Guest Editorial
They’re Taking the Joy Out of Soy
Does soy shrink the brain? Leave you anemic? Promote
rather than prevent cancer? Interfere with your thyroid hormones? Is
soy a toxin, a food or a drug? If you eat soy, look out, here come the
soy bashers. And you won't believe who they are.
By Bill Sardi, Health Reporter
Knowledge of Health, Inc. May 2000
Copyright 2000
It went from being the darling of the natural products
industry to being labeled as a potential toxin. Not even a year ago
it was heralded in Time Magazine as the bean that brought down
cholesterol and the risk of heart disease. Time Magazine said
the Food & Drug Administration was soon to approve a health claim
for soy protein – that it reduced cholesterol for people with elevated
fatty plaque levels in their blood circulation. Just 1.5 ounces of soy,
said Time, can lower both total and LDL "bad" cholesterol levels.
[The Joy of Soy, Time Magazine, June 7, 1999]
What a joy, that soy, a natural food product, would
gain such credibility that the FDA would grant a health claim for it.
It was time for a soy festival. The normally pro-pharmaceutical FDA
had finally succumbed to the reality that foods are a good way to prevent
and even cure disease. The FDA says scientific studies confirm that
25 grams of soy has a significant cholesterol-lowering effect.* There
was an asterisk attached to the FDA announcement however (see below).
A soy burger has 9 to 18 grams, and soy milk about 4 to 9 grams of soy
protein, according to the Soyfoods Association of North America. The
cardiovascular health claim was issued October 26, 1999. [FDA T99-48
Talk Paper]
Just a relatively short time ago soy was considered
a yucky un-American food. But today two-thirds of American consumers
now believe it is healthy to consume soy, which is a big jump from the
14% who felt so in 1997. Soy sales were over $1 billion in 1997 and
are expected to soon jump over the $2 billion mark. Health Products
Business Magazine reports that the number of new soy beverages is
growing at an astounding pace. More soy, more soy!
But no sooner had the FDA approved a cardiovascular
health claim for soy protein than the critics came out of the woodwork,
and not from places one would expect. The greatest criticism of soy
has come from natural health advocates themselves. Hold up on that soy
protein bar, the tofu scramble and the soy milk. You might come down
with Alzheimer's disease, your growing children may shows premature
signs of puberty, your thyroid gland may malfunction and your body may
not be able to absorb essential minerals, according to reports on soy
now circulating in natural health publications.
It took less than a month from the date of the issuance
of a soy health claim for a bombshell to hit the soy industry. On November
19, 1999, the Honolulu Star Bulletin reported on a study conducted
by Lon White, MD, MPH, formerly of the National Institute on Aging and
now with the Pacific Health Research Institute, in Hawaii. Dr. White
and his colleagues indicated tofu (processed bean curd) could induce
"brain aging." Just two servings per week could be harmful said the
subheadline. The newspaper report was generated from an abstract of
a presentation at the Third International Symposium on the role of soy
in Preventing and Treating Chronic Disease. [Journal American College
of Nutrition 19: 242, 2000] Data from that report linked tofu consumption
with Alzheimer's disease and low brain weight upon autopsy. [http://starbulletin.com/1999/11/19/news/story4.html]
By April 29 of this year, Fox News published its version
of the soy debate, acknowledging that soy products like tofu and tempeh
have "moved out of the vegetarian ghetto," but also warned that some
experts claimed that "soy can mimic powerful human hormones and yield
unpredictable results." The wind was changing. Was the soybean craze
just a fad? Fox News quoted Dr. Lon White as saying that soy isoflavones,
one of the active hormonal ingredients in soy, are "true drugs that
are sold without warning." [Fox News April 29, 2000]
David Zava, PhD, a biochemist, chimes in on the anti-soy
bandwagon in the www.JohnLeeMD.com newsletter. A specialist in
breast cancer, Zava accurately points out that occasional soy consumption
is probably the best course to get the benefits out of soy without any
undesirable side effects. But he, unfairly and inaccurately characterizes
some of the components of soy as being nothing short of poison. Zava
says soy contains allergens, mineral blockers, enzyme inhibitors, hormone
modifiers, and iodine blockers that interfere with normal thyroid function.
Zava says soy is a medicine in moderation and a potential poison in
excess. [www.johnleemd.com] The wording is alarming. Soy is beginning
to be compared to hemlock.
