West Coast Woman October 2020

your health
HOW DOES
OBESITY CAUSE CANCER?
The link between obesity and cancer risk is clear.
What’s less clear is how exactly one leads to the other
THE LINK BETWEEN
obesity and cancer risk is
clear. Research shows that
excess body fat increases
your risk for several cancers, including
colorectal, post-menopausal
breast, endometrial, esophageal,
kidney and pancreatic cancers.
What’s less clear is exactly how
being obese increases that risk.
Experts believe it’s largely due to
the inflammation caused by visceral
fat – the fat that surrounds your
vital organs.
“The problem with excessive visceral
fat is that it affects certain processes
in your body. This includes
how your body manages hormones,
like insulin and estrogen,” says Adriana
Coletta, Ph.D. RD, a postdoctoral
fellow in cancer prevention.
“All of this can lead to an increased
cancer risk by affecting
how and when cells divide and die,”
she says.
How does obesity
cause inflammation?
Visceral fat cells are large, and
there are a lot of them. This excess
fat doesn’t have much room for
oxygen. And that low-oxygen environment
triggers inflammation.
Inflammation is the body’s natural
response to injury and disease. For
example, when you get a deep cut,
the area around the cut becomes
red and painful to touch. This minor
inflammation around the wounded
area helps repair the damaged tissue
and aids with the healing process.
But long-term inflammation
caused by excess visceral fat can
damage your body and increase
your risk for cancer.
Cancer happens when cells reproduce
uncontrollably, damaging
the cells around them and causing
illness. The more cells divide and
reproduce, the higher the risk that
something will go wrong and a tumor
will form.
Inflammation
and insulin
The link between inflammation
and insulin – the hormone that
regulates blood sugar – is complex,
Coletta says.
Inflammation caused by obesity
can keep the body from properly
responding to insulin. This is called
insulin resistance. When the body
doesn’t respond to insulin correctly,
it produces more insulin to
make up for that.
The increase in insulin due to insulin
resistance triggers an increase
in the number of cells produced,
which can lead to cancer. “Increased
insulin also affects how hormones
like estrogen are controlled,” says
Coletta. “More insulin can lead to
more available estrogen, which increases
cancer risk.”
How does more
estrogen increase
cancer risk?
“Basically, higher estrogen levels
lead to increased cell production,
which could result in tumor
growth,” Coletta says. Estrogen
is necessary for the body to function.
In women, the ovaries are
the main source of estrogen. In
men, an enzyme converts testosterone
to estrogen. But fat cells
in both men and women can also
make estrogen. This is why too
much estrogen is commonly seen
in obesity.
In women, too much estrogen
is linked to an increased risk for
post-menopausal breast, endometrial
and ovarian cancers.
Cancer and obesity:
What you can do?
One of the most important things
you can do to decrease your cancer
risk is maintain a healthy weight,
Coletta says.
There are steps you can take
to prevent obesity:
• Stay active. Aim for 150 minutes
of moderate activity or 75 minutes
of vigorous activity a week.
• Eat a healthy diet. Fill at least
2/3 of your plate with non-starchy
vegetables, fruit, whole grains or
legumes (beans and peas), and
1/3 or less with animal protein.
• If you drink alcohol, limit
yourself to one drink per day if
you are a woman, and two per
day if you are a man.
• Get plenty of rest. Fatigue can
make you want to eat more, and
make unhealthy choices.
Being obese or overweight hurts
your body’s ability to work well,
Coletta says. Maintaining a healthy
weight is essential for reducing
your risk for cancer.
SOURCE: AICR
How to determine
calorie burn
Of course exercise burns calories,
but which exercises burn the most?
And how do you know? We all
know that when it comes to weight
loss and energy balance, it’s a matter
of calories in versus calories
out. But when you exercise, do you
really know how many calories
you’re burning?
It’s important to learn how many
calories you typically burn so you
can control your weight, prevent
obesity and lower your cancer risk.
Here are some answers to
typical questions:
How do you know how
many calories you’ve
burned during a workout?
Measuring the exact number of
calories you burn can be difficult.
There are a few ways to measure
your calorie burn. You can:
• Use an activity tracker or an
app that will estimate your calorie
burn for you. But be careful
with these. The accuracy can
vary from product to product.
• A heart rate monitor is one of
the best ways to measure your
calorie burn. Your heart rate indicates
how much effort it takes
for you to do a certain activity,
and that effort determines the
calories you burn. If a heart rate
monitor indicates your calorie
burn, it’s more likely to be accurate
than the average activity
tracker because it’s taken your
specific heart rate in to account.
• A MET values chart can also
show you how many calories
are typically burned during
specific activity based on your
weight. This chart was created
by researchers and used
widely throughout the medical
community.
Which helps you lose more
weight: diet or exercise?
Diet. Cutting calories and eating
healthy will help you lose weight.
Exercise alone probably won’t help
you lose weight, but it will help you
keep the weight off.
To lose one pound a week you
should aim for a calorie deficit of
500 calories per day, through a combination
of reducing the calories
you eat and increasing the calories
you burn through physical activity.
This adds up to 3,500 calories per
week, the number of calories in
about one pound of fat.
What factors contribute
to how many calories
are burned?
Several factors contribute to how
quickly an individual burns calories,
including:
• The intensity of an activity being
performed. The more intense
an activity is the more calories
an individual burns.
• Weight. People who weigh more
burn more calories.
• Body composition. Muscle
requires more energy than fat to
maintain. People with more muscle
burn more calories.
How much activity
do I need to do?
To lower your cancer risk, aim for
at least 150 minutes of moderate
physical
activity or
75 minutes
of vigorous
activity
each
week.
Remember,
you
don’t have
to do it all
at once.
You can
break it up
throughout
the
day, too.
SOURCE:
MD
Anderson
Cancer
Center
20 WEST COAST WOMAN OCTOBER 2020