Higher Cancer Risk if You’re Fat

A collaborative meta-analysis of more than a quarter million cases of cancer around the globe finds clearer association between obesity and several types of cancer. The findings are reported in the latest issue of The Lancet.

Following on from findings reported by the World Cancer Research fund last year, the study reveals that risk is increased not only in common cancers such as breast, bowel and kidney, but also in less common cancers such as blood cancers (myeloma and leukaemia) and melanoma (a form of skin cancer). Dr. Andrew Renehan and colleagues from the University of Manchester and Christie Hospital, did a meta-analysis (a combined analysis of 221 previous studies), looking at over 250,000 cases of cancer, to determine the risk of cancer associated with a 5kg/m2 increase in body mass index (BMI). The researchers found in men, a 5kg/m2 increase in BMI raised the risk of oesophageal adenocarcinoma by 52%, thyroid cancer by 33%, and colon and kidney cancers each by 24%. In women, a BMI increase of 5kg/m2 increased the risk of endometrial (59%), gallbladder (59%), oesophageal adenocarcinoma (51%) and kidney (34%) cancers. They also noted weaker, but significant, positive associations between increased BMI and rectal cancer and malignant melanoma in men; postmenopausal breast, pancreatic, thyroid, and colon cancers in women; and leukaemia, multiple myeloma, and non-Hodgkin’s lymphoma in both sexes.

via Science Daily

Researchers from the National Institute of Environmental Medicine in Sweden added, “The number of deaths per year attributable to obesity is about 30000 in the UK and ten times that in the USA, where obesity has been estimated to have overtaken smoking in 2005 as the main preventable cause of illness and premature death.”

Last week we brought you news of the proposed law in Mississippi that would ban restaurants from serving obese people. As reported, the intent was to bring attention to the obesity epidemic rather than to truly pass legislation. As study after study comes out about the risks of obesity, we wonder if further public education is truly enough. It’s not that we take the Mississippi legislation seriously. What we mean is this: are we really dealing with a lack of education? Sometimes we scratch our heads about where the confusion comes in. Sure, we take issue with some of the nutritional “guidelines” offered by government agencies and certain organizations. But does anyone truly believe that a Big Mac is healthy? Do our children’s nutrition textbooks idealize pizza and ice cream? What’s really going on here?

Hmmm. No single, simple answer, we realize. Individuals operating more out of denial than lack of information? Doctors afraid (or tired) of dispensing tough love (not all doctors, we know)? The pharmaceutical industry and phony side of the supplement industry sending the message that a pill can replace individual effort? Political games that subsidize empty calories for WIC Programs and the farming of grains galore? School lunches that too often are bland, nutrient deficient fast food look-a-likes? Yes, we’re flying our curmudgeonly flag today. We see news like this, and actually give a you-know-what. But what now?

What do researchers responding to this study suggest? See for yourself. In their associated statement, the researchers at Sweden’s National Institute of Environmental Medicine offered the following advice:

Efforts will be needed to increase education on diet and physical activity, train health professionals, restrict advertisements of high-calorie and low-nutrient foods, limit access to unhealthy foods in schools and workplaces, levy taxes on sugary drinks and other foods high in calories, fat, or sugar, lower the prices of health foods, and promote physical activity in schools and workplaces. National cancer plans should include all these factors to reduce obesity, and thus decrease cancer incidence and increase survival.

via Science Daily

What do you think? Perspectives? Observations?

Joe 13 Flickr Photo (CC)

Further Reading:

The Biggest Myth About Cancer: That it Just “Happens”

Highlight Health: Top 6 Most Important Cancer Advances of 2007

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13 thoughts on “Higher Cancer Risk if You’re Fat”

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  1. I don’t really understand how obese people deal with statistics like this. I guess they’re of the “it can’t happen to me” mindset. Everyone knows someone who was obese and lived a very long time and they use some rationalization that this will be them. But the truth is that it probably won’t be them and furthermore that very overweight person had an unfulfilling life in many ways.

    The idea of a tax on junk foods is interesting. I’m not sure how I feel about it. But at first glance it sounds great and it could perhaps be used to subsidize cheaper healthier foods.

  2. Josh: “I don’t really understand how obese people deal with statistics like this.”

    Well, speaking as a former fat (though never quite obese) person, you try and try to lose weight and fail miserably until someone gives you good nutritional advice. If you’re lucky, that is.

    I mean, I sorta get what Mark is getting at when he says nobody really thinks a Big Mac or a pizza are health foods. But a lot of people DO think that whole wheat pasta with a low-fat sauce, or whole grain cereal with skim milk are health foods. I can tell you with great certainty that I failed to lose weight on a low-fat diet. Or rather, perhaps I might have succeeded in losing weight on a low-fat diet; I’ll never know because it was physiologically impossible to stick to. That’s not because I was weak willed, either; it’s because my body couldn’t handle the constant carb load. I got the shakes, the cold sweats, and terrible hunger pangs. I now know that those are symptoms of hypoglycemia, a reaction to the high serum insulin caused by excessive carbohydrate consumption, and a condition that is alleviated (temporarily) by the consuming more of the stuff that got you into the mess.

