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Claudia Robinson's
BARF fed JRT, "Looie."
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Marie Z's Lab puppy "Livvy"
feasting on a
turkey neck.
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Flaxseeds
have become very popular lately, because they are a rich source of the
Omega 3 essential fatty acid, also know as Alpha Linoleic Acid (ALA).
Because of its link to good health, flaxseeds are fast becoming a new
food in many diets. Recently, two more studies have shown some
additional benefit to flaxseeds in disease prevention. Along with the
news and increased use has also come some myths and some
misunderstanding.
Flax is a blue flowering crop grown on
the Prairies of Canada for its oil-rich seeds. The seeds of flax are
tiny, smooth and flat, and range in color from light to reddish brown.
Cultivated flax, L. usitatissimum, is of two types: one is
grown for the seed and the other for fiber production. In North
America, it is primarily the oilseed varieties which are produced
commercially. They serve a variety of purposes, including baking and
other food uses. Flax has been grown since the beginnings of
civilization, and people have eaten flaxseeds since ancient times, and
the first recorded uses of flax come from Southern Mesopotamia where
flax was grown as long ago as 5,000 B.C. In the succeeding millennia,
flax spread across Europe, Africa, Asia and finally to North America.
So, what's the
"buzz" on flax?
Recent scientific reports point out that
flaxseeds can have a positive influence on everything from cholesterol
levels to constipation to cancer and heart disease. Scientists at the
American National Cancer Institute singled out flaxseed as one of six
foods that deserved special study.
Here are some highlights:
Relief from
constipation
Eating 50 grams of flaxseeds per day
helped increase the frequency of bowel movements and the number of
consecutive days with bowel movements in a group of older Canadian
adults.
A lower risk for
heart disease
Total cholesterol levels dropped 9 per
cent and LDL (the "bad" cholesterol) decreased 18 per cent
when a group of nine healthy women ate 50 grams of milled flaxseeds a
day for four weeks along with their regular diets, according to a
report from the University of Toronto.
In a similar study with men and women,
50 grams of flaxseeds lowered total cholesterol and showed a constant
trend of about 11 to 16 per cent lower serum lipids (fat in the
blood).
Cancer prevention
Lignans and alpha-linolenic acid are
found abundantly in flaxseeds. Population studies of diet and disease
risk suggest an anticancer role for flaxseed. Long-term studies of
flaxseed effects in women with breast cancer are underway.
Recently 2 studies lend further support
to the flaxseed/cancer prevention issue. The first is in relation to
prostate cancer. The small pilot study was reported in the July issue
of Urology (Urology 2001;58:47-52).
Dr. Wendy Demark-Wahnefried, from Duke
University Medical Center, Durham, North Carolina, and colleagues
studied 25 patients with prostate cancer who were about to undergo a
prostatectomy. The patients were placed on a diet in which only 20% of
total calories came from fat. In addition, patients received 30 g/day
of ground flaxseeds.
Over an average of 34 days, the subjects
experienced a significant decrease in mean total testosterone, free
androgen index and serum cholesterol. In addition, men who had a
Gleason sum score of 6 or less before starting the diet showed a trend
toward decreased PSA.
When the investigators looked at the
prostates after prostatectomy, they found that prostate cancer cells
were dividing much less rapidly and were self-destructing much more
quickly in the treatment subjects compared with matched controls.
The researchers are unsure which part of
the diet produced this cancer-fighting effect. However, Dr. Demark-Wahnefried
said that in cell-culture studies in which prostate cancer cells were
exposed to the lignins from flaxseeds, they found significant
decreases in cell growth. "It looks like these lignins may be
responsible for the results we saw," she added. "If there is
a synergistic effect [with] the low-fat diet portion of the diet, it
is unknown at this time."
(NOTE: Lignans are a type of fiber that
is found in flaxseeds)
Dr. Demark-Wahnefried noted that
although this was a small pilot study, the findings were compelling.
"We will be launching a larger study in January comparing the
effects of a low-fat diet with and without flaxseed
supplementation." Dr. Demark-Wahnefried and colleagues hope to be
able to develop a diet that will retard prostate cancer. In addition,
they are working toward using this strategy to prevent prostate
cancer. "If these results hold, maybe 10 years down the road we
will be testing this diet as a preventative to prostate cancer,"
she said.
(NOTE: I will be reporting soon on a
recently published study on the effects of the Pritikin Program on the
growth rate of prostate cancer cells)
The second recent study is in relation
to breast cancer and was presented last week at the annual meeting of
the American Chemical Society in St. Paul, MN and showed that
flaxseeds can help protect post-menopausal women from breast cancer.
