As America's obesity crisis continues to worsen, a silent but potentially deadly epidemic is arising in its wake. Nonalcoholic fatty liver disease is fast becoming an important public health problem in the U.S.

Although the exact prevalence of the disease is unknown, data published by the American College of Gastroenterology suggest it may affect nearly three-quarters of obese adults in this country. While the condition was virtually unheard of in children before 1980, some experts speculate that fatty liver disease now affects as many as half of obese youngsters.

Nonalcoholic fatty liver disease includes a range of liver conditions, affecting individuals who consume little or no alcohol, a known liver toxin. The mildest type, commonly referred to as simple fatty liver, is characterized by an accumulation of excess fat within the liver.

A potentially more serious form of the disease, nonalcoholic steatohepatitis, is associated with inflammation of the liver and occasionally the formation of fibrous tissue. In some cases, this condition progresses to liver cancer or cirrhosis, marked by progressive, irreversible scarring of the liver.

Although nonalcoholic fatty liver disease isn't understood fully, research shows that in addition to obesity, diabetes and abnormal cholesterol levels are important risk factors. These conditions are present in the vast majority of individuals diagnosed with the disease.

Last year, the results of a study published in the medical journal Obesity revealed that diets rich in high glycemic index foods also may contribute to the problem. Researchers at Children's Hospital in Boston found that mice consuming high glycemic index diets had twice as much liver fat as those consuming low glycemic index diets.

High glycemic index foods are those that raise blood-sugar levels relatively quickly, such as sugar, white bread, white rice and many highly processed sweets and snack foods. Low glycemic index foods — including most vegetables, fruits, legumes and unprocessed grains — tend to elevate blood-sugar levels more slowly.

Studies on humans have produced similar findings. In an Italian study of 247 adults, researchers assessed the effects of dietary patterns on liver fat using ultrasound technology.

The results of the study, published in the American Journal of Clinical Nutrition, revealed that individuals consuming diets with the highest glycemic index were twice as likely to have high-grade fatty liver disease as those consuming diets with the lowest glycemic index.

Diagnosing fatty liver disease isn't always a simple matter, as the condition rarely produces any telltale signs or symptoms in the early stages. The disease often is detected when routine blood tests reveal elevated liver enzymes or when doctors discover slightly enlarged livers during physical examinations.

When symptoms of fatty liver disease do occur, they're usually vague, including fatigue or a dull ache in the upper-right abdomen. Individuals who develop cirrhosis may experience easy bruising and itching, as well as swelling of the hands and feet and yellowing of the skin and eyes.

The presence of abnormal findings may signify a need for additional testing, including a liver scan using ultrasound or CT technology. Performing a liver biopsy, which involves taking a small tissue sample with a needle, is currently the best way to diagnose fatty liver disease definitively.

While there is no standard medical treatment for the disease, changes in diet and activity levels are recommended, along with aggressive management of blood sugar, cholesterol levels and triglycerides. For overweight individuals, slimming down is a critical part of the treatment plan.

It's best to lose weight slowly and steadily, at a rate of just one to two pounds per week, because rapid weight loss can increase fat deposition in the liver and may make matters worse. It's also wise to avoid drinking alcohol and taking any medications that can be toxic to the liver.

Alternative therapies are under investigation. Research suggests that antioxidant supplements, including alpha-lipoic acid and vitamins E and C, may help protect liver cells from injury.

Milk thistle, a member of the daisy family, has been used as a liver tonic for centuries. Natural compounds in the herb help neutralize toxins and can reduce inflammation and scarring of the liver significantly.

Fortunately, most individuals with simple fatty liver disease will not develop a serious illness, but because the course of the disease is difficult to predict, prevention is key. Limiting processed foods, eating plenty of fruits, vegetables and whole grains, and maintaining a normal body weight are smart strategies to protect your liver and improve your overall health.

Rallie McAllister is a board-certified family physician, speaker and the author of several books, including "Healthy Lunchbox: The Working Mom's Guide to Keeping You and Your Kids Trim." Her website is www.rallieonhealth.com. To find out more about Rallie McAllister, M.D., and read features by other Creators Syndicate writers and cartoonists, visit the Creators Syndicate Web page at www.creators.com.

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