- WASHINGTON (Reuters) - Men who eat the most meat and dairy products are
the most likely to die from prostate cancer, while those who eat plenty
of grains and nuts are the least likely to succumb to the disease, an international
study showed Wednesday. A survey of prostate cancer deaths in 59 countries
showed that diet is strongly linked to mortality from the disease, the
second-biggest cancer killer of men after lung cancer. ``Animal energy
was positively associated with prostate cancer mortality,'' James Hebert
of the University of Massachusetts Medical School and his colleagues wrote
in a report in the Journal of the National Cancer Institute.
- ``Overall, we observed protective effects
from higher levels of intake of cereals, nuts and oil seeds (which include
soy consumption) and fish,'' they wrote. They found what a number of other
studies looking at diet's role in heart disease and cancer have found --
that the plant-based diets found in many less-advanced societies are the
healthiest, as long as people get enough to eat.
- ``Our results showed that prostate cancer
mortality is positively associated with dietary factors associated with
affluence, including estimated intakes of energy, total fat and animal
products (specifically milk, meat and poultry),'' they wrote. ``On the
other hand, intakes of cereals, soybeans, other nuts and oilseeds, and
fish were negatively associated with prostate cancer mortality,'' they
added. They noted that several studies have proposed a mechanism for this.
``For prostate cancer and cancers of other sites that are sensitive to
serum (blood) hormone levels, animal fat may influence the risk for cancer
by raising adult's sex hormone levels,'' they wrote. Prostate cancer is
linked with testosterone levels, and is often treated by cutting testosterone
production -- sometimes by surgical or chemical castration.
- Breast cancer in women is linked with
estrogen levels -- and has also been linked with a high-fat diet. Hebert's
team noted that black American men have a prostate cancer rate that is
40 percent higher than the rate found in white men, and that black men
tend to have higher testosterone levels. Colon cancer, the third-biggest
cancer killer in the United States, has also been linked with a diet high
in animal fat and low in fruits, vegetables and whole grains. Hebert's
team looked at the numbers in several different ways. Men who drank the
most alcohol were also the most likely to die from prostate cancer, while
those who ate the most soy products were the least likely to die.
- They said it was not entirely clear whether
fish had a protective effect, because the men who ate the most fish also
ate the most soy. Both fish and soy contain omega-three fatty acids, which
have been shown in tests to inhibit the growth of tumors. The researchers
noted that the lowest death rates from prostate cancer are in countries
such as Japan, where people eat a great deal of soy and fish and less meat.
The differences persisted even when the environment, exercise and other
factors were considered. ``On the basis of the results of this study and
other studies, it appears that the Western diet may contribute to the risk
for prostate cancer mortality,'' they concluded.