In the study, funded by the National
Cancer Institute of the National Institutes of Health, twenty-eight
postmenopausal nuns from a convent in central Minnesota. They took
daily supplements of zero, 5 or 10 grams of ground flaxseeds in
seven-week cycles over the course of a year. "We don't know
exactly how flaxseed does what it does. But we do know that it is
considered to be the most concentrated food source of lignin,"
said Dr. Joanne Slavin, lead investigator and professor of nutrition
and food science. "Lignan appears to lower estrogen in humans by
inhibiting enzymes that are involved in estrogen synthesis."
Flaxseeds provides 75 to 800 times more
plant lignans, a type of phytoestrogen, than most other plant sources.
Phytoestrogens are compounds that appear to interfere with estrogen
metabolism in animals and humans.
The 5- and 10- gram groups showed a
significant decrease in estrogens common to postmenopausal women,
estrone sulfate and estradiol.
Some research suggests a correlation
between estrogen metabolism and an increase of the chemical markers in
the blood associated with development of breast cancer. "Since
previous studies show that increased levels of estrone sulfate and
estradiol may increase a woman's risk of developing breast cancer,
reducing levels of these hormones could be protective against breast
cancer," Slavin said.
"The results are encouraging.
Flaxseeds appears to change the way that estrogen is metabolized by
the body, making the metabolized product less estrogenic," said
Dr. Lillian Thompson, professor of nutrition science at the University
of Toronto. "Estrogen is known to promote tumor growth. So the
reduction of the estrogenic effect can be beneficial.
Other proposed benefits of flaxseeds:
Flax and
Arrhythmia
Flaxseeds are the richest source of
Omega 3 fatty acids. These fats appear to enhance the mechanical
performance and electrical stability of the heart and to protect
against fatal arrhythmias. The mechanism of action likely includes
modifying the fatty acid composition of cell membrane phospholipids,
affecting cell signaling and controlling ion transfers across the cell
membrane (Journal Of Nutrition, 1997; 127:383-393).
Flax, Inflammation,
Heart Disease And the Immune System
Flaxseeds have been shown to reduce many
of the markers of systemic inflammation, including pro-inflammatory
eiconosoids, cytokines, and platelet activating factor. Flaxseeds may
help reduce coronary heart disease and stroke by reducing blood
cholesterol levels and by retarding the progression of
arteriosclerosis by reducing inflammatory responses. This reduction in
pro-inflammatory factors, flaxseeds may show benefits in many
"hyper-stimulated" immune diseases such as rheumatoid
arthritis, psoriasis, multiple sclerosis, and systematic lupus,
erythmatosis.
Over the last few years that I have been
recommending the conservative use of flaxseeds. Many questions have
arisen about flaxseeds. Therefore, I will answer the most common ones
here.
Q. Where can I buy
flaxseeds?
A.
You can buy whole flaxseeds and packaged ground flaxseeds at many bulk
food, and health food stores. Conveniently, many supermarkets are also
selling flax seed in their bulk food sections. Check your local
stores, as more outlets are carrying flaxseeds now than ever before.
This trend will continue as flaxseeds becomes a more popular food
item.
Q. Which is better
for me, whole or ground flaxseeds?
A.
Ground flaxseeds provide more nutritional benefits than does whole
seed. That's because flax seeds are very hard, making them difficult
to crack, even with careful chewing. Grinding flax seeds breaks them
up, making them easier to digest when eaten. Then the body can profit
from all that flax goodness. If whole flax seeds remain unbroken, they
may pass undigested through the body, reducing the nutritional
advantage of eating flax seed in the first place.
Q. How can I grind
the seeds?
A.
Flax seeds are easy to grind, and you likely have the right tool in
your kitchen. Grind flaxseeds at home using a coffee grinder, food
processor or blender. Like coffee beans, you can grind flaxseeds
coarsely or finely and if using in cooking, most recipes call for
finely ground flaxseeds.
Q. What is the
difference between brown flax seed and golden or yellow flaxseeds? Is
one better than the other?
A.
No, one flaxseed is not better for you than another. Brown flaxseeds
provide the same nutritional benefits as golden (or yellow) ones. Both
brown and golden flaxseeds have plenty of lignans and dietary fiber,
and both contain more than 50 per cent alpha-linolenic acid. This is
an omega-3 fat which offers you health and heart fitness. While some
people may prefer yellow-colored seed, brown flaxseeds add the same
nutrition to your diet as do golden ones. This means you can choose
your flaxseeds freely. Brown flaxseeds may be more commonly found than
golden, as more brown than golden flaxseeds are grown commercially.
Note: There is another yellow seed that
looks like flax, but is not flax. It is most likely solin seed, a crop
developed from flax. Solin seeds do NOT provide the same nutritional
benefit of flaxseeds. Solin seeds contain less than one-tenth of the
alpha-linolenic acid found in flaxseeds. Thus, the important omega-3
advantage of flax is missing in solin.
Q. How should I store
flax seed and for how long will it keep?
A.
Whole flaxseeds - Whole flaxseeds come with Nature's own finest
packaging - its natural hard hull keeps it fresh. You can store clean,
dry, good quality whole flaxseeds at room temperature for up to a
year. Some people keep a jar of flaxseeds handy on their kitchen
counter.