Sally Fallon and Mary E. Enig, from the Weston A. Price
Foundation in Washington DC, write in the April-May edition of Nexus
Magazine and the July and August/September issues of TLfDP that
soy is not a perfect food (nobody said it was). They repeat claims that
it contains anti-nutrients and toxins, which inhibit digestion block
and absorption of vitamins and minerals. Fallon and Enig believe most
of the information consumers read about soy is "propaganda."
They say, until a few decades ago, soy was considered
unfit to eat, even in Asia. These self-appointed soy antagonists claim
the enzyme inhibitors in soy cause pancreatic cancer (not so), and that
other components in soy induce clumping of red blood cells. They admit
most of the growth-depressants in soy are removed in processing and
fermentation, but not completely eliminated. The very interest in soy
for cancer prevention emanates from its ability to thwart growth of
tumors.
While Fallon and Enig acknowledge that the Japanese
and Asians have lower rates of breast, prostate and colon cancer and
that they eat 30 times more soy than North Americans, they also indicate
the Japanese have higher rates of other types of cancer, particularly
esophageal, stomach, thyroid, pancreas and liver cancer. They give the
misimpression that soy prevents some tumors and promotes others. This
just isn't an accurate characterization. The stomach cancers in Japan
are attributed to the consumption of pickled, smoked and salted meats
and fish as well as raw sushi that may contain parasites. The frying
of meats promotes the development of carcinogens. The cancer-promoting
agents in these foods can actually be countered by the inclusion of
soy protein with ground meat prior to frying. [Basic Life Science
52: 105-18, 1990] A hidden epidemic among males in Japan is that of
alcoholism, as well as rampant tobacco use, which would be likely causes
of liver, esophageal and stomach cancers. Instead, Fallon and Enig imply
that soy is a hidden carcinogen in Japan.
Fallon and Enig cite the work of Mark Messina, author
of The Simple Soybean and Your Health (Avery Publishing 1994],
who reviewed 26 animal studies at the Third International Soy Symposium.
According to Messina, 65% of these studies confirm the protective properties
of soy against cancer. Fallon and Enig claim that Messina purposely
left out a 1985 study by Rackis which showed that soy increases the
risk of pancreatic cancer in rats. [Advances Experimental Medicine
Biology 199: 33-79, 1986] At a workshop conducted by the National
Cancer Institute, researchers pointed out that the pancreas of a few
species of animals, notably rats and chicks, are extraordinarily sensitive
to dietary protease inhibitors as found in soy. This effect has not
been demonstrated in other species such as hamsters, mice, dogs, pigs,
and monkeys and is "not expected to occur in humans," says the report.
Human populations that consume high levels of soy exhibit decreased
rates of pancreatic cancer. [Cancer Research 49: 499-502, 1989]
While the enzyme (protease) inhibitors in soy protein increase the weight
of the pancreas, they do not appear to produce lesions, abnormal growths
or DNA abnormalities among rats. [Journal Nutrition 117: 247-52,
1987]
One wonders why Fallon and Enig included in their anti-soy
epitaph the story of New Zealand bird breeders Richard and Valerie James.
The James' apparently purchased a new type of bird food that contained
soy, which made their birds sick, impaired their fertility and changed
the coloring of their feathers. The James' related these symptoms of
illness to those of their young children, who had been fed soy-based
formula. The flock of birds under their care was restored to health
by the elimination of the soy-based bird food. But heavens, you don't
see birds naturally eating soybeans. They know better. It's obvious
the James' knew less about bird feed than their feathered pets! That
the James' children were intolerant to soy and may have had soy allergy,
or that they may have had health problems unrelated to soy, serve as
more likely explanations.
Fallon and Enig go on to quote Dr. Claude Hughes' animal
research concerning soy isoflavones and thyroid function. Hughes claims
his work will be "somewhat predictive of what occurs in humans." But
there are differences between animal and human studies, particularly
when it comes to soy. Scientists cannot infer that animal data applies
to humans. Remember Thalidomide, the drug that caused all the birth
defects in Europe? The data on that drug checked out on animals, but
among pregnant women interfered with their offspring's development.
Fallon and Enig cite 68 scientific references in their
Nexus Magazine report. The 40 scientific journal reports cited
were published on average 13 years ago, with many dating back to the
1970s. Among the authoritative references listed in support of their
report were "Cheese Marketing News" and "Natural Health News published
by L & H Vitamin Company." The Weston Price Foundation website,
of which Fallon is president, claims their purpose is to dispel health
myths. Yet a report on their own website indicates "the New Zealand
government is considering removing soy formula from the market and making
it available only by prescription," and lists a citation number #58.
