Diet sodas may be tied to stroke, dementia risk

http://www.cnn.com/2017/04/20/health/diet-sodas-stroke-dementia-study/

(CNN) Gulping down an artificially sweetened beverage not only may be associated with health risks for your body, but also possibly your brain, a new study suggests.

Artificially sweetened drinks, such as diet sodas, were tied to a higher risk of stroke and dementia in the study, which published in the American Heart Association’s journal Stroke on Thursday.
The study sheds light only on an association, as the researchers were unable to determine an actual cause-and-effect relationship between sipping artificially sweetened drinks and an increased risk for stroke and dementia. Therefore, some experts caution that the findings should be interpreted carefully.
No connection was found between those health risks and other sugary beverages, such as sugar-sweetened sodas, fruit juice and fruit drinks.
Are diet sodas dangerous to your health?

Are diet sodas dangerous to your health? 04:19
“We have little data on the health effects of diet drinks and this is problematic because diet drinks are popular amongst the general population,” said Matthew Pase, a senior research fellow in the department of neurology at Boston University School of Medicine and lead author of the new study.
“More research is needed to study the health effects of diet drinks so that consumers can make informed choices concerning their health,” he said.
The new study involved data on 2,888 adults older than 45 and 1,484 adults older than 60 from the town of Framingham, Massachusetts. The data came from the Framingham Heart Study, a project of the National Heart, Lung, and Blood Institute and Boston University.
In the older-than-45 group, the researchers measured for stroke and in the older-than-60 group, they measured for dementia.
“The sample sizes are different because we studied people of different ages,” Pase said. “Dementia is rare in people under the age of 60 and so we focused only on those aged over 60 years for dementia. Similarly, stroke is rare in people aged under 45 and so we focused on people older than age 45 for stroke.”
How diet soda confuses your body

How diet soda confuses your body 01:52
The researchers analyzed how many sugary beverages and artificially sweetened soft drinks each person in the two different age groups drank, at different time points, between 1991 and 2001. Then, they compared that with how many people suffered stroke or dementia over the next 10 years.
Compared to never drinking artificially sweetened soft drinks, those who drank one a day were almost three times as likely to have an ischemic stroke, caused by blocked blood vessels, the researchers found.
They also found that those who drank one a day were nearly three times as likely to be diagnosed with dementia.
Those who drank one to six artificially sweetened beverages a week were 2.6 times as likely to experience an ischemic stroke but were no more likely to develop dementia, Pase said.
“So, it was not surprising to see that diet soda intake was associated with stroke and dementia. I was surprised that sugary beverage intake was not associated with either the risks of stroke or dementia because sugary beverages are known to be unhealthy,” Pase said.
Unhealthy sugary drinks

In response, Lauren Kane, a spokeswoman for the American Beverage Association, issued a statement from the group that said low-calorie sweeteners found in beverages have been proven safe by worldwide government safety authorities.
“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. And according to the National Institutes of Health (NIH), many risk factors can increase an individual’s likelihood of developing stroke and dementia including age, hypertension, diabetes and genetics. NIH does not mention zero calorie sweeteners as a risk factor,” the statement said. “America’s beverage companies support and encourage balanced lifestyles by providing people with a range of beverage choices — with and without calories and sugar — so they can choose the beverage that is right for them.”
Separate previous studies have shown an association between the intake of sugar-sweetened beverages and adverse health effects, such as type 2 diabetes, obesity, heart disease, stroke, and possibly even heart failure.
“This article provides further evidence though on artificially sweetened beverages and their possible effects on vascular health, including stroke and dementia,” said Dr. Ralph Sacco, professor and chair of neurology at the University of Miami Miller School of Medicine, about the new study.
Sacco was a co-author of an editorial published alongside the study in the journal Stroke on Thursday.
“We believe the pathways of which artificially sweetened beverages would affect the brain are probably through vascular mechanisms,” Sacco said.
“When the authors controlled for hypertension and diabetes and obesity the effects diminish, which implies that some of the effects of artificially sweetened beverages could still be going through a vascular pathway,” he said about the new study. “Many strokes are caused by hardening of arteries; and the risk of dementia is also increased by the hardening of arteries in large and small vessels. So, I believe the mechanisms may be through vascular disease, though we can’t prove it.”
Heather Snyder, senior director of medical and scientific operations at the Alzheimer’s Association, called the new study “a piece of a larger puzzle” when it comes to better understanding how your diet and behaviors impact your brain.
“It’s actually really more of your overall diet and overall lifestyle that is linked to cardiovascular disease and diabetes risk, and we do know that heart disease and diabetes are linked to an increased risk of dementia,” said Snyder, who was not involved in the new study.
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“We know that sugary and artificially sweetened beverages are not great for us. This study adds strength to that, and also says they may not be great for your brain, specifically,” she said. “There are alternatives — things we can all do everyday to keep our brains and our bodies as healthy as we can as we age.” Alternatives such as regular cardiovascular exercise that elevates heart rate and increases blood flow and doing puzzles and games to activate and challenge the mind. These are recommendations from the Alzheimer’s Associations list of 10 lifestyle habits to reduce risk of cognitive decline.
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Can Diet Sodas Actually Make You Gain Weight?

If you’re trying to lose weight, choosing diet soda over regular soda might seem like a good idea. You get a caffeine kick and a sweet, bubbly taste similar to the real deal, only without the sugar and calories. But while zero calories sounds a lot better than the 150 calories from a can of regular Coke, several studies have found that artificially sweetened sodas might actually lead to something you were trying to avoid: weight gain.

