Vaak voeding met hoge GI geeft
leverproblemen, ook bij kinderen.*
Uit een eerder Italiaanse studie leek het dat het regelmatig eten van voeding met een hoge
GI (glycemische index) (met de zgn. snelle suikers) het ontstaan van een “vette lever” sterk doet verhogen. Doch de conclusie kon niet getrokken worden omdat er wat misgegaan was met de controlefactoren. Een vette lever, die op termijn tot onherstelbare leverschade leidt, is nog te verklaren bij volwassenen die nogal veel drinken doch steeds meer en meer (Amerikaanse)jeugd vertoont dit ziektebeeld. In deze studie weliswaar met muizen werd duidelijk dat regelmatig voeding met een hoge GI het hele lichaam en de lever duidelijk vetter maakt. Zes maanden kreeg een groep muizen een dieet met hoge GI en een andere groep met een lage GI. Beide dieëten hadden evenveel calorieën, vet, eiwitten en koolhydraten. Na zes maanden hadden allle muizen ongeveer een zelfde gewicht. Echter de groep muizen met het dieet met lage GI waren slank en hadden normale hoeveelheden vet in hun lichaam. De groep muizen met het hoge GI dieet echter hadden in heel hun lichaam, bloed en lever wel twee keer zoveel vet. Op zich is dit niet vreemd want voeding met een hoge GI zorgt voor een extra aanmaak van insuline waardoor het lichaam vet aanmaakt en opslaat. Dat de lever extra vet wordt is ook logisch want de pancreas die de insuline aanmaakt geeft dit het eerste af aan de lever, waar de concentraties dan ook veel hoger kunnen zijn dan in de rest van het lichaam. Inmiddels hebben de onderzoekers een trial opgestart met kinderen van 8-17 jaar om te onderzoeken of voeding met een lage GI ook een vette lever kan herstellen. Normaal probeert men dat met een vetarm dieet doch met weinig resultaat.
Quick Burning Carbs May Cause Fatty Liver
Diets rich in rapidly digested carbohydrates not only expand waistlines, but may also cause fatty liver, a condition that can lead to liver failure and death, finds a new study in mice. If confirmed in humans, the findings suggest that fatty liver disease on the upsurge among Americans as a byproduct of the obesity epidemic may be preventable and possibly treatable through dietary changes. The study appears in the journal
Obesity.
The researchers, led by David Ludwig, MD, PhD, director of the Optimal Weight for Life program at Children's Hospital Boston, fed mice either a high or a low glycemic index diet. High glycemic index foods, including white bread, white rice, most prepared breakfast cereals and concentrated sugar, raise blood sugar quickly. Low glycemic index foods, like most vegetables, fruits, beans and unprocessed grains, raise blood sugar slowly.
On the high glycemic index diet, mice ate a type of cornstarch that is digested quickly whereas on the low glycemic index diet, mice ate a type of cornstarch that is digested slowly. The diets had equal amounts of total calories, fat, protein, and carbohydrate, and the mice were otherwise treated identically.
After six months, the mice weighed the same. However, mice on the low glycemic index diet were lean, with normal amounts of fat in throughout their bodies. Mice on the high glycemic index diet had twice the normal amount of fat in their bodies, blood and livers.
When sugar melts out of high glycemic index food, Ludwig explains, it drives up production of insulin, which tells the body to make and store fat. Nowhere is this message felt more strongly than in the liver, because the pancreas, which makes insulin, dumps the hormone directly into the liver, where concentrations can be many times higher than in the rest of the body. Fat buildup in the liver, or fatty liver, is usually symptomless, but it increases the risk for liver inflammation, which can progress to hepatitis and, in some cases, liver failure.
Fatty liver is becoming more common in Americans, especially in children, says Ludwig. Many cases in adults can be explained by alcoholism, but not the pediatric cases. Where just one case of fatty liver was reported in children in 1980, now between 1 in 4 and 1 in 2 overweight American children are estimated to have the condition. As these millions of children age, some will progress to full blown liver disease.
"This is a silent but dangerous epidemic," says Ludwig. "Just as type 2 diabetes exploded into our consciousness in the 1990s, so we think fatty liver will in the coming decade."
A previous study found that Italians who ate higher glycemic index diets had fattier livers, but the study wasn't tightly controlled. The new study makes clear that the type of carbohydrate can cause fatty liver in animals, independent of other elements of diet or lifestyle.
"Our experiment creates a very strong argument that a high glycemic index diet causes, and a low glycemic index diet prevents, fatty liver in humans," says Ludwig.
Ludwig and colleagues now hope to confirm this in a just launched clinical trial and to show that a low glycemic index diet can reverse fatty liver in overweight children. The children, aged 8 to 17, will be randomized to either the low glycemic diet or a low fat diet.
Low fat diets are currently the standard treatment, Ludwig says, but many children with fatty liver don't respond to them. "We think it is a misconception that the fat you're eating goes into the liver," he says.
Ludwig, author of Ending the Food Fight: Guide Your Child to a Healthy Weight in a Fast Food/Fake Food World (http://www.endingthefoodfight.com), hypothesizes that obesity, sedentary lifestyles and increased consumption of refined carbohydrates are "synergistically" fueling a fatty liver epidemic in children. Ironically, low-fat diets have only made matters worse, replacing fat with sugar or starchy foods that actually increase fat deposition in the body.
"Two low-fat Twinkies, billed as a health food, contain the same amount of sugar as an oral glucose tolerance test a test used to determine how much sugar someone can digest," Ludwig says. He notes that the French delicacy pate de fois gras the fatty liver of a duck or goose is produced by over-feeding the animals with high-glycemic index grains.
To enroll in the clinical trial, which is currently recruiting patients, subjects must be 8 to 17 years old, overweight, and have had an abnormal liver test or been told they might have fat in their liver.
Children's Hospital Boston is home to the world's largest research enterprise based at a pediatric medical center, where its discoveries have benefited both children and adults since 1869. More than 500 scientists, including eight members of the National Academy of Sciences, 11 members of the Institute of Medicine and 10 members of the Howard Hughes Medical Institute comprise Children's research community. Founded as a 20-bed hospital for children, Children's Hospital Boston today is a 377-bed comprehensive center for pediatric and adolescent health care grounded in the values of excellence in patient care and sensitivity to the complex needs and diversity of children and families. Children's also is the primary pediatric teaching affiliate of Harvard Medical School.
Children's Hospital Boston
21 Autumn St., 2nd Fl.
Boston, MA 02115
United States (Oktober 2007)
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