- 08-07-06, 04:04 PM #1
Drinking juice is no better than drinking soda
Drinking juice is no better than drinking soda
"People think juice is healthy, but it's not," says Dr. Robert H. Lustig, professor of pediatric endocrinology at UCSF and director of the Weight Assessment for Teen and Child Health (WATCH) Clinic. "Drinking juice — even if it says "100% natural" — is no better than drinking soda."
Lustig is on a mission to dispel common misunderstandings about juice. He says the perceptions that juice is good for you and that it's natural are not only incorrect, they're also contributing to today's childhood obesity epidemic.
"Juice and soda essentially contain the same carbohydrates, so the body reacts to them the same way," Lustig explains. "Juice contains fructose, glucose and sucrose, while soda contains high-fructose corn syrup, which is 55 percent fructose and 45 percent glucose."
He adds that juice is actually worse than soda because juice has a higher energy density or more calories per ounce. While most sodas have 150 calories in a 12-ounce serving, juices have about 170 calories for the same amount.
"People incorrectly think juice is natural and healthy simply because it's extracted from fruit. But there's nothing natural about extracting juice from fruit," says Lustig. "It's the fruit in its entirety that's good for you. The human body needs the fiber, which is what holds the fruit together. The fiber is the good part of the fruit and the juice is the bad part of the fruit. The juice is nature's way of getting you to eat your fiber."
What also makes juice so bad is that it's high in fructose. On the scale of sugars, fructose is the sweetest. It's followed by high-fructose corn syrup, sucrose or table sugar, glucose and lactose or milk sugar at the bottom of the list. In the United States, fructose ingestion has increased 30 percent in the last 10 years. Because fructose is so sweet, people tend to consume more of whatever it's in.
More harm than good
Fructose is harmful to the body in two ways, explains Lustig. First, it doesn't suppress ghrelin, which is the hunger hormone that's produced in the stomach. When the stomach is empty, ghrelin levels are high, which produces the sensation of hunger. After eating, as the stomach processes the food, ghrelin levels drop (over a half-hour period), producing the feeling of satiety.
However, fructose has no effect on suppressing ghrelin and, therefore, no effect on suppressing hunger. In other words, children can consume a 180-calorie fructose beverage and not have those calories affect this hunger hormone. These unacknowledged calories promote the excess weight gain.
Second, fructose harms the liver. Even though fructose is a carbohydrate in terms of its molecular structure, it acts like a fat when it's metabolized. Both fructose and fat go straight from the bloodstream into the liver, without being regulated the hormone insulin.
This is very different from glucose, which is regulated by insulin as it enters the liver. Insulin turns glucose into glycogen, which is the stored form of glucose and is not harmful. The body can store as much glycogen in the liver as it needs.
However, fructose is metabolized into a compound called acetyl-Co-A. Normally the body processes acetyl-Co-A and oxygen into carbon dioxide, water and energy in a process called the Krebs cycle.
However, the Krebs cycle is unable to process the high amounts of acetyl-Co-A made from fructose present in juices and sodas. The excess acetyl-Co-A can damage the body in several ways.
First, excess acetyl-Co-A can produce a compound that is toxic to beta cells in the pancreas. Some people think this may be what triggers type 2 diabetes. In addition, acetyl-Co-A also is converted to form free fatty acids, which enter the bloodstream and promote atherosclerosis (cholesterol deposits in the arteries). The free fatty acids, can also build up in the liver and cause liver disease similar to what is seen in long-term alcoholism.
"Acetyl-Co-A damages the liver the same way alcohol does," says Lustig. Fructose causes a condition known as nonalcoholic fatty liver disease (NAFLD). This condition, in which fat accumulates in the liver causing inflammation, results in cirrhosis.
"In my practice, I've had a 15-year-old boy who needed a liver transplant from drinking soda – his condition of NAFLD was that bad. I've also had a 6-year-old morbidly obese patient who drank a gallon of orange juice a day," says Lustig.
"The mother thought juice was healthy because she got if from WIC," he explains. WIC stands for Women, Infants and Children, a government entitlement program, which was set up to prevent failure to thrive. Although WIC has now put limitations on the amount of juice it gives families, it not only sends the incorrect message that juice is healthy, but it doesn't provide fresh fruit."
Lustig says this is one of many instances where public policy must change. "We need to educate people on the dangers of juice and soda just like we did with the tobacco industry."
"We also need to get juice and sodas out of the schools. Here in California, sodas are out of the schools, but juice and sports drinks are in instead. We're substituting one bad product for another. They're equally dangerous," explains Lustig.
Obviously, educating the public on the dangers of fructose-laden beverages needs to continue.
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