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The latest, and largest, study to raise concern over diet drinks, published this month in JAMA Internal Medicine, suggests that regularly consuming them may be more dangerous to your health than drinking sugar-laden soft drinks.Nednapa/iStockPhoto / Getty Images

It’s well-documented that an excess intake of sugar-sweetened beverages is unhealthy. Over the past 15 years, studies have linked a regular consumption of sugary drinks to an increased risk of weight gain, obesity, Type 2 diabetes, heart disease, non-alcoholic fatty liver disease and gout, a form of arthritis.

Sugar-sweetened beverages are thought to increase the risk of chronic disease by promoting obesity and elevating blood sugar levels, which may lead to insulin resistance and Type 2 diabetes. Abdominal obesity is also a major risk factor for chronic inflammation, a contributor to many chronic diseases.

Recent reports, though, have suggested diet soft drinks are also not without health consequences. Higher intakes of artificially sweetened soft drinks have been positively associated with heart attack, stroke, dementia and premature death.

The latest (and largest) study to raise concern over diet drinks suggests that regularly consuming them may be more dangerous to your health than drinking sugar-laden soft drinks.

Study details

Published this month in the journal JAMA Internal Medicine, the study tracked 451,743 men and women, with an average age of 51, from 10 European countries for 16 years.

Participants, enrolled between 1992 and 2000, were free of diabetes, heart disease, stroke and cancer at the onset. Each provided data on their diets, including soft-drink consumption, and other lifestyle factors.

The study found that people who drank two or more glasses of soft drinks a day – no matter how they were sweetened – experienced a 17 per cent higher risk of early death from all causes than those who consumed less than one glass a month. One glass of soft drink was equivalent to 250 millilitres, less than a regular-sized can (355 millilitres) of pop.

When sugar-sweetened and artificially sweetened soft drinks were looked at separately, the researchers found that people who consumed artificially sweetened beverages fared worse.

Drinking two or more glasses of diet drinks a day (versus less than one glass a month) was tied to a 26 per cent greater risk of early death. Consuming two glasses of sugary drinks each day heightened the risk by 8 per cent.

Only artificially sweetened soft drinks, and not sugar-sweetened, were associated with dying from coronary heart disease, whereas daily consumption of sugar-sweetened drinks was related to digestive disease deaths.

The study controlled for other risk factors associated with premature death including body weight, smoking, physical activity and alcohol intake.

It’s unclear why artificially sweetened beverages may be associated with a greater risk of early death. There are a few theories, however, based on preliminary research.

Experimental evidence conducted in animals and humans has shown that artificial sweeteners disrupt the composition of gut microbes (that is, the gut microbiota) in a direction that could lead to obesity, glucose intolerance, diabetes and, ultimately, cardiovascular disease.

Artificial sweeteners may also cause biological changes in the brain that influence satiety and weight gain.

The most recent study findings aren’t new. The U.S.-based Women’s Health Initiative Observational Study, published this year, found that, among 81,714 healthy women older than age 50, drinking two or more servings of artificially sweetened drinks a day increased the risk of heart attack, stroke and early death.

Even so, there are a few caveats.

Associations only

This study, as well as others examining the link between diet and sugary soft drinks and disease, is observational and cannot prove cause and effect. It’s possible the observed relationship is because of something else.

High soft-drink consumption may be a marker for an overall unhealthy diet. People may choose a diet drink, for example, to rationalize the extra calories in an unhealthy meal.

It’s also possible participants who drank diet pop at the outset of the study were already at greater health risk. They may have been overweight or had prediabetes, for example.

As well, soft-drink consumption was assessed only once, at the beginning of the 16-year study. It’s not known if participants changed their soft-drink preferences over the study period.

Bottom line

If you’re a daily consumer of artificially sweetened soft drinks (500 millilitres or more), view these latest findings as a yellow flag. Ditto if you regularly drink sugar-sweetened beverages.

While the occasional soft drink isn’t likely harmful, mounting evidence suggests these highly processed beverages, if consumed daily, should be limited.

Replace soft drinks with plain water, sparkling water or unsweetened tea. If you crave flavour, add a wedge of citrus fruit or splash of unsweetened fruit juice to water.

Leslie Beck, a Toronto-based private practice dietitian, is director of food and nutrition at Medcan.

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