Fatty Liver is on the rise among adults and children, but there’s a lot of misunderstanding about what causes it. We cover 12 Root Causes including insulin resistance, nutrient deficiencies, environmental toxins, and more!
Note from Dena: This post was co-written with Sandra Johnson, Dietetic Intern, as part of a research partnership between Back To The Book Nutrition and post-graduate nutrition students from the University of Houston.
Fatty liver is rising in both children and adults. It’s estimated that 20-40% of Americans currently have fatty liver and it’s expected to become the top cause of liver transplants in the next decade (7).
It is the 4th leading cause of death in the U.S. among 45 -54 year olds (7).
What is Fatty Liver?
When fatty liver develops in someone who drinks heavily, it’s called Alcoholic Fatty Liver Disease (AFLD), and when it develops in someone who doesn’t drink much, it’s called Nonalcoholic Fatty Liver Disease (NAFLD). Both conditions are marked by similar liver abnormalities that, if not reversed, can progress to steatohepatitis, cirrhosis, liver cancer, and liver failure. (4)
12 Root Causes of Fatty Liver
Multiple causes for fatty liver have been explored over the years, including the following:
1. High Fructose Intake
Fructose is a type of sugar that occurs naturally in fruits, and in more concentrated forms in fruit juices and foods containing high fructose corn syrup. Unlike other forms of sugar, fructose is metabolized almost entirely in the liver, and regular consumption of sodas, fruit juices, and other foods high in fructose increases fat accumulation in the liver (5).
In addition to overconsumption of fructose specifically, eating more food than the body needs at a given time (especially sugar and fat) causes the body to store the extra energy as fat. One of those fat storage sites is in the liver. (4, 12)
3. Overweight and obesity
Excess body fat results in inflammation and insulin resistance, increasing the amount of free fatty acids in circulation. As discussed above, excess fatty acids are then stored in the liver (as well as other sites throughout the body). This becomes a vicious cycle of body fat causing fatty liver, and fatty liver causing more body fat (4, 12).
4. Blood Sugar Imbalances/Insulin Resistance
Chronically high blood sugar leads to insulin resistance, which is a double whammy for fatty liver. First, excess sugar is more likely to be stored as fat in the liver (and other fat tissue) because insulin resistance prevents it from getting into cells to be used as energy. Second, insulin resistance also encourages more free fatty acids to be taken to the liver for storage. (4, 12).
5. Heavy Alcohol Consumption
Fatty liver develops in over 90% of those who consume 4 or more drinks daily. If someone stops drinking, fatty liver often resolves, assuming it has not yet progressed to more serious liver damage. Alcohol promotes fatty liver in multiple ways: ethanol relies exclusively on the liver for metabolism; alcohol increases blood sugar levels; and chronic alcohol consumption increases oxidative stress, resulting in further damage to the liver and other tissues (13).
Various diseases, injuries, obesity, and other chronic stressors increase inflammation which, in turn, increases oxidative stress, raises blood sugar, and increases risk for insulin resistance. As already discussed, these promote fatty liver (4, 12).
7. Poor Gut Health
Our gut “microbiome” is filled with up to 1,000 different species of bacteria that support healthy immune function, regulate digestion, remove waste products, and keep us healthy. Dysbiosis (an imbalance of “good” and “bad” bacteria) in the intestines leads to decreased nutrient absorption, increased inflammation, and disrupted immune function.
Specifically, H.pylori – a bacterial infection in the stomach – was linked in one meta analysis to 25% higher rates of nonalcoholic fatty liver disease (NAFLD) versus controls. (18)
Any of the above can damage the gut lining, ultimately leading to increased intestinal permeability (“leaky gut”). A leaky gut allows food particles, toxic byproducts, and waste that should be removed from the body to be sent back to the liver to be filtered. Over time, this can greatly burden the liver and has been linked to fatty liver. Thus, improving gut health is an important step in overcoming fatty liver.(1,8,9).
8. Choline Deficiency
Choline deficiency is rarely discussed, but appears to promote fatty liver in a few different ways: (1) by promoting dysbiosis; (2) by promoting insulin resistance; and (3) by decreasing the amount of phosphatidylcholine (which helps carry fat away from the liver) and increasing liver fat accumulation. Furthermore, repletion of choline has been shown to reverse fatty liver (2,6). Liver, egg yolks, meat, and poultry are all good sources of choline.
9. Iron Excess
Ferritin is the storage form of iron in the body and high ferritin may be an early indicator of fatty liver. This can occur due to excess intake of iron from foods or supplements, genetic factors affecting iron metabolism, or inflammation in the body, which raises ferritin. More study is needed to fully understand the role of excess iron, but it seems to promote insulin resistance, oxidative stress, and liver damage. (16).
10. Genetic predisposition
11. Certain Prescription Medications
Drug Induced Steatohepatitis (DISH) is extremely rare, making up only 2% of all cases of fatty liver. Some medications do this by affecting blood sugar and other metabolic issues discussed above, while others appear to affect the liver more directly. Amiodarone, Dronedarone, Tamoxifen, Valproic Acid, Methotrexate, and various antivirals and chemotherapeutic agents may increase risk and should be studied further (14).
12. Heavy Metals and Environmental Toxins
Multiple animal and human studies have made links between various chemical exposures and and fatty liver. More research is needed but minimize exposure to the these chemicals as much as possible (15) :
- Pesticides, herbicides, insecticides, and fungicides (Glyphosate, etc.)
Remember, Thin People Get Fatty Liver Too!
It is a common misconception that only overweight people get fatty liver disease. While people who are overweight or obese are indeed at a greater risk, lean people can also develop fatty liver disease. In fact, lean individuals with fatty liver have higher death rates, than those who are overweight (4,7).
If you are normal weight, but deal with any of the root causes listed above, consider getting tested for fatty liver.
How Do I Know If I Have It?
Wondering if you have fatty liver, and what to do about it? Learn all about Fatty Liver Symptoms and Testing options here!
About the Co-Author
Sandra Johnson, Dietetic Intern has a B.S. in Human Nutrition and Foods from the University of Houston. When she started changing her eating patterns and improving her health to be a better influence for her children, she discovered her passion for nutrition and food.
Disclaimer: Information on this site is intended only for informational purposes and is not a substitute for medical advice. Always consult with a trusted healthcare provider before implementing significant dietary change. Read additional disclaimer info here.
1. Dr. Michael Rusio.(2019). Fatty liver Improves with Probiotics- High- Level Scientific Evidence
6. Loguercio, C., Andreone, P., Brisc, C., Brisc, M.,Burgainesi,E., Chiaramonte, M.,…Federico, A.(2012). Silybin combined with phosphatidylcholine and vitamin E in patients with nonalcoholic fatty liver disease: A randomized controlled trial, Free Radical Biology and Medicine 52(9), 1658-1665.https://www.ncbi.nlm.nih.gov/pubmed/22343419
7. Le, M., Devaki, P., Ha, N., Jun, D., Te, H., Cheung, R. & Nyugen, M. (2017). Prevalence of non-alcoholic fatty liver disease and risk factors for advanced fibrosis and mortality in the United States. PLOS ONE. https://doi.org/10.1371/journal.pone.0173499
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17. Shi, H., Mao, L., Wang, L., Quan, X., Xu, X., Cheng, Y., Zhu, S., & Dai, F. (2021). Small intestinal bacterial overgrowth and orocecal transit time in patients of nonalcoholic fatty liver disease. European journal of gastroenterology & hepatology, 33(1S Suppl 1), e535–e539. https://doi.org/10.1097/MEG.0000000000002157
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