When we hear about fatty liver disease, we can often jump to the image of someone who drinks excessive amounts of alcohol.
But that’s not always the case. In fact, it’s often not the case at all. As you will see in this article below, alcohol is not usually the cause of fatty liver disease.
Fatty liver disease is on the rise, and it is because of the way we eat and the way we (don’t) move. The good news is that a healthy lifestyle can stave off fatty liver disease.
What is fatty liver disease?
Fatty liver disease is the deposition of fat into the liver. Non-alcoholic fatty liver disease is what its name implies. It is fatty liver disease due to factors other than excessive alcohol consumption.
Lipid droplets are storages of fat present in all cells. Metabolic imbalances between the creation and degradation of lipid droplets leads to significant fat storage. This is a key feature of liver cells in patients with fatty liver disease.
Types of fatty liver disease
Non-alcoholic fatty liver disease
Non-alcoholic fatty liver disease encompasses a whole spectrum of liver disorders. These disorders are characterized by the following:
- Abnormal fat accumulation in the liver
- Inflammation
- Dysfunction of liver cells
Alcoholic fatty liver disease
Alcoholic fatty liver disease is the same liver damage as above but happens due to excessive alcohol intake.
Non-alcoholic steatohepatitis
Non-alcoholic steatohepatitis involves progressive liver injury. There is also usually a hepatic inflammation present. Fibrosis can also occur as well.
Simple hepatic steatosis
Simple fatty liver is actually not too serious. It is considered a benign condition, and its prognosis is long term.
Acute fatty liver of pregnancy
Acute fatty liver of pregnancy is an obstetric emergency. It involves a liver failure in the mother. It can have complications for both the mother and the fetus. And, it can even result in death.
Pediatric and adolescent non-alcoholic fatty liver disease
Pediatric and adolescent non-alcoholic fatty liver disease differs from the adult version of these conditions. They should, therefore, be recognized as different and distinct conditions.
What are the symptoms of fatty liver disease?
Oddly enough, fatty liver disease often doesn’t have any symptoms at all. In fact, fatty liver disease is often found by accident on blood tests or imaging performed for other reasons.
The blood tests of someone with fatty liver disease will show elevated liver enzymes. This demonstrates that abnormal liver function is occurring. Non-alcoholic liver disease is the most common cause of high liver enzymes. One possible symptom of fatty liver disease is vague upper abdominal pain.
What causes fatty liver disease?
Non-alcoholic fatty liver disease occurs when the body can no longer effectively store excess energy in fat tissue. Insulin resistance leads to widespread metabolic disturbances throughout the body. There is an accumulation of triglycerides in the liver.
Insulin resistance and extra fats can lead to an increased influx of fats into the liver. This then stimulates the new creation of fats within the liver. This then leads to the accumulation of triglycerides in the liver. Defects in fat utilization via mitochondrial oxidation and fat export can also contribute to the liver’s fat buildup.
Adipocytokine alterations and fat toxicity from saturated fatty acids and fructose may cause liver tissue injury. They do this through pathways involving oxidative and endoplasmic reticulum stress.
Non-alcoholic steatohepatitis results from liver fat toxicity. The key problem here is not the amount of liver fat, but the types of fat molecules that accumulate. Another problem is how these fat molecules are packaged to avoid subcellular injury.
Possible lipotoxic mediators
- Free (unesterified) cholesterol
- Saturated free fatty acids
- Diacylglycerols
- Lysophosphatidylcholine
- Sphingolipids
- Ceramide
Cells that are unable to sequester chemically reactive fat molecules experience a mitochondrial injury. They also undergo endoplasmic reticulum stress and autophagy. All of these are processes that can contribute to non-alcoholic steatohepatitis.
Lipotoxicity kills liver cells through a process called apoptosis. Apoptosis is a highly regulated, non-inflammatory form of cell death. Liver cells also die by necrosis, necroptosis, and pyroptosis. These involve mitochondrial injury, oxidative stress, and release of DAMPs (danger-associated molecular patterns).
The danger associated molecular patterns stimulate tolls like receptor 4 (TLR4) and NLRP3 (NOD-like receptor protein 3). These releases a cascade of pro-inflammatory chemokines and cytokines.
