Sugar-Sweetened Beverages Linked to a Variety of Ills

Miriam E Tucker

October 01, 2015

High-fructose corn syrup has received a lot of bad press in recent years — and deservedly so — but it's only one of the components of sugary drinks that contribute to human ill health, according to data from a new literature review focusing on sugar-sweetened beverages.

The paper was published online September 28, 2015 in the Journal of the American College of Cardiology by Vasanti S Malik, ScD, a research scientist, and Frank B Hu, MD, PhD, professor of nutrition and epidemiology, both at the Harvard TH Chan School of Public Health, Boston, Massachusetts.

"Because we rarely consume fructose in isolation, the major source of fructose in the diet comes from fructose-containing sugars, sucrose and high-fructose corn syrup, in sugar-sweetened beverages and foods. Intake of sugar-sweetened beverages has been consistently linked to increased risk of obesity, type 2 diabetes, and cardiovascular disease in various populations," write Drs Malik and Hu.

Indeed, the review reveals that consuming one or two servings a day of sugar-sweetened drinks raises the risk for type 2 diabetes by as much as 26%, coronary heart disease by 35%, and stroke by 16%. Weight gain, gout, and kidney disease have been linked to their consumption as well.

Drs Malik and Hu have published previously on this topic.

"The purpose of this review was to provide an update of the evidence linking intake of sugar-sweetened beverages to cardiometabolic risk, with an emphasis on the role of fructose," Dr Malik told Medscape Medical News.

However, a major conclusion from the review, she said, is that high-fructose corn syrup and sugar (sucrose) are not that different from one another. "Both contain approximately equal amounts of glucose and fructose. It is not possible to differentiate between the effects of glucose and fructose in epidemiologic studies, since they are consumed together in sugar-containing foods and beverages."

Sugar-Sweetened Beverages Linked to Gout as Well as Obesity, Diabetes, and Heart Disease

Sugar-sweetened beverages are currently the largest source of added sugar in the diet — accounting for about 50%. The World Health Organization and 2015 US Department of Agriculture Dietary Guidelines Advisory Committee recommend limiting intake of all added sugars to no more that 10% of total energy intake (equivalent to about 12 tsps of sugar). One 12-oz serving of soda contains about 10 to 12 tsps of sugar.

The new paper provides an analysis of data for potential replacements of sugared beverages: water is optimal, and unsweetened coffee or tea are acceptable, while fruit juices and artificially sweetened beverages are less ideal.

"The most important information to communicate to patients would be that [sugar-sweetened] beverages are linked to weight gain, diabetes, heart disease, and gout and that to reduce risk of these conditions and to promote health and overall well-being they should be replaced with healthier options," Dr Malik said.

On the other hand, fructose in whole foods such as fruit and vegetables "is not a problem," she noted, explaining that such fructose is absorbed more slowly due to the fiber content of whole fruits and vegetables, whereas fructose in beverages is absorbed rapidly.

Beverages containing added sugar contribute to weight gain because they do not promote satiety, leading to increased energy intake. And because of their high amounts of rapidly absorbable sugar, they induce rapid spikes in blood glucose and insulin levels.

Fructose in these beverages — from any sugar or high-fructose corn syrup — also promotes the accumulation of visceral adiposity, dyslipidemia, and ectopic-fat deposition due to increased hepatic de novo lipogenesis. Fructose also increases production of uric acid, which has been linked to gout and insulin resistance, the doctors say.

Kicking the Soda Habit: Do it Gradually

While noting that "ideally it would be great if physicians advised patients to never drink sugary soda," Dr Malik added, "This may not be realistic, so recommending that they be consumed in limitation or maybe once in a while would be reasonable."

While juices may be perceived as healthy because they contain some vitamins and other nutrients, they also contain similar amounts of sugar — albeit natural rather than added — and intake of juice has been associated with weight gain and diabetes in some studies. Thus, Dr Malik says, a maximum of 4 to 6 oz a day has been recommended.

Artificially sweetened beverages may be a reasonable alternative to sugar-sweetened beverages because they provide few to no calories. However, the authors point out, little is known about the long-term health consequences of consuming artificial sweeteners.

Some studies have linked diet sodas to weight gain, metabolic syndrome, and diabetes, but these findings may be a result of reverse causation — that is, people who already have these conditions or are prone to them may be more likely to drink "diet" drinks.

Yet other evidence suggests that the intense sweetness of artificial sweeteners may condition toward a greater preference for sweets and enhanced appetite.

"Although consumption of artificially sweetened beverages is preferable to [sugar-sweetened beverages] in the short term, further studies are needed to evaluate their long-term metabolic consequences," the doctors write.

In the meantime, Dr Malik advises that physicians can help patients kick the soda habit by recommending consuming diet drinks initially and then gradually replacing them with fruit-infused sparkling water, water, or unsweetened coffee or tea.

This research is supported by National Institutes of Health grants. Dr Hu has received honoraria from the Hass Avocado Board for participating in an academic symposium and research support from Metagenics and the California Walnut Commission. Dr Malik has reported that she has no financial relationships relevant to the contents of this paper to disclose.

J Am Coll Cardiol. Published online September 28, 2015.Abstract


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