The liver, being one of the largest internal organs of the human body, does several important processes. Aside from processing food nutrients and filtering blood, it is mainly responsible for eliminating toxins from the body.
While it is normal to have tiny amounts of fat in liver cells, a condition of excess fat buildup, roughly more than 5%, is becoming very common, especially in Western countries (1). Fatty liver is more commonly known as steatosis, and it now affects approximately 20-40% of the US population. Unfortunately, this condition often goes undiagnosed. It does not usually cause any symptoms and is often an accidental finding in imaging studies like an abdominal ultrasound, MRI, or CT scan, which is requested for another reason.
While drinking excessive amounts of alcohol may cause a fatty liver, in many cases, it does not play a role. The many faces of fatty liver disease will be discussed in detail below, including the causes, risk factors, complications, treatment options, and prevention. Read on to know more.
What Are the Different Types of Fatty Liver Disease and Which Matters the Most?
Basically, there are 2 main types of fatty liver disease, non-alcoholic and alcoholic.
Non-alcoholic fatty liver disease (NAFLD)
This occurs when fat accumulates in the liver of people with no history of heavy alcohol use. It includes the following subtypes:
- Simple Non-alcoholic Fatty Liver, a condition where no inflammation or other complications is accompanying the fat build-up.
- Non-alcoholic Steatohepatitis (NASH) occurs when fat accumulation is accompanied by liver inflammation. When left untreated, this may cause scarring, and in severe cases, it may progress to cirrhosis and liver failure.
- Acute Fatty Liver of Pregnancy (AFLP) is a rare but serious complication of conceiving. The exact cause remains unknown. It normally appears in the 3rd trimester and requires immediate delivery as it may cause dramatic clinical events with significant risks to healthy women and their babies. The liver will most likely return to normal after a few weeks of giving birth, but follow-up care is necessary.
Alcoholic fatty liver disease (AFLD)
As its name implies, this condition is related to alcohol drinking. Alcohol damages the liver, affecting its ability to break down fat. This may lead to fat accumulation and is considered to be the earliest stage of alcohol-related liver disease. Its subtypes include:
- Simple AFLD, a condition where there is no accompanying inflammation or other complications. It is just pure fat accumulation due to excessive alcohol intake.
- Alcoholic steatohepatitis (ASH) presents exactly the same as NASH. There is inflammation of the liver, along with fat accumulation. Complications are the same, too, which includes scarring, cirrhosis, and liver failure. However, the main difference is that ASH can be treated by avoiding alcohol.
Differentiating a simple fatty liver from steatohepatitis is important. Why? Most of the time, having a simple fatty liver will not cause sickness related to the liver while those with liver inflammation and injury to their liver cells are more prone to serious health conditions like scarring, cirrhosis, liver failure, and even cancer (2, 3).
Unfortunately, it requires a liver biopsy to distinguish these two, and it can be very costly. Experts are continuously finding non-invasive ways to identify who are at greater risks for fibrosis. Currently, some are trying biomarkers and scoring systems based on blood tests, as well as elastography, which uses soundwaves to assess the stiffness of the liver. But these techniques are still a work in progress.
What Are the Possible Causes of Fatty Liver?
Aside from alcohol, several factors may play a role in the development of fatty liver:
- Obesity. Low-grade inflammation among obese people may help promote liver fat storage. Evidence shows that approximately 30-90% of obese adults are diagnosed with NAFLD, and the number in kids is on the rise due to childhood obesity (1, 4, 5, 6).
- Excess Belly Fat. Fatty liver may also be present in normal-weight people, especially if they are viscerally obese, which means having too much fat in the waist area (7).
- Insulin Resistance. Elevated insulin levels and insulin resistance are known to increase fat liver storage in patients with type 2 DM and metabolic syndrome (8, 9).
- Too Many Refined Carbs. Frequent intake of refined carbs can promote liver fat storage, especially for patients who are overweight or have insulin resistance (10, 11).
- Sugary Drinks. Sweetened beverages, including soda and energy drinks, contain high amounts of fructose, which has been found to drive fat build-up in the liver of both kids and adults (12, 13).
- Compromised Gut Health. Studies found that having problems with gut barrier function or an imbalance in digestive bacteria can cause NAFLD (14, 15).
