D
Dave
Guest
Soy Toxins
There's plenty yet that you didn't know about soy!
Soy contains several naturally occurring compounds that are toxic to humans
and animals. The soy industry frequently refers to these toxins as
anti-nutrients, which implies that they somehow act to prevent the body
getting the complete nutrition it needs from a food. The soy toxins (such as
phytic acid) can certainly act in this manner, but they also have the
ability to target specific organs, cells and enzyme pathways and their
effects can be devastating.
The soy toxins that Soy Online Service have concerns about are protease
inhibitors, phytic acid, soy lectins (or haemagglutins), nitrosamines,
manganese concentrations and the mysterious soyatoxin. Nitrosamines are not
naturally occurring in soybeans but form during the processing of products
such as isolated soy protein (ISP).
As with any toxin there will be a dose at which negative effects are not
observed. Soy Online Services have examined the scientific data on the soy
toxins and have uncovered several alarming truths:
There is no legislation to protect consumers from soy toxins in raw soy
products.
With the possible exception of soy lecithin, all soy products, no matter how
well treated, contain low to moderate levels of soy toxins; processing
cannot remove them all of any of them.
The soy industry has little in the way of quality control to protect
consumers from exposure to inadequately treated soy products.
Protease Inhibitors
Perhaps the best known of the soy toxins are the protease inhibitors (also
referred to as trypsin inhibitors) which, as the name suggests, are able to
inhibit the action of proteases (including trypsin) which are enzymes that
are involved in the process of dismantling proteins for use by the body.
In the rat, high levels of exposure to protease inhibitors (such as that
found in raw soy flour) cause pancreatic cancer whereas moderate levels
cause the rat pancreas to be more susceptible to cancer-causing agents. The
validity of the rat model to humans has been questioned and the USFDA have
examined the effects of protease inhibitors on the Cebus monkey (JP Harwood
et al., Adv Exp Med Biol 1986 199: 223-37).
The parameters of the Cebus Monkey study were as follows:
Group Number of monkeys Dietary Protein Trypsin Inhibitor (mg/g of diet)
1 8 Lactalbumin 0.12
2 10 Soy Isolate 0.54
3 6 Casein 0.08
4 2 Soy Concentrate 2.41
After five years of chronic ingestion to low levels of trypsin inhibitors,
there was no discernible pancreatic damage effect in monkeys from groups
1-3. However, one monkey in group 4 exhibited moderate diffuse acinar
atrophy, moderate diffuse interstitial fibrosis and moderate chronic
pancreatitis in all three sections of tissue examined. Minimal lymphoid
hyperplasia was noted in the other group 4 monkey.
Therefore, there is good reason to question claims that low levels of soy
protease inhibitors pose no threat to human health. Such a statement has
even been made by the USFDA in response to a health claim petition by
Protein Technologies. The USFDA reported that:
'Concerns have been raised in the past about exposure to trypsin inhibitors
contained in soybeans because these compounds had been found to stimulate
pancreatic hyperplasia and hypertrophy in animals. These concerns have been
allayed because heat treatment removes most of the activity of these
proteases. In addition, recent studies have questioned the applicability of
the animal models, which differ from humans in the type of diet, sensitivity
of the pancreas to trypsin inhibitors, and the anatomic sites of pancreatic
cell proliferation and have found low rates of cancer in populations with
dietary patterns that include soy foods' (FR 63, 217:62977-63015, 1998).
This statement brought an angry response from Professor Irvin Leiner, the
foremost expert on protease inhibitors. In his reply to the FDA Liener
wrote:
'The impression one gets from reading this section is that that there is
little cause for concern as far as the human exposure to soybean trypsin
inhibitors is concerned.... In the interests of a balanced treatment of the
subject, I trust you will give due consideration to the opposing view that
the soybean trypsin inhibitors do in fact pose a potential risk to humans
when soy protein is incorporated into the diet.'
So, if there is valid concern about low levels of protease inhibitors in soy
foods, what about exposures to levels higher higher than those in the Cebus
monkey study? Is there any chance that such exposures could occur in human
diets?
Soy Online Service has noted that there is considerable variability in the
levels of protease inhibitors in commercially available foods and that there
is little to protect consumers from exposure to high levels of protease
inhibitors. For example, a study entitled 'Trypsin inhibitor levels in
soy-based infant formulas and commercial soy protein isolates and
concentrates (RW Peace et al., 1992, Food Res Int, 25: 137-141) found that
trypsin inhibitor levels were as high as 2.72 mg/g in ready to feed soy
formulas and 7.30 mg/g in soy protein concentrate.
