The prevalence of NAFLD has doubled in the last two decades, likely due to rising obesity rates. NAFLD is more common in people who are obese or who have Type 2 diabetes.
Most people associate liver disease with alcohol abuse. However, alcohol is not a contributing factor for the most common form of liver disease in the developed world. Nonalcoholic fatty liver disease occurs when excess fat builds up in the liver. It affects nearly one in three U.S. adults, as well as about 10 percent of children aged 2 or older. NAFLD usually has no symptoms and causes no apparent damage — at first. But it can be a silent precursor to serious complications, including a severe form of hepatitis called NASH, cirrhosis and even liver cancer.
The prevalence of NAFLD has doubled in the last two decades, likely due to rising obesity rates. NAFLD is more common in people who are obese or who have Type 2 diabetes. Approximately half the people with diabetes and 90 percent of those with a BMI greater than 35 have some form of nonalcoholic fatty liver disease. NAFLD is closely associated with other cardiometabolic risk factors, such as elevated cholesterol or triglycerides levels, glucose intolerance, and sleep apnea.
The liver is a complex organ that helps metabolize the fat, carbs and proteins that we eat. But the liver can become overtaxed by excess dietary fat and calories. Eventually, this leads to fat buildup in the liver’s cells, the definition of nonalcoholic fatty liver disease. In most people, this buildup doesn’t cause any symptoms and doesn’t lead to serious liver damage. But in as many as 30 percent of people with NAFLD, this fat accumulation will progress to cause scarring, inflammation, fibrosis and eventually cirrhosis, which is severe scarring that can lead to liver failure. Progression of the disease is likely related to worsening of related risk factors, such as weight gain, increased insulin resistance, poor diabetes control, increased lipids and elevated blood pressure.
Heart disease is the top killer among people with NAFLD, especially among those with progressed disease. Research suggests that NAFLD may lead to heart disease by contributing to blood vessel problems, inflammation, oxidative stress, and worsening cholesterol and triglyceride levels.
Although there are often no symptoms of liver disease, some people do complain of fatigue, nausea, muscle or joint pain, pain in the upper right abdomen, swelling in the abdomen or legs, decreased appetite, or jaundice. Screening for NAFLD can be done with a blood test to measure liver enzymes. A diagnosis requires imaging the liver, typically by ultrasound. A biopsy is needed to learn the progression of the disease.
Treatment for NAFLD involves lifestyle changes. There are currently no FDA-approved medications for treating NAFLD. A weight reduction of just 5 to 10 percent can yield significant benefits for liver health. However, rapid weight loss of more than 3.5 pounds a week may accelerate disease progression. Aim to reduce calories by enough to promote a 1-to-2-pound-per-week weight loss.
Following a diet that is low in saturated fat and sugar will help prevent or treat NAFLD. The dietary focus should be on whole or minimally processed foods that are naturally high in nutrients and naturally low in fat, salt and sugar. This goes along with a heart-healthy diet, which is rich in fruits, vegetables, whole grains and beans, and low in sodium, saturated fat and sugar.
Just as regular exercise reduces the risk factors for cardiac events and diabetes, it also reduces the likelihood of NAFLD. Both cardiovascular exercise and strength training improve insulin resistance and NAFLD. The recommended amount of exercise is 150 minutes per week of moderate exercise plus resistance training two or more times weekly.
Anita Marlay, R.D., L.D., is a dietitian in the Cardiopulmonary Rehab department at Lake Regional Health System in Osage Beach.