What exactly does the liver do? Approximately 500 different functions can be attributed to this vital organ. It helps to filter toxins and waste products from the blood, produces bile to aid digestion, stores energy in the form of glycogen, and plays a role in the metabolism of nutrients and ad infinitum. When the liver is healthy, it is able to perform these functions efficiently. When the liver is affected by a malady a wide range of problems appear. Unfortunately more and more people suffer from liver diseases.
Liver disease accounts for approximately 2 million deaths per year worldwide. The incidence of liver cancer alone accounts for about 700,000 deaths annually. But the biggest culprits of liver malfunction are alcohol and unhealthy diet that cause alcoholic fatty liver disease (AFLD) and non-alcoholic fatty liver disease (NAFLD). The number of people with NAFLD has drastically increased from 391.2 million in 1990 to 882.1 million in 2017. In the USA alone, nearly 250,000 deaths were attributed to ALD in 2010.
What is fatty liver disease?
Fatty liver disease is a condition in which there is an accumulation of excess fat in the liver. There are two main types of fatty liver disease: alcoholic fatty liver disease(ALD) and non-alcoholic fatty liver disease (NAFLD).
Alcoholic fatty liver disease (AFLD)
Heavy alcohol consumption can lead to alcoholic fatty liver disease, a condition in which the liver is damaged by the toxic substances produced during the breakdown of alcohol. The liver is responsible for removing alcohol from the body, but the process of doing so can create harmful byproducts that can harm liver cells, cause inflammation, and weaken the immune system. The more alcohol a person consumes, the more damage they can do to their liver. Alcoholic fatty liver disease is the first stage of alcohol-related liver damage, which can later progress to alcoholic hepatitis and cirrhosis if left untreated.
Non-alcoholic fatty liver disease (NAFLD)
NAFLD is a type of fatty liver disease that is not associated with heavy alcohol intake. There are two types:
Simple fatty liver is a form of NAFLD in which there is an accumulation of fat in the liver but little or no inflammation or damage to liver cells. Simple fatty liver is generally not severe enough to cause significant liver damage or complications.
Nonalcoholic steatohepatitis (NASH) is a form of NAFLD characterized by the presence of fat, inflammation, and damage to liver cells. The inflammation and liver cell damage associated with NASH can lead to scarring of the liver, and if left untreated, NASH can progress to cirrhosis or liver cancer.
Main risk factors of fatty liver disease
Obesity, defined as having a body mass index (BMI) of 30 or higher, can increase the risk of developing fatty liver disease in several ways. The excess fat can lead to the accumulation of fat in the liver, which is a key characteristic of fatty liver disease.
NAFLD is prevalent in obese individuals in the range of 50-90%.
Obesity can also increase the risk of developing other conditions that can increase the risk of fatty liver diseases, such as diabetes, high cholesterol, and high blood pressure. These conditions can disrupt the balance of fats in the liver and contribute to the build-up of triglycerides, a type of fat that can accumulate in the liver and contribute to the development of fatty liver disease.
Overconsumption of alcohol is a leading cause of alcoholic fatty liver disease but it may also contribute to non-alcoholic fatty liver disease. When the body breaks down alcohol, it produces toxic substances that can damage liver cells and promote inflammation. This damage and inflammation can lead to the accumulation of fat in the liver, which is a key characteristic of fatty liver disease.
In addition, alcohol consumption can disorder the balance of fats in the liver and lead to the build-up of triglycerides. The more alcohol a person drinks, the greater their risk of developing the condition.
It is estimated that approximately 90% of people who consume more than 40 grams of alcohol per day (equivalent to about two glasses of wine (175 ml each) or two pints of beer (473 ml each)) will develop alcohol-related fatty liver disease.
Saturated fats are a type of unhealthy fat that is typically found in animal products, such as meat and dairy products, as well as in some plant-based oils, such as coconut oil and palm oil.
