Soda Isn't Only Low in Calcium


To the Editor:

The editorial by Fitzpatrick and Heaney(1) summarizes well the scientific evidence pertaining to the potential links between soft drink consumption and bone health among children and adolescents.

We were dismayed, however, by the lack of attention to the broader context presented by the issue of soft drink consumption among youth and its public health implications. There is much potential benefit to researchers across multiple disciplines from sharing interdisciplinary links between literature related to nutrition, obesity, and bone growth and development. Scientists from different disciplines should be encouraged to read and react to each other's literature in a more holistic way and thereby facilitate more well-rounded evaluation of the evidence and implications that bear on the issue of soft drink consumption and health.

From a perspective focusing only on bone health, the authors present an evidence-based argument that soft drinks present few risks for jeopardizing bone growth and development, particularly if consumed in the context of a diet that is adequate in calcium.

Their conclusion is that “the good news is that you can have soda and good bones, too, so long as you drink your milk … the solution lies not in ‘viewing with alarm’ consumption of things that taste good, but with encouraging and promoting higher dairy intake.” The conclusion of the editorial is of concern given the breadth and seriousness of the public health threat that obesity presents to our nation's youth.(2)

The broader perspective is more complex. The authors allude to the possibility that soft drink consumption may result in displacement of milk and other nutrient-rich beverages, contribute to excess energy or sugar intake, and perhaps contribute to the growing obesity epidemic. However, none of the literature that documents these associations is cited,(3–8) and the risks posed by soft drink consumption are minimized.

Soft drink consumption may have few negative risks for bone health and development. However, soft drink consumption among youth has been linked to higher energy intake, thus increasing the risk of excess weight gain and the development of obesity.(3) Prospective data show that one soft drink per day poses a 60% increase in risk of development of overweight over a 1-year period among youth.(8) Therefore, the authors' conclusion that soft drink consumption poses few health risks as long as milk is also consumed is not quite accurate.

Soft drink consumption, in addition to contributing to excess energy intake, also seems to be displacing milk as a beverage choice.(3,4) If excess energy intake is avoided by substituting soft drinks for more healthful beverages such as milk or fruit juice, nutritional quality decreases. The authors point out that fruit juice and milk have as much sugar and calories as soft drinks, but fail to note that soft drinks are “liquid candy” with no nutritional value, whereas milk and fruit juice provide a range of essential nutrients.(5–7)

Finally, soft drinks have been the target of public health efforts in part because of the alarming secular trends in intake, particularly among adolescents.(6,9,10) Soft drinks are heavily marketed, with a particular focus on teenagers, and these marketing campaigns include aggressive in-school efforts. Soft drink consumption has increased by 196% among adolescent boys in the past two decades from 7 to 22 oz/day.(6) Similar trends have occurred among adolescent girls.(6)

Soft drink consumption among children and adolescents is a complex issue. The narrow focus on bone health outcomes misses the serious public health implications that soft drink consumption poses for obesity risk among youth. A solid base of scientific literature links soft drink consumption with excess energy intake, lower milk and fruit juice intake, and increased risk of overweight. Soft drinks pose a risk for obesity, and their consumption should be limited.