- Researchers have linked artificially sweetened sodas to increased risk of dementia and stroke in two studies published in the journals Stroke and Alzheimer’s & Dementia, Bloomberg reports.
- The observational studies were based on 2,888 people from the Framingham Heart Study Offspring cohort, who have been providing data since 1971. The researchers found those who drank at least one diet soda a day were three times more likely to suffer an ischemic stroke or to develop Alzheimer’s.
- Importantly, such studies can only suggest an association, and do not mean that diet sodas actually cause dementia or stroke. An editorial accompanying the Stroke study noted the results could be due to reverse causality, “whereby sicker individuals consume diet beverages as a means of negating a further deterioration of health”.
Although the statistics suggest a possible link between diet soda and health risks, they do not necessarily draw a straight line from sweetener to stroke or dementia. Experts were quick to repeat the “correlation isn’t causation” mantra and called for caution when interpreting these studies.
They highlighted several flaws, including that the researchers themselves admit when other factors like diabetes, genes and overweight are taken into account, the association with dementia disappears. They also found no association between consumption of sugary drinks and stroke risk – despite this being a well-established link. It is possible people who are already in ill health, particularly those suffering with diabetes, are more likely to choose zero-calorie drinks, thereby skewing these results.
In the meantime, many experts suggest all fizzy drinks, however they are sweetened, should be consumed in moderation. Scientists have long been researching the health risks of soda, and some have suggested a link with weight gain.
In response to this latest study, the American Beverage Association issued a statement highlighting international organizations, such as the U.S. Food and Drug Administration, World Health Organization and European Food Safety Authority, repeatedly have reviewed the safety status of artificial sweeteners, and concluded they are safe.
Whether artificially sweetened drinks carry a health risk or not, consumers increasingly are looking for alternatives, including naturally sweetened low-calorie drinks and bottled water. Bottled water sales overtook those of carbonated soft drinks in the U.S. last year to become the largest beverage category by volume.
Soda sales nationally have been declining as consumers shun sugary drinks in favor of healthier, better-for-you beverages. Taxes slapped on sugary drinks in Berkeley cut sales 21% last year, while in Philadelphia PepsiCo said it would need to lay off 80 to 100 workers after sales dropped 40% following the city's tax. The latest studies are unlikely to noticeably hurt soda sales in the near-term without more definitive proof linking the drink to dementia and stroke, but given the challenges plaguing the beverage lately it's hardly welcomes news.