People who eat lots of high glycemic index (GI) foods not only risk gaining weight, they also run a greater risk of developing a condition that can lead to liver failure and death, finds a new study in mice. The condition is known as non-alcoholic fatty liver disease (NAFLD).
GI refers to how rapidly a food causes blood sugar to rise.
High-GI foods, like white bread and potatoes, tend to spur a quick surge in blood sugar, while low-GI foods, such as lentils, soybeans, yogurt and many high-fibre grains, create a more gradual increase in blood sugar.
There are a number of mechanisms by which high GI diets might contribute to NAFLD, Dr David S. Ludwig of Children's Hospital Boston and colleagues note in the September issue of Obesity; such foods boost insulin secretion, which signals the liver to make fat from food energy and store it.
Ludwig and his team sought to investigate whether a high GI diet might affect the likelihood of developing NAFLD.
How the study was done
They did this by feeding two sets of mice a near-identical diet, with the only difference being that the carbohydrate in the chow of one group of animals was high GI, while in the other it was low GI.
After 25 weeks, the researchers found, the animals on the high GI diet weighed the same amount as those on the low GI diet, but they had twice as much body fat, twice as much fat in their blood, and more than twice as much fat around the liver.
NAFLD, which is now estimated to affect one in three obese children and two out of three obese adults, "is not a benign condition," Ludwig told Reuters Health.
"For reasons that are not fully clear it can progress to hepatitis, scarring of the liver, cirrhosis and liver failure. The scary thing is that this process can occur relatively silently so that by the time it comes to clinical attention, irreversible organ damage may already have occurred."
Ludwig and his colleagues are now launching a study to determine whether feeding children with NAFLD a low GI diet will prevent the condition from getting worse, or even reverse it.
The study is still accepting participants; for more information, click on "Deliver" at www.optimalweightforlife.com. – (Anne Harding, Reuters Health)