Since there is no established acceptable levels of protease inhibitors in
foods and no protection from short-term high level (acute) exposures or long
term low level (chronic) exposures, Soy Online Service offer the following
advice:
Don't feed your baby or infant a soy formula; there are alternatives!
Avoid the direct consumption of raw or partially processed soy products such
as soy flour or soy protein concentrate. Traditionally fermented soy foods
are relatively free of protease inhibitors.
When preparing your own soy foods, such as boiled or roasted soybeans or soy
milk, ensure that they are adequately heated. The traditional Chinese method
for preparing soybeans was a time consuming job that was left to monks. It
involved soaking the beans first and then boiling them twice over 'the full
length of an incense'.
Phytates
The term phytate refers to several compounds that are based on phytic acid
(inositol hexaphosphate). It is the presence of multiple phosphates in
phytates that makes them effective chelating agents, i.e. they have the
ability to bind to certain metal ions. Obviously if metals are bound up in a
phytate-complex, they are less available to the body ( i.e. less
bioavailable) for nutritive purposes.
Phytates are particularly adept at binding metals in their so-called
divalent state, metal ions such as calcium (Ca2+), copper (Cu2+), iron
(Fe2+), manganese (Mn2+) and zinc (Zn2+).
Soybeans contain very high levels of phytate and their are numerous reports
of reduced bioavailablity of various metals from foods containing soy; this
has particular significance for vegetarians and infants fed soy-formulas.
Vegetarians, particularly young women vegetarians, need to be aware that soy
products affect their iron and zinc requirements and it has been recommended
that they utilise strategies that minimise the intake of dietary phytate.
The effects of phytate in soy-formulas are a great concern. The iron and
zinc requirements of developing infants are well documented, particularly
those that relate to cognitive function. There is no question that infants
fed soy-formulas are at greater risk of reduced uptake of various essential
minerals compared with breast-fed infants or infants fed other formulas.
Copper bioavailability is significantly lower in rhesus monkeys fed
low-phytate soy formula from 2 to 4 months.
Iron absorption in infants is approximately doubled by the removal of
phytate from soy formula; a similar effect is observed by doubling the
ascorbic acid content of a soy formula.
Manganese absorption is also doubled by the removal of phytate from soy
formula, but increasing the ascorbic acid content of a soy formula
containing the native amount of phytic acid did not improve manganese
absorption.
Zinc bioavailability from soy formulas is also reduced by phytate. In rhesus
monkeys, zinc absorption was 2.0 times greater from monkey milk compared
with soy formula, 2.2 times greater from whey-predominant formula compared
with soy formula and 1.7 times greater from casein-predominant formula
compared with soy formula. Zinc absorption from dephytinized soy formula was
approximately the same as that from casein-predominant formula.
Soy formulas are typically over-supplemented with minerals and vitamins to
account for the deficiencies caused by phytate, but it is evident that this
does not take care of the problems. Removal of phytate from soy formulas is
altogether a better solution but manufactures have not shown any inclination
do this. Why not? Phytate removal will cost $$$ and it seems to us that soy
formula manufacturers consider economics to be more important than the well
being of infants.
Manganese
The soybean plant has the ability to absorb manganese from the soil and
concentrate it to an extent that soy-based infant formulas can contain as
much as 200 times the level of manganese found in natural breast milk. In
babies, excess manganese that cannot be metabolised is stored in body
organs. Around eight percent of the excess manganese in the diet is stored
in the brain in close proximity to the dopamine-bearing neurons responsible,
in part, for adolescent neurological development.
The implications are that the one in eight infants raised on soy formula
during the first six months of life may be at risk of brain and behavioural
disorders that do not become evident until adolescence. The following two
links discuss the issue of manganese toxicity further.
Is soy-based infant formula brain damaging?
Press Release written by David Goodman, Ph.D.
"How safe is soy infant formula?".
Aluminium
Aluminum and bone disorders: with specific reference to aluminum
contamination of infant nutrients.
Koo WW, Kaplan LA. J Am Coll Nutr. 1988 Jun;7(3):199-214.
Enteral nutrients including human and whole cow milk have low Al, whereas
highly processed infant formulas with multiple additives, such as soy
formula, preterm infant formula, and formulas for specific disorders are
heavily contaminated with Al.
