Experts: Excess sugar consumption leads to a host of diseases

Pittsburgh Post-GazetteJune 9, 2014 

  • Types of sugar

    Sucrose: Common table sugar. It is a 50-50 combination of glucose and fructose. Sucrose quickly breaks down in the intestines into glucose and fructose, which head to the liver via the portal vein, where they undergo different biological processes.

    Glucose: A slightly sweet form of sugar produced by the breakdown of starches and carbohydrates, including sugar, and used to energize cells with the help of insulin. Too much blood glucose can lead to insulin insensitivity, allowing glucose to build up in the blood. The result is metabolic syndrome that can progress to Type 2 diabetes.

    Fructose: A sugar found naturally in fruits. In this form it is not considered a health risk because levels are low; the fiber in fruit delays the rate of metabolism. It can become a problem, though, when consumed as added sugar.

    High Fructose Corn Syrup: A sugar chemically produced from corn starch. This form of fructose is cheaper than sucrose, with the added appeal of providing food texture and serving as a preservative. For these reasons, it is used in a large variety of processed foods, particularly a type used in soft drinks that is a 55-45 combination of fructose to glucose.

Dr. Robert Lustig’s YouTube lectures about the dangers of sugar have raised a few eyebrows in recent years and even drawn some criticism.

But the pediatric endocrinologist’s proclamations are supported by research his team has done at the University of California, San Francisco, with steady confirmation from other scientific studies linking sugar with chronic disease and early death. Among his points are that sugar is poison and that it is unhealthy in any form.

Lustig’s latest YouTube video, “Fat Chance: Fructose 2.0,” has received more than 226,000 views. But his 2009 YouTube lecture, “Sugar: the Bitter Truth,” which details the biological consequences of high fructose corn syrup, is approaching 4.8 million views. He also has two books on the topic.

Sugar is listed in Nutrition Facts food labels by 56 names, including various malts and syrups.

Fructose is drawing attention with the increased use of high fructose corn syrup in foods, especially in soft drinks. Sucrose, or table sugar, is half fructose, which is metabolized in the liver, and half glucose, which is blood sugar that produces cellular energy to muscles and organs.

In the liver, excess fructose is transformed into fat, which can be a factor in elevated cholesterol and arterial plaque.

Lustig says sugar is addictive, although not everyone agrees. Some researchers link high consumption rates to its overabundant availability in American culture and diet.

Links to disease

A recent study by Lustig’s team concludes that 25 percent of Type 2 diabetes is caused specifically by sugar consumption.

Studies also conclude that sugar consumption leads to fatty liver, high triglyceride and bad LDL cholesterol levels, plaque in blood vessels and insulin resistance leading to metabolic syndrome and diabetes.

In February, a study published in the journal JAMA Internal Medicine found “a significant relationship between added sugar consumption and increased risk for cardiovascular disease mortality.”

Those whose added sugar consumption was more than 10 percent but below 25 percent of total daily calories face a 30 percent higher risk of cardiovascular disease than those whose sugar consumption was less than 10 percent. The risk of cardiovascular disease nearly tripled for those whose diet consisted of 25 percent or more of added sugar.

The American Heart Association recommends fewer than 100 calories of sugar daily for women and 150 calories a day for men – about 5 percent or less of total daily calories.

New Nutrition Facts labels proposed by the U.S. Food and Drug Administration, expected to be in place in two years, would require companies to continue listing total sugar but also “added sugar” to help people differentiate between naturally occurring sugar in grains, nuts, fruits and vegetables from those added by the manufacturer to enhance taste, texture or shelf life.

Processed foods

High fructose corn syrup is used in numerous processed foods, including many soft drinks such as Coca-Cola and Pepsi.

Fructose in fruit isn’t considered a health risk because levels are so low, because the fruit fiber slows the rate of metabolism. Sucrose comprises equal amounts of glucose and fructose. Too much of it overwhelms the liver, which causes the liver to start turning some of the fructose into fat, said Kimber Stanhope, a University of California, Davis, nutritional biologist.

The process is compounded by America’s high consumption of foods full of fat and sugar.

While research likely will never provide absolute proof of sugar’s impact on human health, population studies reveal a close association between sugar consumption and metabolic disease. That raises red flags about its harm, much the way the health impacts of cigarette smoking were determined, Stanhope said.

Claims, counterclaims

In his latest video, Lustig noted that “old medicine” recognized infection as the main cause of disease with the vector being the various microbes – viruses, bacteria and fungi. Nowadays, he says, medicine must focus on chronic disease with the vector being “multinational corporations” if we place the blame on food manufacturing and marketing.

Because of the lack of direct evidence Stanhope referred to, food companies maintain there is no proof that consuming sugar causes a person to be more likely to get sick.

But Stanhope, who consumes sugar only on special occasions (about once a month) said evidence is more than sufficient to advise people against its consumption.

“I think the data we have are strong but not definitive,” she said. “People should be looking and listening and realizing that there are no risks associated with reducing sugar intake, but there may be risk in continuing to eat high amounts of sugar while waiting for more definitive scientific evidence. Parents should get their kids off sugar and they should get off sugar themselves.”

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