New research from the US shows that regular consumption of coffee is linked to a reduced risk of a rare autoimmune liver disease called primary sclerosing cholangitis (PSC).

Study investigator Craig Lammert, a gastroenterologist and hepatologist at the Mayo Clinic in Rochester, Minnesota, is presenting the findings at the Digestive Disease Week 2013 conference in Orlando, Florida this week.

Lammert explains in a statement how although PSC is rare, it has “extremely detrimental effects”, so it is important to find ways to reduce the risk of developing this and similar diseases.

He says the study is the first to point to “a novel environmental factor that also might help us to determine the cause of this and other devastating autoimmune diseases”.

The study also appears to add another strand of evidence to the idea that drinking coffee may do more good than harm.

PSC is an autoimmune disease of the bile ducts in the liver. An autoimmune disease is where the body turns against its own cells. Bile ducts are tubes that carry liquid bile from the liver to the intestines: the fluid helps digest food and eliminate worn-out red blood cells, cholesterol and toxins.

PSC is a progressive disease characterized by chronic inflammation of the bile ducts (“cholangitis”) that eventually causes hardening and scarring (“sclerosing”).

The disease damages the liver to the point of liver failure. It can also cause cancer of the bile duct. Liver transplant is currently the only known cure, but this is normally reserved for patients with very severe liver damage.

Primary biliary cirrhosis (PBC) is a another autoimmune liver disease with a similar sounding name to PSC, except in PBC the immune system gradually destroys the small bile ducts in the liver, allowing powerful toxins to build up in the liver, causing irreversible scarring (“cirrhosis”).

For their study, Lammert and colleagues examined three groups of patients: one group had PSC, another had PBC, and the third were healthy patients (the controls).

They found drinking coffee was linked to a reduced risk for PSC, but not PBC.

They also noticed that PSC patients were more likely never to drink coffee, compared to healthy controls.

And on average, PSC patients spent around 20% less time drinking coffee than the controls.

The researchers believe the study shows PSC and PBC may be more different than previously thought. Finding out more about these differences, could give clues as what causes these autoimmune diseases and help develop treatments.

The National Institutes of Health and the American Liver Foundation helped fund the study.

A study published in the journal Vascular Medicine recently suggests that drinking boiled Greek coffee could improve cardiovascular health and increase longevity.

Written by Catharine Paddock PhD