However, even with normal renal function, only 30-60% of an Al load from
parenteral nutrition is excreted in the urine, resulting in tissue
accumulation of Al.
To minimize tissue burden, Al content of infant nutrients should be similar
to "background" levels, i.e., similar to whole milk (less than 50
micrograms/L).
Full Abstract Here
Vitamin B12 Deficiency
Vitamin B 12 deficiency has been recognised as a serious result of soy
consumption for many years. For instance JJ Rackis discusses it in January
1974 in "Biological and Physiological Factors in Soybeans' in the J. Am. Oil
Chemists Soc, pp 161", and Irvin E Liener examines it in 1994 in
"Implications of Anti-Nutritional Components in Soybean Foods in Soybean" in
Critical Reviews in Food Science and Nutrition
There is a simple explanation of some of the physical effects that can
result from a deficiency of this important nutrient at. "Vegans Deficient in
Nutrients".
If the Moorhead trial judge had known this, would these people now be
serving a jail term for the death of their child?
Read about the Seventh Day Adventist Moorheads Here and Here.
Other Toxins
Letter to FDA CONSUMER magazine
http://www.fda.gov/fdac/departs/2000/400_ltrs.html August 2000
The FDA Consumer article on soy spoke of the possible risks of plant
estrogens, but made no mention of the carcinogenic effects of protease
inhibitors found in soy. McGuinness et al. report rats fed raw soya flour
develop cancer of the pancreas ("The effects of long-term feeding of soya
flour on the rat pancreas," Scandinavian Journal of Gastroenterology, 1980;
15:497-502). They say that preheating the flour protected the animals, but
others have said that the high heat required (130 degrees Celsius) to
deactivate the carcinogenic trypsin inhibitors in soya flour denatures the
soy proteins to the point that they become virtually useless. If this is so,
one either chooses less heating, resulting in more surviving trypsin
inhibitors, or more heating, resulting in useless protein.
William Jarvis, Ph.D.
Department of Health Promotion and Education
Loma Linda University
Loma Linda, Calif.
Soyatoxin
The soy industry funds millions of dollars of research each year; what
chance is there for the discoverers of soyatoxin to get funding to continue
their work?
There's plenty yet that you didn't know about soy!
Soy contains several naturally occurring compounds that are toxic to humans
and animals. The soy industry frequently refers to these toxins as
anti-nutrients, which implies that they somehow act to prevent the body
getting the complete nutrition it needs from a food. The soy toxins (such as
phytic acid) can certainly act in this manner, but they also have the
ability to target specific organs, cells and enzyme pathways and their
effects can be devastating.
The soy toxins that Soy Online Service have concerns about are protease
inhibitors, phytic acid, soy lectins (or haemagglutins), nitrosamines,
manganese concentrations and the mysterious soyatoxin. Nitrosamines are not
naturally occurring in soybeans but form during the processing of products
such as isolated soy protein (ISP).
As with any toxin there will be a dose at which negative effects are not
observed. Soy Online Services have examined the scientific data on the soy
toxins and have uncovered several alarming truths:
There is no legislation to protect consumers from soy toxins in raw soy
products.
With the possible exception of soy lecithin, all soy products, no matter how
well treated, contain low to moderate levels of soy toxins; processing
cannot remove them all of any of them.
The soy industry has little in the way of quality control to protect
consumers from exposure to inadequately treated soy products.
Protease Inhibitors
Perhaps the best known of the soy toxins are the protease inhibitors (also
referred to as trypsin inhibitors) which, as the name suggests, are able to
inhibit the action of proteases (including trypsin) which are enzymes that
are involved in the process of dismantling proteins for use by the body.
In the rat, high levels of exposure to protease inhibitors (such as that
found in raw soy flour) cause pancreatic cancer whereas moderate levels
cause the rat pancreas to be more susceptible to cancer-causing agents. The
validity of the rat model to humans has been questioned and the USFDA have
examined the effects of protease inhibitors on the Cebus monkey (JP Harwood
et al., Adv Exp Med Biol 1986 199: 223-37).
