Yale Researchers Weigh the Science on Soft Drinks and Health

Yale University researchers have released results of a study showing clearly that soft drinks are associated with increased caloric intake, higher body weight, a decrease in calcium and other nutrients, and increased risk of Type II diabetes.

The report also noted that studies funded by the food industry were much less likely to show detrimental effects from soft drinks than studies that received no industry funding.

The article analyzed 88 previously published studies obtained through
databases such as MEDLINE, PsycINFO and Web of Science.

Soft drink consumption has dramatically increased in the U.S., from an average of 90 eight-ounce servings per person in 1942 to 600 servings in the year 2000. While many states consider legislation to limit soft drink availability in schools, public debate has centered on whether these beverages in themselves pose a significant public health risk.

 “It is alarming that industry-funded studies so consistently favor industry and that these reports muddy what are otherwise clear waters,” said Kelly D. Brownell, director of the Rudd Center for Food Policy and Obesity at Yale. “Studies funded by the food industry simply did not find the degree of negative health effects from soft drinks that independent scholars discovered.”

 “Individuals and communities need to understand,” he continued, “that not all research is created equal and that researchers must ask critical questions about conflict of interest. It is more evident than ever that soft drink reduction must be a priority and that the weak measures introduced by industry to curb soft drink sales in schools should not be considered adequate.”

Lenny Vartanian, Marlene Schwartz, and Brownell, authored the study appearing in the April issue of the American Journal of Public Health.

The team found in multiple studies that soft drinks were linked to a greater overall caloric intake, and that people did not appear to compensate for sugared beverages by reducing caloric consumption elsewhere. Some studies even associated soft drink consumption with increased caloric intake beyond the calories from the soft drinks themselves.

The team also found that funding source and study design had a strong impact on findings. Reports of longitudinal or experimental studies were more likely to show negative effects of soft drinks.

“Available data indicate a clear and consistent association between soft drink consumption and increased caloric intake,” the article concluded. “Given the multiple sources of calories in a typical diet, it is noteworthy that a single source of energy can have such a substantial impact on caloric intake. This finding alone suggests that it would be prudent to recommend population decreases in soft drink consumption.”

American Journal of Public Health 97: 1-10 (March 2007)