Monday, June 1, 2009

Is obesity the next cancer?

I am reading a very thought-provoking book right now: The Secret History of the War on Cancer by Devra Davis. In this book Dr. Davis lays out a very detailed story of how much of the knowledge on cancer risks related to environmental factors, gathered as long ago as the 1930s, was suppressed in the US mostly due to diligent efforts of chemical and tobacco companies. In fact, today, the National Institutes of Health spends roughly $170 million on lung cancer research alone. Of incidental interest is the fact that despite being the most common cause of cancer deaths in the US, lung cancer's allocation was less than 1/4 of the revenue going to breast cancer in the same year ($726 million). The proportion of these numbers that goes to prevention research is very difficult to find. However, when one is familiar with the scientific literature in this field, it becomes self-evident that the vast majority of the developing interventions is in the treatment arena. And why is this? Well the answers are both complex and obvious -- I go back to my recent statement that health does not generate dollars, disease does, and for so many stakeholders in this instance.

But I did not really want to focus on cancer -- I do, however, recommend that you read Davis's book to learn more, if interested. I wanted to talk about obesity instead. I recently came upon this statement from the very reputable Cochrane Collaboration, an academic group that synthesizes the vast expanses of medical literature into manageable reports: "The current evidence suggests that many diet and exercise interventions to prevent obesity in children are not effective in preventing weight gain, but can be effective in promoting a healthy diet and increased physical activity levels." ( Really? Has human physiology changed that much over the last few decades that we are now refractory to the weight control effects of eating well and having sensible levels of activity? On the other hand, the same group tells us that bariatric surgery "results in greater weight loss than conventional treatment in moderate (body mass index greater than 30) as well as severe obesity. Reductions in comorbidities, such as diabetes and hypertension, also occur. Improvements in health-related quality of life occurred after two years, but effects at ten years are less clear. ( Hmm... interesting. So, diet and exercise do not work, while bariatric surgery does well at controlling obesity and its consequences. Sound familiar? 

Interestingly, research suggests that high fructose corn syrup, the generic sweetener du jour that children and adults guzzle by the pound daily in their sodas, juices, candy and cookies, is sweeter than regular sugar and thus more palatable to the human animal, resulting in higher amounts consumed. Could this be one of the causes of our obesity epidemic? Is bariatric surgery with its expense and risks really the most obvious (not to mention cost-effective) answer? Well, how about studies that link television watching among our children to unhealthy eating habits and lack of exercise, thus resulting in a climb of the BMI among the youngest members of our society? Bariatric surgery again?

So why, you ask, was the evidence for cancer-causing chemicals kept secret for decades, and how is it relevant to the obesity problem? As you can imagine, many chemical manufacturers would have had substantial economic losses had this evidence come to light sooner. Even today, because studies linking exposure to certain substances with development of cancer are epidemiologic in nature, and thus cannot prove causality beyond the shadow of a doubt, evidence is conveniently twisted and discarded by the clever legal structure created around this type of litigation: a strong suggestion of causality is not enough to inject caution into the use of these compounds. In a similar vein, we do not want to hear that it is the way we eat and live that has created the obscenely pervasive obesity epidemic. Why should we, when we have pills and surgery to combat it? After all, this approach does not take the profit away from the manufacturers of high fructose corn syrup (also benefitting from our tax dollars dumped as subsidies into growing corn monocultures), and in fact it creates a market for new instrumentation and procedures for the vast healthcare industry. Prevention? "That is not economically feasible." Let's cut the crap! Prevention takes political will, which we do not seem to have at the moment, as we are all too busy having our cake and eating it too, particularly since life is sweeter with high fructose corn syrup. 

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