Mercury and Tuna: Advice Leaves Questions

Mercury and Tuna: Advice Leaves Questions

A joint EPA and FDA advisory issued last year urged limits on how much
tuna children and some women should eat. But those limits exceed safe
levels for some people, judging by a mercury risk assessment that the
EPA has produced on its own.

August 1, 2005
Fish Line
Mercury and Tuna: U.S. Advice Leaves Lots of Questions
Balancing Interests, Agencies Issue Guidance at Odds With EPA Risk
Assessment
A Schoolboy's Sudden Setback
By PETER WALDMAN
Staff Reporter of THE WALL STREET JOURNAL

SAN FRANCISCO -- One by one, Matthew Davis's fifth-grade teachers went
around the table describing the 10-year-old boy. He wasn't focused in
class and often missed assignments, they said. He labored at basic
addition. He could barely write a simple sentence.

"Our jaws dropped," says his mother, Joan Elan Davis, describing a
teachers' meeting she had requested in late 2003, when her son abruptly
lost interest in homework. Matthew had always excelled in school. In
the fourth grade, he had written and illustrated a series of stories
about a superhero named Dog Man.

Ms. Davis noticed something else: Her son's fingers were starting to
curl, as if he were gripping a melon. And he could no longer catch a
football.

A neurologist ordered tests. They showed Matthew's blood was laced with
mercury in amounts nearly double what the Environmental Protection
Agency says is the safe level for exposure to the metal. Matthew had
mercury poisoning, his doctors said.

The Davises had pinpointed the suspected source: tuna fish. For a year
or so, starting in late 2002, Matthew had gobbled three to six ounces a
day of white albacore tuna. Based on Food and Drug Administration data
for canned albacore, he was consuming a daily dose of mercury at least
12 times what the EPA considered a safe level for a 60-pound child. The
Davises' doctors' prescription was simple: Matthew should stop eating
canned tuna.

Ms. Davis, an artist, says she and her husband, a corporate executive,
had been proud of their son for choosing tuna over junk food. Now, she
asks herself: "Was I a bad parent? Was it my fault I didn't know there
was mercury in tuna?"

One reason she didn't know was that the government had never said so.
The FDA had known for many years that canned tuna contained mercury,
which studies link to learning impairment in children. Consumer groups
long urged the agency to address the issue. But it wasn't until March
2004, after regulatory tussles between health advocates and the tuna
industry and between clashing scientists for the FDA and EPA, that
those agencies issued a mercury advisory that cited tuna. That joint
EPA and FDA advisory urged limits on how much tuna children and some
women should eat.

But the limits set in the advisory may exceed safe levels for some
people, judging by a mercury risk assessment that the EPA produced on
its own years earlier.

The federal advisory said that nursing mothers and women who are
pregnant or may become so should eat no more than 12 ounces of chunk
light tuna a week. For solid white albacore, which is higher in
mercury, it set a six-ounce weekly limit. Young children, it said,
should eat "smaller portions." No advice was given for men or older
women.

The maximum mercury ingestion the EPA deems safe is one microgram a day
for each 22 pounds of body weight. If a 130-pound woman ate as much
albacore tuna as the joint federal advisory allows, she would exceed
that safe level by 40%.

If the joint advisory had been available in 2003 and the Davises,
following its advice about "smaller portions" for children, had given
Matthew just half a can of albacore a week, he still would have
consumed 60% more mercury than the EPA can say with confidence is safe.

"This is a glaring example of shutting out science," says Vas Aposhian,
a University of Arizona toxicologist. He quit the FDA's Food Advisory
Committee in early 2004 because he felt the agency ignored the panel's
instructions to hew closely to the EPA's mercury maximum.

Senior EPA and FDA officials deny the advisory is unscientific. The
EPA's daily limit for mercury intake, called a "reference dose," isn't
some "bright line" that distinguishes safe from unsafe, officials of
both agencies say. To provide an ample margin of safety, the EPA had
set the limit at just one-tenth of the mercury level that had been
found to affect children's learning.

And the EPA limit is extra-cautious in another way, says David Acheson,
the FDA's director of food safety and security. It was based on a study
of prodigious fish eaters in the Faroe Islands of Denmark that found
neurobehavioral effects, such as learning and language deficits, in
children who'd had high bloodstream mercury at birth. But those effects
were "subtle" and insubstantial, Dr. Acheson emphasizes, not "clear,
long-lasting mental disability."

