Monthly Archives: April 2011

I firmly believe that sugar is toxic…and addictive.  Gary Taubes has done an amazing job with this article.   It is LONG, but well worth the read.  I have given you exerpts from it below.  To read the article in full click here.  I also suggest you watch Robert Lustig’s lecture.  To do so click here.

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IS SUGAR TOXIC?

By GARY TAUBES

April 13, 2011

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.

This brings us to the salient question: Can sugar possibly be as bad as Lustig says it is?

If I didn’t buy this argument myself, I wouldn’t be writing about it here. And I also have a disclaimer to acknowledge. I’ve spent much of the last decade doing journalistic research on diet and chronic disease — some of the more contrarian findings, on dietary fat, appeared in this magazine —– and I have come to conclusions similar to Lustig’s.

Lustig’s argument, however, is not about the consumption of empty calories — and biochemists have made the same case previously, though not so publicly. It is that sugar has unique characteristics, specifically in the way the human body metabolizes the fructose in it, that may make it singularly harmful, at least if consumed in sufficient quantities.

The phrase Lustig uses when he describes this concept is “isocaloric but not isometabolic.” This means we can eat 100 calories of glucose (from a potato or bread or other starch) or 100 calories of sugar (half glucose and half fructose), and they will be metabolized differently and have a different effect on the body. The calories are the same, but the metabolic consequences are quite different.

The fructose component of sugar and H.F.C.S. is metabolized primarily by the liver, while the glucose from sugar and starches is metabolized by every cell in the body. Consuming sugar (fructose and glucose) means more work for the liver than if you consumed the same number of calories of starch (glucose). And if you take that sugar in liquid form — soda or fruit juices — the fructose and glucose will hit the liver more quickly than if you consume them, say, in an apple (or several apples, to get what researchers would call the equivalent dose of sugar). The speed with which the liver has to do its work will also affect how it metabolizes the fructose and glucose.

In animals, or at least in laboratory rats and mice, it’s clear that if the fructose hits the liver in sufficient quantity and with sufficient speed, the liver will convert much of it to fat. This apparently induces a condition known as insulin resistance, which is now considered the fundamental problem in obesity, and the underlying defect in heart disease and in the type of diabetes, type 2, that is common to obese and overweight individuals. It might also be the underlying defect in many cancers.

If what happens in laboratory rodents also happens in humans, and if we are eating enough sugar to make it happen, then we are in trouble.

Th[e] correlation between sugar consumption and diabetes 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.

Emerson’s argument was countered by Elliott Joslin, a leading authority on diabetes, and Joslin won out. But his argument was fundamentally flawed. Simply put, it went like this: The Japanese eat lots of rice, and Japanese diabetics are few and far between; rice is mostly carbohydrate, which suggests that sugar, also a carbohydrate, does not cause diabetes. But sugar and rice are not identical merely because they’re both carbohydrates. Joslin could not know at the time that the fructose content of sugar affects how we metabolize it.

Joslin was also unaware that the Japanese ate little sugar. In the early 1960s, the Japanese were eating as little sugar as Americans were a century earlier, maybe less, which means that the Japanese experience could have been used to support the idea that sugar causes diabetes. Still, with Joslin arguing in edition after edition of his seminal textbook that sugar played no role in diabetes, it eventually took on the aura of undisputed truth.

Until Lustig came along, the last time an academic forcefully put forward the sugar-as-toxin thesis was in the 1970s, when John Yudkin, a leading authority on nutrition in the United Kingdom, published a polemic on sugar called “Sweet and Dangerous.” Through the 1960s Yudkin did a series of experiments feeding sugar and starch to rodents, chickens, rabbits, pigs and college students. He found that the sugar invariably raised blood levels of triglycerides (a technical term for fat), which was then, as now, considered a risk factor for heart disease. Sugar also raised insulin levels in Yudkin’s experiments, which linked sugar directly to type 2 diabetes. Few in the medical community took Yudkin’s ideas seriously, largely because he was also arguing that dietary fat and saturated fat were harmless. This set Yudkin’s sugar hypothesis directly against the growing acceptance of the idea, prominent to this day, that dietary fat was the cause of heart disease, a notion championed by the University of Minnesota nutritionist Ancel Keys.

A common assumption at the time was that if one hypothesis was right, then the other was most likely wrong. Either fat caused heart disease by raising cholesterol, or sugar did by raising triglycerides. “The theory that diets high in sugar are an important cause of atherosclerosis and heart disease does not have wide support among experts in the field, who say that fats and cholesterol are the more likely culprits,” as Jane E. Brody wrote in The Times in 1977.

At the time, many of the key observations cited to argue that dietary fat caused heart disease actually support the sugar theory as well. During the Korean War, pathologists doing autopsies on American soldiers killed in battle noticed that many had significant plaques in their arteries, even those who were still teenagers, while the Koreans killed in battle did not. The atherosclerotic plaques in the Americans were attributed to the fact that they ate high-fat diets and the Koreans ate low-fat. But the Americans were also eating high-sugar diets, while the Koreans, like the Japanese, were not.

Another question still needs to be asked…[W]hat 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.

One observation is that death rates from cancer, like those from diabetes, increased significantly in the second half of the 19th century and the early decades of the 20th. As with diabetes, this observation was accompanied by a vigorous debate about whether those increases could be explained solely by the aging of the population and the use of new diagnostic techniques or whether it was really the incidence of cancer itself that was increasing. “By the 1930s,” as a 1997 report by the World Cancer Research Fund International and the American Institute for Cancer Research explained, “it was apparent that age-adjusted death rates from cancer were rising in the U.S.A.,” which meant that the likelihood of any particular 60-year-old, for instance, dying from cancer was increasing, even if there were indeed more 60-years-olds with each passing year.

The second observation was that malignant cancer, like diabetes, was a relatively rare disease in populations that didn’t eat Western diets, and in some of these populations it appeared to be virtually nonexistent. In the 1950s, malignant cancer among the Inuit, for instance, was still deemed sufficiently rare that physicians working in northern Canada would publish case reports in medical journals when they did diagnose a case.

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.

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.”

Sugar scares me too, obviously. I’d like to eat it in moderation. I’d certainly like my two sons to be able to eat it in moderation, to not overconsume it, but I don’t actually know what that means, and I’ve been reporting on this subject and studying it for more than a decade. If sugar just makes us fatter, that’s one thing. We start gaining weight, we eat less of it. But we are also talking about things we can’t see — fatty liver, insulin resistance and all that follows. Officially I’m not supposed to worry because the evidence isn’t conclusive, but I do.

Gary Taubes (gataubes@gmail.com) is a Robert Wood Johnson Foundation independent investigator in health policy and the author of “Why We Get Fat.” Editor: Vera Titunik (v.titunik-MagGroup@nytimes.com).

Image courtesy health.howstuffworks.com