Acid reflux, commonly known as heartburn, occurs when stomach contents flow back up into the esophagus. This backwash, known as gastroesophageal reflux (GER), irritates the esophageal lining, which lacks the stomach’s protective layer. Frequent or chronic reflux is called Gastroesophageal Reflux Disease (GERD). Soda generally exacerbates this condition by introducing multiple physical and chemical elements that trigger symptoms.
How Carbonation Triggers Heartburn
The primary physical mechanism by which soda contributes to reflux is carbonation, the infusion of carbon dioxide gas under pressure. When this dissolved gas reaches the warm stomach environment, it rapidly expands, creating bubbles and causing gastric distension. This expansion significantly increases the pressure inside the stomach.
The increased intra-abdominal pressure pushes stomach contents, including acidic digestive juices, upward toward the esophagus. The stomach is normally sealed off from the esophagus by the lower esophageal sphincter (LES). The pressure from the carbonation can physically force the LES to open or trigger transient LES relaxations (TLESRs).
These brief, involuntary relaxations allow stomach acid to escape into the esophagus, leading to heartburn. Sodas, including both full-sugar and diet varieties, are major contributors to this pressure-induced reflux event.
The Dual Threat of Soda’s pH and Ingredients
Beyond the physical pressure of carbonation, the chemical composition of sodas presents a dual threat. Sodas, whether regular or diet, are highly acidic, often having a pH as low as 2.5 to 3.0, comparable to stomach acid itself. Introducing this acidic liquid can directly irritate an already inflamed esophagus, even if the LES remains closed.
This extreme acidity is often due to added ingredients like citric, phosphoric, and carbonic acids. Many sodas also contain caffeine, a known physiological trigger for acid reflux. Caffeine chemically induces the relaxation of the LES, compounding the mechanical pressure from carbonation.
Furthermore, the high sugar content in regular sodas can indirectly affect reflux symptoms by altering gastric emptying or contributing to fermentation. Even diet sodas, with artificial sweeteners, can disrupt the gut microbiome, affecting overall digestive health.
Hydration Options That Soothe Acid Reflux
For individuals managing acid reflux, shifting away from sodas to alternative beverages can provide significant symptom relief. Plain water is one of the best choices, as sipping it throughout the day helps dilute stomach acid and washes down any acid that may have refluxed. Adequate hydration also supports proper gastrointestinal function.
Several alternatives can soothe the digestive tract:
- Herbal teas like chamomile, ginger, and licorice may help reduce inflammation and calm the stomach lining. Peppermint tea should be avoided, as it can relax the LES and worsen symptoms.
- Alkaline beverages, such as unsweetened coconut water or plant-based milks like almond milk, have a higher pH that can temporarily neutralize stomach acid.
- Non-acidic fruit and vegetable juices, such as carrot, melon, or aloe vera juice, provide flavor without irritating acidity.