The struggle to find the right balance on mercury is part of a larger
issue: How to deal with dozens of industrial chemicals now known to
linger in the environment and the human body in trace amounts. Mercury
emissions, about 40% of which in the U.S. come from coal-fired power
plants, settle into oceans, lakes and rivers. Then people take in
mercury by eating large fish that have accumulated an organic form of
the metal in their flesh by consuming smaller fish.

People vary in how they react to mercury they ingest and how fast they
purge it. The EPA's exposure limit is based on its calculation that
mercury above 5.8 parts per billion in young women's bloodstreams may
pose a danger to their babies. By this measure, 5.7% of U.S. infants,
or 228,000 a year, could be at risk of mercury poisoning during
gestation, based on the latest blood survey of women of childbearing
age by the Centers for Disease Control and Prevention.

The maximum safe level might be lower still, says the EPA's top mercury
risk assessor, Kathryn Mahaffey, based on recent evidence that fetuses
concentrate more mercury in their blood than do their pregnant mothers.

Former EPA Administrator Michael Leavitt says the reason the government
didn't make the mercury-in-fish advisory tougher was to avoid scaring
people away from fish. "Mercury is bad and fish is good. We needed to
choose the right words that would give people a sense of knowledge
without creating unwarranted fear," says Mr. Leavitt, now head of the
Health and Human Services Department. He adds that scientists, not
bureaucrats, worked out the guidelines, reconciling the varying views
of FDA and EPA researchers.

The EPA senior scientist handling that reconciliation, Rita Schoeny,
says there is no way to know for sure whether people who follow the
fish advisory and consume more mercury than the EPA's limit are
actually safe. Asked whether she agreed with what the advisory said
about tuna, she didn't respond except to say: "I think what we have in
the advisory is good public-health advice."

At Bumble Bee Seafoods, executive vice president John Stiker
acknowledges the federal tuna-eating advice could lead some people to
exceed the EPA safe level for mercury. But he says it's not a big
problem because the average American eats only 10 servings of tuna a
year, and just 35% of that is the higher-mercury type, albacore.

Food companies have long lobbied to mitigate any FDA action on canned
tuna, one of the top-grossing supermarket items in revenue per unit of
shelf space. Five years ago, after risk assessments by the EPA and the
National Academy of Sciences raised fresh worries about mercury, the
FDA began preparing to revise a 1979 advisory that said it was all
right to consume four micrograms of mercury a day per 22 pounds of body
weight -- four times the EPA's maximum.

Food companies urged the FDA not to single out canned tuna. In private
meetings with FDA officials in fall 2000, industry and agency documents
show, the industry argued that health data were inconclusive, that
citing canned tuna would drive down its consumption by 19% to 24%, and
that seafood producers "would face the distinct possibility of numerous
class action lawsuits."

A strict advisory "could have an irreversible impact on American
dietary habits, profoundly affecting consumers and producers of seafood
and resulting in significant segments of the population turning away
from the proven health benefits of fish consumption," said a 2000
letter to an FDA commissioner from three trade groups: the National
Food Processors Association, the National Fisheries Institute and the
U=2ES. Tuna Foundation.

When the FDA issued a revised mercury advisory in 2001, it urged women
of childbearing age to shun four high-mercury species: swordfish,
shark, king mackerel and tilefish from the Gulf of Mexico. It didn't
mention tuna. Yet cumulatively, according to data provided by the EPA,
the four species it urged avoiding account for less than 10% of
Americans' mercury ingestion from fish, while canned tuna accounts for
about 34% of it.

Echoing industry arguments, FDA scientists also rejected the study of
fish eaters in Denmark's Faroe Islands, saying dietary differences made
the data inapplicable to Americans. The FDA stood by its 1979
mercury-consumption limit that was much higher than the EPA's.

Some EPA scientists griped that FDA officials were coddling food
companies. "They really consider the fish industry to be their clients,
rather than the U.S. public," charges Deborah Rice, a former EPA
toxicologist now working for the state of Maine. The FDA's Dr. Acheson
denies that commercial concerns played a role in the agency's decision
making.

