Soy, Fish May Cut Cancer Risk
Studies Shed New Light on Diets That May Protect Against Cancer
Nov. 14, 2006 -- Soy and fish won attention today for their possible cancer
prevention qualities at a meeting of cancer researchers in Boston.
According to the research findings:
Those findings come from two different studies presented at the Frontiers in
Cancer Prevention Research Meeting, being held by the American Association for
However, the researchers warn, it's too soon to make dietary promises about
the cancer prevention qualities of soy and fish from these studies.
Soy & Breast Cancer
The study looking at soy was based on interviews with 1,500 women aged 20-55
of Chinese, Japanese, and Filipino descent. The women were living in Los
Angeles, San Francisco, and Hawaii.
Researchers included the National Cancer Institute's Larissa Korde, MD,
The researchers questioned the women -- and their mothers, when possible --
about how much soy they ate as kids, teens, and adults.
They found that women with the highest childhood soy intake were 58% less
likely to get breast cancer than those with the lowest intake.
In this study, women with the highest childhood soy intake ate soy -- mainly
tofu -- a little more than twice a week. Those with the lowest childhood soy
intake ate soy about once a month, Korde says.
Women who ate the most soy as teens or adults were about 25% less likely to
have breast cancer than those who skimped on it.
The study results weren't affected by family history of breast cancer and
were "strikingly consistent," Korde says.
She calls the findings "provocative" but says they need to be
Meanwhile, the researchers aren't telling anyone to load their kids' diets
"Our study suggests that soy intake during childhood may have a
biological effect on breast carcinogenesis [breast cancer development],"
Korde says, but she calls for further studies on the topic.
Men, Fish, and Colorectal Cancer
The second study found that men who eat fish frequently may be less likely
to develop colorectal cancer than those who rarely eat fish.
The researchers included Megan Phillips, a graduate student at the Harvard
School of Public Health.
The study reviewed data on about 22,000 men from the Physicians' Health
Study. In that large health study, in 1983, the men reported how often they ate
fish and shellfish over the course of a year.
Over the next 18 years, 501 of the men developed colorectal cancer.
"What we found was that men who ate the most fish -- and that was five
or more servings per week of fish -- compared to the least fish -- less than
one time per week -- had a 40% lower risk of developing colorectal cancer,"
She notes that previous studies haven't always found the same thing when it
comes to fish consumption and colorectal cancer.
"I think it's premature to make a recommendation for how much fish men
should eat to reduce their risk of colorectal cancer," she says.
"But I do think it provides possibly another reason for men to include
fish in their diet in addition to the benefit that we know about for heart disease," she says.
"The best recommendation at this time is a balanced diet," Elizabeth
Platz, ScD, MPH, told reporters in a teleconference.
A healthy diet includes fruits, vegetables, and plant-based proteins -- and
balances calories consumed with calories burned, she says.
Platz is an associate professor in the epidemiology department at Johns
Hopkins Bloomberg School of Public Health in Baltimore.