Lipotoxic liver cell injury attracts inflammatory cells, particularly activated macrophages. These surround ballooned liver cells as crown-like structures. Injured liver cells liberate plasma membrane-derived extracellular vesicles. These tend to circulate in the plasma of people with non-alcoholic steatohepatitis. They are pro-inflammatory.
Metabolic dysfunction leads to fat toxicity. This results in a pattern of cellular inflammation in the liver. This is all relevant to liver fibrosis and liver cancer.
Risk factors
Potential risk factors for fatty liver disease include the following:
- Obesity
- Type 2 diabetes
- Insulin resistance
- High blood pressure (which is called hypertension in the medical world)
- High cholesterol (which is called dyslipidemia in the medical world)
- Family history of fatty liver disease
- Poor diet
- Sedentary lifestyle/lack of exercise
- Chronic obstructive pulmonary disease (COPD for short)
- High body fat
- Sleep apnea
- Hepatitis C
The prevalence of non-alcoholic fatty liver disease is highest in populations with pre-existing metabolic conditions.
These include obesity and type 2 diabetes. The worldwide prevalence of fatty liver disease is increasing in conjunction with the growing obesity epidemic.
Researchers have also noted a correlation between fatty liver disease and dysbiosis of the gut microbiome. The liver connects to the gut and gastrointestinal system through the portal vein. There is a gut liver axis, and that means gut imbalances can have effects on the liver.
Stages of fatty liver
Non-alcoholic fatty liver disease is a spectrum. This spectrum ranges from mild hepatic steatosis to non-alcoholic steatohepatitis. Liver disease is known as a “silent disease,” meaning it can progress over many years to become non-alcoholic steatohepatitis.
Hepatic steatosis can be mild. But if it is happening along with insulin resistance and increased oxidative stress, it may lead to progressive disease.
Non-alcoholic steatohepatitis can lead to liver cell injury and inflammation. It can also result in cirrhosis of the liver, liver failure, and even liver cancer. More severe stages of fatty liver disease may require a liver transplantation.
The most severe stages of fatty liver can result in death. Between one and two-thirds of non-alcoholic steatohepatitis cases progress to liver fibrosis or cirrhosis (liver scarring). Non-alcoholic fatty liver disease is an independent risk factor for heart disease. It also leads to an increased risk of death.
Diagnosis
The diagnosis of fatty liver disease depends on a variety of assessment tools. These include liver biopsy and radiological liver tests such as ultrasound. It also involves blood tests like liver enzymes. Your doctor will likely perform a physical examination as well.
The gold standard in diagnosis of fatty liver disease is a liver biopsy. There are some limitations to this test, though. It is invasive, expensive, and there have been reports of variability between samples.
New research has shown that serum-based markers of fatty liver disease (such as cytokeratin-18 fragments) offer promise as possible future testing options.
Diagnosis and proper tracking of the progression of fatty liver disease are difficult. This is because fatty liver disease is so complex. The biggest challenge for diagnosticians is finding a non-invasive e way to diagnose non-alcoholic steatohepatitis.
This is because no reliable biomarkers have been found to detect or predict liver inflammation in non-alcoholic fatty liver disease.
Methods
- Ultrasound is often suggested as a first-line screening tool for fatty liver disease. A fatty liver will appear to be bright on ultrasound. However, the diagnosis of non-alcoholic fatty liver disease requires exclusion of other causes of chronic liver disease.
- Acute fatty liver of pregnancy is diagnosed using the Swansea criteria.
- One of the most important steps in the management of the non-alcoholic fatty liver disease is identifying advanced fibrosis. This can be determined through transient elastography or using what’s called a FIB-4 score.
- MRI technology can help to detect steatosis and identify the stage of fibrosis. However, MRI isn’t used in routine practice yet.
Treatment
The treatment of non-alcoholic fatty liver disease revolves around addressing associated metabolic risk factors. It also involves improving insulin resistance through weight loss and exercise.
Lifestyle changes
The first-line approach for fatty liver disease is lifestyle modification. This includes slow and steady weight loss, improved dietary habits, and increased daily aerobic physical activity.
Weight loss
Weight loss is the most effective way to promote liver fat removal. Several controlled studies have shown that lifestyle changes can lead to the desired seven to ten percent weight loss. This percentage of weight loss is associated with reduced liver fat, less fibrosis, and less remission of non-alcoholic steatohepatitis. So, cognitive-behavioral therapy can help in achieving this amount of weight loss.
Bariatric surgery
Even larger effects can be obtained after bariatric surgery-induced weight loss. One study showed that 80% of patients with non-alcoholic fatty liver disease who got bariatric surgery had a resolution of steatohepatitis one year later.
Antioxidant therapy
Antioxidant therapy can be beneficial in some patients with biopsy-proven fatty liver disease. This includes the use of vitamin E.
Gut liver axis
You can also treat fatty liver disease through the gut liver axis. You can do this by using probiotics, prebiotics, and synbiotics. The results of a meta-analysis research study showed that probiotics could be helpful in fatty liver disease. Probiotics lowered levels of alanine aminotransferase (AL) and aspartate transaminase (AST). They also decreased total cholesterol and HOMA-IR (homeostasis model assessment of insulin resistance).
When it comes to drug therapies, there is currently no consensus regarding the treatment of fatty liver disease. Treatments targeting the pathophysiological mechanisms of non-alcoholic fatty liver disease exist.
However, these carry some potential risks and are not universally effective. Insulin sensitivity agents, such as pioglitazone, show some promise.
They can improve the health of liver cells in patients with non-alcoholic steatohepatitis. However, there is not necessarily the long term benefit of these medications.
Diet for fatty liver
A balanced diet in terms of quality and quantity of calories is a cornerstone of fatty liver disease management.
Low-calorie diet
A low-calorie diet can be helpful. It is also important to avoid fructose, soft drinks, meat, and saturated fatty acids. This is because these foods have a demonstrated detrimental association with non-alcoholic fatty liver disease—phytochemical compounds, such as dietary polyphenols, control inflammation. Inflammation is one of the mechanisms by which non-alcoholic fatty liver disease can evolve into non-alcoholic steatohepatitis.
Mediterranean diet
The Mediterranean diet can also be helpful for fatty liver disease. This diet has a higher consumption of fish and plant-based foods. It involves less consumption of meat and dairy products.
The Mediterranean diet is rich in polyunsaturated fats, polyphenols, vitamins, and carotenoids. These compounds have anti-inflammatory and antioxidant effects. This, therefore, helps to prevent cardiovascular risk factors. Research has also shown the Mediterranean diet reduces the risk of metabolic syndrome.
Changing your diet can reduce fatty liver, even when you don’t lose any weight. It can also help to improve metabolic changes such as insulin resistance and your lipid profile. The Mediterranean Diet pattern helps to achieve this goal.
In fact, the Mediterranean diet was recommended as the diet of choice for the treatment of non-alcoholic fatty liver disease by Clinical Practice Guidelines. The Mediterranean diet can also help to lose weight over a long time period. However, this diet can improve metabolic status and fatty liver even without any weight loss.
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Prevention
Nutrition plays an essential role in preventing the development of fatty liver disease. A healthy liver diet can also prevent the progression to later stages of fatty liver disease for those who already have it.
The Mediterranean diet, in particular, is a gold standard in preventative medicine. This is due to the harmonic combination of foods with antioxidant and anti-inflammatory properties that this type of diet provides.
Preventing a condition such as fatty liver disease is always easier than treating it.
That is why we suggest taking control of your lifestyle now. So, get in some aerobic exercise each and every day if you can. Cut out some of the potential dietary factors, such as soft drinks, meat, fructose, and saturated fatty acids. You may even want to consider following the Mediterranean diet, which is high in anti-inflammatory and antioxidant ingredients.
You can improve your fatty liver by making dietary changes, even if you don’t lose weight. However, losing weight can amplify the effects of the other lifestyle changes you make.
For this reason, try to cut back on your caloric intake. You now know the different types and stages of fatty liver disease, as well as the risk factors to avoid and symptoms to watch out for. If you have further questions, ask your health care provider what you can do to prevent fatty liver disease today.
