A couple of years ago, we examined the case being made by a prominent obesity researcher — Dr. Robert Lustig of the University of California, San Francisco — that sugar has toxic effects in the body that can lead to obesity, diabetes, and other ailments associated with the metabolic syndrome. We noted at the time, however, that no large-scale study had been conducted to examine the effects of sugar consumption, and that performing a randomized controlled trial with varying amounts of sugar in the diet would be very difficult.
As it turns out, Lustig was as hungry as anyone for new data on this subject. Last week, he was one of the authors of a study published in the journal PLOS ONE that examined the correlation between sugar availability and rates of Type 2 diabetes worldwide. According to an article in the Los Angeles Times, the researchers used data from the United Nations’ Food and Agricultural Organization on sugar availability worldwide, since this information is more closely tracked than direct sugar consumption. They also looked at rates of Type 2 diabetes over time in 175 different countries, as well as components of the diet in these countries other than sugar. By comparing these sets of data, they found that in countries where rates of diabetes had gone up, sugar consumption had gone up slightly earlier and in about the same proportion as the increase in diabetes.
Using statistical methods, the researchers calculated that a daily 150-calorie increase in the availability of sugar is associated with a 1.1% increase in the incidence of Type 2 diabetes. This association was seen after controlling for other factors such as overweight and obesity, total calories consumed, aging within populations, and levels of income and urbanization. Out of all the dietary components that were examined — including meat, fiber, fruit, oil, and grain consumption — only the availability of sugar was found to be associated with the rate of diabetes within countries.
Most of the medical and journalistic response to this study appeared to be positive, supporting its findings and the need to curb sugar intake. Dr. Walter Willett, a prominent nutritionist at the Harvard School of Public Health, noted in the Los Angeles Times article that the study probably underestimated the role of added sugars in the development of diabetes, since the data it used did not distinguish between naturally occurring sugar in fruits and more refined forms of sugar. And in his New York Times blog, Mark Bittman compared the study to ones that linked cigarettes to lung cancer in the 1960’s and asserted that the need for regulation is just as great in this case. The nutrition site GI News, however, takes issue with the study’s method of controlling for overweight and obesity, claiming that it fails to account for known differences in health risks among different racial groups. This means, the authors write, that any association between sugar and diabetes might be dwarfed by a more accurate assessment of the relationship between obesity and diabetes, independent of sugar intake.
What’s your reaction to this study — do you suspect that sugar is uniquely involved in the development of diabetes, or are you skeptical of such claims? Do you think your own sugar consumption played a role in developing diabetes? If sugar does lead to diabetes, do you think this mean it should be more strictly regulated? Leave a comment below!