Reuters Health Information (2005-06-21): Soy intake linked with reduced hepatocellular carcinoma risk
Soy intake linked with reduced hepatocellular carcinoma risk
Last Updated: 2005-06-21 16:48:00 -0400 (Reuters Health)
NEW YORK (Reuters Health) - Consuming miso soup and
other soy foods may reduce the risk of hepatocellular carcinoma (HCC),
according to the results of a study published in the June 10th issue of
the International Journal of Cancer.
Dr. Gerald B. Sharp, of the National Institute of Allergy and
Infectious Diseases, Bethesda, Maryland, and colleagues conducted a
case-control study within a cohort of Japanese A-bomb survivors to
determine if consumption of soy foods reduces the risk of HCC.
The researchers compared the prediagnosis consumption of
isoflavone-rich miso soup and tofu to HCC risk. The team adjusted for
hepatitis B (HBV) and C (HCV) viral infection, which are major HCC risk
factors in this population.
Included in the study were 176 confirmed cases of HCC diagnosed
between 1964 and 1988, and 560 control subjects who died of diseases
other than liver cancer. Dietary information collected at least 2 years
prior to diagnoses or death was examined.
Subjects who ate miso soup or tofu more than five times per week had
a 50% lower risk of HCC compared with those who ate soy-containing
foods no more than once per week.
The odds ratio for miso soup remained unchanged at 0.5 after
adjusting for year of birth, sex, HBV, HCV and other variables. The
adjusted OR for tofu was 0.9.
"There was a statistically significant interaction (p < 0.0001)
between sex and HCV in the etiology of HCC, with women being at greater
risk than men," Dr. Sharp's team writes. Overall, 78% of female cases
had HCV infection, compared with 37% of male cases. Corresponding
numbers for female and male controls were 7% and 11%, respectively.
The authors note that these findings are consistent with results of
other studies. The lower HCC risk associated with higher soy
consumption intake "may reflect a counteracting effect of isoflavones
on estrogen and testosterone levels that reduces HCC risk," the
Int J Cancer 2005;115:290-295.