Anti-carb crusader Gary Taubes has an article in the NY Times magazine focusing on sugar as the cause of insulin resistance. This works as a bit of a response to Megan McArdle, who oversimplifies Taubes' position in her "Are Grains Making Us Fat?" post.
(To briefly recap Taubes' view - something, possibly sugar or excess carbs, provokes insulin resistance; once a person has developed insulin resistance, all refined and easily digestible carbohydrates will cause a problem. There is also a whole different set of arguments against grains, but Taubes is not making them.)
Back to the Times (Mr. Sulzberger, tear down this wall!):
Is Sugar Toxic?
By GARY TAUBES
On May 26, 2009, Robert Lustig gave a lecture called “Sugar: The Bitter Truth,” which was posted on YouTube the following July. Since then, it has been viewed well over 800,000 times, gaining new viewers at a rate of about 50,000 per month, fairly remarkable numbers for a 90-minute discussion of the nuances of fructose biochemistry and human physiology.
Lustig is a specialist on pediatric hormone disorders and the leading expert in childhood obesity at the University of California, San Francisco, School of Medicine, which is one of the best medical schools in the country. He published his first paper on childhood obesity a dozen years ago, and he has been treating patients and doing research on the disorder ever since.
The viral success of his lecture, though, has little to do with Lustig’s impressive credentials and far more with the persuasive case he makes that sugar is a “toxin” or a “poison,” terms he uses together 13 times through the course of the lecture, in addition to the five references to sugar as merely “evil.” And by “sugar,” Lustig means not only the white granulated stuff that we put in coffee and sprinkle on cereal — technically known as sucrose — but also high-fructose corn syrup, which has already become without Lustig’s help what he calls “the most demonized additive known to man.”
It doesn’t hurt Lustig’s cause that he is a compelling public speaker. His critics argue that what makes him compelling is his practice of taking suggestive evidence and insisting that it’s incontrovertible. Lustig certainly doesn’t dabble in shades of gray. Sugar is not just an empty calorie, he says; its effect on us is much more insidious. “It’s not about the calories,” he says. “It has nothing to do with the calories. It’s a poison by itself.”
If Lustig is right, then our excessive consumption of sugar is the primary reason that the numbers of obese and diabetic Americans have skyrocketed in the past 30 years. But his argument implies more than that. If Lustig is right, it would mean that sugar is also the likely dietary cause of several other chronic ailments widely considered to be diseases of Western lifestyles — heart disease, hypertension and many common cancers among them.
Before we highlight the cancer scare let's have a little history:
This correlation between sugar consumption and diabetes [over the last thirty years - TM] is what defense attorneys call circumstantial evidence. It’s more compelling than it otherwise might be, though, because the last time sugar consumption jumped markedly in this country, it was also associated with a diabetes epidemic.
In the early 20th century, many of the leading authorities on diabetes in North America and Europe (including Frederick Banting, who shared the 1923 Nobel Prize for the discovery of insulin) suspected that sugar causes diabetes based on the observation that the disease was rare in populations that didn’t consume refined sugar and widespread in those that did. In 1924, Haven Emerson, director of the institute of public health at Columbia University, reported that diabetes deaths in New York City had increased as much as 15-fold since the Civil War years, and that deaths increased as much as fourfold in some U.S. cities between 1900 and 1920 alone. This coincided, he noted, with an equally significant increase in sugar consumption — almost doubling from 1890 to the early 1920s — with the birth and subsequent growth of the candy and soft-drink industries.
And the cancer:
One more question still needs to be asked, and this is what my wife, who has had to live with my journalistic obsession on this subject, calls the Grinch-trying-to-steal-Christmas problem. What are the chances that sugar is actually worse than Lustig says it is?
One of the diseases that increases in incidence with obesity, diabetes and metabolic syndrome is cancer. This is why I said earlier that insulin resistance may be a fundamental underlying defect in many cancers, as it is in type 2 diabetes and heart disease. The connection between obesity, diabetes and cancer was first reported in 2004 in large population studies by researchers from the World Health Organization’s International Agency for Research on Cancer. It is not controversial. What it means is that you are more likely to get cancer if you’re obese or diabetic than if you’re not, and you’re more likely to get cancer if you have metabolic syndrome than if you don’t.
This goes along with two other observations that have led to the well-accepted idea that some large percentage of cancers are caused by our Western diets and lifestyles. This means they could actually be prevented if we could pinpoint exactly what the problem is and prevent or avoid that.
...
Now most researchers will agree that the link between Western diet or lifestyle and cancer manifests itself through this association with obesity, diabetes and metabolic syndrome — i.e., insulin resistance. This was the conclusion, for instance, of a 2007 report published by the World Cancer Research Fund and the American Institute for Cancer Research — “Food, Nutrition, Physical Activity and the Prevention of Cancer.”
So how does it work? Cancer researchers now consider that the problem with insulin resistance is that it leads us to secrete more insulin, and insulin (as well as a related hormone known as insulin-like growth factor) actually promotes tumor growth.
