Friday, November 02, 2007

Obesity and Cancer - Food and Cancer

Actually if you read the news articles about the Report claiming to "prove without a doubt" that obesity is a serious risk factor for cancer, which I understand has been making the headline news for many days, you might get the impression that it talks about obesity alone. But the report which is available at View/Download report actually only has one chapter on obesity although mini rants on obesity and cancer are woven into the report in several other places. And what I found while perusing the actual report is that the news claims about it, far exceed the real thing - the report talks about probabilities mostly and does not provide any new information (although they take hundreds of pages for their non informative report).

According the excellent analysis article on the Junk Food Science blog, these scientists somehow avoided including the largest and one of the most respected studies done on cancer risks called the "Women's Health Initiative". It seems, the blog continues, that they left out quite a few important studies, all of which did not agree with their desired premise i.e. that obesity causes cancer.

They do admit that they are guessing why fatness might raise the risk for cancer (and they also admit that fatness LOWERS the risk for pre menopausal breast cancer). Here is the excerpt:

There are several general mechanisms through which body
fatness and abdominal fatness could plausibly influence cancer risk. For example, increasing body fatness raises the
inflammatory response, increases circulating oestrogens, and
decreases insulin sensitivity. The physiological effects of obesity are described in more detail in Chapter 8. The effects of body fatness-related hormonal changes and inflammation on cancer processes are detailed in box 2.4
In searching for box 2.4, referenced throughout the paper, I found that their big theory is that fat is chronically inflamed due to the fact that fat tissue stores macrophages. But this is a connection which has not been proven to be bad and in fact, fat people tend to have LESS cancer and when they DO get cancer, they survive chemo better than slim people. (Gaesser, BIG FAT LIES, CA, 2002 for one). Also in the pig study, it was strongly suggested that the bodyfat in a pig helped NOT only protect against infectuous disease but ALSO against cancer - the opposite of what this new report is claiming (the pig study was one which did NOT make front page news of course).

Based on studies of pigs, researchers said, that fat helps fend off illness.
Besides keeping a body warmer, fat cells, or adipocytes, produce hormonelike proteins in reaction to invading toxins, behaving much like immune cells that fight disease.
"Adipocytes can be functional and beneficial without creating obesity," said Michael Spurlock, an animal sciences professor at Purdue University in West Lafayette, Ind.
Writing in the American Journal of Physiology, Spurlock and colleagues from the university's veterinary school said fat cells play a role in helping insulin regulate blood sugar levels and can aid the immune system's response to cancerous cells. (American Journal of Physiology, Jan 2004)

Stephen Milloy points out in his article debunking this study that:

scientists don’t really understand carcinogenesis very well. It’s known that the risk of cancer increases with age possibly because of the deterioration of DNA repair mechanisms and a few well-documented risk factors, such as family history of cancer, heavy smoking, and exposure to certain viruses and some exposures to radiation. Outside of those and perhaps a few other risk factors, the occurrence of cancer is largely inexplicable.
There are many of us who might have noticed that the groups which seem to get the most cancer are

1) slim people
2) dieters (i.e. I have known MANY people who lose a great deal of weight and THEN come down with cancer!)
3) smokers
4) for the female cancers - those on birth control medication (placed on the FDA list of cancer causing chemicals in 2004)

This report offers some insights on the whys and wherefores of cancer which may be, according to the American Cancer Society, as much as 85 percent LIFESTYLE related. And because of the erroneous information on obesity and the constant admonitions to "maintain a healthy weight" as determined by BMI, a scale invented in the mid 1800's which does not take bone mass, muscle or even gender into consideration and is, according to the CDC, suggesting weights which are "underweight" and thus not healthy for many people, I fear some of the good things the report has to say might be missed by all in the media's frenzied effort to sell us - yet another - diet.

Most cancer is preventable, the report tells us. Considering that in 1900 they reported 210 cases of cancer in the USA and even when I was a tot in the 1950's, cancer was a relatively rare disease, one does wonder about how much IS preventable. However the suggestions by the researchers seem over simplified and missing quite a few key factors which have been identified as carcinogenic in many other sources. Here's what they say:

Most cancer is preventable. The risk of cancers is
often influenced by inherited factors. Nevertheless,
it is generally agreed that the two main ways to
reduce the risk of cancer are achievable by most
well informed people, if they have the necessary
resources. These are not to smoke tobacco and to
avoid exposure to tobacco smoke; and to consume
healthy diets and be physically active, and to
maintain a healthy weight. Other factors, in
particular infectious agents, and also radiation,
industrial chemicals, and medication, affect the risk
of some cancers.
But making healthy food choices, a balanced diet containing fiber as well as a lot of veggies but low in saturated fat and avoiding transfat completely will likely reduce the risk of cancer as will as little as 20 minutes of walking, 4 or 5 times a week. However, the report's caution to avoid red meat again has no real foundation in science and in fact, red meat may have some micronutrients which are not found in other foods and even in other meats. Obviously if you eat nothing BUT red meat that may not be healthy but avoiding it altogether might be equally unhealthy. Red Meat is a good source of vitamin B12, the lack thereof which can cause neuropathy and more.

Also my bet is that the scientists totally ignored that some 94 worldwide studies suggested a strong link between the artificial sweetener, "aspartame" or "nutrasweet" and cancer especially leukemia and brain cancer!

As for maintaining a healthy weight, science STILL has not determined what IS a healthy weight for most people (but the CDC noted that people with BMIs in the overweight range seem to live longer than those in the "normal" (BMI 22-25) range.

In 2005, the CDC reassessed their data and found that 112,000 people (not 300,000 people) had died from obesity related diseases however, they also added that since people with BMIs in the overweight zone (BMI 25-29) live longer than those in the "normal ranges", one had to subtract 86,000 from the 112,000 and that leaves 26,000 people who die from obesity related disease... less than who die from gunshot accidents!

Report on CDC and healthy weights and obesity deaths

It should also be noted that for 95 percent of the public, maintaining a "healthy weight" (according to BMI) means yo yo dieting or weight cycling which has been STRONGLY suggested in many clinical studies to not only RAISE the risk for most illness but also raise the risk for heart disease as well.

I haven't heard the news stories (I don't listen to the news - because it's so filled with lies) but I would bet that they DON'T AT ALL, emphasize the suggestion in the report to exercise cardio 30 minutes daily, which is a very good idea for all of us regardless of weight.

My bets are that this study was supposed to be the "piƩce de resistance" - the study no one could argue with but since there are already two fine articles debunking the study's claims, perhaps it may fall short of its expectations and merely provide news headlines perhaps scaring a few fat people into Weight Loss Surgery.

Bottom line, this report provides nothing new, and a lot of wrong information about obesity AND cancer yet leaves out some of the most IMPORTANT information about carcinogens in the environment and in the foods we consume. In short it is just the usual rant against obesity cloaked in a different format and published for one reason alone... to sell diets and news papers. ho hum....

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