A new international study has found that drinking sugary or artificially sweetened beverages in later life does not raise the risk of dementia in older adults. The research was carried out by Zhejiang University School of Medicine in China and several American researchers.
Their findings were published in JAMA Psychiatry and offer new insight into how diet affects brain health in older age.
Dementia is a serious condition that causes memory loss and mental decline, often worsening over time. It affects many older adults and places a heavy burden on families and healthcare systems. While there is no cure, scientists believe that lifestyle factors such as diet and exercise may help prevent or delay dementia.
Sugar is often a focus because it contributes to obesity and diabetes, which are known to increase the risk of dementia. In the U.S., nearly one in five older adults gets a major part of their added sugar from sweetened drinks.
Previous studies on animals have shown that high sugar intake may lead to harmful brain changes, such as the build-up of β-amyloid and increased apolipoprotein E, both of which are linked to Alzheimer’s disease.
However, studies in humans have not been consistent. Some found a higher risk of dementia in people who drink a lot of sugary beverages, while others found no link.
To get a clearer answer, the researchers behind this new study combined data from six large U.S. studies. In total, they looked at 10,974 adults aged 65 and older. The average age was 73, and about 60% were women. The study followed participants for more than 10 years, tracking both their beverage habits and their mental health.
Participants reported how often they drank sugary or diet drinks using food surveys that had been tested for accuracy. Researchers also excluded any participants who developed dementia within two years of the start of the study to reduce the chances that early signs of dementia were affecting their diet.
The team then followed the participants’ medical records and health check-ups to see who developed dementia over time.
During the follow-up period, 2,445 people developed dementia. But when the researchers compared those who drank sugary or diet drinks daily with those who rarely drank them, they found no meaningful difference in dementia risk.
People who drank sugar-sweetened beverages every day had a slightly lower hazard ratio (0.90), and those who drank diet drinks had a neutral risk (1.00). These numbers suggest no increased or decreased risk tied directly to sweet drink intake in later life.
Importantly, the results were consistent across different groups, including men and women, and people with different levels of education or health conditions. The researchers also tested their results with different methods, and the findings held up.
To make sure their methods worked, they also looked at another factor known to affect brain health: the Mediterranean diet. As expected, people who followed this diet more closely had a lower risk of dementia. This served as a “positive control,” confirming that the study could detect real links when they existed.
The scientists say their results should be taken as reassurance: for older adults, having a sweetened drink now and then probably doesn’t harm the brain. However, they also warn that this does not mean sugary drinks are healthy overall.
Sugary drinks can still contribute to heart disease, obesity, and diabetes, which is why most dietary guidelines advise people to cut back on them.
Another important point the researchers made is that this study only looked at diet in older age. It’s possible that drinking a lot of sugary beverages earlier in life might have a greater effect on the brain, especially when the body and brain are still developing or more flexible.
They believe that future studies should focus on younger people to better understand how lifelong habits affect dementia risk later on.
In conclusion, while sugary and diet drinks are not great for your body in general, drinking them in old age does not seem to increase your chances of getting dementia. Instead of focusing only on cutting out sweet drinks late in life, the study suggests that people—and public health efforts—should pay more attention to healthy habits formed earlier in life.
If you care about brain health, please read studies about Vitamin B9 deficiency linked to higher dementia risk, and cranberries could help boost memory.
For more health information, please see recent studies about heartburn drugs that could increase risk of dementia, and results showing this MIND diet may protect your cognitive function, prevent dementia.
The research findings can be found in JAMA Psychiatry.
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