    I can’t think of a crueller thing for a society to do than to publish study after study that says that obesity is bad for our health, and then give obese people the very advice that is going to make them fatter and fatter. No wonder we have a fat acceptance movement!

  3. P.S. I read the recommendations of the study authors as, “If the message doesn’t have its intended effect, don’t question the message. Just shout louder.”

    Efforts will be needed to increase education on diet and physical activity, train health professionals, restrict advertisements of high-calorie and low-nutrient foods, limit access to unhealthy foods in schools and workplaces, levy taxes on sugary drinks and other foods high in calories, fat, or sugar, lower the prices of health foods, and promote physical activity in schools and workplaces.

  4. I think that the main problem *isn’t* that the public isn’t getting the message (they got the message, but it was the wrong message about how to achieve weight control), but that the experts *just don’t understand or want to truly interpret the scientific data*. Instead they substitute ideological bias and give advice for sloth and gluttony as if that’s all that counts.

    I didn’t fully understand that (but long suspected it) until I read Gary Taubes’ book, Good Calories, Bad Calories: Challenging the Conventional Wisdom on Diet, Weight Control and Disease. Taubes’ excellent review of the history of nutrition studies, physiology, and biochemistry lays it out well – the contemporary “science of nutrition and obesity” we are hammered with isn’t rigorous, isn’t even all that scientific, and even when well done and the data says something rather compelling (like it isn’t merely calories in, calories out or that driving insulin up with carbohydrates increases fat storage and inhibits the release of body fat for energy), the conclusion and subsequent advice is something else entirely – just a rehash of “excess fat storage is due to sloth and gluttony”. Now they’re just simplifying it into Eat Less, Move More, like we are slothful and gluttonous morons.

    So now we’re stuck with a couple generations of lousy “checkbook science” and “consensus science” ( a recipe for incorrect and biased conclusions) and no one seemed to notice that it wasn’t even “hard” science until recently. The ones who noticed were marginalized, silenced, and ignored. The low fat message has stuck like glue, nearly everyone is hooked on processed cheap convenience foods, and the parade of highly indoctrinated experts still harangues us on sloth and gluttony, but now they’re also hitting us with diseases of sloth and gluttony, that they helped inflate.

  5. Thanks for the post. I think it’s important to point out that the higher cancer risk with obesity is an association. Causality hasn’t been established.

    If I were Gary Taubes, I’d say that the cancer and the obesity are probably both promoted by the same thing- excess insulin and blood glucose due to overconsumption of refined carbs.

    If I were me, I’d agree with Gary Taubes.

  6. obesity is THE most obvious form of “metabolic syndrome” and – following Taubes – the key elements in obesity are the effects of high carbohydrates on insulin.
    Also, high blood glucose causes a cascade of ill effects – including destruction of white blood cells – reducing immunity – more stress on the liver (fatty liver disease) greater reactive chemical processes (advance glycation end products) etc etc.

    all these components, plus the replacement of animal fats with omega 6 vegetable oils, with their proven immunosuppressive characteristics, puts the body under great oxidative stress and compromises its first lines of defence – all leading to cancer promotion of all types.

  7. It’s not just education, but the ingrained nature of the misinformation. Trying to explain why low-carb is better than low-fat and that fat in the diet really has nothing to do with fats in the blood is like poking myself in the eye with a sharp object. It is part education – but it’s got to be a reversal of what has been taught for so many years. That’s not what the government is talking about – they still include low-fat, more complex carbs in the message. The other commenters on this topic are right on.

  8. And the fat misinformation isn’t just about cancer, either. Last night I turned on the TV to a locally produced program on the local PBS station, focused on the burgeoning Alzheimers rates and the future impact on the state of CA. I knew it was locally produced because I recognized the lab interiors at the institute where my husband works, and one of his colleagues was interviewed.

    But I wanted to scream at the TV when the narrator began to talk about prevention of Alzheimers and recommended a low fat, low saturated fat diet! Anti-oxidents were also mentioned, with a still life of wine and grapes shown (the case for anti-oxidents isn’t a slam-dunk either, but you wouldn’t know it from the media). Those two things were all that were offered for prevention suggestions. The rest of the story about on-going research was about dicovering drug treatment (which, while proving very difficult, will be a financial boon to the lucky drug companies that come up with something with even a minimal level of efficacy.

    The brain is at least 60% fat and my “library” research (I’m not the scientist in the family) indicates that high insulin (due to high CHO intake) is at least part of the mystery of Alzheimers origins, not saturated fat, cholesterol, or even total fat (except perhaps, lack of it for stuctural use). Most of what I have been coming across says that for the elderly, low cholesterol levels are associated with increased risk of dementia, too.

    It has gotten to the point where I don’t even bother reading the weekly “health” section of the newspaper anymore because the info in it is so out of context, incomplete, useless and misleading, and too often, downright wrong and extremely biased (especially against saturated fat). And while the internet has its own pitfalls, it is still the best way to navigate through all the baloney to explore health issues and info.