Is Milk From
Grass-Fed Cows
More
Heart-Healthy?
Costa Rican
study hints at
heart attack
protection
through milk
fat.
(Reuters Health)
- If milk does
the heart good,
it might do the
heart better if
it comes from
dairy cows
grazed on grass
instead of on
feedlots,
according to a
new study.
Earlier
experiments have
shown that cows
on a diet of
fresh grass
produce milk
with five times
as much of an
unsaturated fat
called
conjugated
linoleic acid (CLA)
than do cows fed
processed
grains. Studies
in animals have
suggested that
CLAs can protect
the heart, and
help in weight
loss.
Hannia Campos of
the Harvard
School of Public
Health in Boston
and her
colleagues
found, in a
study of 4,000
people, that
people with the
highest
concentrations
of CLAs -- the
top fifth among
all participants
-- had a 36
percent lower
risk of heart
attack compared
to those with
the lowest
concentrations.
Those findings
held true even
once the
researchers took
into account
heart disease
risk factors
such as high
blood pressure
and smoking.
The new findings
suggest that CLA
offers
heart-healthy
benefits that
could more than
offset the harms
of saturated fat
in milk, Campos
said.
"Because pasture
grazing leads to
higher CLA in
milk, and it is
the natural feed
for cattle, it
seems like more
emphasis should
be given to this
type of
feeding," she
told Reuters
Health by email.
Dairy products
in the U.S. come
almost
exclusively from
feedlots, she
added. And cow's
milk is the
primary source
of CLA. (Beef
contains a small
amount.)
Campos and her
colleagues
looked to Costa
Rica for their
study, where
pasture grazing
of dairy cows is
still the norm.
They identified
nearly 2,000
Costa Ricans who
had suffered a
non-fatal heart
attack, and
another 2,000
who had not.
Then they
measured the
amount of CLA in
fat tissues to
estimate each
person's intake.
Since CLA
typically
travels with a
host of other
fats, the
researchers went
a step further
to tease apart
its effects from
those of its
predominantly
unhealthful
companions, they
report in the
American Journal
of Clinical
Nutrition. The
difference in
risk attributed
to CLA
subsequently
rose to 49
percent.
"Whole-fat milk
and dairy
products have
gotten such a
bad reputation
in recent years
due to their
saturated fat
and cholesterol
contents, and
now we find that
CLA may be
incredibly
health-promoting,"
Michelle
McGuire,
spokesperson for
the journal's
publisher, the
American Society
for Nutrition,
and associate
professor at
Washington State
University, told
Reuters Health
in an email.
"Whole milk is
not the
villain!"
Each year,
approximately
1.5 million
Americans will
suffer a heart
attack. A third
will not
survive.
The evidence may
now be piling
up: another
paper out of
Sweden in the
same issue of
the journal as
the Costa Rican
study also hints
at heart attack
protection
through milk
fat.
Further, the
benefits of CLA
may extend
beyond the heart
to the
prevention of
cancer and
diabetes,
suggests
McGuire,
pointing to
results of other
animal studies.
"Milk is
actually the
only food ever
'designed by
nature' to be
fed to mammals,"
she added. "We
need to look to
milk as the
perfect food and
learn everything
we can from it."
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