Their claim may be true, but when the reader looks for the citation
in the end notes, it is missing. So the reader has to wonder why. It
appears that Fallon and Enig are making a career out of bashing soy,
but are they backing up their opinions with good science?
Much of Fallon and Enig's criticism is generated from
reports on the use of soy infant formulas. In 1998, K.O. Klein of the
Department of Clinical Science at the A.I. duPont Hospital for Children
in Wilmington, Delaware, reported that soy-based infant formulas had
been used for over 60 years and fed to millions of infants worldwide
and studied in controlled research. Klein says the medical literature
provides "no evidence of endocrine effects in humans from infant consumption
of modern soy-based formulas. Growth is normal and no changes in timing
of puberty or in fertility rates have been reported in humans who consumed
soy formula as infants." [Nutrition Reviews 56: 193-204, 1998]
The Journal of Pediatrics also conducted an earlier study that
came to a similar conclusion. [Journal Pediatrics 124: 612-20,
1994]
With no supporting evidence, Fallon and Enig state that
learning disabilities among male children have reached epidemic proportions
and that soy infant feeding, which began in the 1970s, "cannot be ignored
as a probable cause for these tragic developments." Yet no citations
are listed to back up their claim. They go on to say that one percent
of all girls show signs of puberty before the age of three and quote
a 1997 report in the Journal of Pediatrics. But that report makes
no mention of soy.
Fallon and Enig also make the claim that Asians have
lower rates of osteoporosis than Westerners, not because of soy consumption
but because their diet provides plenty of vitamin D from shrimp and
seafood and plenty of calcium from bone broths. They provide no references
for this claim. They go on to claim that high rates of osteoporosis
in Western society are attributed to the substitution of soy oil for
butter. They advocate butter as a traditional source of vitamin D that
helps to build strong bones.
Butter only provides about 56 units of vitamin D, and
shrimp about 152 units of vitamin D per 100 gram serving, which are
almost insignificant according to the latest reports on the need for
vitamin D. [US Department of Agriculture data] Skin exposure to sunlight
is the primary source of vitamin D. Even sunlight-deprived women who
consume a diet that provides 600 IU of vitamin D/day have been found
to be lacking in this essential nutrient. [Journal Internal Medicine
247: 260-68, 2000] Recent reports indicate blood levels of vitamin D
don't even begin to rise till 4000 IU of vitamin D is consumed. [American
Journal Clinical Nutrition 69: 842-56, 1999] The textbooks need
to be re-written for vitamin D, and Fallon and Enig are using out-dated
information. Furthermore, butter raises cholesterol. [European Journal
Clinical Nutrition 52: 650-54, 1998]
Did all of these negative scientific reports on soy
somehow escape the attention of the FDA reviewers? Is the FDA run by
individuals who are completely beholden to commercial interests? The
Federal Register, October 26, 1999, Volume 64, Number 206, provides
a 66-page discussion on the positive and negative reports concerning
soy and health in relation to the approval by the Food & Drug Administration
that soy protein helps to reduce cardiovascular risk by lowering cholesterol.
The report, written by the Food & Drug Administration, cites 167
pertinent scientific studies.
According to an FDA scientific review, soy does not
interfere with childhood growth, does not cause pancreatic or breast
cancer, does not significantly interfere with mineral absorption as
long as dietary consumption is adequate, does not induce early puberty,
and does not interfere with fertility. Soy may induce allergies, but
that is not sufficient reason to ban it from the marketplace. Epidemiological
studies do not confirm that soy accelerates the rate or incidence of
brain aging nor does soy increase the prevalence of thyroid disorders.
There is a consistent body of scientific evidence that soy protein consumption
results in a significant reduction in total and LDL cholesterol for
those whose cholesterol is elevated (above 250 mg per deciliter blood
sample).* Approximately 25 grams of soy is needed to produce this health
benefit. This is the asterisk noted earlier in this report. Soy doesn't
lower cholesterol among individuals with normal blood fats.
It's not like soy hasn't been investigated thoroughly.
Health reporter Jack Challem notes that in a three-year period from
1996-98, over 1000 articles on soy isoflavones were published in medical
journals. But once the gate was opened for a health claim for soy (cholesterol
reduction), the rest of the still-to-be-confirmed health claims were
ushered in. Some scientific reports indicate soy can reduce hot flashes
among menopausal females, promote bone formation and may reduce the
risk of cancer. Consumers are likely to think that if a little bit of
soy is OK, then more is even better.
