That Common Drink Linked to Dementia Is Probably in Your Fridge

That Common Drink Linked to Dementia Is Probably in Your Fridge

The Drink in Question Is Sugar, Not Caffeine

EatingWell's October 12 feature identified the "common drink" as sugar-sweetened beverages: soda, sweet tea, sweetened fruit juices and energy drinks. Nutritionist Maggie Moon, quoted in the piece, drew a careful line: sugary drinks do not cause dementia on their own, but long-term excess worsens known risk factors such as high blood pressure, diabetes and heart disease.

More Than Two Servings a Day Showed Higher Risk

The article also cites a large 2023 study finding that people who drank more than two sugar-sweetened beverages a day had a higher dementia risk than people who drank none. Over time, the extra sugar feeds type 2 diabetes, high blood pressure and obesity, all of which damage the blood vessels that supply the brain.

A 2025 Review Put Alzheimer's Risk Up 49%

The New York Post's October 1 roundup cited a 2025 review: people who drank the most sugar-sweetened beverages had a 49% higher risk of Alzheimer's disease, while artificially sweetened drinks, including diet sodas sweetened with aspartame, were associated with a 42% higher risk.

Governments Already Have a Sugar Line

The official guidance is not new. The World Health Organization recommends keeping free sugars below 10% of total energy intake, with a further reduction to below 5%, roughly 25 grams or six teaspoons a day, judged beneficial. The American Heart Association caps added sugar at 25 grams a day for women and 36 grams for men. The 2024 Lancet Commission on Dementia Prevention, Intervention and Care lists 14 modifiable risk factors and estimates that addressing them could prevent or delay about 45% of cases; diabetes is on that list.

The Path Runs Through the Heart and Blood Vessels

A review published in the August 2026 issue of Annual Review of Nutrition, authored by 26 researchers, repeatedly ties diets high in sugar-sweetened drinks to higher dementia and stroke risk. Brain imaging in the studies it covered showed smaller brain volumes among people with high intake of fatty and sugary drinks, and white matter damage in some of them. In animal experiments, mice fed a high-fat diet with added sugar or salt accumulated more of the toxic proteins linked to Alzheimer's disease in brain regions tied to memory.

Half of American Calories Come From Ultra-Processed Food

The same review notes that ultra-processed foods supply about 55% of Americans' daily calories. A Brazilian study following 10,775 adults for a median of eight years found that people getting more than 19.9% of their calories from ultra-processed food showed faster declines in planning and overall thinking scores, an association that held only among those who did not closely follow the MIND diet. Between 2017 and 2018, US adults averaged 34.8 grams of added sugar a day from sugary beverages, the largest single source of added sugar in their diets.

The Counter-Evidence Is Real

Not every study agrees. First Check's fact check noted that the 2017 Northern Manhattan Study, following 947 older adults, linked each extra daily diet soda to a 39% higher dementia risk, with more than one a day associated with roughly four times the risk. But a 2025 analysis of six prospective US cohorts covering 10,974 older adults found no significant association between artificially sweetened beverage consumption and dementia. The same check stressed that the field shows correlation, not causation.

Experts Stop Short of Blame

Owen Carmichael of Louisiana State University's Pennington Biomedical Research Center, lead author of that review, said some of the data is concerning but that many questions remain about how these relationships work and what they mean for long-term cognitive health. He offered two working theories: damage to the heart and blood vessels, and food additives that may disrupt brain chemistry. Researchers also caution that percentages from observational studies describe relative risk, not any individual's odds of becoming ill.

Coffee and Tea Point the Other Way

The direction is not uniformly bad. A cohort study of 131,821 participants, reported by ScienceDaily and published in JAMA, found that two to three cups of caffeinated coffee a day, or one to two cups of tea, was associated with lower dementia risk and slower cognitive decline, while decaffeinated drinks showed no such link.

What To Do With the Finding

The practical consensus is to swap the sweet stuff first: replace sugary drinks with water, unsweetened tea or plain milk, and replace some ultra-processed calories with unprocessed food. The review cited research suggesting that replacing just 10% of calories from ultra-processed food with unprocessed foods could lower dementia risk by 19%. The mechanisms, and the size of the real-world benefit, still need to be pinned down.