For the study, scientists at Washington University in St. Louis gave adult zebrafish antibiotics to remove most gut bacteria. They then checked how the fish processed glucose and watched whether the fish intestines produced sorbitol. Sorbitol is a sugar alcohol that naturally exists in some fruits. It is also made commercially for sugar-free, low-calorie and diabetic-friendly foods.
What is Sorbitol and how it rises in the body
Sorbitol is about 60% as sweet as sugar and has 35% fewer calories per gram. The human body can also make sorbitol when glucose levels rise, which is why sorbitol is linked to diabetes. Gut bacteria play a major role in breaking down sorbitol inside the body. The new study, as per the New York Post, suggests that even healthy people can get high enough glucose after meals to trigger sorbitol production.
Normally, gut bacteria break down small amounts of sorbitol — like what you get from fruit — into a harmless byproduct. “However, if you don’t have the right bacteria, that’s when it becomes problematic,” said biochemist Gary Patti, whose lab ran the study, the New York Post reported. If the gut doesn’t have the right bacteria, sorbitol builds up faster than microbes can break it down. This can happen if someone eats too much glucose, too much sorbitol, or both.
Sorbitol and liver disease risk
When sorbitol levels get too high, the gut can’t break it down, so it goes to the liver. There, the body turns sorbitol into fructose. Fructose is already known to feed MASLD (Metabolic dysfunction–associated steatotic liver disease) — earlier called nonalcoholic fatty liver disease — because the liver turns extra fructose into fat.
That fat builds up in liver cells, leading to inflammation, scarring and possibly permanent liver damage. Some experts do not fully agree with the study’s findings. “This study has several limitations, including relying on research on fish, which cannot be directly applied to humans,” said Carla Saunders, president of the Calorie Control Council.
She added, “Sorbitol… has been repeatedly confirmed as safe by global authorities for decades… which is why it’s… in more than 53,000 products worldwide.” MASLD is very common in the US, but most people don’t know they have it because early stages usually have no symptoms. “Some may feel more tired than usual or notice vague discomfort… but these signs are nonspecific,” said Dr. Leana Wen, emergency physician and CNN medical analyst, according to New York Post.
One study found that among nearly 3 million adults with MASLD, less than 1% had been diagnosed before. Doctors usually detect MASLD when routine blood tests show mild liver enzyme problems or when imaging like an abdominal ultrasound picks it up. Wen said diagnosis depends on checking metabolic risk factors like excess weight, diabetes or prediabetes, high blood pressure and high cholesterol.
If caught early, MASLD can often improve or even reverse with lifestyle changes such as weight loss, regular exercise and managing diabetes, as per New York Post. There are no medicines approved specifically for MASLD, but two drugs — Rezdiffra (resmetirom) and Wegovy (semaglutide) — help treat MASH, the more advanced stage. “These two medicines… are meant to be used along with, not instead of, lifestyle changes,” Wen said.
FAQs
Q1. Does sorbitol increase the risk of liver disease?
A new study suggests too much sorbitol may reach the liver and turn into fructose, which can raise the risk of fatty liver disease.
Q2. Is sorbitol safe to eat in sugar-free foods?
Experts say sorbitol is considered safe, but critics note the new study shows possible risks when gut bacteria cannot break it down properly.