AnimalNet Oct. 31/04
Are these
seeds good for us? Just the flax, ma'am
What avian
flu mistakes?
Spain sees
livestock 'blue tongue' ailment stabilising
how to subscribe
Are
these seeds good for us? Just the flax, ma'am
October 31, 2004
The Gazette (Montreal)
D6
Joe Schwarcz, director of McGill University's Office for Science and Society (www.OSS.McGill.ca),
writes in this column, "Let them eat flax!" The chickens that is.
That's what researchers told egg producers bent on improving the nutritional
value and the public image of eggs. Let's face it, when "eggs" are
mentioned, the first word that often comes to mind is "cholesterol,"
which in turn conjures up thoughts of clogged arteries and premature demise.
In truth, cholesterol in eggs makes a far smaller contribution to blood
cholesterol than the saturated fats found in meat and full-fat dairy products.
Still, eggs suffer from an image problem. Omega-3 fats, on the other hand, are
positively basking in the limelight these days. Found mostly in fish, these fats
have been linked with a reduced risk of heart disease, breast cancer,
inflammatory bowel disease and arthritis. Slipping these fats into eggs would
certainly be a healthy boost to their image! Especially considering that many
people worry about pollutants like mercury and PCBs which crop up in fish.
Flaxseed is one of the few plant sources high in omega-3 fats. The term
"omega-3" refers to the molecular structure of these fats, indicating
the presence of a carbon-carbon double bond on the third carbon from the end of
the molecule. Alpha-linolenic acid (ALA), the specific omega-3 found in
flaxseed, differs slightly from eicosapentaenoic acid (EPA) and docosahexaenoic
acid (DHA) which are the major fats in fish. Most research has focused on the
health benefits of the latter two, but ALA itself has also been linked with a
reduced risk of heart disease.
Furthermore, some ALA is converted to EPA and DHA in the human body, as well as
in the chicken body. Feeding flaxseeds to chickens makes great use of the
"you are what you eat" phenomenon, and results in eggs that have
roughly 12 times more omega-3 fats than regular eggs.
Of course, the important question is whether eating such eggs makes a
significant contribution of omega-3s to the diet. Perhaps surprisingly, it does.
Canadian guidelines recommend 1.1 grams of omega-3s for women and 1.5 grams for
men on a daily basis.
An omega-3 egg has roughly 0.35 grams of ALA and 0.13 grams of EPA and DHA, so a
couple of eggs provide a significant portion of the recommended intake. About
the same as a couple of ounces of a high-oil fish, like salmon. No nutritional
authorities suggest that we should be eating two eggs every day, but five to
seven a week is reasonable. And even at that rate, switching to omega-3 eggs
makes sense; it's equivalent to a weekly serving of fish.
By now you're thinking that this must be too good to be true. There must be a
"but" coming up, right? Right! Back in 1994, the scientific community
was stunned by a study that linked high blood levels of alpha-linolenic acid
with an increased risk of prostate cancer. Total fat consumption had been
associated with this cancer before.
That was no great surprise, since dietary fat is known to increase the
production of male sex hormones which are linked to prostate cancer.
Furthermore, many pesticides are fat soluble and a high fat diet increases the
body's pesticide load which of course is undesirable. But all previous
indications had been that a diet high in fish oils decreases the risk of
prostate cancer.
Could ALA be different from other omega-3s? While it clearly decreased the risk
of heart disease, was it increasing the risk for prostate cancer? Several
studies since have also suggested that ALA may be linked to prostate cancer, but
there is a lot of controversy surrounding the issue.
Plasma levels of ALA, for example, show no association with ALA levels in tissue
taken from prostate cancer patients. The prudent analysis of the data suggests
that it is probably not a good idea for men to consume flax oil on a regular
basis.
Ready for another "but?" Consuming flax seeds themselves has
consistently been linked with a reduced risk of prostate cancer, as well as
breast cancer. Perhaps this is because other components of the seed, such as
lignans, have decided anti-cancer properties and may overcome any detrimental
effect that may be attributed to ALA.