The parameters of the Cebus Monkey study were as follows:
Group Number of monkeys Dietary Protein Trypsin Inhibitor (mg/g of diet)
1 8 Lactalbumin 0.12
2 10 Soy Isolate 0.54
3 6 Casein 0.08
4 2 Soy Concentrate 2.41
After five years of chronic ingestion to low levels of trypsin inhibitors,
there was no discernible pancreatic damage effect in monkeys from groups
1-3. However, one monkey in group 4 exhibited moderate diffuse acinar
atrophy, moderate diffuse interstitial fibrosis and moderate chronic
pancreatitis in all three sections of tissue examined. Minimal lymphoid
hyperplasia was noted in the other group 4 monkey.
Therefore, there is good reason to question claims that low levels of soy
protease inhibitors pose no threat to human health. Such a statement has
even been made by the USFDA in response to a health claim petition by
Protein Technologies. The USFDA reported that:
'Concerns have been raised in the past about exposure to trypsin inhibitors
contained in soybeans because these compounds had been found to stimulate
pancreatic hyperplasia and hypertrophy in animals. These concerns have been
allayed because heat treatment removes most of the activity of these
proteases. In addition, recent studies have questioned the applicability of
the animal models, which differ from humans in the type of diet, sensitivity
of the pancreas to trypsin inhibitors, and the anatomic sites of pancreatic
cell proliferation and have found low rates of cancer in populations with
dietary patterns that include soy foods' (FR 63, 217:62977-63015, 1998).
This statement brought an angry response from Professor Irvin Leiner, the
foremost expert on protease inhibitors. In his reply to the FDA Liener
wrote:
'The impression one gets from reading this section is that that there is
little cause for concern as far as the human exposure to soybean trypsin
inhibitors is concerned.... In the interests of a balanced treatment of the
subject, I trust you will give due consideration to the opposing view that
the soybean trypsin inhibitors do in fact pose a potential risk to humans
when soy protein is incorporated into the diet.'
So, if there is valid concern about low levels of protease inhibitors in soy
foods, what about exposures to levels higher higher than those in the Cebus
monkey study? Is there any chance that such exposures could occur in human
diets?
Soy Online Service has noted that there is considerable variability in the
levels of protease inhibitors in commercially available foods and that there
is little to protect consumers from exposure to high levels of protease
inhibitors. For example, a study entitled 'Trypsin inhibitor levels in
soy-based infant formulas and commercial soy protein isolates and
concentrates (RW Peace et al., 1992, Food Res Int, 25: 137-141) found that
trypsin inhibitor levels were as high as 2.72 mg/g in ready to feed soy
formulas and 7.30 mg/g in soy protein concentrate.
Since there is no established acceptable levels of protease inhibitors in
foods and no protection from short-term high level (acute) exposures or long
term low level (chronic) exposures, Soy Online Service offer the following
advice:
Don't feed your baby or infant a soy formula; there are alternatives!
Avoid the direct consumption of raw or partially processed soy products such
as soy flour or soy protein concentrate. Traditionally fermented soy foods
are relatively free of protease inhibitors.
When preparing your own soy foods, such as boiled or roasted soybeans or soy
milk, ensure that they are adequately heated. The traditional Chinese method
for preparing soybeans was a time consuming job that was left to monks. It
involved soaking the beans first and then boiling them twice over 'the full
length of an incense'.
Phytates
The term phytate refers to several compounds that are based on phytic acid
(inositol hexaphosphate). It is the presence of multiple phosphates in
phytates that makes them effective chelating agents, i.e. they have the
ability to bind to certain metal ions. Obviously if metals are bound up in a
phytate-complex, they are less available to the body ( i.e. less
bioavailable) for nutritive purposes.
Phytates are particularly adept at binding metals in their so-called
divalent state, metal ions such as calcium (Ca2+), copper (Cu2+), iron
(Fe2+), manganese (Mn2+) and zinc (Zn2+).
Soybeans contain very high levels of phytate and their are numerous reports
of reduced bioavailablity of various metals from foods containing soy; this
has particular significance for vegetarians and infants fed soy-formulas.
Vegetarians, particularly young women vegetarians, need to be aware that soy
products affect their iron and zinc requirements and it has been recommended
that they utilise strategies that minimise the intake of dietary phytate.
The effects of phytate in soy-formulas are a great concern. The iron and
zinc requirements of developing infants are well documented, particularly
those that relate to cognitive function. There is no question that infants
fed soy-formulas are at greater risk of reduced uptake of various essential
minerals compared with breast-fed infants or infants fed other formulas.
Copper bioavailability is significantly lower in rhesus monkeys fed
low-phytate soy formula from 2 to 4 months.
