The omega-3 wars are heating up. Omega-3 fatty acids
have gotten a lot of positive press lately. Clinical
studies suggest that the omega-3 fatty acids EPA and
DHA may reduce the risk of heart attacks and strokes
and help reduce the pain and stiffness associated with
inflammation. Other studies show that DHA in particular
is important for brain development and may even reduce
ADD and ADHD in children and slow mental decline in
adults. But where should you get those omega-3 fatty
acids – particularly if you’re concerned about the
presence of PCBs and mercury in many ocean fish?
People have relied on fish oil supplements for years,
but the new kid on the block is krill oil. If you
believe the krill oil manufacturers, you would think
that krill oil is better utilized, purer, more
effective, and more sustainable than fish oil. So what
is the truth? Is krill oil really better than fish oil?
Let’s look at the science and let the chips fall where
Let’s start at the beginning. What is krill oil? krill
are small crustaceans that are found in deep ocean
waters. They look a bit like tiny shrimp. Krill are
rich source of omega-3 fatty acids, especially EPA and
DHA. They are near the bottom of the food chain. In
fact, they are where many of the ocean fish actually
get their omega-3 fatty acids. Because they’re near the
bottom of the food chain, they are less contaminated
with PCBs and mercury than the predators at the top of
the food chain. At this point you’re probably thinking
that they’re sounding pretty good. But, we need to dig
a bit deeper.
First we need to look at the oils themselves. In most
fish oil supplements the omega-3 fatty acids are found
primarily as triglycerides. In the high purity, high
potency pharmaceutical grade fish oil supplements the
omega-3 fatty acids are found primarily as ethyl
esters. In krill oil the omega-3 fatty acids are found
as a mixture of triglycerides and phospholipids. So
what is the difference?
The krill oil manufacturers would have you believe that
omega-3 phospholipids are more rapidly absorbed than
omega-3 triglycerides and are directly incorporated
into cell membranes. As a biochemist I find that last
statement highly misleading. In fact, triglycerides and
phospholipids in the foods that we eat are broken down
to their component parts and reassembled several times
before they actually make it into cell membranes. So
omega-3 phospholipids may be more rapidly absorbed, but
they are not directly incorporated into cell membranes.
Notice that I said “may be more rapidly absorbed”. I
didn’t say “are more rapidly absorbed”. Those words
were chosen carefully, because the science isn’t clear.
Some of the companies who sell krill oil claim that
they have clinical studies showing that krill oil is
substantially better absorbed than fish oil. But those
studies are unpublished and, therefore, unreliable. If
you look at the three published studies comparing krill
oil and fish oil absorption, the data are much less
For example, one study (Lipids Health Dis., 2011,
10:145. Doi:10.1186/1476-511X-10-145) reported a higher
uptake of omega-3 fatty acids into the bloodstream from
krill oil than from fish oil in either the triglyceride
or ethyl ester form. However, those differences were
not statistically significant. A second study (Nutr.
Res., 2009, 29: 609-615) found no difference in the
uptake of omega-3 fatty acids into the bloodstream
between krill oil in menhaden oil. And a third study
Lipids, 2011, 46: 37-46) found no difference in the
uptake of omega-3 fatty acids into the bloodstream or
in markers of inflammation and oxidative stress between
subjects taking krill oil or fish oil. So if krill oil
has any advantage in terms of uptake and utilization of
omega-3 fatty acids, it’s pretty marginal.
Another claim of the krill oil manufacturers is that
krill oil is less contaminated than fish oil. While
that may be true for some of the fish oil products on
the market, it’s definitely not true of the high purity
pharmaceutical grade fish oil supplements.
And finally, what about the claim that krill oil is
more sustainable? There is no question that
sustainability of our fish supply is an important
issue. But, what krill oil proponents forget is that
small fish eat the krill; bigger fish eat the smaller
fish and so on. Depleting the bottom of the food chain
on which ocean fish rely will eventually affect their
sustainability just as much as overfishing.
And, on the negative side, krill oil is generally more
expensive and has lower concentrations of omega-3 fatty
acids than fish oil. So, is it worth the added cost?
I’ll let you be the judge.
So what’s the bottom line for you?
1) The so-called advantages of Krill oil appear to be
greatly over hyped.
– Based on the scientific studies published to date
any advantage in uptake and utilization of omega-3
fatty acids from krill oil is minimal at best.
– The purity argument is a red herring (If you’ll
pardon the pun). Differences in purity are more likely
to depend on the purification methods and quality
control standards of the manufacturer than on the
source of the oil.
– The sustainability argument is another red herring.
In the long run it doesn’t matter whether you deplete
the bottom of the food chain or the top of the food
2) Finally, my advice to you whether you use krill oil
or fish oil is to be sure to choose a company that
manufactures a high purity pharmaceutical grade oil,
has rigorous quality control standards, and has
published clinical studies showing that their
supplement is well utilized.
To Your Health!
Dr. Stephen G Chaney