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There has been a slew of studies this week on the health effects of sugar-sweetened beverages and caffeinated-energy drinks, as these products become more of a concern to public-health officials. But the evidence is not always as clear-cut as you might think.
Global Death Toll
The big headline grabber came from a scientific meeting of the American Heart Association in New Orleans where researchers reported Tuesday that 180,000 deaths worldwide may be associated with the rampant consumption of sugary drinks.
The findings are based on an analysis of data from the 2010 Global Burden of Diseases Study. The researchers linked local consumption rates to chronic diseases. These beverages contribute to excess body weight, which in turn, increases the risk of developing diabetes, cardiovascular diseases and some cancers, noted Gitanjali Singh, a co-author of the study at the Harvard School of Public Health in Boston.
Over all, the drinks are associated with 133,000 diabetes deaths a year, 44,000 deaths from cardiovascular diseases and 6,000 cancer deaths, the researchers concluded.
One surprising finding was that people in low- and middle-income countries seem to consume far more of these beverages than their counterparts in some high-income countries. For instance, people living in Mexico – among the biggest sugary-drink consumers on a per-capita basis – had the highest death rate due to these beverages, with 318 deaths per million adults linked to sugar-sweetened beverages, said a statement released with the study.
By contrast, Japan – one of the countries with lowest per-capita consumption – had the lowest death rate associated with the consumption of sugary beverages, at about 10 deaths per million adults.
The beverage industry was quick to slag the study. It "is more about sensationalism than science," said a statement from the American Beverage Association. "The researchers make a huge leap when they take beverage intake calculations from around the globe and allege that those beverages are the cause of deaths."
The industry may have some valid criticisms about the methodology. It can be extremely difficult to determine the specific health effects of a single component of the diet. After all, a person who downs gallons of sugary beverages may also eat a lot of junk food or have a generally poor diet.
Despite the shortcomings of this particular study, health experts generally agree it's bad to overindulge. "Sugary drinks have no nutritional value other than the sugar that's added – if you want to call that value," said Kim Raine, a professor in the School of Public Health at University of Alberta.
In a separate study presented Thursday at the AHA meeting, researchers took aim at energy drinks.
They analyzed data from seven previously published studies to show how energy drinks may undermine cardiovascular health. Some of the work focused on the QT interval – a segment of the heart's rhythm on an electrocardiogram test. The results showed the QT interval was significantly lengthened in young people who had just consumed one to three cans of energy drinks.
When the QT interval is prolonged, it can cause serious irregular heartbeats contributing to heart attacks and sudden death, explained Sachin Shah, the lead author and assistant professor at the University of the Pacific in Stockton, Calif.
Other data showed energy drinks are associated with a hike in blood pressure. "Patients with high blood pressure or long QT syndrome should use caution and judgment before consuming an energy drink," Shah warned in a statement.
But it wasn't all bad news on the beverage front. In fact, in some cases, energy drinks may save lives, according to Australian researchers. They investigated long-distance truck drivers between 2008 and 2011 in New South Wales and Western Australia. The study compared 530 drivers who crashed their vehicle while on a long-distance trip with 517 drivers who had not had a crash in the previous 12 months.
The finding, published Tuesday on the website of the British Medical Journal, revealed that drivers who consumed caffeinated substances such as coffee or energy drinks to help them stay awake were 63 per cent less likely to crash than drivers who did not use caffeinated products.
The researchers concluded caffeinated substances "can significantly protect against crash risk." However, they cautioned the benefit is only short term. "Energy drinks and coffee certainly don't replace the need for sleep," said the study's lead author, Lisa Sharwood of the University of Sydney.
Indeed, one good study about energy drinks is unlikely to dampen demand for greater controls on the food and beverage industry.
Some of Canada's leading obesity experts have just published a paper in the Journal of Public Health Policy, urging the federal government to ban food and beverage ads targeting children.
"Canada has some of the highest rates of TV advertising of unhealthy food and beverages in world," said the lead author, Kim Raine of the University of Alberta.
"I think we need to put some controls on what kids are exposed to," she added. "There is a fair amount of evidence that shows marketing influences kids preferences, their requests and even their food consumption. And it has been associated with childhood obesity."