The natural health gurus are correct on one point. Soy
is being over-promoted by billion-dollar companies that grow the beans.
Estrogenic compounds are found in other natural foods such as alfalfa
sprouts and sunflower seeds, but they aren't being aggressively marketed
by multi-national agricultural companies. One of these corporate giants
uses shill companies as a front to their soy promotion efforts so as
to hide their involvement. The United Soybean Board works more openly
to get more soy into the diets of school lunch programs. [www.soyfoods.com]
Because the FDA approved soy as a healthy food that reduces cholesterol
among adults with high blood fats is no reason to promote it as an alternative
source of protein for growing children. Its growth inhibitors and mineral
chelators aren't ideally appropriate for children.
But to show you how confusing the debate on soy gets,
consider the following two quotations from health experts:
On December 9, 1999, Doctor's Guide on the internet
reported that there is no clear-cut evidence that estrogens from plants
such as soy actually prevent breast cancer. Walter Willett, MD, DrPH,
Chairman of the Department of Nutrition and Professor of Epidemiology
and Nutrition at Harvard School of Public Health in Boston said "a few
studies even found that phyto (plant) estrogens promote cancer. We do
not know if plant estrogens increase or decrease risk."
Yet Herman Adlercreutz MD of the University of Helsinki
says there is "no evidence in the literature suggesting that phytoestrogens,
present in amounts found in human foods, could have biological effects,
or stimulate already existing cancer, and there is also no evidence
that such phytoestrogens could initiate cancer." [Annals of Medicine
29: 95-120, 1997]
So what are we to conclude? Soy does/doesn't, prevent
cancer. With that kind of doubt being created on its cancer prevention
benefits, and its safety being clouded by reports that allege soy causes
brain disease, one wonders if consumers will even feed soy to their
pets. Who knows, some environmentalists may soon ask for the soy toxin
to be removed from garbage dumps.
Who is behind the scenes in the soy debate? Who can
profit? Pharmaceutical companies don't like the idea of a food competing
with the patented hormone blockers, like raloxifene and Tamoxifen. In
the September 1998 issue of Nutrition Science News, health reporter
Jack Challem notes that tamoxifen and raloxifene reduce the risk of
breast cancer but tamoxifen increases the risk of endometrial cancer
and blood clots in the lungs, and with raloxifene are more likely to
suffer from hot flashes and leg cramps. Tamoxifen increases the risk
of going blind from cataracts by about 400%. [American Journal Ophthalmology
125: 493-501, 1995]
Let's see if we can make some sense of the soy debate.
1. The reason why soy gained the attention of Western
health researchers is because the American diet is almost completely
devoid of phytoestrogens. Hormones can get out of balance, and hyperthyroid
and over-production of estrogen can produce symptoms and pose health
problems as much as low hormone levels. A small amount of plant estrogens
in the diet may act as hormone controlling agents.
2. Like any food, soy may induce allergies. So does
cow's milk, eggs, wheat, corn and fish. But nobody is warning the public
away from these foods.
3. While mother's milk is widely promoted for newborns,
when baby needs to be weaned, cow's milk or soy-milk formulas are often
relied upon. Cow's milk appears to result in superior bone mineral content,
but soy formula appears to produce similar bone mineral content to breast
milk. [Journal Pediatrics 113: 205-07, 1988; Journal Pediatrics
110: 687-92, 1987] Soy milk formula appears to produce similar weight
gain (growth rates) as produced with cow's milk formula in young infants.
[Pediatric Research 15: 1240-44, 1981] Soy infant formulas can
be modified to suspend minerals and thus improve bone mineral content.
Modified soy formula has been shown to improve bone mineral content
among infants comparable to cow's milk formula. [American Journal
Diseases Children 146: 1302-05, 1992]
For infants who are allergic to cow's milk, soy milk
is the alternative of choice. But even one in four allergic infants
have problems tolerating soy formula. Better to look into whey milk
formulas. Whey milk is probably superior to soy milk when it comes to
minimizing allergic reactions among infants. [Arerugi 46: 1044-51,
1997] In one study 84-99% of infants who were allergic to cow's milk
were able to consume whey protein formula without allergic reaction.