Other less common causes include:
- Rapid weight loss
- Infections like hepatitis C
- Medications such as methotrexate, tamoxifen, amiodarone, and valproic acid
A growing body of evidence shows that NAFLD develops as a result of a complex process that includes not only environmental insults but also genetic susceptibility. Severity and progression are also modulated by epigenetic factors like liver-specific DNA methylation changes and microRNAs that can greatly affect liver transcriptome (16).
Signs and Symptoms of Fatty Liver
In most cases, patients with fatty liver are asymptomatic. Some may feel tired or complain of discomfort due to pain in the upper right quadrant of the abdomen.
In severe cases, complications like liver scarring or fibrosis may occur and cause a life-threatening condition called cirrhosis. This condition often presents with the following signs and symptoms:
- Weight loss
- Decreased or loss of appetite
- Yellow skin and eyes
- Web-like clusters of blood vessels under the skin
- Abdominal pain and swelling
- Leg swelling
- Enlarged breast in men
Who Are At Greater Risk?
While drinking high amounts of alcohol increases your risk of developing fatty liver, you may also be at greater risk if you are:
- Hispanic or non-Hispanic whites
- Middle-aged or older
- Taking medications like corticosteroids and cancer drugs
You are also more likely to get a fatty liver if you have:
- Insulin resistance
- Type 2 DM
- Polycystic Ovary Syndrome (PCOS)
- Metabolic syndrome
- High cholesterol levels
- High triglyceride levels
- High blood sugar levels
- History of infections like hepatitis C
- Family history of fatty liver disease
- Exposure to some toxins
How Is Fatty Liver Diagnosed?
Because there are often no symptoms, as previously mentioned, it is never easy to identify fatty liver disease. Doctors normally see it as an accidental finding if you have abnormal results on liver function tests that were requested for other reasons. To confirm a diagnosis, doctors should dig deeper into their family and medical history. You will be asked about alcohol use to know whether the fat in your liver could be a sign of AFLD or NAFLD. Doctors will also ask about the medicines you are currently taking as some could cause NAFLD.
A comprehensive physical exam will also be performed to look for signs of jaundice. Blood tests, imaging studies, and sometimes, a biopsy is needed to confirm liver enlargement and fibrosis.
What Can You Do?
The good news is that the most effective treatment so far for a fatty liver disease does not involve the use of expensive drugs and medical procedures, but rather lifestyle changes! However, these are typically hard to achieve and maintain for most people. Listed below are some tips to help you treat or reverse fatty liver:
1. Lose Weight and Avoid Overeating
Weight loss is among the most effective ways to reverse fatty liver if you are overweight or obese. In fact, it has shown to promote loss of liver fat in patients with NAFLD, regardless of whether weight loss was achieved through dietary changes alone or in combination with exercise or surgery (17, 18, 19, 20, 21). Reducing calorie intake by 500 calories daily also led to an 8% loss of body weight and a significant decrease in the fatty liver score (18).
Physical activity can be an effective way to decrease liver fat. Studies have shown that endurance exercises and resistance training performed several times weekly can greatly decrease the amount of fat stored in your liver cells, regardless of whether you have lost weight or not (22, 23, 24). Obese patients with NAFLD who exercised for 30-60 minutes 5 times weekly for 4 weeks had a 10% decreased in liver fat, even if their weight remained stable (24).
HIIT has also been proven to be very helpful in decreasing liver fat. Patients with type 2 DM who performed HIIT for 12 weeks had an impressive 39% reduction in liver fat (25). What’s more, it appears that even low-intensity exercises can also help target liver fat. People with diabetes who worked out twice weekly for a year had similar reductions in both liver and abdominal fat, regardless of whether their routine intensity was low to moderate or high (26).
Choosing something you like doing and can stick with is your best exercise strategy!
3. Cut Back on Refined Carbs
While it may seem like the most logical way to reverse fatty liver is to cut back on dietary fat, experts say that the majority of liver fat comes from fatty acids, and approximately 26% is formed via de novo lipogenesis (DNL) (27).
During DNL, excess carbs are turned into fat. The rate at which DNL occurs increases with high intakes of fructose-rich foods and drinks (28). Evidence showed that consuming diets low in refined carbs like can help reverse NAFLD (11).
