Sparkling water, water infused with carbon dioxide gas, is a popular alternative to sugary drinks. Questions often arise about its potential health implications, particularly its contribution to cancer risk. This article explores the scientific evidence surrounding sparkling water and its components to address these concerns.
Understanding Carbonation and Acidity
Sparkling water is created by dissolving carbon dioxide gas into water under pressure, a process known as carbonation. This forms carbonic acid, which gives the water its characteristic fizz and a slightly acidic taste. Plain sparkling water is mildly acidic, with a pH typically ranging from 4.7 to 5.0, compared to neutral plain water.
The acidity of sparkling water has raised concerns about its impact on dental health. Tooth enamel can demineralize when the pH in the mouth drops below 5.5. Frequent consumption of acidic beverages, including sparkling water, can contribute to enamel erosion. Flavored sparkling waters, which often contain additional acids like citric acid, can be even more acidic, with pH levels sometimes as low as 2.7 to 3.4, comparable to some sodas. Studies suggest that flavored sparkling waters may have an erosive effect on teeth similar to orange juice. Despite these dental considerations, the carbonation process or the mild acidity of plain sparkling water has not been linked to cancer in scientific studies.
Examining Potential Additives and Contaminants
Concerns about sparkling water and cancer often stem from potential additives and environmental contaminants that might be present, especially in flavored or enhanced varieties.
Artificial sweeteners are frequently used in flavored sparkling waters to provide sweetness without added calories. Regulatory bodies like the U.S. Food and Drug Administration (FDA) and the European Food Safety Authority (EFSA) generally consider these sweeteners safe for consumption at approved levels. While the International Agency for Research on Cancer (IARC) classified aspartame as “possibly carcinogenic to humans” (Group 2B) based on limited evidence, the Joint FAO/WHO Expert Committee on Food Additives (JECFA) reaffirmed its acceptable daily intake. Overall, there is no consistent scientific evidence directly linking artificial sweeteners to cancer in humans at typical consumption levels.
“Natural flavors” are common in flavored sparkling waters. While generally recognized as safe (GRAS) by the FDA, no direct cancer link has been established for them.
Benzene, a known carcinogen, has been a concern in beverages. It formed in some soft drinks containing benzoate preservatives and ascorbic acid, particularly when exposed to heat, light, and certain metal ions. This was a contamination issue, not an inherent property of carbonated water. Manufacturers largely reformulated their products to minimize benzene formation. Current levels in commercial beverages are typically well below the 5 parts per billion (ppb) limit set by the EPA for drinking water.
Per- and polyfluoroalkyl substances (PFAS), often referred to as “forever chemicals” due to their persistence, represent a more recent concern. These chemicals can enter water sources through environmental contamination and have been detected in some bottled waters, including sparkling water. PFAS exposure has been linked to various health issues, including certain cancers. Their presence is a contamination issue that regulatory bodies are actively addressing, with new drinking water standards for certain PFAS set to 4 ppt, effective in 2024.
Current Scientific Understanding
Overall scientific evidence does not directly link plain sparkling water consumption to an increased cancer risk. Major health organizations and regulatory bodies generally concur on its safety when produced under appropriate conditions. The FDA, for instance, oversees the safety of bottled water, including sparkling varieties, through established manufacturing practices and testing protocols.
Additives like artificial sweeteners have undergone scrutiny, but organizations such as the JECFA have concluded that the evidence associating aspartame consumption with cancer in humans is not convincing at commonly consumed doses. Concerns regarding contaminants like benzene have largely been mitigated through industry reformulations and regulatory oversight, ensuring that levels in beverages are well below safety thresholds. PFAS chemicals, while a valid and ongoing environmental and public health concern, represent an external contamination issue rather than an inherent property of sparkling water itself. Plain sparkling water is not widely considered a carcinogen.
Balancing Consumption
Plain sparkling water is a healthy, hydrating alternative to sugary soft drinks, providing hydration without added sugars or calories. Choosing unflavored varieties can help consumers avoid potential concerns associated with artificial sweeteners or complex natural flavors.
Moderation is advisable, especially for flavored options, due to their potential for increased acidity and impact on dental enamel. For those concerned about contaminants like PFAS, home carbonation using filtered tap water offers greater control over the water source and any added ingredients. The current scientific evidence does not support a direct link between sparkling water and cancer, positioning it as a safe choice for hydration for the general public.