As it was explained to me by Craig Thompson, who has done much of this research and is now president of Memorial Sloan-Kettering Cancer Center in New York, the cells of many human cancers come to depend on insulin to provide the fuel (blood sugar) and materials they need to grow and multiply. Insulin and insulin-like growth factor (and related growth factors) also provide the signal, in effect, to do it. The more insulin, the better they do. Some cancers develop mutations that serve the purpose of increasing the influence of insulin on the cell; others take advantage of the elevated insulin levels that are common to metabolic syndrome, obesity and type 2 diabetes. Some do both. Thompson believes that many pre-cancerous cells would never acquire the mutations that turn them into malignant tumors if they weren’t being driven by insulin to take up more and more blood sugar and metabolize it.
What these researchers call elevated insulin (or insulin-like growth factor) signaling appears to be a necessary step in many human cancers, particularly cancers like breast and colon cancer. Lewis Cantley, director of the Cancer Center at Beth Israel Deaconess Medical Center at Harvard Medical School, says that up to 80 percent of all human cancers are driven by either mutations or environmental factors that work to enhance or mimic the effect of insulin on the incipient tumor cells. Cantley is now the leader of one of five scientific “dream teams,” financed by a national coalition called Stand Up to Cancer, to study, in the case of Cantley’s team, precisely this link between a specific insulin-signaling gene (known technically as PI3K) and tumor development in breast and other cancers common to women.
Most of the researchers studying this insulin/cancer link seem concerned primarily with finding a drug that might work to suppress insulin signaling in incipient cancer cells and so, they hope, inhibit or prevent their growth entirely. Many of the experts writing about the insulin/cancer link from a public health perspective — as in the 2007 report from the World Cancer Research Fund and the American Institute for Cancer Research — work from the assumption that chronically elevated insulin levels and insulin resistance are both caused by being fat or by getting fatter. They recommend, as the 2007 report did, that we should all work to be lean and more physically active, and that in turn will help us prevent cancer.
But some researchers will make the case, as Cantley and Thompson do, that if something other than just being fatter is causing insulin resistance to begin with, that’s quite likely the dietary cause of many cancers. If it’s sugar that causes insulin resistance, they say, then the conclusion is hard to avoid that sugar causes cancer — some cancers, at least — radical as this may seem and despite the fact that this suggestion has rarely if ever been voiced before publicly. For just this reason, neither of these men will eat sugar or high-fructose corn syrup, if they can avoid it.
“I have eliminated refined sugar from my diet and eat as little as I possibly can,” Thompson told me, “because I believe ultimately it’s something I can do to decrease my risk of cancer.” Cantley put it this way: “Sugar scares me.”
Obviously this is all preliminary and inconclusive, but still...
HOW INCONCLUSIVE? On April 4, 2011 a link between metabolic syndrome and liver cancer was reported. Another study showed a link between diabetes and the incidence of cancer:
SUNDAY, April 3 (HealthDay News) -- Diabetes is already linked to a number of complications, but emerging evidence suggests an increased risk of cancer can be added to that list.
A new study found that women with diabetes had an 8 percent increased risk of developing cancer generally, while men with diabetes had a 9 percent higher risk when rates of prostate cancer were excluded from the calculation.
The risk of dying from a cancer was also higher in people with diabetes -- 11 percent greater for women and 17 percent higher in men.
If it can be shown that excessive sugar consumption leads to metabolic syndrome and diabetes, then the sugar-cancer chain is forged.
ERRATA: Sugar in the American diet is estimated by the USDA here (p. 8 of 10). The USDA describes trends in the American diet from 1970 to 2005 in this report; added sugars rose by 19 percent and that excludes the surge in apple juice consumption (fruit consumption rose from 241 to 272 lbs per person per year, but apple juice contributed 16 lbs of that 31 lbs increase.)
BOLD PREDICTIONS: Within fifty years Coca Cola and the NFL will be the fodder of campfire stories meant to scare excitable pre-teens. It can't happen? Sixty years ago Frank and Dean were the Kings of Cool, smoking cigarettes live on national television; now they would get busted and the President of the United States is heckled in his own home for being a smoker.
If high school football were invented today, any school board listening to the injury rate and equipment expense would laugh out loud. It's days are numbered.
And Coke? Sales will be regulated as cigarettes are today, and sales to minors won't be legal. And someone somewhere will be charged with child abuse for giving a kid a Coke. Really.
EVERYTHING OLD IS NEW AGAIN: Here is Jack Lalanne decrying "sugarholics" back in the 50's (or 60's?).
THE GOOD NEWS: Although individuals can opt for a low carb diet, no President or Surgeon General could endorse a diet free of corn, wheat, rice and potatoes - how would America (or the world) feed itself? However, refined sugar and high fructose corn syrup are simply not essential to nutrition or subsistence.
REASONING BY ANALOGY: Most cigarette smokers don't get lung cancer; most drinkers don't become alcoholics. Would we conclude that neither tobacco nor alcohol have toxic potential?
The fact that some people consume a lot of sugar with no ill effect proves little.
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