Auburn, April 25---As the saying goes, there
are two things in life that are certain: death and taxes.
If you’re obese, sedentary or consume too much
saturated fat, add to that list a greater likelihood of developing
certain forms of cancer, especially breast and prostate cancer.
"We’re not quite sure how these components
(obesity, sedentary lifestyle or high-fat diets) actually contribute
to these cancers," says Dr. Robert Keith, an Alabama
Cooperative Extension System nutritionist. "They’re all tied
"It’s hard sorting everything out, though it
does seem certain excess body fat is a big contributor."
While many people traditionally have thought of body
fat as just a storage place for energy, researchers have learned it
involves more than that, Keith says. Fat tissue, in fact, appears to
be a very active substance within the body.
"One of the things it can produce is a
steroid-type hormone," Keith says. "It produces
estrogen-like hormones, and if you have excess body fat, you tend to
produce more of them."
Research has shown some forms of breast cancer as
well as prostate cancer are sensitive to these hormones. Cells
exposed to these hormones become more metabolically active and begin
dividing at abnormally higher rates.
"We know this whole process is linked with body
fat, but we’re not quite sure how," Keith says. "We’re
not sure whether it stems from eating too much saturated fat or
consuming too many calories."
Experts also suspect a link between body fat and
colon cancer, though not in the same way as hormone-related cancer.
Some researchers even suspect this particular cancer may stem from
factors that are related to excessive body fat but that are
"We know that people who exercise a lot have
lower incidences of colon cancer – possibly because they tend to
eliminate more often," Keith says. "Conversely, people who
are obese tend to exercise the least and to eliminate less
Even so, Keith says, researchers have had a hard
time isolating the root cause of colon cancer because obesity and
exercise are so closely tied together.
"These two factors are hard to separate because
obesity and low levels of physical activity are so closely
linked," Keith says. "When someone gets colon cancer, is
it because he was obese or because he didn’t exercise?"
Other obesity-related factors also may contribute to
colon cancer, Keith says.
For example, people who eat high-fat foods, a major
contributor to obesity, tend to secrete more bile in their
intestines. Bile can be converted into a carcinogen after reaching
the intestinal tract and is suspected by some to contribute to an
increased colon-cancer risk.
Nevertheless, Keith says it’s important to
remember that obesity and high-fat diets are only two of the risk
factors associated with breast, prostate and colon cancer. Fit
people who exercise regularly are not immune to these types of
cancers, though they reduce their risk significantly by following
What science finally determines to be the root
cause(s) of cancer isn’t the biggest issue for consumers, Keith
says. What is important is for consumers to understand the close
link between three factors that contribute to breast, prostate and
colon cancer: obesity, sedentary lifestyles and high-fat diets.
"I’m not sure what science will finally
determine is the ultimate cause – or causes – of these types of
cancer," he says. "This I do know: If you’re overweight,
sedentary or consume too many high-fat foods, you face an increased
risk of certain types of cancer."
"So the important thing, from the standpoint of
consumers, is adopting a healthier lifestyle that will reduce these
Robert Keith, Extension nutritionist, 334-844-3273.)