You’re probably familiar with at least some of the factors that affect your heart—blood pressure and cholesterol, for example. But how much do you know about the state of your liver?

It might sometimes be an afterthought, but your liver plays crucial roles—metabolizing fats, carbs, and protein, and helping to process medications and clear toxic substances such as ammonia from the body.

Additionally, chronic liver diseases—for which age is often a risk factor—are on the rise. And some of these illnesses are more likely to be fatal in older adults.

Here, how to keep your liver healthy and detect problems early, before they become serious:

A Litany of Liver Troubles

More than 100 types of liver disease have been identified, but three in particular are of increasing concern, according to the American Liver Foundation: hepatitis C, nonalcoholic fatty liver disease (NAFLD), and liver cancer.

Hepatitis C, a contagious viral infection, can lead to cirrhosis (liver deterioration and scarring), liver failure, and liver cancer if left untreated. The Centers for Disease Control and Prevention (CDC) esti­mates that up to 3.9 million Americans have the chronic form of the disease, which is curable with medication.

NAFLD, a condition in which excess fat builds up in the liver, is far more common, affecting up to 40 percent of Americans, according to the National Institute of Diabetes and Digestive and Kidney Diseases. A subset of that group has a type of NAFLD called nonalcoholic steato­hepatitis (NASH), where liver cells ­become damaged and inflamed, which can lead to scarring and cancer. Most people with NAFLD have no symptoms, though some experience fatigue and pain in the upper-right abdomen.

No drugs are ­approved for NAFLD or NASH; doctors recommend gradual weight loss—at least 7 percent of your body weight over a year—as a treatment for both. 

5 Ways to Keep Your Liver Healthy

Following a heart-healthy lifestyle—and beating back weight gain and obesity, risk factors for NAFLD and NASH—goes a long way. To protect your liver:

Eat a balanced diet. Fill up on whole grains, nuts, vegetables, lean protein, and healthy fats—and limit saturated fat, sugar, and sodium.

Exercise regularly. It helps you maintain a reasonable body mass index, which safeguards against NAFLD and NASH, says liver specialist Steven K. Herrine, M.D., professor of medicine at Thomas Jefferson University in Philadelphia.

Drink in moderation. Excessive alcohol use is the second most common cause of cirrhosis, after hepatitis C, and a risk factor for alcoholic hepatitis (liver inflam­ma­tion and cell destruction) and fatty liver, or steatosis. Not everyone who drinks to excess develops liver disease, but limiting drinks to one per day will reduce your risk of alcohol-­related liver disease.

Beware of supplements. Many medications can affect the liver. But increasingly it’s supplements (such as green tea ­extract) that can lead to acute and sometimes chronic liver problems.

Keep an eye on acetaminophen (Tylenol and generic) use. Though this is generally a safe drug, Consumer Reports' medical experts advise taking no more than 3,250 mg per day. 

When to Get Tested

By the time liver diseases are ­advanced, symptoms—such as jaundice, abdominal pain, swollen legs, weight loss, itchy skin, and vomiting—warrant a consult with your doctor. But with early liver damage, there are frequently no signs or symptoms. So when should you be tested?

The CDC recommends a blood test for hepatitis C for all adults born between 1945 and 1965; they’re six times more likely to be infected with the virus than any other age group is.

Testing for other liver problems is espe­cially important if you have risk factors for liver disease (such as diabetes and obesity). Whatever the results, making lifestyle changes and taking medications for cholesterol, blood sugar, and blood pressure, if necessary, can reverse the damage. It often makes sense to try such strategies before rushing to do imaging to confirm a diagnosis, says Herrine at Thomas Jefferson University.