SCIENTISTS SUSPECT OMEGA-3 FATTY ACIDS COULD SLOW ACUTE WOUND HEALING
COLUMBUS,
Ohio – A recent study shows that popular fish oil supplements have an
effect on the healing process of small, acute wounds in human skin. But
whether that effect is detrimental, as researchers initially suspected,
remains a mystery.
The omega-3 fatty acids
found in fish oils are widely considered to benefit cardiovascular
health and other diseases related to chronic inflammation because of
their anti-inflammatory properties. But insufficient inflammation
during the initial stage of wound healing may delay the advancement of
later stages.
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Jodi McDaniel |
In
the study, blister wounds on the arms of people taking fish oil
supplements were compared to the wounds of people taking a placebo. The
wounds healed in about the same amount of time – but at the local
cellular level, something unexpected happened. The levels of proteins
associated with initiating and sustaining inflammation were higher in
the blister fluid in people who had taken the active fish oil
supplements. The researchers had expected those proteins to be lowered
by the increased systemic presence of omega-3 fatty acids in the blood.
“That finding was hard to explain,” said Jodi McDaniel, lead author of the study and an assistant professor of nursing at Ohio State University.
“These proteins may have other functions that we don’t yet fully
understand. And our results also suggested there could be a difference
between men and women in the amount of inflammatory proteins that are
produced, because on average, women had lower levels of one of the
proteins.”
If the polyunsaturated fatty acids in
the fish oils do indeed delay acute wound healing, then they probably
should be discontinued for awhile by patients scheduled for surgery,
McDaniel said. They appear to have enough of an effect that patients
should at least inform their doctors if they’re taking a fish oil
supplement, she added.
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“We’re
just trying to figure out how to evaluate what omega-3s do and how to
advise people to take these supplements. Our goal isn’t to stop
supplement use but to fill in the picture of what conditions they help
and what they might hurt.”
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But
there could still be a bright side to the supplements’ ability to alter
those proteins and other molecular substances that control inflammation
locally. Fish oil’s systemic anti-inflammatory power, which has been
illustrated in previous studies, still might assist in the healing of
chronic wounds at the local level. Chronic wounds are essentially stuck
in an inflammatory stage that slows or prevents transition to the later
stages needed for complete healing. That mechanism needs to be explored
further, McDaniel said.
“There’s so much information out
there now about omega-3s and they clearly have lots of potential,”
McDaniel said. “We’re just trying to figure out how to evaluate what
they do and how to advise people to take these supplements. Our goal
isn’t to stop supplement use but to fill in the picture of what
conditions they help and what they might hurt.”
The research is published in a recent issue of the journal
Wound Repair and Regeneration.
Study
participants were divided into two groups of 15 healthy adults each.
One group took a placebo, and the other took an active supplement
containing 1.6 grams of eicosapentaenoic acid (EPA) and 1.1 grams of
docosahexaenoic acid (DHA) daily for four weeks. EPA and DHA are the
polyunsaturated fatty acids obtained primarily from fish oil that serve
as the basis of most standard omega-3 supplements.
Previous research has suggested that these fatty acids affect the production of proteins called proinflammatory cytokines,
which signal biological processes during the inflammatory stage of
wound healing. The primary cytokines in the process are interleukin-1
beta (IL-1b), interleukin-6 (IL-6) and tumor necrosis factor-alpha
(TNF-a).
But research had not yet addressed how the interaction
between fatty acids and these cytokines might affect human wounds.
McDaniel
and colleagues expected to find that research participants taking the
fish oil supplements – and therefore being affected by their
anti-inflammatory properties – would have significantly lower levels of
the cytokines in their blister wounds during the initial stage of
inflammation, resulting in a slower healing process.
Instead,
the group taking the fish oil had significantly higher levels of IL-1b
in their blister wounds than did the placebo group 24 hours after the
wounds were created. The active group also had higher levels of IL-6
and TNF-a cytokines in their blisters over time than did the placebo
group, but those differences in levels were not significant. The
blisters took an average of 10.7 days to completely heal in the active
supplement group and an average of 9.8 days in the placebo group, but
the difference was not significant.
The results suggest
that the function of these cytokines still isn’t completely understood,
McDaniel said. And the scientists were also surprised to find that
gender appeared to make a difference in cytokine production. Men were
more likely than women among the active supplement group to have higher
levels of the IL-1b cytokine in their wounds. McDaniel said that some
studies have suggested that estrogen plays a role in inhibiting the
production of this particular protein during the inflammatory stage of
wound healing, but more research is needed.
McDaniel and
colleagues are following up with a similar study in which they are
adding a low-dose aspirin to both the fish oil supplement and placebo
groups. Some research has shown that aspirin can facilitate the
anti-inflammatory properties of omega-3 fatty acids, and low-dose
aspirin is commonly included in the medication regimen of patients with
cardiovascular disease.
The researchers also will look at
different biological markers in blister wounds to see if the
combination of fish oil and aspirin produces compounds that function as
what McDaniel called “stop and go switches” in controlling
inflammation.
“If we find that the fish oil can work in
an anti-inflammatory fashion at the local level of wound sites, we
would consider moving on to the chronic wound population,” McDaniel
said. “Even if we find that there are times when omega-3 fatty acids
should not be taken in advance of creating an acute wound, such as in
elective surgery, we still have high hopes that fish oil might be
beneficial for chronic wounds in certain situations.”
This research was supported by the National Institutes of Health/National Institute of Nursing Research Predoctoral National Research Service Award Fellowship program; Sigma Theta Tau International, Epsilon Chapter; and Ohio State University Alumni Grants for Graduate Research & Scholarship.
Co-authors
on the study were Martha Belury of Ohio State’s College of Education
and Human Ecology and Karen Ahijevych and Wendy Blakely of Ohio State’s
College of Nursing.
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Contact: Jodi McDaniel, (614) 292-1345; Mcdaniel.561@osu.edu
Written by Emily Caldwell, (614) 292-8310; Caldwell.151@osu.edu
