Many Don’t Need
ColonoscopiesA review of 31 studies
showed that a fecal
immunochemical test
(FIT), a noninvasive
test that identifies
hidden blood in stool,
is effective in detecting
colorectal cancer.
This is the strongest
evidence yet that
average-risk pa-
tients can safely
avoid getting a
colonoscopy unless
they have an abnor-
mal FIT result.The Right Amount
of CarbsPeople who derive be-
tween 40 and 70 per-
cent of their calories
from carbohydrates
have a lower mortality
risk than those on low-
or high-carb diets, ac-
cording to a recent
study. Carb restriction
can aid weight loss in
the short term, but it
usually means filling
up on fats. Consuming
too many carbs, though,
can lead to blood sugar
problems.FEELING GOOD COULD
SLOW TUMOR GROWTH
F
rom savoring a piece of cake to hugging a
friend, many of life’s pleasures trigger a simi-
lar reaction in the brain—a surge of dopamine,
the “feel-good” chemical. Recent research suggests
this reward circuit may do much
more than make us smile.
Researchers implanted
skin and lung cancer cells
in mice, then stimulated
the dopamine-releasing
neurons in the ventral
tegmental area (VTA) of
their brains. The rush
of dopamine disabled a
group of cells that promote
tumor growth. That allowed
the immune system to respond
more effectively to the tumors, which were 40 to
52 percent smaller and lower in weight in mice that
received VTA stimulation than in those that didn’t.
“By artificially activating [the VTA],” says the study’s
coauthor, Asya Rolls of Technion-Israel Institute of
Technology, “we can affect the nervous system and,
in turn, the immune system.”
Moreover, the researchers explain, once the im-
mune system is activated in this way, it appears to
create a “memory” of the foreign agents to which
it has been exposed, allowing it to respond more
efficiently to them in the future.
Rolls doesn’t believe that positive thinking alone
can cure cancer. But the study’s authors hope that
cancer patients might someday receive brain stim-
ulation as an add-on therapy that could, in turn,
reduce the need for traditional treatments such as
chemotherapy and radiation.Reader’s Digest News from the World of Medicine
34 july/august 2019 | rd.com
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