There is growing scientific consensus that one of the most common types of sugar, fructose, can be toxic to the liver, just like alcohol. Fructose is the sugar that makes fruit taste sweet. For most people, there’s nothing wrong with eating fructose in its natural state, in fruit. (updated July 18 2022)
But today, manufacturers extract and concentrate the fructose from corn, beets and sugarcane, removing the fiber and nutrients (minerals, vitamins, enzymes, antioxidants) in the process. Getting frequent, high doses of fructose throughout the day, without fiber to slow it down, is more than our bodies were designed to handle.
Nearly all added sugars contain significant amounts of fructose. Typical formulations of high-fructose corn syrup contain upwards of 50% fructose, depending on processing methods. Table sugar and even sweeteners that sound healthy, like organic cane sugar, are 50% fructose.
What’s unique about fructose is that, unlike any other sugar, it’s processed in the liver. Small amounts of fructose, meted out slowly, are not a problem for your liver. Think of eating an apple – its sweetness comes with a lot of chewing that takes time. The apple’s fiber slows down its processing in the gut.
But when we consume large amounts of fructose, particularly in liquid form on an empty stomach, it slams the liver with more than it can handle.
As with alcohol, a little added fructose, consumed with fiber-rich foods, is OK. It’s only when we frequently consume large quantities, in concentrated form, that fructose becomes a health hazard.
Liver damage is a looming health issue
For a long time, doctors mainly worried about life-threatening liver disease in alcoholics. But since 1980, there has been growing concern about two new conditions linked to fructose consumption, as well as to obesity and other unhealthy dietary additives, such as trans-fats:
- Non-alcoholic fatty liver disease (NAFLD): This is characterized by excess fat build-up in the liver.
- Non-alcoholic steatohepatitis (NASH): This is characterized by fatty liver, inflammation and “steatosis,” which is essentially scarring as the liver tries to heal its injuries. That scarring gradually cuts off vital blood flow to the liver.
About one-quarter of NASH patients will progress on to non-alcoholic liver cirrhosis, which requires a liver transplant or else it can lead to death.
Since 1980, the incidence of NAFLD and NASH has doubled, along with the rise of fructose consumption.
Approximately 6 million individuals in the United States are estimated to have progressed to NASH and some 600,000 to NASH-related cirrhosis. Eating a lot of trans-fats, being overweight and not exercising also can contribute to NASH. Most people with NASH also have Type II diabetes.
What is alarming is that NASH is now the third-leading reason for liver transplantation in America. And it will become the most common if recent trends continue. Rates of NASH have doubled in America during the past 20 years alongside a dramatic increase in sugar consumption.
Estimates vary, but conservatively, 31% of American adults and 13% of kids suffer from NAF