How sweet it is! The American diet
, that is. While the current recommendation is a maximum intake of eight teaspoons of sugars a day, one 12-ounce can of regular soda (or a 20-ounce bottle of VitaminWater) delivers eight or nine teaspoons. That means you are at or over the limit before you’ve eaten a single cookie or container of fruit-flavored yogurt, or even some commercial tomato soups or salad dressings with added sugars. The result is an average daily intake of more than 20 teaspoons of sweet calories
Although much fuss has been raised about high-fructose corn syrup, when it comes to calories and weight gain, it makes no difference if the sweetener was derived from corn, sugar cane, beets or fruit juice concentrate. All contain a combination of fructose and glucose and, gram for gram, supply the same number of calories. All contribute to the excessive caloric intake that has resulted in an epidemic of obesity
among Americans in the last 25 years.
Dr. George Bray, a specialist in obesity and metabolism at the Pennington Biomedical Research Center of Louisiana State University, has calculated that “the current epidemic of obesity could be explained by the consumption of an extra 20-ounce soft drink each day.”
Calories Without Nutrients
Among the most recent substances to take a turn as dietary villain is high-fructose corn syrup, a relatively cheap and reliable sweetener criticized, among other reasons, for being “artificial.”
But Michael Jacobson, director of the consumer advocacy group Center for Science in the Public Interest
, said in an interview that consumers should not think they are doing themselves a favor by turning to products with sugar instead.
“If the food industry got rid of all the high-fructose corn syrup and replaced it with sugar, we’d have the same problems we have now with obesity, diabetes
and heart disease,” he said. “It’s an urban myth that high-fructose corn syrup has a special toxicity.”
Neither ordinary sugar — sucrose — nor high-fructose corn syrup contains any nutrients other than sweet calories, and both are added in prodigious amounts to beverages and many foods that offer few if any nutrients to compensate for their caloric input.
“What consumers need to do is cut down on both,” Dr. Jacobson said. “Sugary foods either add calories or replace other, more nutritious foods.”
Food processors latched onto high-fructose corn syrup for several reasons. It is a more reliable and usually cheaper product, free of the price controls and trade fluctuations of sucrose. It is more stable in acid mediums like sodas and fruit drinks, and it prolongs the shelf life of more solid foods.
So why are so many people concerned about the sweetener derived from corn? From a health perspective, several reasons offered are frivolous.
Some consumers consider high-fructose corn syrup to be an “artificial” ingredient, whereas sugar is believed to be “natural.” They are equally artificial or natural depending on how you define the terms, since neither occurs in nature in the form they are used; both must be extracted from plant material.
Some consumers fear the genetically modified enzymes or corn used to produce high-fructose corn syrup. Yet enzymes do not become part of the product, genetically modified corn is not a health hazard, and, anyway, almost every food we consume has been genetically modified.
Similar to Sugar
Still, there are possible unresolved health concerns about high-fructose corn syrup that warrant further research. But before going into those, it is helpful to have a clear understanding of the product in question.
High-fructose corn syrup is made by converting the starch in corn to a substance that is about 90 percent fructose, a sugar that is sweeter than the sugar that fuels the body cells, called glucose, and processed differently by the body. The fructose from corn is then mixed with corn syrup, essentially pure glucose, to produce one of two mixtures called high-fructose corn syrup: 55 percent fructose and 45 percent glucose, which is used to sweeten soft drinks, and 42 percent fructose and 58 percent glucose, which is used in products like breads, jams and yogurt.
Neither substance is radically different from ordinary sugar, which is 50 percent fructose and 50 percent glucose. The main difference is that in high-fructose corn syrup, the two sugar molecules are chemically separated, and in sucrose they are linked. Whether this difference is meaningful to health is still debated.
Small Amounts Matter
Whether fructose comes from high-fructose corn syrup or sucrose, Dr. Barry M. Popkin said in an interview, it is “really not part of our natural diet. Fruit contains only tiny amounts of it. We’ve gone from a few grams of it a day to tablespoons of it.”
Dr. Popkin, a professor of global nutrition at the University of North Carolina
and the author of “The World Is Fat” (Avery, 2008), pointed out that it takes almost a pound of oranges to produce eight ounces of juice, which concentrates the sugars and strips away the appetite-satiating fiber and bulk of the fruit. “An eight-ounce glass of juice from oranges, apples or grapes has about five to eight teaspoons of sugar,” he said. “Calorically and nutritionally, it’s much better to eat the fruit.”
Dr. Bray does not consider fructose in the amounts now in the American diet to be benign. “There’s nothing to suggest it’s good for you,” he said. “As the amounts consumed increase, you begin to see effects that are not seen when it is consumed in much smaller amounts.”
Fructose, he explained, is metabolized primarily in the liver, which favors the formation of fats.
“It is not surprising that several studies have found changes in circulating lipids
when subjects eat high-fructose diets,” he wrote in an editorial in The American Journal of Clinical Nutrition
in 2007. A study by Elizabeth J. Parks and colleagues at the University of Minnesota
, for example, found that triglyceride levels rose when people consumed mixtures containing more fructose than glucose.
Another study, by nephrologists at the University of Florida
, found that fructose consumption raised blood levels of uric acid
, which can foster “metabolic syndrome,” a condition of insulin resistance and abdominal obesity associated with heart disease and diabetes.
And a study by Chi-Tang Ho, professor of food science at Rutgers University
, found “astonishingly high” levels of substances called reactive carbonyls in 11 carbonated soft drinks
. These molecules, which form when fructose and glucose are unbound, are believed to cause tissue damage. They are elevated in the blood of people with diabetes and linked to complications of the disease. Dr. Ho estimated that a can of soda has five times the concentration of reactive carbonyls found in the blood of an adult with diabetes.
To consumers unwilling to give up soft drinks, Dr. Bray, a slender man who follows his own advice, suggests choosing diet sodas sweetened with aspartame, which he said has none of the once-feared health effects.