Nonalcoholic fatty liver disease (NAFLD) is a condition that occurs in people who consume little or no alcohol.
People who consume excessive alcohol can develop a condition referred to as Alcohol associated Fatty Liver Disease (AFLD). NAFLD patients can progress to an inflammatory form of the disease referred to as nonalcoholic steatohepatitis (NASH) which can progress to scarring (cirrhosis) and liver failure.
In the United States, NAFLD is the most common form of chronic liver disease.
In the early stages this condition typically has no symptoms. As it progresses to cirrhosis symptoms can include yellowing of skin and eyes (jaundice), abdominal pain, and general feeling of tiredness. One of the main causes of NAFLD is obesity and excess intake of carbohydrates, especially refined carbohydrates. Blood tests that indicate a predisposition to develop NAFLD are elevated fasting blood sugar, insulin, triglycerides, and cholesterol.
Some other conditions such as hypothyroidism, obstructive sleep apnea and Type 2 Diabetes also predispose people to NAFLD.
The main way to prevent and treat NAFLD is to consume a healthy plant-rich diet low in carbohydrates, achieve a lean body weight, and exercise 150-300 minutes weekly. This is because about 70% of obese people have NAFLD to some degree. There are basically 2 types of fat; the first is subcutaneous fat and is the fat we can see around our waists and is a more benign fat, the second is visceral adipose tissue (VAT) which is the fat around organs, around our heart and around arteries. VAT is more malignant because it is highly inflammatory and this fat pours fat cells directly into the portal vein which empties directly into the liver resulting in NAFLD. The best way to prevent and treat NAFLD is by reducing carbohydrates, and specifically reducing the intake of fructose. Many soft drinks and packaged foods contain high fructose corn syrup, which is a major causative agent of the NAFLD epidemic in the US. Table sugar is 50% glucose and 50% fructose. While glucose is the main energy source for our cells, fructose needs to be converted to glucose in the liver before it can be utilized for energy. When the liver gets overloaded with fructose, it converts the excess fructose into fat and NAFLD can ensue. Natural fruits also contain fructose, but in low amounts with a considerable amount of fiber. So, generally, fruit consumption does not contribute to NAFLD. Added sugar and high fructose corn syrup are the main drivers of NAFLD in the US.
A study published in JAMA (Journal of the American Medical Association):
Randomized Controlled Trial JAMA . 2019 Jan 22;321(3):256-265. doi: 10.1001/jama.2018.20579.
Effect of a Low Free Sugar Diet vs Usual Diet on Nonalcoholic Fatty Liver Disease in Adolescent Boys: A Randomized Clinical Trial.
- 40 hispanic boys with biopsy proven NAFLD.
- 8 weeks of no fructose (They continued to consume glucose).
- 50% reduction of liver fat by MRI at 8 weeks.
A study published in Seminars in Liver Disease . 2021 Jun 19. doi: 10.1055/s-0041-1723751. Online ahead of print.
Effects of Mediterranean Diet in Patients with Nonalcoholic Fatty Liver Disease: A Systematic Review, Meta-Analysis, and Meta-Regression Analysis of Randomized Controlled Trials.
- 6 Randomized controlled trials were selected.
- This meta-analysis demonstrated that Med-Diet improved hepatic steatosis and insulin resistance in patients with NAFLD. Thus, Med-Diet is a beneficial pharmaconutritional therapy in patients with NAFLD.