Change of Course

In April 2003, his agency changed course, following years of prodding
by health advocates, some members of Congress and the agency's own
outside food advisory panel. The FDA said it would base future mercury
warnings on the EPA's stricter limit. Late in 2003, FDA and EPA
officials proposed their first joint mercury advisory at a meeting of
the FDA's Food Advisory Committee.

At the hearing, FDA scientists said they had put fish in three
categories: high in mercury, medium and low. The level for the
low-mercury group was that of canned light tuna, explained FDA official
Clark Carrington. "In order to keep the market share at a reasonable
level, we felt like we had to keep light tuna in the low-mercury
group," he said, according to the meeting's official transcript.

Later, the FDA's Dr. Acheson reiterated that point. He told the meeting
the fish categories "were arbitrarily chosen to put light tuna in the
low category."

Says Maine's Dr. Rice: "Here's the FDA making what are supposed to be
scientific decisions on the basis of market share. What else is there
to say?"

Asked about this, Dr. Acheson gives a different reason why the
low-mercury group was pegged to light tuna. He says it was because a
woman weighing 140 pounds could eat 12 ounces of it a week and stay at
or below the EPA reference dose.

The FDA's outside advisory panel asked the agencies to rework the
advisory, saying it didn't adequately spell out mercury risks from
canned tuna. In particular, members of the panel urged a specific
warning about the higher-mercury albacore tuna.

But food processors lobbied the administration. At the White House,
they implored officials not to single out albacore. They said doing so
would only drive people, especially the poor, to eat more junk food,
says a scientist who was there.

In meetings with companies, there are indications administration
officials sometimes expressed views not in sync with those of all
agency scientists.

At the EPA, three companies met with Steve Johnson, then deputy
administrator, on Feb. 23, 2004. The three were the StarKist unit of
Del Monte Foods Co.; Chicken of the Sea, part of Thailand's Thai Union
Frozen Products PCL; and Bumble Bee, which is owned by Connors Bros.
Income Fund in Toronto.

The three companies later wrote to then-EPA chief Mr. Leavitt that Mr.
Johnson -- who now heads the agency -- had assured them that "the EPA
did not consider any children to be at risk from mercury poisoning." An
EPA spokeswoman denies Mr. Johnson said that. Asked about the denial,
Bumble Bee's Mr. Stiker said, "I was at the meeting. It was clear that
that was said at the meeting by Steve Johnson and others in that
room.... We were assured the EPA did not consider any U.S. children to
be at risk of mercury poisoning."

The FDA tested the planned advisory with focus groups of women of
childbearing age, the target of the warning. Some complained they
didn't understand the vague advice to give kids "smaller portions."
Others said the advisory was ambiguous because it encouraged them to
eat fish but not too much.

'His Brain Food'

Like many parents, the Davises in San Francisco always thought fish was
great. They knew it was high in omega-3 fatty acids, which they
understood could help brain development. They were delighted, Ms. Davis
says, when Matthew started eating what she calls "his brain food" for
lunch and snacks.

It struck Matthew that something was wrong one day at recess, he says,
when his buddy Zach could suddenly catch and throw a football much
better than he could. He remembers his father, a little while later,
getting frustrated when his son couldn't hit a baseball. "I kept
telling Dad I was rusty," Matthew says.

After the meeting with his teachers, the Davises spent thousands of
dollars on tutors, but still Matthew struggled. A specialist gave him a
diagnosis of "mixed learning disability," which just made his parents
mad because they had watched him do so well in school before.

Then Matthew's father happened to read an article in the San Francisco
Chronicle describing adults with similar problems as a possible result
of eating too much swordfish, tuna steaks and other high-end fish in
restaurants. Ms. Davis remembers bolting to the pantry and throwing
away eight pouches and 20 cans of StarKist albacore tuna.

Spokeswomen for StarKist and Chicken of the Sea referred questions to
the U.S. Tuna Foundation. The trade group's executive director, David
Burney, says the study of mercury in heavy fish eaters of the Faroe
Islands had found only minor effects in kids. It wasn't as if they
"couldn't function in school," he says, adding: "There is no connection
between a learning disability and mercury."