[Journal Pediatric Gastroenterology Nutrition 26: 398-401, 1998]
In another study, whey milk formula reduced the incidence of allergy
among 6-month old infants by over 5 times compared to cow's milk. [European
Journal Pediatrics 154: 488-94, 1995] Furthermore, whey appears
to produce the same growth rates as cow's milk. [Allergy 51:
192-95, 1996]
4. Some of the components of soy have been mistakenly
identified as anti-nutrients. For example, IP6-phytic acid, the primary
mineral chelator in soy, was branded as an anti-nutrient because it
blocks mineral absorption. Minerals, particularly iron, calcium and
zinc, are important during childhood growth. It is easy to improve iron
absorption in soy infant formulas by adding some vitamin C. [Pediatric
Research 36: 816-22, 1994] But adults tend to over-mineralize as
they grow older. The threat of iron overload is universal in male adults
and postmenopausal females. Calcium tends to accumulate in the joints
(arthritis), heart valves (mitral valve), kidneys (kidney stones), blood
vessels (atherosclerosis) and lens of the eye (cataracts) with advancing
age. So there is a need for dietary mineral chelators, to prevent calcifications
and iron-induced oxidation in living human tissues, particularly with
advancing age. In 1987 Ernst Graf, PhD, was the first to describe IP6-phytic
acid, found in whole grains and nuts, as a potent antioxidant and mineral
chelator. It is the only antioxidant known that can completely counter
the adverse effect posed by the hydroxyl radical, a free radical species
involved in all cancers. [The Lancet, September 19, 1987]
Most soy protein products already have undergone processing to remove
most of the IP6-phytic acid anyway. [Acta Paediatrica 402: 105-08,
1994] The removal of IP6-phytic acid from soy increases iron absorption.
[American Journal Clinical Nutrition 60: 567-72, 1994]
The IP6-phytic acid in soy has been found to reduce
the risk of colon cancer in an animal study via its ability to chelate
iron. [Proceedings Society Experimental Biology & Medicine
221: 80-86, 1999] The IP6-phytic acid in soy may be the primary ingredient
that helps to control cholesterol. [Journal Nutrition 125: 606-611S-
1995]
IP6-phytic acid is not only found in soy, it is provided
in other whole grains, particularly bran. But no one is proposing that
bran is toxic because of its IP6-phytic acid content. Cow's milk (probably
due to its lactoferrin content), and eggs also tend to decrease the
bioavailability of iron from plant foods. [Federal Proceedings
42: 1716-20, 1983]
The primary reason why adults do not get enough of some
minerals with advancing age is the diminished production of hydrochloric
acid, not the inclusion of IP6-phytic acid in whole grains and soy.
[Advances Experimental Biology Medicine 249: 173-84, 1989] Soybean
compounds such as IP6-phytic acid, protease inhibitors and isoflavones,
among others, appear to reduce the incidence of colon, prostate and
breast cancer. [Journal Nutrition 125: 733-743S, 1995]
5. Why get so bothered about soy? Indeed, spices such
as thyme, oregano and turmeric bind with estrogen or progesterone and
are thus known to be hormone blockers. [Proceedings Society Experimental
Biology Medicine 21: 369-78, 1998] Even though the American diet
is said to be lacking in soy phytoestrogens, beer contains significant
amounts of isoflavones (probably from hops). [Steroids 63: 14-20,
1998]
6. Science backs the consumption of soy protein and/or
soy extracts (phytoestrogen-isoflavones) for males with prostate tumors.
In immune-depressed rodents whose prostate glands were inoculated with
human cancer cells, soy significantly reduced the size of tumors and
the number of blood vessels that feed tumors. [Journal Nutrition
129: 1628-35, 1999]
7. There is a great difference between animal and human
studies. Soybean cereal has been shown to interfere with the growth
of young rodents. [Medicina 59: 747-52, 1999] But in infants,
there was no difference noted in weight gain nor pancreatic enzyme production
when fed soy or a whey protein formula. [Scandinavian Journal Gastroenterology
32: 273-77, 1997] Be wary of so-called experts who only quote animal
data to support their claims that soy is toxic or unhealthful.