Combining the Mediterranean and very low-carb diets have shown very impressive results. One study showed that patients who did a Mediterranean ketogenic diet had experienced reductions in liver fat, and at least 3 participants have achieved complete resolution of fatty liver (29).
4. Take Foods and Drinks That Can Promote Loss of Liver Fat
One of the best ways to treat and reverse fatty liver disease is with diet. Listed below are some of the best foods and drinks you can include in your healthy liver diet:
- Coffee can help lower the number of abnormal liver enzymes, thus lowering your risk of liver damage (30, 31).
- Broccoli has helped prevent fat accumulation in mice (32). Eating more greens like Brussels sprouts, kale, and spinach can also promote weight loss.
- Tofu, which is soy protein, was found to help reduce fat buildup in the liver of rats (33).
- Fatty fish like salmon, sardines, trout, and tuna are high in omega-3 fatty acids. These can help improve liver fat levels and control inflammation (34, 35).
- Carbs from whole grains like oatmeal can boost your energy. Their high fiber content also fills you up, which can help in maintaining your ideal weight.
- Walnuts are also rich in omega-3 fatty acids. Evidence showed that patients with fatty liver disease benefited from eating walnuts. Their liver function tests were improved significantly (36).
- Avocados contain healthy fats and chemicals that may delay liver damage (37). They are also rich in fiber, which can help with weight control and maintenance.
- Dairy products like milk are also rich in whey protein, which was effective in preventing liver damage in rats (38).
- Sunflower seeds are excellent sources of vitamin E, an antioxidant that can help protect the liver from further damage.
- Olive oil is rich in omega-3 fatty acids. It is a better choice for cooking as compared to butter, margarine, or shortening. Olive oil has shown to decrease liver enzymes and control weight (39).
- Garlic does not only add flavor to our food, but evidence also shows that it can help reduce body weight and fat in patients with fatty liver disease (40).
- Green tea can help interfere with fat absorption, though the results are not conclusive yet. Experts are still checking whether green tea can decrease fat storage in the liver and improve its function (41). Other benefits include lowering cholesterol and helping with sleep.
5. Take Supplements
Results from many studies suggest that certain herbs, vitamins, and other supplements can help reduce liver fat and decrease your risk of liver disease progression. However, in many cases, experts say that more research is needed for confirmation. Also, it is very important to speak with your doctor before taking any supplements, especially if you have other medications.
Milk Thistle or Silymarin
This is well known for its liver-protecting effects (42). Studies have shown that milk thistle alone or in combination with vitamin E can help reduce inflammation, insulin resistance, and liver damage in patients with NAFLD (43, 44, 45, 46).
Patients who took a silymarin-vitamin E supplement, along with a low-calorie diet had twice the reduction in liver size as compared to others who followed the same diet minus the supplement (46). The dosages used were 250–376 mg per day. However, more studies are still needed to confirm its effectiveness and safety for long-term use.
This plant compound has been proven to significantly decrease blood glucose, insulin, and cholesterol levels, as well as other health markers (47). One study involving more than 180 patients with NAFLD showed that taking 500 mg of berberine 3 times daily can give you an impressive 52% reduction in lover fat, not to mention the improvements in insulin sensitivity (48). But despite encouraging results, further studies are needed to confirm its effectiveness for NAFLD.
Omega-3 Fatty Acids
We all know that omega-3 fatty acids can be credited with several health benefits. Studies are consistently showing that taking omega-3s can help improve liver health in both kids and adults. In a study involving more than 50 overweight kids with NAFLD, results showed that those who took DHA had a 53% reduction in liver fat as compared to only 22% in the placebo group. They also lost more fat around the heart and the belly (49). Furthermore, in a study of 40 adults diagnosed with fatty liver, 50% of those who had fish oil along with dietary changes had reductions in liver fat, while 33% had a complete resolution (50).
The dosages of omega-3 fatty acids in these studies were 500-1000 mg per day in kids and 2-4 grams per day in adults.
Fatty liver can cause a myriad of health problems. Luckily, it can be reversed if addressed immediately and correctly. Following a healthy diet, performing regular exercises, and perhaps taking supplements can help reduce excess liver fat and decrease your risk of developing more serious complications.