The notion that chronic, low-level mercury exposure can diminish
children's learning capacity was affirmed in 2000 by a panel of experts
convened by the National Academy of Sciences. Citing "a large body of
scientific evidence showing adverse neurodevelopmental effects" on
children from mercury, the NAS panel endorsed the EPA's choice of the
1997 Faroe Islands study, led by Philippe Grandjean of Harvard, as the
basis for the agency's reference dose.

It noted that a similar study of fish eaters in the Seychelles Islands
in 1998 hadn't found any effects on childhood development from
mercury-tainted fish, but concluded the Faroe Islands results were more
reliable because they were firmly supported by other studies.

Matthew Davis's symptoms -- declines in concentration, coordination and
learning ability -- were classic signs of mercury toxicity, says one of
his doctors, Jane Hightower, who has published studies of such toxicity
in her patients. She notes that in some kinds of fish, mercury content
varies widely, exposing diners to random spikes. In chunk light tuna
and snapper, some samples had seven times as much mercury as the
average for the species, as measured by the FDA. Certain samples of
canned albacore tuna showed a spike to 2=BD times the average.

As for the fresh and frozen tuna found in tuna steaks, its mean mercury
level was comparable to that of canned albacore.

Industry Marketing

The tuna industry has continued to aim some marketing at pregnant women
and kids. An ad sponsored by the U.S. Tuna Foundation last year, which
specified the new federal consumption guidelines, reassured "pregnant
and nursing women and young children" that canned tuna "is absolutely
safe to eat." Extolling the benefits of fish's omega-3 fatty acids for
babies' eyes and brains, the ad said: "No government study has ever
found unsafe levels of mercury in women or young children who eat
canned tuna."

By "unsafe levels," says the foundation's Mr. Burney, the ad wasn't
referring to mercury above what the EPA declares safe, but to the
actual blood-mercury level of Faroe Islands infants. That level is 10
times as high as the EPA's safe level.

Mr. Burney maintains that no Americans come close to having a toxic
level of mercury in their blood. Accordingly, he rejects the notion
that Matthew Davis or anyone else could get mercury poisoning from
eating canned tuna. "That's the dumbest thing I've ever heard in my
life," Mr. Burney says.

Bumble Bee's Mr. Stiker, when told of Matthew's problem, said it didn't
make sense to him because only early-childhood development can be
affected by trace amounts of mercury. "The hype has far outstripped the
science" on mercury in fish, he said, with the result that canned-tuna
sales are falling more than 10% a year. "We're getting killed because
of this perception," he said.

Today, nearly two years after Matthew quit eating albacore tuna, his
blood-mercury level is zero and his condition is dramatically improved.
Although his doctors don't know if he had any permanent damage, signs
so far are that he didn't. Sports and homework come much easier again.
Matthew played the lead in a local performance of "Charlie and the
Chocolate Factory." He is writing stories again.

His mother wrote about her son's struggle for the school newsletter.
The family hasn't consulted a lawyer and doesn't plan to sue anyone,
Ms. Davis says. But "I think about what I could have lost, and it makes
me angry," she says.

The American Medical Association called on the FDA a year ago to
consider requiring stores to post warnings and mercury-content data
wherever fish is sold. Dr. Acheson of the FDA says the agency opposes
mandated warning labels or market postings. "We feel the best way to
get the word out is via the advisory," he says, calling it "an optimal
balance between the benefits of eating fish and the risks of mercury."

MrPepper11 wrote:
: Mercury and Tuna: Advice Leaves Questions
:
: A joint EPA and FDA advisory issued last year urged limits on how much
: tuna children and some women should eat. But those limits exceed safe
: levels for some people, judging by a mercury risk assessment that the
: EPA has produced on its own.
:
: August 1, 2005
: Fish Line
: Mercury and Tuna: U.S. Advice Leaves Lots of Questions
: Balancing Interests, Agencies Issue Guidance at Odds With EPA Risk
: Assessment
: A Schoolboy's Sudden Setback
: By PETER WALDMAN
: Staff Reporter of THE WALL STREET JOURNAL
:
: SAN FRANCISCO -- One by one, Matthew Davis's fifth-grade teachers went
: around the table describing the 10-year-old boy. [...]

There is almost no omega-3 fatty acids in /canned/ tuna. I think that there
are very little nutritional reasons to eat it at all. Small mackerel, salmon
and sardines would be better choices.

