The world has a major drinking problem, and it is a killer.
The drink of choice is not alcohol, but sodas, fruit drinks, sport drinks, flavored waters, and other beverages loaded with sugar in any of its incarnations, according to investigators who spoke at a symposium sponsored by the International Atherosclerosis Society.
The human body has adapted through evolution to imbibing water, breast milk, and little else–certainly not Coke, Pepsi, Hawaiian Punch, or Gatorade. But our acquired taste for sugar-sweetened beverages and for sweeter food than what our primal ancestors could have imagined is in large measure responsible for expanding waistlines and rising rates of diabetes and cardiovascular disease, said Dr. Barry Popkin of the University of North Carolina at Chapel Hill.
“We’ve had, in the high-income world, two remarkable changes over the last 20-30 years,” Dr. Popkin said. “One is a shift away from water, low-sweetened coffees and teas, and a little bit of alcohol, to a diet dominated by caloric sweeteners in everything we consume, particularly beverages.”
Study findings suggest that when infants are exposed to sweet tastes, they will express a preference for sweet foods even years later. Yet there are virtually no long-term studies showing how such exposure to sweetness and sweet food affects caloric needs and subsequent eating patterns, Dr. Popkin said.
“In the quantities now consumed, fructose is probably harmful to a great many people in our populations,” said Dr. George Bray, who researches the metabolic effects of sugary beverages at Louisiana State University’s Pennington Biomedical Research Center in Baton Rouge.
Exposure to fructose has been shown to have detrimental effect on thermogenesis, lipids and metabolites, and blood pressure, said Dr. Bray, pointing to a 1993 study in which volunteers were monitored for metabolic changes following an oral load of glucose or fructose (Am. J. Clin. Nutr. 1993;58:766s- 770s). Fructose stimulated oxygen consumption more than did glucose, but had a smaller effect on insulin stimulation. Fructose also increased respiratory quotient more than did glucose, and there was a suggestion that fructose may increase de novo lipogenesis.
Short-term dietary studies have shown that compared with water or glucose, fructose is associated with weight gain, and increases in blood pressure, plasma inflammatory markers, lipid metabolism, insulin resistance, and visceral fat stores.
In a 10-week parallel-arm Danish study of 41 overweight men and women, one group received 813 kcal/d of sugar-containing beverages and the other received 240 kcal/d of artificially sweetened beverages. Patients on the sucrose-sweetened beverages gained about 1.5 kg (3.3 lbs) over the 10 weeks, while those who had aspartame-sweetened drinks lost almost the same amount (Am. J. Clin. Nutr. 2002;76:721) .
Patients in the sucrose group also had a mean 3.8/4.1 mm Hg increase in blood pressure. However, in the aspartame group, systolic BP declined by 3.1 mm Hg, and diastolic pressure declined by 1.2 mm Hg.
Volunteers who drank sugar-sweetened beverages have also been shown to have increases in the inflammatory markers haptoglobin, transferrin, and C-reactive protein, whereas aspartame-sweetened beverage drinkers had large declines in the same markers.
“Right now, sugar-sweetened beverages account for almost 10% of total calories in both child and adult diets in the U.S.,” according to Dr. Frank Hu of the Harvard School of Public Health in Boston.
‘If you look at a 12-ounce can of soda, it has about 120-150 calories, and has about 10 teaspoons of sugar … so drinking a can of soda is analogous to doing an oral glucose tolerance test.”
Data from large, decades-long cohort studies, including the Nurses’ Health Study, and the Health Professionals Follow-Up Study, show consistent, dose-related associations between sweetened beverage consumption and type 2 diabetes incidence, Dr. Hu said.
In a yet-to-be-published study, looking at prepregnancy consumption of sweetened beverages and the risk of gestational diabetes in more than 13,000 women in the Nurses’ Health Study cohort, soft-drink consumption was associated with about a 25% increase in risk of gestational diabetes during 8 years of follow-up.
Several countries are beginning to take steps to reduce the health effects from such high sugar consumption.
“Mexico will have the highest rate of diabetes in another 10-20 years,” Dr. Popkin said. He noted that the Mexican government has switched from whole milk to 1.5% milk, and will later shift to skim milk, in programs feeding more than 20 million citizens. In addition, Mexico’s schools are working to ban all sugar-sweetened beverages, provide safe drinking water, and allow the sale of water and low-fat milk.
The Mexican government also is considering taxing added sugars in beverages per gram, as well as fat content in milk, and has launched a national media campaign to alert citizens to the dangers of hidden fats and sugars.
Europe, France, and the United Kingdom are banning vending machines in schools, and are forbidding television advertising of sweetened drinks.
Within the U.S., Maine has instituted a soft-drink tax for the purposes of health promotion, and Massachusetts, New York, and other states are considering similar measures. Many states and metropolitan areas are also requiring calorie labeling on beverages sold in fast-food outlets, according to Dr. Popkin.
Dr. Popkin noted that while he applauds those efforts, there are still major steps that need to be taken. Macroeconomic options include removing food subsidies for substances, such as sugar and corn, used to create sweeteners, and the institution of excise or value-added taxes to cover all sugary beverages, he said.