A cough is a sudden, forceful reflex action triggered by irritation in the throat or airways, serving to clear mucus or foreign irritants from the respiratory tract. Many people instinctively reach for familiar beverages, including soda, hoping for relief. Investigating the physical and chemical effects of soda suggests that this popular carbonated drink is counterproductive to healing and can often make a cough worse.
The Temporary Sensation of Relief
The initial feeling that soda provides relief is rooted in a temporary physical sensation in the throat. Cold liquids briefly numb irritated nerve endings in the pharynx, momentarily interrupting the tickle or scratchy feeling that triggers a cough reflex. This cooling effect may be perceived as soothing, especially in cases of throat inflammation or soreness.
Carbonation—the dissolved carbon dioxide gas—may also encourage a clearing swallow reflex. This action can feel like it is clearing the throat, validating the perception that the beverage is helping. However, this is a localized, fleeting physical effect that masks the underlying irritation rather than providing therapeutic benefit.
How Acid and Sugar Exacerbate Coughs
Regular soda consumption introduces a potent combination of high sugar content and acidity, both of which actively work against the body’s efforts to heal. The substantial amount of refined sugar can impair immune function, as high intake is linked to temporary suppression of white blood cell activity. This suppression is detrimental when the body is fighting an infection causing the cough.
Sugar also promotes an inflammatory state, which is counterproductive when the respiratory tract is already inflamed. The high acidity of most sodas, combined with carbonation, presents a significant risk for triggering or worsening acid reflux (GERD).
Carbonation causes gaseous distension of the stomach, which puts pressure on the lower esophageal sphincter (LES), causing it to relax. When the LES relaxes, stomach acid can flow back up into the esophagus and throat, a condition called laryngopharyngeal reflux (LPR). LPR is a major cause of persistent, chronic coughing.
Soda is also a poor hydrating choice because the sugar and, in some cases, caffeine, can act as mild diuretics. Dehydration causes respiratory mucus to thicken, making it more difficult to clear from the airways and intensifying the need to cough.
Proven Hydration and Soothing Strategies
The most effective strategies for cough relief center on soothing irritation and promoting proper hydration to thin mucus. These alternatives focus on healing the underlying irritation or managing the mucus, providing genuine therapeutic benefit.
Warm liquids are recommended because the heat helps loosen and thin mucus, making it easier for the body to expel. Herbal teas or broth provide this benefit while also soothing the back of the throat.
Honey acts as a demulcent; its thick, viscous texture coats the irritated throat lining, providing a protective layer that calms the cough reflex. Studies suggest that honey can be as effective as some over-the-counter cough preparations, and it is easily consumed in a spoonful or mixed into warm water or tea.
Another effective technique is steam inhalation, which involves breathing in warm, moist air from a hot shower or a humidifier. This moist air helps to lubricate the throat and airways, thinning the mucus and relieving dryness.
Simple measures like gargling with warm salt water can reduce inflammation and temporarily soothe a scratchy throat. For persistent irritation, over-the-counter cough drops or lozenges stimulate saliva production, which naturally moistens the throat and helps suppress the impulse to cough.