--
Juhana

On Tue, 2 Aug 2005 07:45:01 +0300, Juhana Harju wrote in
on
sci.environment,sci.med.nutrition,misc.kids,misc.h ealth.alternative :

There is almost no omega-3 fatty acids in /canned/ tuna.

As long as we can trust the USDA data, it seems it much depends on the type
of conservation, oil or water...

"Fish, tuna. white, canned in oil, drained solids"
20:5 n-3 66mg , 22:6 n-3 178mg

"Fish, tuna. white, canned in water, drained solids"
20:5 n-3 233mg , 22:6 n-3 629mg

Besides, cannned white tuna seems to have more of Omega-3s than generic
"canned light tuna" (is that yellowfin? they don't specify).


On the flip side, according to the U.S. Food and Drug Administration,
"canned light tuna" is much safer than "white albacore" when it comes to
mercury.

http://www.cfsan.fda.gov/%7Edms/admehg3.html

* Five of the most commonly eaten fish that are low in mercury are
shrimp, canned light tuna, salmon, pollock, and catfish.
* Another commonly eaten fish, albacore ("white") tuna has more
mercury than canned light tuna. So, when choosing your two meals of fish
and shellfish, you may eat up to 6 ounces (one average meal) of albacore
tuna per week.



"Fish and Shellfish With Lower Levels of Mercury"
[...]
MERCURY CONCENTRATION (PPM) in TUNA (Canned, Light)
mean 0.12 median 0.08 min ND max 0.85 no. of samples 131
source of data FDA SURVEY 1990-03

"Mercury Levels of Other Fish and Shellfish"
[...]
MERCURY CONCENTRATION (PPM) in TUNA (Canned, Albacore)
mean 0.35 median 0.34 min ND max 0.85 no. of samples 179 source of
data FDA SURVEY 1990-03

X'Posted to: sci.environment,sci.med.nutrition,misc.kids

Enrico C wrote:
:: On Tue, 2 Aug 2005 07:45:01 +0300, Juhana Harju wrote in
:: on
:: sci.environment,sci.med.nutrition,misc.kids,misc.h ealth.alternative :
::
::: There is almost no omega-3 fatty acids in /canned/ tuna.
::
:: As long as we can trust the USDA data, it seems it much depends on
:: the type of conservation, oil or water...
:: [...]

There is something in the processing methods which reduces the amount of
omega-3 fatty acids in canned tuna.

--
Juhana

Juhana Harju wrote:
:: Enrico C wrote:
:::: On Tue, 2 Aug 2005 07:45:01 +0300, Juhana Harju wrote in
:::: on
:::: sci.environment,sci.med.nutrition,misc.kids,misc.h ealth.alternative
:::: :
::::
::::: There is almost no omega-3 fatty acids in /canned/ tuna.
::::
:::: As long as we can trust the USDA data, it seems it much depends on
:::: the type of conservation, oil or water...
:::: [...]
::
:: There is something in the processing methods which reduces the
:: amount of omega-3 fatty acids in canned tuna.

"The larger commercial canneries, such as Starkist ™, cook their fish twice.
First, they bake the fish whole on a rack, which results in a loss of
natural beneficial oils. Then the fish is de-boned and put into the can,
along with flavorings like vegetable broth, and additives such as
pyrophosphate or hydrolyzed casein. The cans are sealed, and the fish is
cooked again. This process allows the companies to de-bone the fish fillets
faster and produce a higher volume of product."

Source: http://www.whfoods.com/genpage.php?tname=george&dbid=97

--
Juhana

Juhana Harju a écrit dans le message ...
Juhana Harju wrote:
:: Enrico C wrote:
:::: On Tue, 2 Aug 2005 07:45:01 +0300, Juhana Harju wrote in
:::: on
:::: sci.environment,sci.med.nutrition,misc.kids,misc.h ealth.alternative
:::: :
::::
::::: There is almost no omega-3 fatty acids in /canned/ tuna.
::::
:::: As long as we can trust the USDA data, it seems it much depends on
:::: the type of conservation, oil or water...
:::: [...]
::
:: There is something in the processing methods which reduces the
:: amount of omega-3 fatty acids in canned tuna.

