MediQAre Sugar Substitutes Linked to Faster Memory Decline?
A study of nearly 13,000 adults in Brazil found that people who consumed the most low- and no-calorie sweeteners had a 62% faster decline in memory and thinking skills over eight years. The link was strongest in adults under 60 and those with diabetes, though the study does not prove cause and effect.
In short
- People who consumed the most low- and no-calorie sweeteners had a 62% faster decline in memory and thinking skills over eight years.
- The link to faster cognitive decline was strongest in adults under 60 and people with diabetes.
- This observational study shows an association, not proof that sweeteners directly damage the brain.
You might reach for a diet soda or sugar-free yogurt to cut back on sugar. But new research suggests that some common sugar substitutes may be linked to faster declines in memory and thinking skills over time.
Researchers in Brazil followed 12,772 adults for about eight years. They found that people who consumed the most low- and no-calorie sweeteners experienced a 62% faster cognitive decline than those who consumed the least. Based on test scores, this difference was equal to roughly 1.6 additional years of brain aging.
Which sweeteners were studied?
The researchers looked at seven sweeteners often found in ultra-processed foods like diet sodas, flavored waters, energy drinks, and low-calorie desserts:
- aspartame
- saccharin
- acesulfame-K
- erythritol
- xylitol
- sorbitol
- tagatose
Six of these were linked to faster declines in overall thinking and memory. Tagatose was the only exception, though this does not prove it protects the brain. Sorbitol, a type of sweetener called a sugar alcohol, had the highest average intake at 64 mg per day.
People in the highest consumption group averaged 191 mg per day. For comparison, 191 milligrams of aspartame is roughly the amount found in one can of diet soda. Those in the lowest group averaged just 20 mg per day.
Who was most affected?
The link between sweeteners and faster cognitive decline was not the same for everyone. It was stronger in two specific groups:
- Adults younger than 60 showed faster declines in verbal fluency, which is the ability to quickly find and say words.
- People with diabetes showed a stronger association than those without the condition.
"While we found links to cognitive decline for middle-aged people both with and without diabetes, people with diabetes are more likely to use artificial sweeteners as sugar substitutes," said study author Claudia Kimie Suemoto of the University of São Paulo.
Does this mean sweeteners damage the brain?
No. This was an observational study, meaning it shows an association rather than a proven cause. Researchers cannot conclude from this study that consuming these sweeteners directly damages the brain or causes memory loss. Other unmeasured factors could help explain the relationship.
Also, dietary information came from participants' own memories of what they ate, which may not perfectly reflect actual habits. More research is needed to confirm these findings.
The bottom line: if you regularly use sugar substitutes, especially if you have diabetes or are under 60, it is worth paying attention to how much you consume while scientists learn more.
What you can do now
- Check ingredient labels on diet sodas, sugar-free yogurts, and energy drinks to see which sweeteners you consume.
- Track how many artificially sweetened foods and drinks you have each day to understand your intake.
- Discuss your use of sugar substitutes with your doctor, especially if you have diabetes or are under 60.
- Wait for further research before making major diet changes, as this study shows an association, not a proven cause.
Questions you may have
Do all sugar substitutes have this link to memory decline?
The study examined seven sweeteners. Six, including aspartame, saccharin, and erythritol, were linked to faster cognitive decline. Tagatose was the only one with no observed association, but this does not prove it is safer.
Does this mean I will get memory problems if I drink diet soda?
Not necessarily. The study shows an association, not a direct cause. These estimates describe changes in test performance, and they do not mean everyone who consumes these sweeteners will experience memory problems.
Why were people with diabetes more affected?
The researchers found a stronger association in people with diabetes. The study author noted that people with diabetes are more likely to use artificial sweeteners as sugar substitutes, but more research is needed to understand why the link was stronger.
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