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The Growing Epidemic of Non-alcoholic Steatohepatitis (NASH) Fatty Liver Disease
By Tina Pavane
When you think about epidemics that plague modern man, fatty liver disease is not likely to come to mind. But collateral damage to the liver is joining the growing list of health consequences attributed to our ever-expanding waistlines, poor diet, and unhealthy lifestyle.
You may be more familiar with the liver diseases that occur in heavy drinkers of alcohol, or with liver infections such as hepatitis C, but non-alcoholic fatty liver disease (NAFLD), the type of liver disease that affects people who do not consume excessive alcohol, is rapidly on the rise.
NAFLD is actually a spectrum of liver diseases that ranges from the simple, mostly harmless form, called non-alcoholic fatty liver (NAFL), to the potentially deadly forms such as non-alcoholic steatohepatitis (NASH), fibrosis, and cirrhosis.
About 25% of adults have the benign form of the disease (NAFL), and 3-5% go on to develop NASH4. It is estimated that the number of people with NASH will increase 63% by the year 20301.
Unfortunately, there is currently no way to know which people with the simple form of fatty liver disease will progress to NASH, or how long it will take2. What’s more worrisome is that NASH is poised to become the leading cause of liver transplantation in the near future3, surpassing hepatitis C virus, the current leader.
And that has the medical community wondering if they might soon be facing a new epidemic with few resources to stop it.
How Does a Healthy Liver Become a Fatty Liver?
The liver is a workhorse organ. It is charged with many tasks — removing toxins, making proteins for many necessary body functions, helping to digest food, and storing fat. It’s that last job, dealing with fat, that’s problematic.
The cells of the liver, called hepatocytes, can be easily overwhelmed when it has to deal with too much fat. In the early stages of the disease, when the liver cells are plump but not yet overcome, it can continue to remain harmless. But in some people, liver fat accumulation leads to inflammation and cell injury. That’s when it has progressed to the more dire form of the disease, non-alcoholic steatohepatitis or NASH (steato meaning fat, and hepatitis meaning inflammation of the liver)5.
As more and more liver cells die, the liver becomes riddled with scars (fibrosis) and as this worsens, cirrhosis, liver failure, or liver cancer can follow4. This type of liver damage is irreversible.
How Do You Know You Have Non-alcoholic Steatohepatitis (NASH)?
There are few, if any, symptoms of NASH — even in its advanced stages — that alert patients and doctors that the disease is present. While some people complain of fatigue, malaise, and right upper belly discomfort, most have no symptoms at all. This leaves doctors mostly in the dark about which of their patients may be harboring the disease.
There is no simple way to diagnose the disease. Researchers are looking hard to find a circulating biomarker or chemical that can be traced back to a fatty liver, so it can be detected in the blood. And Pfizer is among a group of international researchers supporting the hunt for a reliable test. Until then, the only diagnostic tool is to visualize the liver with imaging technologies, e.g. ultrasound and MRI, and perform a needle biopsy, which is considered the gold standard for NASH diagnosis, where a small sample of the liver is removed and examined under the microscope. Unfortunately, that method is just not practical for everyone with vague or no symptoms.
Who Is Most At Risk For NASH?
While lean people (and children) can also get NASH, it is more common in people who have some, or all, of these conditions: obesity, high blood pressure, Type 2 diabetes, insulin resistance, high triglycerides, abnormal cholesterol, or genetic risk factors6. More than 80% of people with NASH are overweight or obese, 72% have abnormal blood lipids (cholesterol and triglycerides), and 44% have Type 2 diabetes. Nearly 40% of the US adult population, and 13% worldwide are obese7.
Risk factors for NASH:
- Obesity and overweight
- High blood pressure
- Abnormal cholesterol (low high-density lipoprotein HDL)
- High Triglycerides
- Insulin resistance
- Type 2 diabetes
- Diet high in sugar (fructose)
- Certain medications
- Shift work8
- Environmental toxins
- Certain genetic diseases
How Can You Treat Fatty Liver and NASH?
Treatments for NASH that take aim at a fatty liver are being studied in earnest, including at Pfizer, the best hope right now is to take measures to treat the risk factors that can lead to it. If you find out you have a fatty liver in its early stages you can try to prevent it from progressing by changing to a healthier lifestyle, and treating any medical conditions that increase fat to the liver. Vitamin E and drugs that improve how the body uses insulin are sometimes used to treat some of the risk factors.
The only potentially life-saving option when the disease advances to end-stage liver failure or liver cancer is a liver transplant.
Lifestyle modifications to prevent NASH4
- Lose 7 to 10% of body weight if overweight or obese
- Increase physical activity and exercise intensity
- Reduce saturated fats in diet
- Stop drinking sugary beverages
- Limit alcohol to ≤1 drink/day for women and ≤2 drinks/day for men
- Drink two or more cups of caffeinated coffee a day (reduces fibrosis)
While there are currently no approved medicines for the treatment of NASH, there is hope on the horizon with research ongoing across the pharmaceutical industry, academia, and among advocacy organizations.
1 Estes C et al., “Modeling the epidemic of nonalcoholic fatty liver disease demonstrates in exponential increase in burden of disease,” Hepatology. 2018 Jan; 67(1): 123–133.
2 International Project to Help Detect a Liver Disease Called NASH Gets $35M Boost, https://getscience.com/content/international-project-help-detect-liver-disease-called-nash-gets-35m-boost, accessed 21 Feb 2018
3 Siddique, Osama et al. “Rising Rate of Liver Transplantation in the Baby Boomer Generation with Non-Alcoholic Steatohepatitis in the United States.” Journal of Clinical and Translational Hepatology 5.3 (2017): 193–196. PMC. Web. 21 Feb. 2018.
4 Diehl, Anna and Day, Christopher M.D Cause, “Pathogenesis, and Treatment of Nonalcoholic Steatohepatitis.” N Engl J Med 2017; 377:2063-2072
5 World J Gastroenterol. 2014 Sep 28; 20(36): 12956–12980.; https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4177476/pdf/WJG-20-12956.pdf
6 Chalasani, Naga et al. “The Diagnosis and Management of Non-alcoholic Fatty Liver Disease: Practice Guideline by the American Gastroenterological Association, American Association for the Study of Liver Diseases, and American College of Gastroenterology.”
Gastroenterology , Volume 142 , Issue 7 , 1592 – 1609 21 Feb. 2018
7 World Health Organization, Obesity and Overweight Fact Sheet, Reviewed February 2018, Accessed 22 Feb 2018
8 Kenichiro, Y. et al. Dietary habits and behaviors associated with nonalcoholic fatty liver disease. World J Gastroentero. February 2014. https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3930974/#B48