Reality check: Is your daily diet soda increasing your risk of dementia, stroke?

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Can taxing sugary drinks reduce obesity?
A new report commissioned by various health organizations says Canadians are consuming way too many sugary drinks, and it’s contributing to obesity and serious illness. As Allison Vuchnich reports, the study also calls on the Canadian government to impose a tax on sugary drinks – Mar 16, 2017

Research is shedding light on how diet soda may be sabotaging your weight and waistline, but what about your risk of stroke and dementia?

A new American study is warning that a daily artificially sweetened drink may be tied to an almost three times increased risk of encountering a stroke or dementia compared to people who drink diet soda less than once a week.

The findings were published Thursday in the American Heart Association’s journal Stroke.

“Our study shows a need to put more research into this area given how often people drink artificially sweetened beverages,” Dr. Michael Pase, the study’s lead author and a senior fellow at the Boston School of Medicine, said.

His long-term observational study is not pointing to a cause and effect relationship, just a trend linking diet drinks to stroke and dementia.

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READ MORE: Why diet soda may be making you eat more

For Pase’s research, he looked more than 4,000 people coming out of the Framingham Heart Study – an ongoing study that began in 1948 and closely followed the health trajectories of thousands of U.S. residents.

Over the course of seven years, the researchers looked at how often people were drinking sugary and artificially sweetened drinks. After that, they traced the study participants’ health for about a decade to document who ended up with dementia or suffered a stroke.

Turns out, 97 people suffered a stroke in the subsequent years while 81 people were diagnosed with dementia.

People who drank at least one diet soda a day were three times more likely to encounter stroke and 2.9 times more likely to develop Alzheimer’s disease.

There was no relationship between stroke and dementia risk and sugary drinks, though.

READ MORE: How much sugar and how many calories are in your summertime drink?

“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,” Pase noted.

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He told Global News that the study participants who drank more diet sodas tended to have Type 2 diabetes. That signals they could be carrying more weight, working out less or making bad choices when it comes to mealtime.

“We’re not sure if people who are unhealthy are more likely to choose diet beverages or if diet beverages lead to a higher risk of eating more sugar,” Pase explained.

READ MORE: Should the word ‘diet’ be banned from diet sodas? Consumer group thinks so

The scientific community has already emphasized that they don’t fully understand the mechanisms behind aspartame, stevia and other artificial sweeteners. In some cases, they may trigger people to eat more.

“We know that having too much sugar in the diet and eating too many unhealthy foods high in cholesterol is associated with developing obesity and diabetes. This, in turn, is a risk factor for stroke,” Pase said.

Other studies have already referred to weight gain in the stomach area after drinking too much diet soda, according to Nalini Sen, director of research at the Alzheimer Society of Canada.

Thirty per cent of people who have a stroke end up developing vascular dementia in the following year, she said.

Stroke and cardiovascular disease are implicated in 50 per cent of all dementia cases, too.

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READ MORE: Reality check: Is diet soda adding to your belly fat?

Sen said the evidence isn’t clear enough to make a firm statement when it comes to diet soda and dementia risk, though.

Dr. Patrice Lindsay, director of stroke research at Heart & Stroke, said the concern is “valid,” though.

“Any sugar-sweetened drinks or artificially sweetened drinks should be minimized in any diet,” she said.

But scientists need to unfold why people are reaching for diet drinks: do they make the decision because they have vascular disease, risk factors for chronic disease, or they have a taste preference?

READ MORE: A tax on sugary drinks would save 13,000 lives and raise $43B, Canadian study suggests

“That’s the challenge because it’s likely that some of those people have diabetes, are pre-diabetic or have hypertension and have been educated to moderate their lifestyle factors,” Patrice said.

Pase calls his findings a “first important step.” His next steps are to look at what may be good for the brain so consumers have options on what to reach for instead of being told to avoid certain food and beverages.

For its part, the American Beverage Association said in a statement that artificially sweetened drinks are safe.

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READ MORE: Sugary drinks tied to 63,000 deaths in the next 25 years, Canadian report warns

“The FDA, World Health Organization, European Food Safety Authority and others have extensively reviewed low-calorie sweeteners and have all reached the same conclusion — they are safe for consumption,” the statement said.

“While we respect the mission of these organizations to help prevent conditions like stroke and dementia, the authors of this study acknowledge that their conclusions do not — and cannot — prove cause and effect.”

Read the full study.

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