When the body consumes a diet high in saturated fats, it can lead to the accumulation of fat in the liver and disruption of the balance of fats in the liver which contributes to the build-up of triglycerides.
In addition, a high-fat diet, especially one high in saturated fats, can lead to other lifestyle factors that increase the risk of fatty liver diseases, such as obesity and lack of physical activity. A diet high in saturated fats is also typically low in nutrients, which can lead to deficiencies in essential vitamins and minerals that are important for liver health.
The study found that a diet containing high levels of processed food, red meat, high-fat dairy, and refined grains increased the risk of NAFLD by 56%.
Diabetes can increase the risk of developing fatty liver disease in several ways. People with diabetes are more likely to be overweight or obese, which is a key risk factor for fatty liver disease. In addition, high blood sugar levels are common in people with diabetes and often causes fat accumulation in the liver.
It is estimated that 59.67% of type 2 diabetes patients have NAFLD.
People with diabetes are also at a higher risk of developing other conditions that can increase the risk of fatty liver diseases, such as high cholesterol and high blood pressure.
There are several ways in which physical inactivity may contribute to the development of fatty liver disease. One is through weight gain. People who are physically inactive tend to have a higher body mass index (BMI). Excess body fat, especially abdominal fat, can increase the risk of developing fatty liver disease.
Another way is by disrupting the normal balance of lipids (fats) in the body. Physical activity helps to promote the breakdown of fats in the body, which can help to prevent their accumulation in the liver. In contrast, physical inactivity may lead to an increase in the levels of fats in the liver, which can contribute to the development of fatty liver disease.
In a study of over 13,500 people, around 23% reported having a nonalcoholic fatty liver disease (NAFLD). The frequency of NAFLD varied based on how many hours per day the participants reported sitting. The group that reported sitting for the longest periods of time had the highest frequency of NAFLD (26.2%), while those who reported sitting for the shortest periods of time had the lowest frequency of NAFLD (20.2%).
People with metabolic syndrome, a group of conditions including high blood pressure, high blood sugar, and excess fat around the waist, are at an increased risk of developing fatty liver disease.
According to research from the Keck School of Medicine of USC, high levels of cholesterol can worsen fatty liver disease. High cholesterol can ruin the balance of fats in the liver and contribute to the build-up of triglycerides, a type of fat that can accumulate in the liver and contribute to the development of fatty liver disease. High cholesterol can also increase the risk of developing other conditions that can increase the risk of fatty liver diseases, such as obesity, high blood pressure, and diabetes. This specifically refers to LDL, also known as the ‘bad cholesterol’.
In men, the prevalence of fatty liver peaks between 40 and 50, while in women, it peaks between 60 and 69 years of age.
Males are more likely to have non-alcoholic fatty livers than females (22–42% in men versus 13–24% in women). The prevalence of non-alcoholic fatty liver is fully comparable between men (22–42%) and women (19–31%) in postmenopausal women, suggesting a protective role of estrogen.
What are the symptoms of fatty liver disease?
One of the major issues with both nonalcoholic fatty liver disease (NAFLD) and alcoholic fatty liver disease is that they often do not cause noticeable symptoms until they have progressed to a more advanced stage. This means that these diseases can often go undiagnosed until they have caused significant damage to the liver.
In the event that you do experience symptoms (that are usually subtle and may be attributed to other causes), they may include:
In the right upper abdomen, there is pain or a feeling of fullness
A feeling of nausea, loss of appetite, or weight loss
The skin and the whites of the eyes are yellowish
Legs and abdomen are swollen
A feeling of extreme fatigue or mental confusion
Five ways to prevent fatty liver disease
As the liver plays a central role in various body functions it is of utmost importance to keep it healthy. Unfortunately, there is no approved medical treatment of fatty liver disease. But this may serve as an additional motivation for taking good care of your liver. Protecting the liver can be achieved through lifestyle changes.
