People with viral cirrhosis from diseases such as hepatitis C are at an increased risk of developing liver cancer - about 80 per cent of people with hepatocellular carcinomas have cirrhosis.
The extent of chronic hepatitis C infection is hard to determine because of the level of undiagnosed infection, but is believed to be present in some 250,000 people in England. An increase in infection in the 1960s and 1970s and increased diagnosis is likely to result in a rise in illness and death over the next five to 10 years, said a 2001 report from the UK's chief medical officer.
The scientists at Osaka City University gave 21 women with viral liver cirrhosis a daily supplement of 45mg vitamin K2 (menaquinone) for a period of two years. A group of 19 women with the disease received a placebo for the same time.
Liver cancer was detected in only two of the 21 women given vitamin K2 but nine of the 19 women in the control group, reports the team in today's issue of JAMA (292:358-361). After adjustment for age, severity of disease and treatment, the researchers found the women receiving vitamin K supplementation were nearly 90 per cent less likely to develop liver cancer.
It is not clear how vitamin K may prevent liver cancer but previous findings have indicated that vitamin K2 may play a role in controlling cell growth, noted the researchers.
They concluded that "there is a possible role for vitamin K2 in the prevention of hepatocellular carcinoma in women with viral cirrhosis".
Vitamin K is a fat-soluble vitamin that is produced in the intestine, with excess amounts stored in the liver. It can also be found in leafy green vegetables such as broccoli and spinach, vegetable oils, cereals and some meats and cheeses.