Ground flaxseeds - Any food that is high
in vegetable fat requires some care in handling and storing. Once you
grind flaxseeds, there is greater risk of it developing an off-flavor
and taste. That's why it's best to grind whole flaxseeds as you need
them. This ensures its freshness. After grinding, you should
refrigerate it in an airtight, opaque container. Ground flaxseeds
handled this way will keep for up to 90 days.
Q. Does flax contain
gluten?
A.
Flax contains no gluten.
Q. How many calories
are in flaxseeds?
A. 1
Tablespoon of whole flaxseeds (11 grams) contains about 50 calories,
2.5 grams of protein, 3.5 grams of fiber, 23 mg of calcium, 33 mcg of
folate, and 2.5 grams of essential Omega 3 fatty acid. Although flax
seed is over 82% fat, over half (57%) of the fat in flaxseeds are in
the form of the Omega 3 essential fatty acid.
Q. What about
flaxseed Oil and/or flaxseed oil supplements?
I do not recommend the use of flaxseed
oil or flaxseed oil supplements. Like all oils, flaxseed oil is a
concentrated source of calories. Also, there are other benefits to
consuming whole flaxseeds that would not be available in the oil. One
of these is a type of fiber found in flaxseeds called lignans. Lignans
have been shown to have anticancer effects and are associated with a
reduced risk of breast cancer. Additionally, flaxseeds are a good
sources of iron, zinc, calcium, protein, potassium, magnesium, vitamin
E and folate. These important nutrients play many beneficial roles in
health maintenance and disease prevention. Flaxseed oil is pure fat
and virtually void of all or most of these nutrients (except for
vitamin E). Flaxseed oil is also a Poly-Unsaturated fatty acid (PUFA),
and there is evidence that extracted PUFA oils can suppress the immune
system, and possible increase growth rate of certain cancers and/or
tumors. If you want the benefit of flax, eat the seed and avoid the
oil.
Q. Is there any
research linking flaxseed oil to cancer?
A.
Research from Charles Myers, MD, at the University of Virginia Medical
School in Charlottesville showed that flaxseed oil causes a 300%
increase in the growth of prostate cancer cells. Dr Myers said, 'It is
the most powerful stimulus we know of for prostate cancer cells.' This
information appeared in an article in the February 2000 issue of his
Newsletter, Prostate Forum
I wrote him personally and was sent the
following references.
P.K. Pandalai, et al. "The effects
of omega-3 and omega-6 fatty acids on in vitro prostate cancer
growth" Anticancer Res 16: 815-820, 1996
E Giovannucci, et al. " A
Prospective study of dietary fat and risk of prostate cancer"
Journal National Cancer Institute" 85: 1571-1579, 1993.
P Gann, et al "Prospective study of
plasma fatty acids and risk of prostate cancer" Journal National
Cancer institute" 86: 281-286, 1994
S.O Anderson et al, "Energy,
nutrient intake, and prostate cancer risk: a population-based
case-control study in Sweden" International Journal of Cancer 68:
716-722, 1996
P.A Godley, et al "Biomarkers of
essential fatty acid consumption and risk of prostate cancer
carcinoma" Cancer Epidemiology Biomarkers and Prevention.
5:889-895, 1996
S Harvei, et al. "Prediagnostic
level of fatty acids in serum phospholipids: omega 3 and omega 6 fatty
acids and the risk of prostate cancer." International Journal of
Cancer. 71: 554-551, 1997
He says that while there is no benefit
shown to flax oil, these studies do show a negative effect. He also
states that the whole flaxseeds may offer some benefit.
Q. Are there any
downsides to consuming the whole seed?
A.
Yes. Like all nuts and seeds, flaxseeds are very high in calorie
density. Therefore, if we are going to use flaxseeds, we must do so in
moderation and be careful about the portion size. 1 tablespoon of
whole flaxseeds, or 1 1/2 tablespoon of ground flaxseeds will provide
an adequate amount of the omega 3 fatty acids and has only 50
calories. I wouldn't recommend anyone to consume more then 2
tablespoons of whole flaxseeds or 3 tablespoons of ground flaxseeds in
a day.
Q. What's the easiest
way to use flaxseeds?
A.
Simple, add the ground flaxseeds to your morning oatmeal or other
cereal. If you do any baking, flax seed can be added to many baked
products. Personally, I blend whole flaxseeds in a fruit smoothie each
morning. Some people like to eat the ground flaxseeds by themselves
and say they have a sweet nutty flavor.
In summary, flaxseeds have many
nutritional benefits and can be a valuable addition to a healthy diet.
If you are someone who doesn't consume any fish, or doesn't eat enough
green leafy veggies, then flax seed is a vitally important source of
omega 3 fatty acids for you. But remember, go easy on the flax, a
little goes a long way.