendations.
• Sodium alginate provides notable relief from postprandial symptoms without systemic side effects, making it an effective, safe, and favorable therapeutic option for GERD management.

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