Omega-3's are not only found in fish. Alpha Linolenic Acid is an omega-3 and
is in these concentrations: Canola oil 10%, flaxseed or linseed oil 57%,
black currant oil 14%, soybean oil 7%. Michael R. and Mary Dan Eades, M.D.,
Protein Power, Bantam Books, 1996

"Different types of omega-3s. Key omega-3 fatty acids include
eicosapentaenoic acid (EPA) and docosahexanoic acid (DHA), both found
primarily in oily cold-water fish such as tuna, salmon, and mackerel. Aside
from fresh seaweed, a staple of many cultures, plant foods rarely contain
EPA or DHA.

However, a third omega-3, called alpha-linolenic acid (ALA), is found
primarily in dark green leafy vegetables, flaxseed oils, and certain
vegetable oils. Although ALA has different effects on the body than EPA and
DHA do, the body has enzymes that can convert ALA to EPA. All three are
important to human health." *Preceeding was taken from the link below*

http://www.wholehealthmd.com/refshelf/substances_view/1,1525,992,00.html

Not all Omega-3's are necessarily good for you though. In "Protein Power"
the case is made that ALA "slows down the gatekeeper"-delta 6 desaturase.
This enzyme controls Linoleic Acid amounts used to synthesize eicosanoids
into Series 1 and 2. Series 1's being generally good and Series 2 generally
bad.

This is how I understand it anyway.

Dave

The 'Paleolithic' diet is probably not a model to follow. The
first 90% of the last 150,000 years of our evolutionary history
is likely to be more biologically appropriate than the last 10%
regarding cancer risks (and also likely, longevity):

Urology. 2001 Apr;57(4 Suppl 1):31-8.

Similarities of prostate and breast cancer: Evolution, diet, and estrogens.

Coffey DS.

James Buchanan Brady Urological Institute, The Johns Hopkins Hospital,
Baltimore, Maryland 21287-2101, USA.

Environment determines the risk of both prostate and breast cancer, and
this risk can vary >10-fold. In contrast, no risk exists for human
seminal vesicle cancer demonstrating tissue specificity. There is also
species specificity, because there is no risk for prostate cancer in any
other aging mammal except the dog. A study of evolution indicates that
the prostate and breast appeared at the same time 65 million years ago
with the development of mammals. All male mammals have a prostate;
however, the seminal vesicles are variable and are determined by the
diet so that species primarily eating meat do not have seminal vesicles.
The exception is the human, who has seminal vesicles and consumes meat,
although this is a recent dietary change. Human lineage departed from
other higher primates 8 million years ago. The closest existing primate
to humans is the bonobo (pigmy chimpanzee), which does not eat meat but
exists primarily on a high fruit and fresh vegetable diet. Homo sapiens
evolved only about 150,000 years ago, and only in the last 10% of that
time (10 to 15 thousand years ago) did humans and dogs dramatically
alter their diets. This is the time when humans domesticated the dog,
bred animals, grew crops, and cooked, processed, and stored meats and
vegetables. **All current epidemiologic evidence and suggestions for
preventing prostate and breast cancer in humans indicates that we should
return to the original diets under which our ancestors evolved. The
recent development of the Western-type diet is associated with breast
and prostate cancer throughout the world.** It is believed that the
exposure to and metabolism of estrogens, and the dietary intake of
phytoestrogens, combined with fat intake, obesity, and burned food
processing may all be related to hormonal carcinogenesis and oxidative
DNA damage. An explanatory model is proposed.

PMID: 11295592 [PubMed - indexed for MEDLINE]

some excerpts from the full paper:

"There appear to be very similar lifestyle risk factors accompanying
both prostate and breast cancer, including a lower risk associated with
high intake of fruits, vegetables, fiber, and soy products and,
alternatively, a higher risk associated with increased intake of red
meat, animal fats, dairy products, and steroid exposure, as well as body
mass and birth weight."

"Approximately 7 million years ago humans evolved from a common ape
ancestor, with our closest relative being the pigmy chimpanzee called
the bonobo. Like the other great apes, the bonobo eats primarily fruits
and vegetables and no meat."

"Other types of chimpanzees occasionally eat meat as opportunist
scavengers, sometimes even with very limited hunting. Even in humans,
highly effective hunting was not the major source of high meat caloric
intake until later in human development. When early hominoids such as
"Lucy" came down from the trees 4 million years ago and began to roam
the savannas, they picked up the ability to become hunter-gatherers."

