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.

 

Bioavailability of zinc in milk and soy protein-based infant formulas.
Momcilovic B, Belonje B, Giroux A, Shah BG. J Nutr. 1976 Jul;106(7):913-7.

Thus, to provide equivalent amounts of available zinc, the total zinc content of the soy protein-based formula would need to be at least 20% higher than that of the formula containing milk protein.

Full Abstract Here

 

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 three articles discuss the issue of manganese toxicity further:

 

Is soy-based infant formula brain damaging?  Press Release written by David Goodman, Ph.D.  

 

ADD-ing it up: soy infant formula, ADD/ADHD and manganese toxicity

Kaayla T. Daniel, PhD, CCN, 2162 Candelero Street, Santa Fe, NM 87505
Phone: +1 505 984 2093
Email: wholenutrifionist@earthlink.com
Website: http://www.thewholesoystory.com/

Abstract
Manganese is an essential trace mineral, but high levels are neurotoxic to newborns. Infants fed soy infant formula ingest as much as 80 times more manganese per day than those who are breast fed. Although healthy toddlers, children and adults exposed to excess manganese can usually eliminate most of it, infants cannot because their immature livers are not fully functional. At the same time, their growing brains and other organs are highly susceptible to damage from neurotoxins. This article reviews research showing that neonates exposed to the high levels of manganese present in soy formula are at increased risk for neurodevelopmental abnormalities, including an impaired ability to make the neurotransmitter dopamine and damage to the substantia nigra, caudate, putamen and globus pallidus areas of the brain. These findings suggest that soy infant formula is a likely contributor to the epidemic of ADD/ADHD and other cognitive and behavioral disorders.

This paper is a slightly revised and updated version of Chapter 21 from my book The Whole Soy Story: The Dark Side of America’s Favorite Health Food (Publisher: NewTrends Publishing, Inc. (March 10, 2005); ISBN: 0967089751). © Copyright 2005 Pearblossom Private School, Inc.—Publishing Division. All rights reserved.

"How safe is soy infant formula?".

 

Manganese content of soy or rice beverages is high in comparison to infant formulas.

Cockell KA, Bonacci G, Belonje B.

Nutrition Research Division, Bureau of Nutritional Sciences, Food Directorate, Health Canada, Ottawa, Ontario, Canada. kevin_cockell@hc-sc.gc.ca

OBJECTIVE: Well-meaning but inadequately informed parents may perceive plant-based beverages such as soy beverages (SB) or rice beverages (RB) as an alternative to infant formula. Manganese (Mn) is an essential mineral nutrient found at high levels in plants such as soy and rice. Excessive Mn exposure increases the risk of adverse neurological effects. METHODS: We analysed, by atomic absorption spectrometry, the Mn content of 36 SB, 5 RB, 6 evaporated milks (EM), 14 soy-based infant formulas (SF) and 16 milk-based infant formulas (MF), obtained from commercial outlets in Ottawa, Canada. RESULTS: SB had the highest levels of Mn (16.5 +/- 8.6 micro g/g dry wt, mean +/- s.d.), followed by RB (9.9 +/- 1.7 micro g/g dry wt). Mn levels of individual SB/RB ranged from 2 to 17 times the mean Mn content of SF (2.4 +/- 0.7 micro g/g dry wt) and 7 to 56 times that of MF (0.70 +/- 0.35 micro g/g dry wt). EM contained very little Mn (0.02 +/- 0.03 micro g/g dry wt). Calculated mean Mn intakes from SB/RB by infants up to 6 months of age, assuming complete substitution of these products (0.78 L/day), approached the Tolerable Upper Intake Level (UL) for 1-3 year olds (no UL for Mn is available for infants under 1 year of age). Expressed as micro g Mn/100 kcal, SB/RB exceeded the range derived from ULs and typical energy intakes of 1-3 year olds. CONCLUSIONS: SB/RB should not be fed to infants because they are nutritionally inadequate and contain Mn at levels which may present an increased risk of adverse neurological effects if used as a sole source of nutrition.

 

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.

 

Vitamin B1 Deficiency

Soy is deficient in Vitamin B1.     In extreme cases...as in the one below,where it seems the formula maker ( a Heinz subsidiary) omitted to fortify the formula with Vitamin B1 to compensate for the nutritional risks of consuming too much soy.

THREE BABIES HOSPITALIZED WITH BERIBERI
Three infants between the ages of five months and a year were hospitalized in Soroka Hospital in Be'er Sheva last night, for fear that they, too, may have been inflicted with the Remedia-B1 syndrome.  The number of hospitalized babies in the Remedia case is now eight; 17 instances have been discovered, and three babies have died, including one who died six months ago.  The condition of three babies in Schneider Children's Hospital has improved, although a fourth is still unconscious. 

The Health Ministry issued instructions last night for all parents who have fed their babies Remedia's soy-based milk substitute in the past two months to take them for check-ups.  The country's health funds will distribute free Vitamin B1 syrup to babies who need it.

The Health Ministry now assumes that the mysterious disease is nothing other than beriberi, a severe thiamine (B1) deficiency, which some feel is a "third world" disease.   Beriberi has become very rare in the western world because most foods are vitamin-enriched.  However, it can occur in breast-fed infants when the mother has an inadequate intake of thiamine, in infants fed formulas with inadequate thiamine supplements, and in developing countries with limited diets based largely on milled rice.

The Remedia formula is not poisonous, but it does not contain the all-important Vitamin B1 - contrary to the list of ingredients on the package.  The formula was changed several months ago, but the list of ingredients did not reflect the new composition.  Not only did the stock of Remedia's competitor Materna jump 41% yesterday, but the State Prosecution is now considering a criminal investigation against the directors of Remedia.

 

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?