"The larger commercial canneries, such as Starkist ™, cook their fish
twice.
First, they bake the fish whole on a rack, which results in a loss of
natural beneficial oils. Then the fish is de-boned and put into the can,
along with flavorings like vegetable broth, and additives such as
pyrophosphate or hydrolyzed casein. The cans are sealed, and the fish is
cooked again. This process allows the companies to de-bone the fish fillets
faster and produce a higher volume of product."

Source: http://www.whfoods.com/genpage.php?tname=george&dbid=97

--
Juhana



The web site you refer to has as much credibility as you
have (zero) though not quite as loonie.

JL

On Tue, 2 Aug 2005 12:23:31 +0300, Juhana Harju wrote in
on
sci.environment,sci.med.nutrition,misc.kids :
[...]
Juhana Harju wrote:
:: There is something in the processing methods which reduces the
:: amount of omega-3 fatty acids in canned tuna.

"The larger commercial canneries, such as Starkist ™, cook their fish twice.
First, they bake the fish whole on a rack, which results in a loss of
natural beneficial oils. Then the fish is de-boned and put into the can,
along with flavorings like vegetable broth, and additives such as
pyrophosphate or hydrolyzed casein. The cans are sealed, and the fish is
cooked again. This process allows the companies to de-bone the fish fillets
faster and produce a higher volume of product."

Source: http://www.whfoods.com/genpage.php?tname=george&dbid=97


On an Italian article, http://www.pubit.it/sunti/pes0302m.html ,
I read of a 60 to 90 minute long pre-cooking in seasoned brine at
100-105°C, and then a 60 minute long sterilization in autoclave at 121°C
after canning.



X'Posted to: sci.environment,sci.med.nutrition,misc.kids


--
Enrico C

On Tue, 2 Aug 2005 12:10:53 +0200, Enrico C wrote in
on
sci.environment,sci.med.nutrition,misc.kids :

On Tue, 2 Aug 2005 12:23:31 +0300, Juhana Harju wrote in
on
sci.environment,sci.med.nutrition,misc.kids :
[...]
Juhana Harju wrote:
:: There is something in the processing methods which reduces the
:: amount of omega-3 fatty acids in canned tuna.

"The larger commercial canneries, such as Starkist (TM), cook their fish twice.
First, they bake the fish whole on a rack, which results in a loss of
natural beneficial oils. Then the fish is de-boned and put into the can,
along with flavorings like vegetable broth, and additives such as
pyrophosphate or hydrolyzed casein. The cans are sealed, and the fish is
cooked again. This process allows the companies to de-bone the fish fillets
faster and produce a higher volume of product."

Source: http://www.whfoods.com/genpage.php?tname=george&dbid=97


On an Italian article, http://www.pubit.it/sunti/pes0302m.html ,

On "Il Pesce", a magazine specialized in the Italian fishery sector.

I read of a 60 to 90 minute long pre-cooking in seasoned brine at
100-105°C, and then a 60 minute long sterilization in autoclave at 121°C
after canning.

I should point out that that article confirms the industrial double-cooking
process as described by the WHFoods web page you cited, including the loss
of much of the lipid, which percolate during the precooking step.

X'Posted to: sci.environment,sci.med.nutrition,misc.kids

On Tue, 2 Aug 2005 12:23:31 +0300, Juhana Harju wrote in
on
sci.environment,sci.med.nutrition,misc.kids :

Juhana Harju wrote:
:: Enrico C wrote:
:::: On Tue, 2 Aug 2005 07:45:01 +0300, Juhana Harju wrote in
:::: on
:::: sci.environment,sci.med.nutrition,misc.kids,misc.h ealth.alternative
:::: :
::::
::::: There is almost no omega-3 fatty acids in /canned/ tuna.
::::
:::: As long as we can trust the USDA data, it seems it much depends on
:::: the type of conservation, oil or water...
:::: [...]
::
:: There is something in the processing methods which reduces the
:: amount of omega-3 fatty acids in canned tuna.

"The larger commercial canneries, such as Starkist (TM), cook their fish twice.
First, they bake the fish whole on a rack, which results in a loss of
natural beneficial oils. Then the fish is de-boned and put into the can,
along with flavorings like vegetable broth, and additives such as
pyrophosphate or hydrolyzed casein. The cans are sealed, and the fish is
cooked again. This process allows the companies to de-bone the fish fillets
faster and produce a higher volume of product."