1Stay in a healthy weight range
Maintaining a healthy weight is an important way to prevent fatty liver disease, both alcoholic fatty liver disease (AFLD) and nonalcoholic fatty liver disease (NAFLD). Excess body weight, especially abdominal fat, is a major risk factor for both types of fatty liver disease. When you are overweight or obese, your liver can become overloaded with fat, leading to the accumulation of excess fat in the liver, which can lead to liver damage and inflammation.
The study found that people with a higher body mass index (BMI), which is a measure of body fat, had a significantly higher risk of developing fatty liver disease. Specifically, the risk of fatty liver disease was 3.55 times higher in the overweight population (BMI ranging from 25 to 30) and 7.59 times higher in the obese population (BMI 30 and higher) compared to the normal-weight population. This suggests that maintaining a healthy weight is an important factor in reducing the risk of fatty liver disease.
2Engage in regular physical activity
Exercising regularly is an important way to prevent fatty liver disease, both alcoholic fatty liver disease (AFLD) and nonalcoholic fatty liver disease (NAFLD). When you exercise, your body burns calories and reduces excess fat, which can help to prevent the accumulation of fat in the liver. In addition, regular physical activity can improve insulin sensitivity, which can help to prevent the development of NAFLD.
The good news is that both vigorous and moderate-intensity activities are equally linked to liver health improvements. The study found that vigorous exercise may be additionally effective at reducing weight, body fat, and blood pressure in people with nonalcoholic fatty liver disease. However, moderate exercise can also provide benefits for the prevention and treatment of NAFLD. It appears that most of the positive effects of exercise on NAFLD are due to weight loss.
The study showed that increasing physical activity by an additional 2,500 steps per day was associated with a significant 38% reduction in the risk of chronic liver disease and a 47% lower development risk of nonalcoholic fatty liver disease (NAFLD). In people with a previously diagnosed liver disease, those in the top quartile of physical activity had an 89% reduced risk of liver-related death and an 85% reduced risk of all-cause mortality compared to those in the bottom quartile. Additionally, walking an additional 2,500 steps per day was associated with a 44% reduction in the progression of liver disease. These findings suggest that increasing physical activity can have significant benefits for liver health.
3Eat a healthy diet rich in plants
A healthy diet for preventing fatty liver disease includes unprocessed, natural foods that are high in complex carbohydrates, fibre, and protein. These types of foods can provide sustained energy and help a person feel full, making it easier to maintain a healthy weight. This is a good place to start when trying to make changes to your diet to reduce the risk of fatty liver.
The Mediterranean diet is a particularly good dietary choice to reduce the very risk as it limits the intake of processed food, added sugar, and saturated fatty acids. The study showed that the Mediterranean diet decreased the risk of developing NAFL by 23% while the Western-type diet increased the very risk by 56%.
The following foods may be especially helpful for people with fatty liver disease:
Garlic may offer benefits for individuals with non-alcoholic fatty liver disease (NAFLD). A 2016 study published in Advanced Biomedical Research found that taking garlic powder supplements was associated with reduced body weight and body fat mass in people with NAFLD. These findings suggest that incorporating garlic into your diet may help improve liver health and reduce the risk of developing NAFLD.
Omega-3 fatty acids
People with non-alcoholic fatty liver disease may benefit from omega-3 fatty acids, according to a 2016 review. It has been shown that omega-3 fatty acids can reduce liver fat and raise high-density lipoprotein cholesterol (good cholesterol).
Foods that are high in omega-3s are salmon, sardines, walnuts, and flaxseed. Incorporating these types of foods into your diet may help support healthy liver function and reduce the risk of NAFLD.
A 2019 animal study found that decaffeinated coffee reduced liver damage and inflammation in mice that were fed a diet high in fat, fructose, and cholesterol. These findings suggest that drinking coffee may have potential benefits for people with NAFLD, although further research is needed to confirm these results in humans.