8. The fact that isoflavones in soy are reduced significantly
by their first pass through the liver following ingestion, limits their
hormonal effects, particularly on children. [Proceedings Experimental
Biology Medicine 217: 386-92, 1998] Recent data shows that neither
soy, nor soy isoflavones, exert estrogenic effects on vaginal tissues
in postmenopausal females. [Journal Clinical Endocrinology 84:
3479-84, 1999] In monkeys, soy phytoestrogens reduced cholesterol but
did not affect the reproductive hormones. [Journal Nutrition
126: 43-50, 1996]
9. A recent study conducted among 31 patients with high
cholesterol, who were provided 33 grams per day of soy protein (providing
86 mg of isoflavones), reveals that LDL "bad" cholesterol levels were
significantly reduced even among subjects who were already taking vitamin
E supplements (400-800 IU). The soy protein did not increase the risk
of hormone-induced cancers. [Metabolism 49: 537-43, 2000]
10. Soy is a known goiterogen. It may interfere with
iodine, a trace mineral required for thyroid function. [Biochemical
Pharmacology 54: 1087-96, 1997] Infants with congenital low thyroid
output, when placed on soy formula, need to have their thyroxine dose
increased. [Journal American College Nutrition 16: 280-82, 1997]
Infants with normal thyroid output need not be concerned. But adults
who are on thyroid hormone replacement would be wise to review their
consumption of soy with their physician and to be aware of symptoms
such as fatigue and loss of hair, which may occur with low thyroid.
11. What about the link between brain shrinkage and
soy consumption? Dr. Lon White MD, the lead researcher who reported
this link, compromised his own credibility when he was quoted as saying:
"Those who ate a lot of tofu, by the time they were 75 or 80 looked
five years older." Tell us Dr. White, did you count the wrinkles? We
await corroborative research studies.
12. Stephen Holt, MD, writing in Natural Pharmacy,
has done the best job of sorting out information about soy. He says
soy protein should be distinguished from the soy extracts or isoflavones.
Consumption of up to 120 milligrams of soy isoflavones from soy foods
should not be considered worrisome. He says phytoestrogens in soy are
far weaker than the potent synthetic or natural estrogens commonly prescribed
to women for menopause symptoms. But he does caution against excessive
consumption of soy isoflavones in food supplements or from fermented
sources (tempeh, miso) which Fallon and Enig advocate. His guess is
no more than 45 milligrams of conjugated isoflavones from fermented
or supplmental sources daily. [Natural Pharmacy, April 2000]
While soy has gained the most attention because it is
backed by powerful agribusiness, its cousin lignan may soon become a
more desirable phytoestrogen. Herman Adlercreutz, one of the world's
top isoflavone researchers, emphasizes the importance of other phytoestrogens.
"Don't forget the lignans," he says. [Nutrition Science News,
September 1998] We can see why researchers are turning their attention
to lignan.
Lignan is a normal component of the diet, albeit it
is only consumed in small amounts. It is a phytoestrogen that does not
interfere with thyroid function. Lignan is most abundant in flaxseed.
Lignans in flaxseed have been compared to Tamoxifen, a hormone-blocking
drug often prescribed in cases of breast cancer. [Cancer Letters
125: 69-76, 1998] Adlercreutz says the areas of the world where consumption
of isoflavones and lignans are high have low rates of prostate, breast
and colon cancer. Animal experiments confirm that lignans and isoflavones
prevent cancer in blood vessel disease. [Annals Medicine 29:
95-120, 1997] When rates of disease are investigated by the type of
phytoestrogen, both isoflavones derived from soy, and lignans found
in flaxseed, whole-grain rye bread, berries and some vegetables, are
attributed to the reduction in breast, prostate and colon cancer. Where
consumption of lignan is low (USA, Finland, Sweden, Australia) breast
cancer levels are high. [Baillieres Clinical Endocrinology Metabolism
12: 605-23, 1998]
In one study prostate tumor cells were injected into
rodents who were placed on different diets. Only 50% of the sites injected
with tumor cells grew tumors among the animals on soy, and only 30%
of injection sites exhibited tumors among the animals that consumed
lignan-rich rye bran. The tumors that did grow were smaller in the animals
consuming soy and rye bran and there was less secretion of prostate
specific antigen (PSA). The addition of fat to the rye bran diet reduced
its protective effect against prostate cancer. [Prostate 42:
304-14, 2000]
In a study where rodents were given a tumor-promoting
agent, a diet enriched in soy did not reduce the number of colon tumors
(1.38 tumors per animal) compared to a diet low in soy isoflavones (1.36
tumors per animals. But a lignan-rich rye bran diet did reduce the number
of tumors! (0.17 tumors per animal). [Carcinogenesis 20: 927-31,
1999]
Summary
Soy is not hemlock. It is not a toxin, nor does it contain
toxins. Soy is like table salt. Overuse can be troublesome. Learn to
use it sparingly. If you are looking for lignans in your diet, throw
in some flaxseeds, or cold-pressed lignan-rich flaxseed oil. Lignan
may soon create a greater stir among health advocates than soy.
Correspondence:
Bill Sardi
Health Reporter
Knowledge of Health
E-mail: BSardi@aol.com