Although aspartame, sucralose, saccharin and other artificial sweeteners are FDA-approved, and the National Cancer Institute and other health agencies say they are generally safe in limited qualities, recent studies might make you think twice before drinking your next diet soda.

A study published in PLOS ONE in November 2016 tracked the body measurements and diets of 1454 participants (741 men, 713 women) in the U.S. over the course of 28 years, with a median followup of 10 years. The results showed that low-calorie sweetener users tend to have a higher average body mass index, a 2.6-centimeter larger waist circumference and a 53 percent higher incidence of abdominal obesity compared to participants who never reported using low-calorie sweetener.

Similarly, a 2008 study monitored the weights of 3,682 individuals for 7-8 years. After ruling out factors such as diet, exercise or diabetes status that might skew the data, the researchers determined that drinking artificially sweetened beverages (versus none) was associated with an almost doubled risk of being overweight or obese.

So why might diet soda cause weight gain? One reason is that even though artificial sweeteners are hundreds or even thousands of times sweeter than regular sugar, your brain is no fool.

“Some studies show that sugar and artificial sweeteners affect the brain in different ways,” writes Harvard’s School of Public Health.

Case in point: In a 2008 UC San Diego study, researchers scanned the brains of volunteers who sipped water sweetened with sugar as well as water sweetened with sucralose, the zero-calorie artificial sweetener you’ll find in Splenda. The resulting MRI scans showed that the brain can distinguish between the calories from the non-caloric sweetener, although the conscious mind could not. As the authors of the study suggested, sucralose “may not fully satisfy a desire for natural caloric sweet ingestion.” Thus, artificial sweeteners might cause you to crave or consume more sugary foods, which tend to have more calories.

One of the most convincing arguments is the psychological factor. When I posed the question, “Do you think diet soda causes weight gain?” to my Diet Coke-loving friend, she admitted that the word “diet” might make diet soda drinkers feel like they can have a treat later.

“The same can be said for exercise. It’s not that exercise does not burn calories. People reward themselves for exercising by overeating,” she said, adding that “diet foods in general can be less satisfying, which may cause cravings for more food.”

A 2010 study published in the Yale Journal of Biology and Medicine concluded that “artificial sweeteners, precisely because they are sweet, encourage sugar craving and sugar dependence.”

There are a number of other explanations for the diet soda/weight gain enigma, as Sharon Fowler, an adjunct assistant professor in the Department of Medicine at the University of Texas Health Science Center in San Antonio, explained to the Washington Post.

Besides thinking they have “extra permission [to eat],” soda drinkers might be altering our all-important gut bacteria, Flower noted. A 2014 study of mice found that sweeteners and/or the acid in diet soda may impact gut flora, which may lead to obesity and related ailments such as diabetes.

Of course, there is no definitive scientific proof that artificial sweeteners cause weight gain. I must note that aforementioned studies only show correlation, not causation. In fact, there are numerous diet soda studies that have conflicting results in which the beverage actually reduces the intake of calories and promotes weight loss or maintenance.

The American Beverage Association said in a statement to the Washington Post that “previous research, including human clinical trials, supports that diet beverages are an effective tool as part of an overall weight management plan. Numerous studies have repeatedly demonstrated the benefits of diet beverages—as well as low calorie sweeteners, which are in thousands of foods and beverages—in helping to reduce calorie intake.”

While we should be wary of the source—the American Beverage Association is in the business of promoting soda-drinking—James Hamblin, a senior editor at The Atlantic, also acknowledged this point in an article where he argued that “artificial sweeteners probably don’t cause weight gain, when used strategically.”

“The conclusion lands in support of artificial sweeteners in the right context, specifically when they are substituted for sugar,” Hamblin wrote, citing a 2014 American Journal of Clinical Nutrition meta-analysis. “People tend to see ‘modest weight loss,’ suggesting that low-calorie sweeteners (LCSs) indeed ‘may be a useful dietary tool to improve compliance with weight-loss or weight-maintenance plans.'”

Ultimately, the science is not settled. Nevertheless, sales of the most popular diet soda brands such as Diet Coke and Diet Pepsi have slumped year after year.

Consumers are increasingly wary of the purported health risks linked to the controversial sweetener aspartame as well as diet soda’s “unintended boomerang effect on appetite,” according to U.S. News. Consumers are switching to bottled water or healthier drinks such as tea and fruit or vegetable juices instead.

“There’s plenty of scientific evidence suggesting that artificial sweeteners are linked to weight gain, not weight loss,” said Gary Ruskin, co-director of U.S. Right to Know, a consumer group. “So how can Diet Coke and Diet Pepsi be advertised as ‘diet’ products?”

In 2015, U.S. Right to Know asked the Federal Trade Commission (FTC) and Food and Drug Administration (FDA) to investigate Coca-Cola and PepsiCo for falsely advertising “Diet Coke” and “Diet Pepsi” as “diet” drinks. The FTC and FDA declined to act on the requests.

So what should a diet soda aficionado do in the face of all this bad press?

The best alternative is to take matters into your own hands and DIY. Get one of those home soda makers that are all the rage (there are several good models on the market) or keep a few bottles of sparkling water in the fridge. Then add a splash of grape juice, a few drops of vanilla, a sprig of mint, or use a more exotic recipe, and you’ll have a glass of low-calorie bubbly goodness without any nasty chemicals, caramel coloring or artificial sweetener.