Seltzer water, or carbonated water, is made by dissolving carbon dioxide (CO2) gas into plain water under pressure. For many people, this popular beverage causes a feeling of fullness or abdominal swelling. This physical reaction is a direct consequence of ingesting the pressurized gas, which temporarily causes abdominal distension. While generally harmless and temporary, this common physiological response can cause discomfort.
The Science of Carbonation and Gas
Carbonation forces carbon dioxide to dissolve into the liquid, creating a supersaturated solution stable only under high pressure. When seltzer is consumed, the liquid warms up rapidly as it enters the stomach, and the pressure is released. This change in environment causes the dissolved CO2 to quickly exit the liquid solution, forming the gas bubbles known as effervescence.
The accumulation of this newly released gas inside the stomach causes a noticeable expansion, or distension, of the stomach wall. This distension is what registers in the body as the feeling of being bloated or full. For most individuals, this gas is quickly vented upward through the esophagus as a burp, providing rapid relief from the pressure.
If the gas is not quickly expelled through belching, it moves further down the digestive tract into the small intestine. Once in the intestines, the gas contributes to a more persistent and uncomfortable sensation of bloating. The body must then process this gas through absorption into the bloodstream or eventual release as flatulence.
Hidden Ingredients That Worsen Bloating
While carbonation is the primary cause of immediate gas, added components in many commercial flavored seltzers can significantly compound the bloating effect. Many zero-calorie flavored drinks use artificial sweeteners or sugar alcohols, such as xylitol, erythritol, or sorbitol, to provide sweetness without sugar. These compounds are known as Fermentable Oligosaccharides, Disaccharides, Monosaccharides, and Polyols (FODMAPs).
The human small intestine often struggles to fully absorb these sugar alcohols due to their chemical structure. When the unabsorbed remnants reach the large intestine, resident gut bacteria rapidly ferment them as a food source. This bacterial fermentation produces substantial additional gas, primarily methane and hydrogen, which exacerbates bloating and discomfort.
Other common additives include citric acid and malic acid, used for flavoring and preservation to create a tart taste. While generally safe, these added acids can sometimes irritate a sensitive stomach lining, especially in individuals with conditions like gastroesophageal reflux disease (GERD). This irritation can slow the rate at which the stomach empties, contributing to a prolonged feeling of fullness and bloating.
Strategies for Reducing Carbonation-Related Discomfort
To minimize the gas and bloating associated with seltzer, the method of consumption can be adjusted to allow the CO2 to escape gradually. Drinking seltzer slowly, or sipping it rather than gulping, gives the gas time to rise and be released as a burp before it travels deeper into the digestive system. Avoiding the use of straws can also help, as they often cause a person to swallow extra air along with the liquid.
The temperature of the beverage also plays a role in how much gas is released upon consumption. Carbon dioxide remains more tightly dissolved in cold liquids; therefore, allowing seltzer to warm up slightly before drinking can help some of the gas escape beforehand. This simple change reduces the amount of pressurized gas that reaches the stomach, lessening the potential for internal distension.
Being mindful of the product’s ingredient list is an effective strategy, especially when choosing flavored varieties. Opting for unflavored seltzers or those without artificial sweeteners or sugar alcohols eliminates the compounded gas production from bacterial fermentation. Finally, avoiding seltzer immediately before or during a large meal is advisable, as the full stomach makes the introduction of extra gas more likely to cause significant discomfort.