Aerobic exercise can improve fatty liver disease, according to new research findings.

Michael Hunter MD

Aug 9, 2020·6 min read

Fatty liver (hepatic steatosis) is on the rise, with about 25 percent of the disease’s population. Diabetes, obesity, and other disorders marked by insulin resistance are associated with the condition. Fatty liver can progress to more severe liver disease.

If not managed, fatty liver can progress to more severe liver disease (and other medical problems) can occur. Today, we look at some basics before turning to a new study from Ireland that shows the value of exercise in improving it.

The liver is large and is the second biggest organ in our bodies. It helps process nutrients from what we eat and drink and removes toxins from the blood. Fatty liver occurs because of the accumulation of fat in the liver. While the liver typically has some fat, having too much can lead to medical problems.

Over time, excessive liver fat can lead to inflammation, which in turn can damage your liver. Resultant scarring can then lead to liver failure. If the fatty liver condition is the product of excessive alcohol consumption, it is alcoholic fatty liver disease. On the other hand, if the fatty liver is not due to too much alcohol, it is non-alcoholic fatty liver disease. This latter form affects upwards of 25 to 30 percent of people in the United States and Europe.

What causes fatty liver disease?

Risk factors for fatty liver include:

• Obesity. Inflammation associated with excessive weight can enhance the storage of fat in the liver.
• Waist fat. Excessive fat around the belly (even if you have a healthy weight) can raise the risk of fatty liver.
• Insulin resistance. Insulin resistance and high insulin levels lead to more fat storage in the liver when there is type 2 diabetes or metabolic syndrome.
• Diet. Excessive refined carbohydrates can promote fat storage in the liver, especially if you are overweight or have insulin resistance.
• Sugary beverages. Sugar-sweetened drinks such as like soda and energy drinks are high in fructose. This consumption can cause fat to accumulate in your liver.
• Gut functioning. An imbalance in gut bacteria or problems with gut barrier function (“leaky gut”) raises the risk of getting a fatty liver.
• Other. High cholesterol, pregnancy, polycystic ovary syndrome, a history of hepatitis C infection, and certain medications can increase risk. The last include tamoxifen, methotrexate, amiodarone, and valproic acid.

The good news? A non-alcoholic fatty liver is the first stage of liver disease. It often can be reversed, avoiding a more severe liver condition we call non-alcoholic steatohepatitis (NASH). It is challenging to know who will progress to this more concerning condition. For those who develop NASH, severe scarring (cirrhosis) that hurts liver function can occur. The chances of liver cancer increase, too.

What are the symptoms of fatty liver?

Selected symptoms may include:

• Generalized fatigue
• Slight discomfort in the right or center abdominal area
• Some have abnormal blood tests, including a rise in liver enzymes or insulin levels.

If fatty liver progresses to NASH, the following symptoms may develop:

• Loss of appetite
• Nausea and vomiting
• Moderate to severe abdominal pain
• Yellowing of eyes and skin

It is essential to regularly see your doctor for standard exams and blood tests to diagnose fatty liver at the early, reversible stage.

Physical activity can help.

Non-alcoholic fatty liver disease can raise our risk of heart disease, kidney disease, and diabetes. Fortunately, physical activity can reduce liver fat. This drop appears to be the case for endurance exercise, resistance training, or high-intensity interval training (HIIT) several times per week. This reduction can occur even in the absence of weight loss.

As an example, one study examined high-intensity interval training (HIIT). Researchers randomized 28 patients with type 2 diabetes (metformin and diet-controlled) to 12 weeks of HIIT or standard care.

This study is the first to show exercise results in improvements in heart structure and function and a considerable reduction in liver fat. The subjects who exercised had a remarkable 39 percent reduction in liver fat.

However, even lower-intensity exercise can result in drops in liver fat. An Italian study suggests that exercise intensity is not critical. Scientists report that people with diabetes who worked out twice weekly for a year had reductions in liver and abdominal fat. The improvement appeared similar, whether their exercise intensity was considered low-to-moderate or moderate-to-high.

Exercise improves the liver: Biopsy proof.

A new study from Trinity College Dublin provides another illustration of how fitness can improve fatty liver diseases. In this study, fitness appeared to be more important than did weight loss. Here are the findings:

Researchers reported the first study to show meaningful improvements in liver outcomes following an exercise-only intervention. The subjects did not experience significant weight loss. The scientists demonstrated this improvement by using liver biopsies. This study represents the first time liver biopsies have demonstrated an exercise benefit on the liver.

Improvements in the liver were associated with increases in fitness levels. Now the bad news: Subsequent follow-up showed no retention of the exercise-related benefits.

Here is the study author’s response: “The lack of sustainability of the benefits of exercise is concerning, and there is an urgent unmet need to enable patients to engage in exercise therapy in the community setting continually.”

Working out drops liver fat. The exercise type appears not to be critical. But, the benefits of exercise are short-lived if the physical activity is not consistent and sustained over time.

Action plan for fatty liver

Alas, we have no medications for the management of fatty liver disease. In this context, I leave you with lifestyle interventions that may help to reverse fatty liver disease. Your medical care team may suggest strategies such as:

• limiting alcohol consumption
• dietary changes (Watch out for trans fats, saturated fats, and refined carbohydrates. Consider a diet rich in plants — fruits, vegetables, legumes, and whole grains.)
• lose weight, as appropriate
• exercise (for example, at least 30 minutes, five days per week)

If you develop complications, your care team may suggest lifestyle change recommendations, medications, or even surgery. In the extreme case of liver failure, select patients may need a liver transplant.

I’m Dr. Michael Hunter. Thank you for joining me today.

Images of fatty liver courtesy of wikipedia: