Nonalcoholic Fatty Liver Disease: What Is It?

Find out all about nonalcoholic fatty liver disease and what causes it, as well as treatment.
Nonalcoholic Fatty Liver Disease: What Is It?
Diego Pereira

Reviewed and approved by el médico Diego Pereira.

Last update: 30 January, 2023

Nonalcoholic fatty liver disease, also known as NAFLD, is more common than you might think. Researchers estimate that up to 30% of the population in developed countries suffer from it, and, as it usually doesn’t produce symptoms, most of them are undiagnosed. We’ll show you everything you need to know about NAFLD.

Most people associate liver disease with alcohol consumption. The metabolism of alcohol produces toxins that affect the liver (90% is metabolized in this organ) Lifestyle and habits can also affect the liver, as is the case with the disease we’re looking at today.

Symptoms of nonalcoholic fatty liver disease

As Johns Hopkins Medicine points out, nonalcoholic fatty liver disease is often referred to as silent liver disease.

This is because people can deal with it for years, even decades, without showing any sign of it. Many times the symptoms don’t appear when the organ damage is greatest, although this is usually reserved for alcoholic fatty liver disease (AFLD).

Since the condition causes no symptoms most of the time, it’s detected by chance. That is, when the patient undergoes health tests that directly or indirectly reveal the condition. Of course, this isn’t to say that no patient shows signs of the disease. The most common are the following:

  • Weight loss
  • Weakness or fatigue
  • Itching on the surface of the skin (which lasts for hours or days)
  • Spider-shaped blood vessels in the skin
  • Yellowing of the skin and mucous membranes (jaundice)

In the most severe cases, fluid retention, cramps or abdominal pain, confusion, episodes of internal bleeding and liver failure manifest.

These episodes are rare, since they’re more related when the trigger for the condition is a high intake of alcohol. Despite this, some NAFLD patients with particularly bad lifestyle habits may be exposed to such complications.

Causes of nonalcoholic fatty liver disease

Nonalcoholic fatty liver disease linked to diabetes.
Metabolic problems tend to favor the appearance of fatty liver in a significant proportion of patients.

Experts agree that nonalcoholic fatty liver disease is the most common liver disease worldwide. In part, it’s because there are multiple triggers, ranging from lifestyle habits to underlying illnesses.

The list is very long, and the relationship between these and the accumulation of fat in the liver is still not fully understood, but here are the main ones:

  • Arterial hypertension
  • Excess weight and obesity
  • Type 2 diabetes
  • Insulin resistance or elevated blood glucose values
  • High concentrations of fat in the blood, especially cholesterol and triglycerides
  • Polycystic ovary syndrome
  • Sleep apnea
  • Hypopituitarism (underactive pituitary gland)
  • Hypothyroidism and hyperthyroidism
  • Genetic predisposition (up to 2/3 of patients have relatives with NAFLD)
  • An unbalanced diet with little intake of fruits, vegetables and legumes

This is only a selection of the catalysts of the disease, as in practice there can be many more. The intake of certain medications, rapid weight loss, malnutrition, and exposure to certain toxins can explain many of the episodes.

NAFLD is often triggered by multifactorial causes, so that the combination of one or several indicated elements can mediate its development. It’s important to highlight the relationship between non-alcoholic fatty liver disease and metabolic syndrome.

Metabolic syndrome and fatty liver

Metabolic syndrome is a diagnosis used to refer to a number of traits that are associated with being overweight and obese. For example, wide waist, high blood glucose levels, and high blood cholesterol levels (to name just a few). As experts indicate, most patients with metabolic syndrome develop fatty liver disease.

In fact, the relationship is so direct that NAFLD is often considered just another feature of the syndrome. The alterations that occur at the metabolic level lead to the excessive accumulation of fat in the organ, so much so that it exceeds 5% of the weight of the liver (the standard amount at the time of diagnosing the condition). If you’ve been diagnosed with metabolic syndrome or share its traits, chances are you also have NAFLD.

Non-alcoholic fatty liver treatment

Nonalcoholic fatty liver disease and its treatment.
Lifestyle changes are essential in order to achieve better metabolic control and reduce fatty liver lesions.

As researchers point out, the treatment of non-alcoholic fatty liver is done considering three key elements: a balanced diet, regular exercise, and weight loss. In children, youth, and adults, this produces promising and rapid results. Its approach is, therefore, non-invasive and can be adapted to the needs of each patient.

Only a small portion of them are candidates for bariatric surgery. This is chosen in severe cases and when the patient can’t develop an exercise or diet regimen that facilitates weight loss. Consult with the specialist to see if this is an option in your case or not.

No drug treatments have been approved for fatty liver disease. Vitamin E and pioglitazone can complement the main therapy (exercise and diet), although with limited results. Avoiding alcohol intake and managing underlying conditions ( high blood pressure, diabetes, and so on) are also part of the treatment for NAFLD.

Although it’s true that the liver has a great capacity to regenerate, the truth is that liver failure is a real consequence if some patients don’t follow a prescribed treatment. If you suspect that you suffer from non-alcoholic fatty liver disease, don’t hesitate to consult a specialist to initiate the relevant medical tests.



  • Bellentani, S., Scaglioni, F., Marino, M., & Bedogni, G. Epidemiology of non-alcoholic fatty liver disease. Digestive diseases. 2010; 28(1): 155-161.
  • Neuschwander-Tetri, B. A. Non-alcoholic fatty liver disease. BMC medicine. 2017; 15(1): 1-6.
  • Paschos P, Paletas K. Non alcoholic fatty liver disease and metabolic syndrome. Hippokratia. 2009;13(1):9-19.
  • Smith, B. W., & Adams, L. A. Non-alcoholic fatty liver disease. Critical reviews in clinical laboratory sciences. 2011; 48(3): 97-113.

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