"This major phase shift in food style occurred only about 10,000 years
ago, when humans became farmers and domesticated both plants and
animals. This technology quickly evolved into a tighter focusing of
human diets from wild fresh vegetables and fruits to an eating pattern
toward limited plants that could be domesticated and grown in great
quantities and stored, like wheat, rice, barley, corn, potatoes, and
other tubers. This resulted in approximately 20 plant types rapidly
replacing the high diversity of 3,000 plants and fruits that were
earlier eaten fresh as they came into season and were gathered from the
wild. With large-scale domestication and breeding of cattle came a high
meat intake, and this was combined with storage, curing, drying, and
cooking as well as a propensity to use milk and cheese from dairy
processing. Cooking, burning, and smoking produce high levels of
heterocyclic molecules, many of which make adducts to DNA, and are
carcinogens."

"Since separating from the great apes and chimpanzees approximately 8
million years ago, humans evolved into Homo sapiens sapiens that are
very similar to our present form in little as 150,000 years. However, we
dramatically changed to a Western-style diet only in the very recent
past (ie, 15,000 years)--at a pace much faster than we could
biologically evolve (Table V). This Western diet consists of high meat
and fat; dairy products; stored, processed, and cooked meats; and low
fruit and fiber intake, along with a more sedentary lifestyle."

"In summary, we were not biologically selected by the evolution process
to eat the way we do today, and the damage is manifested in prostate and
breast cancer. Indeed, all of the present suggestions of the National
Cancer Institute and the American Cancer Society as to how Americans
might reduce their chances of getting prostate and breast cancer revolve
around adapting dietary changes in our lifestyle back toward the early
human diet of more fruits; a variety of fresh vegetables and fiber; less
burning, cooking, and processing; diminished intake of dairy products,
red meat, and animal fats, as well as decreasing weight and increasing
aerobic exercise. That is, we must return to a diet and lifestyle that
more closely matches the first 135,000 years before technology modified
our lifestyle and diet."

TABLE V. Human development and the change of diet
Time During Human Development (150,000 years)
First 90% (135,000 years) ; Last 10% (15,000 years)
Diet: high; low
Fruit: high ; low
Fiber: high; low
Plant diversity: high (3000); low (20)
Red meat: low; high
Animal fat: low; high
Dairy products: low; high
Food: fresh/wild ; cooked/preserved
Movement: High; Sedentary

"Certainly, looking for simple relation will not be sufficient, but
delineating the exact mechanisms of cell cycle control and stem cell
development in prostate cancer should be helpful in understanding these
early preneoplastic lesions and their relation to diet. In the end, we
still must explain why approximately 90% of prostate and breast cancers
are sporadic and acquired, and why only 10% are directly inherited in a
Mendelian manner. The acquired cancers may indicate why this phenomenon
is so geographically centered and may be capable of being altered. If
these cancers are set in place within the neonatal or developmental
periods, as has been proposed by many, then this process will require
far more research to unravel the timing of these critical events."

"The first 90% of the last 150,000 years of our evolutionary
history is likely to be more biologically appropriate than the
last 10% regarding cancer risks (and also likely, longevity)"

Probably true, but remember that males who leave more successful
offspring have not necessarily been long-lived. (The research I
referred to is Y-chromosome based because that chromosome is not
recombinant. See http://www5.nationalgeographic.com/genographic/
for some of it.)

I'm looking at the very limited food sources of the extreme
continental north where today's dominant male line spent a lot of
time after the exodus from Africa - not much flax oil or spinach!
And, no access to salt water. There would be some berries, but my
primary suspicion for a possible source of omega-3's is the
lichen that are eaten by caribou/reindeer. Also, the northern
Canada equivalent to the Laplanders drink huge quantities of
lichen tea to handle their high-protein diet. Fish omega-3 comes
from algae, and lichen are half algae.

Thanks for all suggestions, I appreciate them and am keeping them
on file. But, I'm hoping for some real data on the very few
people who continue today to live as our male-line ancestors must
have in that specific area.

I thought the brain has to make its own lipids, due to the constraints of
the blood brain barrier.  If so, dietary omega 3 would only be important for
other systems.