Home' Trinidad and Tobago Guardian : March 26th 2014 Contents B44
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Polyunsaturated fats generally come from plant-based foods such as nuts, seeds and vegetable oils. Omega-3
fatty acids, a type of polyunsaturated fats, are found in fish.
The types of fat people get in their
diet may not be as closely related to
their risk of heart disease as previously
believed, a new review of past studies
Guidelines from the US federal gov-
ernment and recommendations from
the American Heart Association call for
increased consumption of polyunsatu-
rated fatty acids and lower consumption
of saturated fats.
But researchers found people s risk
of heart disease varied little based on
how much of those fats they ate.
Polyunsaturated fats generally come
from plant-based foods such as nuts,
seeds and vegetable oils. Omega-3 fatty
acids, a type of polyunsaturated fats,
are found in fish.
On the other hand, most saturated
fats in the American diet come from
foods of animal origin, including red
meat and high-fat dairy products.
The authors of the new review say
uncertainties in evidence have led to
considerable variation in international
guidelines on fat intake. They also say
the use of self-reported diet information
may have resulted in problems classi-
fying the different fatty acids that people
"We intended to help resolve the
existing uncertainties around fatty acids
and their potential association with
coronary heart disease risk," Dr Rajiv
Chowdhury told Reuters Health in an
Chowdhury, from the University of
Cambridge in the UK, led the review
that was published in the Annals of
He and his colleagues collected data
from 72 previously published studies of
more than 600,000 people from 18
Those included studies that measured
the types of fatty acids people consumed
or had in their blood, as well as those
that randomly assigned people to take
fatty acid supplements or not.
All of the studies followed participants
to see who developed heart problems
like heart attacks, heart disease or coro-
When Chowdhury and his team
analysed data on fatty acid intake, they
found that none of the types of saturated
or polyunsaturated fats had a significant
impact on heart disease risk. However,
consumption of trans fat---found in some
processed foods and some forms of stick
margarine---was tied to a 16 per cent
increase in risk. Guidelines call for avoid-
ing trans fats altogether.
When the researchers examined
markers of fatty acids in the blood, they
also found little difference in heart risk
based on levels of saturated or polyun-
saturated fats. But the results varied for
individual fatty acids.
The researchers found that higher
blood levels of two forms of omega-3
fatty acids---docosahexaenoic acid (DHA)
and eicosapentaenoic acid (EPA)---were
associated with a lower risk of heart
They did not see a significant reduc-
tion in heart disease risk with any of
the fatty acids in studies that randomly
assigned some participants to take them
in supplement form. Doses used in the
studies ranged from 2 to 5.5 grammes
per day of added oils and 0.3 to 6 grams
per day when capsules were used.
"The pattern of findings from this
review did not support the current car-
diovascular guidelines that encourage
high consumption of total long-chain
omega-3 polyunsaturated fatty acids
and suggest reduced consumption of
total saturated fatty acids," Chowdhury
But he said further careful research
and specifically large-scale clinical trials
are required before making a conclusive
judgment and changing dietary guide-
Linda Van Horn, from the North-
western University Feinberg School of
Medicine in Chicago, told Reuters Health
the study was well done and demon-
strated that some fatty acids are better
than others. But it s not enough to
change current guidelines, she added.
Van Horn chaired the 2010 US
Dietary Guidelines Advisory Committee
which was involved in creating federal
recommendations and is a spokesperson
for the American Heart Association.
She was not involved in the new review.
"People need to eat as has been rec-
ommended---this paper changes nothing
about the adverse impact of saturated
fat," she said.
Van Horn pointed out that there is
no biological need for saturated fats.
"People like their burgers and their
hot dogs," she said, "but this study still
doesn t make them nutritious."
"Frankly I m really worried this will
confuse consumers," Duffy MacKay told
Reuters Health of the findings.
MacKay is senior vice president of
scientific and regulatory affairs for the
Council for Responsible Nutrition, a
trade association in Washington, DC.
He was not involved in the new research.
"It may possibly be used by some as
a licence to ignore these decades of
good advice, common sense and Grand-
ma s advice, and go right for the cheese
breads," he said.
He said the report doesn t change
what s perceived as a heart-healthy diet.
"I think the concept of a diet high in
polyunsaturated fat, low in saturated fat
and low in trans fat still holds a lot of
weight based on decades of research,"
MacKay also said this report does
nothing to change the need to get certain
fatty acids in the diet.
"It all pointed toward the contribution
of EPA and DHA as maintaining heart
health and preventing cardiovascular
disease, which to me is promising," he
Van Horn said the emphasis is still
on choosing plant-based foods and fish.
effects of dietary
fats on heart disease
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