The most popular soft drinks today are pretty much empty calories. However, this statement may imply that soft drinks have no effect on our health, and put them in a better light than they deserve.
The "empty calories" part of soft drink means that it contains little or no vitamins, minerals, protein, fibre, or any other meaningful nutrient. Soft drinks do, however, contain simple sugars or sugar substitutes and food additives, which may contribute to a wide range of illnesses. A new study from Brigham and Women's Hospital in Boston suggests that drinking just two artificially sweetened soft drinks a day can increase the risk of kidney problems.
Researchers gave food questionnaires to 3,256 women of average age 67 who were already participants in the Nurses' health Study. The questionnaires asked about beverage intake, frequency (options ranged from twice a day to less than once a month), and whether the beverage was sweetened with sugar or artificial sweeteners. They then compared the results of the questionnaires to the kidney function of the women, discovering that women who drank two or more soft drinks a day had a 30% greater decline in kidney function. Interestingly, the results held true even after age, physical activity, high blood pressure and diabetes were taken into account.
Researcher Dr. Julie Lin, assistant professor of medicine at Harvard Medical School and a staff physician at Brigham and Women's Hospital in Boston, said, "Thirty percent is considered significant," especially considering baseline kidney functioning among participants at the start of the study was considered good. In addition to soft drink consumption, excess sodium consumption was also linked to a decline in kidney function, but no link was found with drinking less than 2 soft drinks per day or with drinking beverages sweetened with real sugar.
The researchers note that the study has some flaws, including the use of food intake questionnaires, which are notoriously inaccurate. Further research is necessary to confirm the findings based on actual soft drink intake. There is also the possibility that the link with kidney function decline might have resulted from long-term consumption rather than quantity per day, since many of the participants were older adults. However, since soft drinks generally do not provide any useful nutrition to our bodies, consuming them in minimal quantities is probably best.