Drinking an artificially sweetened drink every day is associated with a significantly increased risk of developing stroke and dementia, according to research at the Boston University School of Medicine.
The study, published in the American Heart Association journal Stroke, found that daily drinkers were three times more likely to suffer from stroke than those who drank such beverages once a week or less.
The same apparent effect was found for dementia, but this diminished after other risk factors were taken into account.
Over seven years the researchers analysed data from 2,888 people over the age of 45 for the stroke study and 1,484 people over the age of 60 for the dementia study.
After 10 years there were 97 cases of stroke, 82 of which were caused by blocked blood vessels, and 81 cases of dementia.
Matthew Pase, the paper’s lead author, said: ‘Our study shows a need to put more research into this area given how often people drink artificially sweetened beverages.
‘Although we did not find an association between stroke or dementia and the consumption of sugary drinks, this certainly does not mean they are a healthy option. We recommend that people drink water on a regular basis instead of sugary or artificially sweetened beverages.
‘Even if someone is three times as likely to develop stroke or dementia, it is by no means a certain fate. In our study, three per cent of the people had a new stroke and five per cent developed dementia, so we’re still talking about a small number of people developing either stroke or dementia.’
The Framingham Heart Study is a large prospective cohort study that began in the 1940s; its data is analysed every four years. Considerable knowledge has been gained about the natural history of risk factors for cardiovascular and neurovascular disease as a result of this study.
Soft drink and other dietary components were assessed by food-frequency questionnaire (FFQ) on three separate occasions during the follow-up period with each FFQ giving information on dietary intake in the previous 12 months.
Soft drink intake was measured from never or less than one a month up to more than six drinks a day with a clear distinction between drinks sweetened with sugar or artificial sweetness.
Data was analysed at separate levels with the first level adjusting for limited risk factors and the second adjusting for multiple risk factors implicated in stroke and Alzheimer’s disease.
No relationship was noted between the consumption of sugar-sweetened drinks and the risk of stroke. On the other hand, regardless of how the data was analysed, those consuming more than one artificially sweetened drink a day were at almost three times the risk of a stroke.
This data is consistent with the findings of other large studies.
Interestingly, there seemed to be no relationship between the consumption of sugar-sweetened drinks and Alzheimer’s disease. The relationship between artificially sweetened drinks and Alzheimer’s appears more tenuous; consumption of more than one drink a day appeared to triple the risk in the first analysis but not in the more detailed analysis.
We must remember that this is an observational study — it cannot infer direct causation, ie, that diet soft drinks cause stroke or Alzheimer’s disease. The correlation between the two can be explained at multiple levels; many obese people, for example, will consume diet drinks as part of an effort to be healthier. Many diabetics will do the same thinking they can indulge without the blood sugar problems that other drinks may cause.
Take-home message: there appears to be a tenuous link between stroke and Alzheimer’s disease and the consumption of artificially sweetened drinks. The sweeteners themselves have already been linked to deleterious health outcomes in animal studies, so perhaps it might be wise to limit consumption of them.
Research score: 3/5