Heartburn, the burning sensation felt in the chest and throat, is a common symptom of acid reflux, which occurs when stomach acid flows back into the esophagus. As seltzer water has become a popular alternative to sugary sodas, many people wonder whether the carbonated beverage is a safe choice. The central question is whether seltzer water helps dilute stomach acid or instead aggravates the underlying symptoms.
The Direct Effect of Carbonation on Heartburn
Seltzer water is generally not a helpful beverage for managing heartburn and often works to worsen the symptoms. The primary reason for this is the carbonation, which is simply carbon dioxide gas dissolved under pressure. When this carbonated liquid enters the stomach, the dissolved gas is released.
This release of gas causes the stomach to distend, leading to an increase in internal pressure. This sudden increase in pressure within the stomach is the first step in a cascade of events that can lead to a reflux episode.
While carbonation does not directly increase the production of stomach acid, the gas it introduces is enough to destabilize the system. The physical presence of the gas and the resulting pressure is the main issue, which sets the stage for acid to travel upward.
How Seltzer Affects the Lower Esophageal Sphincter
The mechanism for how seltzer water aggravates acid reflux is centered on the Lower Esophageal Sphincter (LES). The LES is a ring of muscle that acts as a valve between the esophagus and the stomach, designed to prevent stomach contents from coming back up. For reflux to occur, this valve must temporarily relax or weaken.
The stomach distension caused by the carbon dioxide gas in seltzer is a known trigger for a transient relaxation of the LES. When the stomach stretches rapidly due to the gas, it signals the LES to open briefly, a reflex that usually allows for venting excess air through a belch. This transient relaxation is the physiological window through which acidic stomach contents can escape into the esophagus.
Ingestion of a carbonated beverage has been shown to increase the frequency of this transient LES relaxation and can also decrease the basal pressure of the LES itself. This combination of increased pressure from the gas and a more relaxed valve makes it easier for stomach acid to flow upward, resulting in the burning sensation of heartburn.
Beyond Bubbles: The Acidity of Flavored Seltzers
While the physical effect of carbonation is the main problem, the chemical composition of flavored seltzers introduces a second complicating factor. Plain seltzer water is already slightly acidic due to the carbon dioxide dissolving to form carbonic acid, typically giving it a pH range around 3.0 to 4.0. Flavored versions, however, are significantly more problematic.
Many flavored seltzers contain added acids, such as citric acid, malic acid, or lactic acid, to enhance the flavor profile. These added ingredients further lower the beverage’s pH, sometimes making it comparable to a soft drink.
Introducing a highly acidic beverage into the stomach contributes to the total acid load that the digestive system must manage. When the LES relaxes due to the carbonation, the substance that splashes back includes the external acid from the flavored seltzer. This increases the potential for irritation and inflammation in the sensitive esophageal lining, compounding the issue caused by the bubbles.
Safer Beverages for Managing Acid Reflux
For individuals prone to heartburn, the best baseline beverage is plain, still water, which helps to dilute stomach acid without causing distension. Still water is neutral and does not introduce the pressure that triggers the LES to relax. Regular small sips of water can also help to wash acid back down into the stomach, clearing the esophagus.
Certain herbal teas offer a soothing effect and can be safely consumed. Specifically, ginger tea and chamomile tea are often recommended, as they possess anti-inflammatory properties and do not contain the caffeine that can trigger reflux. Non-citrus fruit juices, such as apple, pear, or melon juice, are also low-acid alternatives that are generally well-tolerated.
These safer alternatives work by either being naturally low in acid or by not creating the physical pressure that carbonation does. Unlike seltzer, these drinks do not promote stomach distension or force the LES open. Choosing still, non-acidic, or mildly alkaline beverages is a simple, effective dietary adjustment for minimizing the discomfort of acid reflux.