Drinking Soda Tied to Poor Brain Health and Alzheimer’s Risk

June 14, 2017

Two new studies link soda consumption to early signs of Alzheimer’s disease and poor brain health. Although the studies do not prove cause and effect, they suggest that drinking sodas — whether they are sugar sweetened or diet — may be linked to accelerated brain aging and an increased risk of Alzheimer’s or other forms of dementia.

One study, in the journal Alzheimer’s and Dementia, looked at more than 4,000 middle-aged adults. They were given brain scans and memory tests and filled out detailed questionnaires about what they ate and drank.

The researchers, from Boston University and other research centers, found that the more sugary sodas someone regularly drank, the worse they tended to do on memory tests.Those who drank the most sugary drinks also tended to have more shrinkage of the brain. In other studies, reduced brain volume has been tied to an increased risk of developing Alzheimer’s disease years later.

Those who drank one or two sugary sodas a day had shrinkage of the brain that corresponded to one to two years of aging compared with those who didn’t drink sugary sodas or other sugar-sweetened beverages. They also tended to do worse on memory tests, scoring about the same as someone five or six years older. A typical can of sugar-sweetened soda or similarly sweetened beverage contains up to 10 teaspoons of sugar, or about 150 calories.

Those who regularly drank more than two sugary drinks daily performed even worse on memory tests, scoring the equivalent of someone more than a decade older.

The researchers considered variables like diabetes and high blood pressure, which have also been linked to an increased risk of Alzheimer’s. But even after controlling for these risk factors, increased sugar consumption was tied to accelerated brain aging and brain shrinkage.

And for those concerned about sugar intake, turning to diet sodas may not be the answer. The second study, in the American Heart Association’s journal Stroke, found that drinking diet sodas was also tied to an increased risk of dementia and increased stroke was another risk associated.

That study analyzed data from the Framingham Heart Study, which followed a large group of residents from Framingham, Mass., over many years. The researchers, some of whom were involved in the first study, found that among almost 1,500 people over 60, those who drank at least one diet beverage daily had nearly three times the risk of developing Alzheimer’s or other forms of dementia over the next 10 years compared to those who drank diet sodas less than once a week.

The authors note that as in the earlier study, they cannot prove cause and effect. Many of those in the study may have been drinking diet soda because they had diabetes or been overweight, which are known to raise the risk of dementia.

“We recommend that people drink water on a regular basis instead of sugary or artificially sweetened beverages,” the authors advise.

Increasingly, research shows that what we eat and drink can have an impact on the long-term health of our brain. Sugary sodas and other drinks can lead to weight gain, and obesity in midlife has been tied to an increased risk of Alzheimer’s in old age. Diabetes, also tied to obesity and poor diets, can severely impact blood vessel health, including the health of blood vessels in the brain.

“Real” foods that are not artificially modified or industrially processed and as fresh as possible, including a heart-healthy diet rich in fruits and vegetables and whole grains, on the other hand, has been tied to a lower risk of Alzheimer’s in old age.

By ALZinfo.org, The Alzheimer’s Information Site. Reviewed by Marc Flajolet, Ph.D., Fisher Center for Alzheimer’s Research Foundation at The Rockefeller University.

Sources: Matthew P. Pase, Jayandra J. Himali, Paul F. Jacques, et al: “Sugary beverage intake and pre-clinical Alzheimer’s disease in the community.” Alzheimer’s and Dementia, April 2017.  Matthew P. Pase, et al: “Sugar and artificially sweetened beverages and the risks of incident stroke and dementia: a prospective cohort study.” Stroke, April 20, 2017.


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