Iron absorption in infants is approximately doubled by the removal of
phytate from soy formula; a similar effect is observed by doubling the
ascorbic acid content of a soy formula.
Manganese absorption is also doubled by the removal of phytate from soy
formula, but increasing the ascorbic acid content of a soy formula
containing the native amount of phytic acid did not improve manganese
absorption.
Zinc bioavailability from soy formulas is also reduced by phytate. In rhesus
monkeys, zinc absorption was 2.0 times greater from monkey milk compared
with soy formula, 2.2 times greater from whey-predominant formula compared
with soy formula and 1.7 times greater from casein-predominant formula
compared with soy formula. Zinc absorption from dephytinized soy formula was
approximately the same as that from casein-predominant formula.
Soy formulas are typically over-supplemented with minerals and vitamins to
account for the deficiencies caused by phytate, but it is evident that this
does not take care of the problems. Removal of phytate from soy formulas is
altogether a better solution but manufactures have not shown any inclination
do this. Why not? Phytate removal will cost $$$ and it seems to us that soy
formula manufacturers consider economics to be more important than the well
being of infants.
Manganese
The soybean plant has the ability to absorb manganese from the soil and
concentrate it to an extent that soy-based infant formulas can contain as
much as 200 times the level of manganese found in natural breast milk. In
babies, excess manganese that cannot be metabolised is stored in body
organs. Around eight percent of the excess manganese in the diet is stored
in the brain in close proximity to the dopamine-bearing neurons responsible,
in part, for adolescent neurological development.
The implications are that the one in eight infants raised on soy formula
during the first six months of life may be at risk of brain and behavioural
disorders that do not become evident until adolescence. The following two
links discuss the issue of manganese toxicity further.
Is soy-based infant formula brain damaging?
Press Release written by David Goodman, Ph.D.
"How safe is soy infant formula?".
Aluminium
Aluminum and bone disorders: with specific reference to aluminum
contamination of infant nutrients.
Koo WW, Kaplan LA. J Am Coll Nutr. 1988 Jun;7(3):199-214.
Enteral nutrients including human and whole cow milk have low Al, whereas
highly processed infant formulas with multiple additives, such as soy
formula, preterm infant formula, and formulas for specific disorders are
heavily contaminated with Al.
However, even with normal renal function, only 30-60% of an Al load from
parenteral nutrition is excreted in the urine, resulting in tissue
accumulation of Al.
To minimize tissue burden, Al content of infant nutrients should be similar
to "background" levels, i.e., similar to whole milk (less than 50
micrograms/L).
Full Abstract Here
Vitamin B12 Deficiency
Vitamin B 12 deficiency has been recognised as a serious result of soy
consumption for many years. For instance JJ Rackis discusses it in January
1974 in "Biological and Physiological Factors in Soybeans' in the J. Am. Oil
Chemists Soc, pp 161", and Irvin E Liener examines it in 1994 in
"Implications of Anti-Nutritional Components in Soybean Foods in Soybean" in
Critical Reviews in Food Science and Nutrition
There is a simple explanation of some of the physical effects that can
result from a deficiency of this important nutrient at. "Vegans Deficient in
Nutrients".
If the Moorhead trial judge had known this, would these people now be
serving a jail term for the death of their child?
Read about the Seventh Day Adventist Moorheads Here and Here.
Other Toxins
Letter to FDA CONSUMER magazine
http://www.fda.gov/fdac/departs/2000/400_ltrs.html August 2000
The FDA Consumer article on soy spoke of the possible risks of plant
estrogens, but made no mention of the carcinogenic effects of protease
inhibitors found in soy. McGuinness et al. report rats fed raw soya flour
develop cancer of the pancreas ("The effects of long-term feeding of soya
flour on the rat pancreas," Scandinavian Journal of Gastroenterology, 1980;
15:497-502). They say that preheating the flour protected the animals, but
others have said that the high heat required (130 degrees Celsius) to
deactivate the carcinogenic trypsin inhibitors in soya flour denatures the
soy proteins to the point that they become virtually useless. If this is so,
one either chooses less heating, resulting in more surviving trypsin
inhibitors, or more heating, resulting in useless protein.
William Jarvis, Ph.D.
Department of Health Promotion and Education
Loma Linda University
Loma Linda, Calif.
Soyatoxin
The soy industry funds millions of dollars of research each year; what
chance is there for the discoverers of soyatoxin to get funding to continue
their work?