Source: http://www.whfoods.com/genpage.php?tname=george&dbid=97

That web page also confirms that water-packed or oil-packed makes a real
difference, anyway... The data on EPA and DHA content they cite are just
the same as USDA's.

"To get the most omega 3 fats from your canned tuna, choose water-packed
tuna rather than oil-packed. The oil mixes with some of the tuna's natural
fat, so when you drain oil-packed tuna, some of its omega 3 fatty acids
also go down the drain. Since oil and water don't mix, water-packed tuna
won't leach any of its precious omega 3s."
[...] "100 grams (about 3 ½ ounces ) of light tuna canned in water and
drained contained 0.272 grams of omega-3 fatty acids, derived from EPA
(0.047g), DHA (0.223g), and ALA (0.002g). While tuna canned in oil and
drained contained almost a third less omega 3s: 100 grams of light meat
tuna canned in oil and drained provided 0.202 grams of omega-3 fatty acids
in the form of EPA (0.027g), DHA (0.101g), and ALA (0.074g)."

X'Posted to: sci.environment,sci.med.nutrition,misc.kids

Enrico C wrote:
:: On Tue, 2 Aug 2005 12:23:31 +0300, Juhana Harju wrote in
:: on
:: sci.environment,sci.med.nutrition,misc.kids :
::: Juhana Harju wrote:
::::: Enrico C wrote:
::::::: On Tue, 2 Aug 2005 07:45:01 +0300, Juhana Harju wrote in
::::::: on
::::::: sci.environment,sci.med.nutrition,misc.kids,misc.h ealth.alternative
:::::::
:::::::: There is almost no omega-3 fatty acids in /canned/ tuna.
:::::::
::::::: As long as we can trust the USDA data, it seems it much depends
::::::: on the type of conservation, oil or water...
::::::: [...]
:::::
::::: There is something in the processing methods which reduces the
::::: amount of omega-3 fatty acids in canned tuna.
:::
::: "The larger commercial canneries, such as Starkist (TM), cook their
::: fish twice. First, they bake the fish whole on a rack, which
::: results in a loss of
::: natural beneficial oils. Then the fish is de-boned and put into the
::: can,
::: along with flavorings like vegetable broth, and additives such as
::: pyrophosphate or hydrolyzed casein. The cans are sealed, and the
::: fish is cooked again. This process allows the companies to de-bone
::: the fish fillets faster and produce a higher volume of product."
:::
::: Source: http://www.whfoods.com/genpage.php?tname=george&dbid=97
::
:: That web page also confirms that water-packed or oil-packed makes a
:: real difference, anyway... The data on EPA and DHA content they cite
:: are just the same as USDA's.

I am doubtful about the analyze results of USDA. To give you one example: in
the USDA source the amount of arachidonic acid in farmed salmon is
_extremely_ high but after consulting Finnish specialists in the field of
fish research it seems that those USDA figures are _exceptional_ and not
typical in farmed salmon - according to that Finnish scientist source in
Finland they have never encountered that high arachidonic acid amounts in
farmed fish.

:: "To get the most omega 3 fats from your canned tuna, choose
:: water-packed tuna rather than oil-packed. The oil mixes with some of
:: the tuna's natural fat, so when you drain oil-packed tuna, some of
:: its omega 3 fatty acids also go down the drain. Since oil and water
:: don't mix, water-packed tuna won't leach any of its precious omega
:: 3s." [...] "100 grams (about 3 ½ ounces ) of light tuna canned in
:: water and drained contained 0.272 grams of omega-3 fatty acids,
:: derived from EPA (0.047g), DHA (0.223g), and ALA (0.002g). While
:: tuna canned in oil and drained contained almost a third less omega
:: 3s: 100 grams of light meat tuna canned in oil and drained provided
:: 0.202 grams of omega-3 fatty acids in the form of EPA (0.027g), DHA
:: (0.101g), and ALA (0.074g)."

There are water-packed tuna products with a total fat content of 0.5% only.
That means clearly that although these products are water-packed there is
almost no omega-3 fatty acids left. So you cannot count on water-packing as
a good way to preserve fats. I think that what really counts is the cooking
and processing methods. One should also realize that the USDA figures might
not be typical (as seems to be the case in farmed salmon).

--
Juhana