A study at Duke University clearly showed that men awaiting surgery for prostate
cancer benefited from a daily consumption of three tablespoons of ground flax.
Testosterone levels were lowered and there was a decrease in cancer cell
proliferation.
So we now have the following scenario: Eating flax seed is good. It protects
against heart disease and cancer. Consuming flax oil is questionable because of
the connection between ALA and prostate cancer.
Wouldn't it be great if the ratio of ALA to DHA and EPA in flax could be altered
to increase the latter? After all, the greatest benefits for omega-3s have been
seen with the fish oils. Well, it looks like genetic engineering in this
instance is going to deliver the goods!
Genetic modification of plants has been criticized for various reasons,
including the fact that so far the consumer has seen no obvious direct benefit
of the technology.
Now researchers at the University of Hamburg have succeeded in genetically
modifying flax plants to produce more DHA and EPA. They managed to isolate the
gene from a species of algae that codes for an enzyme that converts ALA into DHA
and EPA and have introduced it into flax plants. (Fish, of course, derive their
omega-3 fats from eating algae).
This will make not only for healthier flax for human consumption but also for
improved animal feed. Chickens dining on genetically modified flax seeds will
produce eggs with a higher DHA and EPA content and men will have less of a
concern about the alpha-linolenic acid content of flax oil.
Where does this leave us? Ground flaxseed is a great addition to the diet, and
may be even better when the genetically modified version becomes available.
So, let them eat flax! Chickens and people.
What
avian flu mistakes?
October 30, 2004
MetroValley Newspaper Group
0001
Canadian Food Inspection Agency officials, according to this story, didn't admit
they made mistakes during the spring's avian flu crisis, but Abbotsford poultry
producers were cited as saying it took as long as 10 to 12 days before the CFIA
killed thousands of diseased birds in a barn near the Abbotsford Airport.
B.C. Chicken Growers Association president Rick Thiessen was cited as saying
this worried local producers, as the barn fans continued to blow dust and
feathers from the infected birds into the outside air surrounding the barn and
that there was a real concern the virus would spread to other farms in this
manner.
Dr. Cornelius Kiley of the CFIA was cited as dismissing Thiessen's concern,
saying that the CFIA had depopulated birds within 48 hours of testing positive,
and that discussing today the amount of time that it took to kill the birds
"is not meaningful."
Producers disagreed.
Thiessen was cited as saying the virus shouldn't have jumped the five-kilometre
control zone in the first place, arguing that shoddy bio-security methods were
to blame.
It appears the disease was initially spread by people or equipment moving from
barn to barn, however, experts now believe it was transmitted through dust
particles.
Kiley was cited as saying that the low pathogenic H7N3 virus that showed up in
Abbotsford literally exploded into a highly pathogenic form of the disease,
noting that one gram of bird feces, for example, contained enough virus to
infect one million birds - meaning that poultry barns developed into literal
virus factories.
The story says that epidemiologists now theorize the virus spread because it was
in the bird feces, shavings and dust of the poultry barns, and the dust blew to
other poultry barns that were in close proximity to each other.
About 190 people took part in a two-day Canadian poultry industry forum in
Abbotsford on Wednesday and Thursday, with government and industry
representatives committing to review their emergency management plans.
Kiley said lessons were learned during the outbreak, recalling that it was a
stressful period for everyone involved.
Spain
sees livestock 'blue tongue' ailment stabilising
October 29, 2004
Agence France Presse
MADRID - The Spanish government was cited as saying on Friday it believed the
"blue tongue," a virus borne by midges affecting cattle, was
stabilising to the degree that restrictions on livestock movement could be
scaled back, with a spokeswoman for the ministry of agriculture, fisheries and
food quoted as saying, "Incidence of the virus has stabilized."
The spokeswoman added that it was "satisfied with such restrictive measures
having been adopted which have been effective."
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