Including a variety of whole vegetables in your diet is beneficial for people with non-alcoholic fatty liver disease. Broccoli is a particularly good choice. A 2016 animal study found that the consumption of broccoli for a long period of time prevented fat accumulation in mice’s livers.
Catechin is one of the antioxidants found in green tea. The effects of this antioxidant may be beneficial to people with fatty liver disease, according to research.
4Consume enough protein
An adequate protein intake is necessary for the liver to carry out its various functions, such as synthesizing hormones and removing toxins and waste products from the body. Proteins also play a role in the synthesis of new liver cells as well as prevent fatty buildups and damage to the cells.
Soy and whey protein have been shown to reduce liver fat buildup according to a review in the journal Nutrients published in 2019. Women with obesity who ate 60 grams of whey protein every day for four weeks showed a 20% decrease in liver fat.
To achieve daily protein intake and make the liver healthier, most adults should have around 0.8 grams of protein per kilo of body weight. For instance, if you weigh 70 kg you need to have around 55 g of protein daily.
5Avoid drinking too much alcohol
Heavy alcohol consumption can contribute to the development of both alcoholic and non-alcoholic fatty liver diseases. Alcohol-related liver disease affects approximately 7 out of 10 people who are dependent on alcohol.
The liver plays a key role in breaking down and eliminating toxins from the body, and excessive alcohol consumption can place a significant burden on the liver. Over time, this can lead to the accumulation of fat in the liver, which can increase the risk of developing fatty liver. Additionally, alcohol is high in calories, and consuming large amounts of alcohol can contribute to weight gain, which is a major risk factor for the development of NAFLD.
Interestingly, according to the analysis, individuals with modest to moderate alcohol intake had a lower risk of developing non-alcoholic fatty liver disease compared to non-drinkers. The study found that modest to moderate alcohol intake was associated with a 31% protective effect against NAFLD. These findings suggest that consuming alcohol in moderation may have a protective effect against the development of NAFLD. However, it is important to note that excessive alcohol consumption can increase the risk of developing fatty liver, so it is important to drink in moderation and follow guidelines for safe alcohol consumption.
Alcohol intake (on the days when consumed) for adults should be limited to two drinks or less in a day for men and one drink or less for women, based on the Dietary Guidelines for Americans.
6Sleep 7-8 hours regularly
There are several potential reasons why getting enough sleep may help prevent the development of non-alcoholic fatty liver disease. First, sleep plays an important role in regulating metabolism. Adequate sleep may help maintain healthy levels of insulin and glucose, which can help prevent the accumulation of fat in the liver. Second, sleep deprivation has been linked to increased levels of inflammation, which may contribute to the development of NAFLD. Finally, lack of sleep can also lead to weight gain and obesity, which are major risk factors for the development of NAFLD.
Based on analysis of data from 70,000 participants, it was found that individuals who slept for less than 5 hours per day had a 59% higher risk of developing NAFLD compared to those who slept for more than 7 hours per day, based on the analysis of data from 69,493 participants.
Fatty liver disease is an asymptomatic silent killer that affects the lives of at least 1 in 10 people globally. The very disease has no medical cure and what is worse may result in serious conditions like hepatitis and liver cancer. The good thing is that you may protect your liver through lifestyle changes. By taking on and loyally following healthy choices in terms of diet, exercise, alcohol consumption, and sleep, you can reduce your risk of developing fatty liver and improve your overall health.
Not enough? Here is more from our colleagues
If you want to learn more about liver diseases, we recommend you read the book ‘How Not to Die’ by Michael Greger. Not only does it provide insight into preventing and dealing with liver diseases and other severe conditions but it also offers tips on having a healthy lifestyle that can protect you from diseases and premature death. This article is, in fact, inspired by the book. It is a must-read for anyone looking to improve their overall health and longevity.
Here is a video about dietary choices for treating a fatty liver:
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