When starchy diet damages liver

Carbohydrate foods that digest very quickly such as white bread and white rice are absorbed very quickly in the body. Excessive consumption of such foods however creates a build-up of fat overtime around the liver, slowly killing it, reports Sade Oguntola

Having a good breakfast is an indication that the day has started well. When a breakfast is rich in food items like potatoes, white bread, white rice and cornflakes, foods that are classified as “highly-glycemic”, they may be contributing to a dangerous liver condition that can lead to liver failure and death.

Fatty liver is exactly as it sounds - a build-up of fat deposits around the organ. Fat build-up in the liver, or fatty liver, is usually without symptoms but it increases the risk of liver inflammation, which can progress to hepatitis and, in some cases, liver failure.

Researchers, led by David Ludwig, director of the Optimal Weight for Life program at Children’s Hospital in Boston, fed some mice with both high and low glycemic index diet. High-glycemic index food, including white bread, white rice, cereals and concentrated sugar, raised blood sugar quickly, while low-glycemic index foods, like vegetables, fruits, beans and unprocessed grains, raised blood sugar slowly. Glycemic index is a measure of how quickly energy contained in the food is absorbed by the body, producing a rise in blood sugar levels. High GI foods lead to sharp rises in blood sugar level and similar rises in insulin level, as the body releases the chemical in response.

On the high-glycemic index diet, some mice ate a type of cornstarch that is digested quickly and on the low-glycemic index diet, another set of 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, the mice on the low-glycemic index diet were lean, with normal amounts of fat in their bodies. The mice on the high-glycemic index diet had twice the normal amount of fat in their bodies, blood and livers.

Dr David Ludwig, who led the research, said that because the processed carbohydrates are absorbed so quickly, they trigger the release of more of the chemical insulin, which tells the body to lay down more fat.

No where 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.

Dr Ludwig said that the results would also apply to humans, and even children, in whom fatty liver is becoming far more common. He described fatty liver as a silent but dangerous epidemic that obesity, sedentary lifestyles and increased consumption of refined carbohydrates is currently fueling in children.

Ludwig and his colleagues now hope to confirm this in a recently launched clinical trial and also to show that a low-glycemic index diet can reverse fatty liver in overweight children. A set of children, aged 8 to 17, will be randomized to either the low-glycemic diet or a low-fat diet.

A previous study found that Italians who ate higher glycemic index diets had livers that were fatter than normal, but the study wasn’t tightly controlled. The new study makes clear this type of carbohydrate that can cause fatty liver in animals, independent of other elements of diet or lifestyle.

Tam Fry, National Obesity Forum board member and chairman of the Child Growth Foundation, accepting that eating a diet rich in high-glycemic food led to increase in fat said, “fatty liver is going to be one of the tragedies of the future unless we do something about it.”

The British Dietetic Association spokesman and a dietician, Azmina Govindja, said that the biggest threat from a diet rich in high-glycemic food was development of insulin resistance - the first sign of type 2 diabetes. Govindja stressed that “there is a place for high-glycemic carbohydrates in moderation as part of a balanced diet, but there is good research that eating too much can increase the risk of insulin resistance - and this can lead to serious health problems.”

A nutritionist at the University College Hospital (UCH), Ibadan, Mr Tunde Ajobo, explained that no matter the amount and type of food taken, if it is not properly utilized, it is bound to take its toll on the body. When the excess carbohydrate intake gets converted to fat and lays down under the skin and on other organs such as the liver, it tends to affect the liver’s activities which include the storage of essential vitamins, detoxification of drugs and production of bile required for fat utilization.

According to him, a diet that is not highly glycemic should be the preferred choice because it allows for free flow of blood to the organ and ensures that the liver does not become jeopardized.

Rather than have foods that are classified high-glycemic, low GI foods that may help include unprocessed fruit, nuts, pulses and grains, including rye or granary bread, spaghetti, apples and oranges.

According to a group of researchers from Mexico, in the September issue of the Journal of Lipid Research, an American Society for Biochemistry and Molecular Biology journal, inclusion of soy protein is also good in alleviating fatty liver.

Fatty liver, a complication of high levels of insulin and insulin-resistance according to Dr. Nimbe Torres of the Instituto Nacionalde Ciencias Medicas Y. Nitrition in Mexico can be alleviated with a diet rich in soy. She found that the consumption of soy protein prevented the accumulation of fat and cholesterol in the liver despite the development of obesity and high levels of insulin-resistance in the rats.

“We also observed that the effects of soy protein were due to a low expression of genes involved in the synthesis of fatty acids and triglycerides in the liver,” explained Dr. Torres in the Journal of Lipid Research.