5 Studies on Saturated Fat — Time to Retire the Myth?
5 Studies on Saturated Fat — Time to Retire the Myth?
This was
originally based on observational studies showing that people who consumed a
lot of saturated fat had higher rates of death from heart disease.
The
diet-heart hypothesis states that saturated fat raises LDL (bad) cholesterol in
the blood, which then supposedly lodges in the arteries and causes heart
disease.
Even
though this hypothesis has never been proven, most official dietary guidelines
are based on it.
While the
issue is still debated, numerous recent studies have found no link between
saturated fat consumption and heart disease.
This
article reviews 5 of the large, most comprehensive and most recent studies on
this issue.
1. Hooper
L, et al. Reduction in
saturated fat intake for cardiovascular disease . Cochrane Database
Systematic Review, 2015.
Details: This
systematic review and meta-analysis of randomized controlled trials was
performed by the Cochrane collaboration — an independent organization of
scientists.
This
review includes 15 randomized controlled trials with over 59,000 participants.
Each of
these studies had a control group, reduced saturated fat or replaced it with
other types of fat, lasted for at least 24 months, and looked at hard
endpoints, such as heart attacks or death.
Results: The
study found no statistically significant effects of reducing saturated fat in
regard to heart attacks, strokes, or all-cause deaths.
Although
reducing saturated fat had no effects, replacing some of it with
polyunsaturated fat led to a 27% lower risk of cardiovascular events (but not
death, heart attacks, or strokes).
Conclusion: People
who reduced their saturated fat intake were just as likely to die, or get heart attacks or strokes,
compared with those who ate more saturated fat.
However,
partially replacing saturated fat with polyunsaturated fat may reduce the risk of
cardiovascular events (but not death, heart attacks, or strokes).
These
results are similar to a previous Cochrane review conducted in 2011.
2. De
Souza RJ, et al. Intake of
saturated and trans unsaturated fatty acids and risk of all-cause mortality,
cardiovascular disease, and type 2 diabetes: Systematic review and
meta-analysis of observational studies. BMJ,
2015.
Details: This
systematic, observational review of studies looked at the association of
saturated fat and heart disease, stroke, type 2 diabetes, and death from
cardiovascular disease.
The data
included 73 studies, with 90,500–339,000 participants for each endpoint.
Results: Saturated
fat intake wasn’t linked with heart disease, stroke, type 2 diabetes, or dying
of any cause.
Conclusion: People
who consumed more saturated fat weren’t more likely to experience heart
disease, stroke, type 2 diabetes,
or death from any cause, compared with those who ate less saturated fat.
However,
the results from the individual studies were very diverse, so it’s hard to draw
an exact conclusion from them.
The
researchers rated the certainty of the association as “low,” emphasizing the
need for more high quality studies on the subject.
3.
Siri-Tarino PW, et al. Meta-analysis of
prospective cohort studies evaluating the association of saturated fat with
cardiovascular disease. American
Journal of Clinical Nutrition, 2010.
Details: This
review looked at evidence from observational studies on the link between
dietary saturated fat and risk of heart disease and stroke.
The
studies included a total of 347,747 participants, who were followed for 5–23
years.
Results: During
follow-up, about 3% of participants (11,006 people) developed heart disease or
stroke.
Saturated
fat intake wasn’t linked to an increased risk of cardiovascular disease, heart
attacks, or strokes, even among those with the highest intake.
Conclusion: This
study didn’t find any association between saturated fat intake and
cardiovascular disease.
4.
Chowdhury R, et al. Association of
dietary, circulating, and supplement fatty acids with coronary risk: A
systematic review and meta-analysis. Annals
of Internal Medicine Journal, 2014.
Details: This
review looked at cohort studies and randomized controlled trials on the link
between dietary fatty acids and the risk of heart disease or sudden cardiac
death.
The study
included 49 observational studies with more than 550,000 participants, as well
as 27 randomized controlled trials with more than 100,000 participants.
Results: The
study didn’t find any link between saturated fat consumption and the risk of
heart disease or death.
Conclusion: People
with higher saturated fat intake weren’t at an increased risk of heart disease
or sudden death.
Furthermore,
the researchers didn’t find any benefit to consuming polyunsaturated fats
instead of saturated fats. Long-chain omega-3 fatty acids were an exception, as
they had protective effects.
5. Schwab
U, et al. Effect of the
amount and type of dietary fat on risk factors for cardiometabolic risk
factors, and risk of developing type 2 diabetes, cardiovascular diseases, and
cancer: A systematic review. Food
and Nutrition Research, 2014.
Details: This
systematic review assessed the effects of the amount and type of dietary fat on
body weight and the risk of type 2 diabetes, cardiovascular disease, and
cancer.
Participants
included both people who were healthy and those with risk factors. This review
included 607 studies, including randomized controlled trials, prospective
cohort studies, and nested case-control studies.
Results: Consuming
saturated fat wasn’t linked to an increased risk of heart disease or an
increased risk of type 2 diabetes.
The
researchers found that partially replacing saturated fat with polyunsaturated
or monounsaturated fat may lower LDL (bad) cholesterol concentrations.
It also
may decrease the risk of cardiovascular disease, especially in men.
However,
substituting refined carbs for saturated fat may increase the
risk of cardiovascular disease.
Conclusion: Eating
saturated fat doesn’t increase the risk of heart disease or type 2 diabetes. However,
partially replacing saturated fat with polyunsaturated fat may help reduce the
risk of heart disease, especially in men.
KEY FINDINGS
1.
Reducing saturated fat intake has no effect on your risk of
heart disease or death.
2.
Replacing saturated fat with refined carbs seems to increase
your risk of heart disease.
3.
Replacing saturated fat with polyunsaturated fat may reduce your
risk of cardiovascular events, but results for heart attacks, strokes, and
death are mixed.
The bottom line
People
with certain medical conditions or cholesterol problems may need to watch their
saturated fat intake.
However,
the study results selected for this article are pretty clear that, for the
average individual, saturated fat has no significant association with heart
disease.
That
said, replacing saturated fat with unsaturated fat may offer slight benefits.
This
doesn’t mean that saturated fat is “bad” — just that it’s
neutral, while some unsaturated fats are particularly healthy.
By
replacing something that’s neutral with something that’s very healthy, you’ll
get a net health benefit.
Healthy
sources of unsaturated fats include nuts, seeds, fatty fish, extra virgin olive
oil, and avocados.
At the
end of the day, there doesn’t seem to be any reason for the general population
to worry about saturated fat.
There are
other issues that are much more worthy of your attention, like avoiding sugary
soda and junk food, eating healthy food, and exercising.
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