Unless you’ve been living under a rock somewhere for the last several
years, you’ve probably heard about the health benefits of eating
fatty fish or taking fish oil supplements. Well, it looks like you might
be able to add fat loss alongside the other benefits like heart, blood
(cholesterol/triglycerides), brain, skin and joint health (and the rest
of the list, which is too long to print here).
The biologically active ingredients that seem to make fatty fish so beneficial
are are the long chain omega-3 (n-3) fatty acids, EPA and DHA. At least
a half a dozen human studies and more than two dozen animal studies have
been completed in the last 10 years which suggest that these omega-3 fatty
acids found in fish may help you lose more fat. However, the fat loss benefit
is not as much as some people want you to believe…
The results of two new studies on fish oil and fat loss were just released
earlier this year. In one study published by the International Journal
of Obesity, researchers from Reykjavik Iceland tested the effects of fish
or fish oil consumption equivalent to 1.5 grams of combined EPA/DHA on
body weight and body composition as part of a calorie restricted diet.
(1)
The subjects were 324 young overweight men and women who followed one
of four experimental protocols for 8 weeks:
(1) sunflower oil capsules (control)
(2) lean fish
(3) fatty fish (salmon)
(4) fish oil capsules
The researchers reported the following results:
“In young, overweight men, the inclusion of either lean or fatty
fish, or fish oil as part of a hypoenergetic diet resulted in 1 kilogram
more weight loss after 4 weeks than a similar diet without seafood or supplement
of marine origin. The addition of seafood to a nutritionally balanced energy-restricted
diet may boost weight loss.”
It should be noted that the study was supported by the Seafood Plus organization
and there were some limitations in the design that could have influenced
the subject’s compliance.
The second study, conducted at the University of South Australia and published
in the American Journal of Clinical Nutrition (2) investigated the effect
of combining fish oil supplements with regular aerobic exercise.
In a 12-week, placebo-controlled study, the subjects were divided into
four groups:
(1) sunflower oil
(2) sunflower oil plus exercise
(3) fish oil
(4) fish oil plus exercise.
The fish oil groups were given 6 grams of high DHA fish oil per day, which
contained a total of 1.9 grams of long chain omega-3 fatty acids. The exercising
groups performed aerobic exercise three days per week for 45 minutes.
As you might expect, the fish oil plus exercise group came out with the
best results:
- minus 1.2% body fat (compared to no decrease in the other
groups)
- minus 2 kilograms/4.4 lbs (compared to no decrease in the
non exercise group).
Unfortunately, there was a limitation in this study as well: The food
intake of the subjects was self reported, which is known to be notoriously
inaccurate.
There have been several other human studies on fish oil and fat loss in
the last ten years or so and the majority of the findings have been positive.
The research is compelling and there have been numerous, and very plausible
mechanisms of action proposed.
However, more and more often, I am hearing people in the health, fitness
and nutrition industries making some pretty bold and I daresay, premature
and outrageous claims about what fish oil can do for fat loss; claims which
are not supported by the research.
The studies on fish oil and fat loss are encouraging, but the vast majority
of research has been on animals (rats, mice and hamsters) and there have
been limitations in nearly all the human studies so far, including:
Small sample sizes, short study durations, statistically insignificant
results, lack of randomization, no control groups, imprecise body composition
testing, measurement errors, self-reporting of food intake, low compliance
control and fish industry or supplement industry-sponsored bias.
Even if you take the results of the existing research at face value, the
fat loss really isn’t all that impressive - an extra pound here,
an extra kilo there.
Many of the research results barely reach statistical significance, and
you even have to wonder if these small improvements in fat loss are simply
correcting omega-3 deficiency or fixing omega-3 and omega-6 imbalance… therefore,
will they continue over a longer time period or is this a one time improvement?
One of the earlier studies showed the same kind of measurable but modest
results: The fish oil group that took 1.8 grams of combined EPA/DHA daily
lost 2 pounds and the non fish oil group lost only 0.7 pounds after 3 weeks
(3).
Of course, you’ll probably take all the fat loss help that you can
get, and since there are already enough good reasons to eat fatty fish
for cardiovascular disease prevention and other health benefits, it’s
really a no brainer to eat fish such as salmon, trout, mackerel or sardines
at least twice a week. (By the way, with the exception of King Mackerel,
these are species which have not been reported as having problems with
mercury contamination).
Alternately, you can use a fish oil supplement to get the equivalent in
omega-3 fatty acids as found in the fish. Non fish eaters or vegetarians
can use flaxseed oil, a plant-based source of Alpha Linolenic Acid (ALA)
which converts in the body to EPA and DHA (the efficiency and amount of
conversion has been a subject of controversy, however).
Based on the three studies cited above, it looks like 1.5 to 2.0 grams
per day of combined DHA/EPA is the right dose when fat loss is the goal
(although some suggest you should consider body weight when choosing the
dosage, i.e., 1 gram total fish oil for each 20 lbs body weight, so a big
guy might go with as much as 3.0 grams)
Most fish oil capsules come in 1,000 mg size at a 30% concentration, so
if you took five 1000mg capsules a day, that would give you 1.5 grams of
EPA/DHA; about the same as you’d get in 3 ounces (85 g) of salmon.
Note: other studies on fish oil and fat loss tested 3.0 to 4.0 g/day of
EPA/DHA, but the American Heart Association has warned against taking more
than 3 g EPA/DHA per day without a physicians supervision, as there may
be potential contraindications and side effects such as increased bleeding
time. Based on the research, more fish oil will NOT burn more fat, so be
wary of the “mega dose gurus.”
Another tip: Don’t fall for the “premium price” necessarily
means better quality party line. Quality and purity are important, but
you can get molecularly-distilled, mercury, PCB, Dioxin, Organochlorine-free,
3rd party tested-to-meet-label-claims fish oil for less than ten bucks
per bottle of 400 (one gram) capsules… yet I have seen “fish
oil gurus” selling the exact same thing for $50 to $60 claiming that
everyone else’s products are “contaminated” and “inferior” in
quality. If that’s true, then I’d like to see those products
submitted to consumer lab for voluntary 3rd party independent analysis
and head to head comparison on purity AND cost effectiveness. If they come
out superior and cost effective, I will gladly publicize the results myself.
The bottom line is it looks like fish oil may be a legitimate help to
your fat loss efforts, especially when combined with exercise, as there
may be an important synergy there. However, the idea that fish oil is some
kind of miracle fat burner is just not true.
Like Mulder on the X-files, “I want to believe”… but
we need much, much more research before we can say for certain exactly
how much body composition improvement you can really expect from eating
fatty fish or taking fish oil supplements.
References:
(1) Hill AM. Combining fish-oil supplements with regular aerobic exercise
improves body composition and cardiovascular disease risk factors. Am J
Clin Nutr. 86(5): 1267-1274. 2007
(2) Thorsdottir I et al. Randomized trial of weight loss diets for young
adults varying in fish and fish oil content. Int J Obesity. May 2007. pp
1-7
(3) Couet C. Effect of dietary fish oil on body fat mass and basal fat
oxidation in healthy adults. Int J Obes. 21: 637-643. 1997
