Colloquium on GM for NGOs & Civil Society OrganisationSheepdrove Trust & Roddick Foundation

Sources and Mechanisms of Health Risks from Genetically Modified Crops and Foods

Sheepdrove, 26th Feb 2013

Dr Michael Antoniou

Earth Open Source

www.earthopensource.org

GM Food Safety: should we be worried?Genetically modified (GM) crops are produced through a procedure that is radically different from conventional plant breeding:

New technology: only ~40 years old.

Does not involve natural sexual reproduction methods.

Allows transfer of one or few genes between totally unrelated organisms, employing artificial combinations of genetic material.

Crosses species barriers to reproduction in ways that do not occur naturally

Produces combinations of genes that have not evolved to work together in a coordinated integrated whole

GM transformation process is inefficient: frequently uses antibiotic resistance genes to select for transformants, which can persist in final crop.

GM Food Safety: why should we be worried? Generation of GM plants (and animals) involves the random

insertion or splicing of a foreign gene into the host DNA/genome and is not a “clean” process.

GM transformation process as a whole - transgene insertion plus tissue culture - is highly mutagenic: GM to a lesser or greater degree, disrupts host genetic order and function.

Combined effects of GM (mutation effects; novel combinations of gene products):

can disrupt genetic and protein biochemical function

lead to the generation of novel toxic effects, allergies and altered nutritional value.

Therefore, GM crops pose new risks to food safety that need to be evaluated for both acute and especially chronic toxic effects.

There are three sources of health risks that can potentially arise from GM foods:

1. The introduced foreign GM gene (“transgene”):GM gene product directly (e.g. Bt toxin)Altered plant biochemistry caused by GM gene product (e.g. enzymes conferring herbicide tolerance)

2. Higher exposures to herbicides used in conjunction with the cultivation of GM crops (e.g. glyphosate)

3. Altered plant biochemistry caused by mutagenic effect of the GM transformation process

Only four crops and two traits dominate GM based agriculture:

Soy beans Maize or corn Canola or oilseed rape Cotton

• All the GM soy and some corn varieties are engineered to be tolerant to glyphosate based herbicide application (mostly Roundup formulations)

• Most corn and cotton are predominantly engineered to express versions of the insecticidal Bt toxin protein; some combine both Bt toxin and glyphosate tolerance

• Cultivation restricted to a few nations: N & S America

Health Risk Evaluation of GM FoodSubstantial Equivalence, Generally Recognised as

Safe and “Comparative Assessment”

General biochemical analysis only.Assessment of known toxins/allergens only.

GM and non-GM parental plant are “substantially equivalent” ifthey contain similar amounts of biochemical components withinlimits of natural variation.

No feeding trials formally required if substantial equivalence is found.

FLAWS: Only looks at gross biochemical composition; only looksat known components.

NOTE: BSE cow is “substantially equivalent” to a normal cow!

Animal feeding toxicity tests are not mandatory anywhere in the world

Organisation for Economic Co-operation and Development (OECD):Sets guidelines for industry to conduct animal feeding studies to evaluate toxicity of chemical products (e.g. herbicides, insecticides)Multiple doses (at least 3 to determine dose response effects)More than one animal Only 90 days durationHas not issued guidelines for GM feed/food toxicity feeding studies

However:Industry has adopted the chemical toxicity OECD guidelines to GM feed/food animal feeding studiesApplications for marketing within the EU [Note: not all OECD guidelines are followed by industry; e.g., use of at

least 3 doses, use of multiple animals species].

Heath Risk Evaluation of GM Foods

Industry’s approach:compare GM crop / food with large number of varieties unrelated to GM variety under study grown at different times and locations Use data in the literature (“historical norms”) Outcome:increases variables or “noise” in the systemmasks rather than highlights effect of GM process

Only scientifically valid comparators: GM vs non-GM parent (“isogenic”) grown at same time and location

Determining the effect of the GM transformation process:CompositionalAnimal toxicity feeding studiesNeed to minimise variables

Industry GM Crop Applications to EU

For example: MON863, MON810, NK603 corn

GM substantially equivalent to non-GM

90 day feeding studies in rats

Multiple non-isogenic non-GM comparators (note: goes against EU guidelines)

Statistically significant differences in organ function (e.g. liver, kidney, blood system) between GM and non-GM not significant:Fell within large range of variation caused by using non-isogenic controls

EU regulators accepted these arguments; passed all as safe for consumption

Controlled Animal Feeding Studies Show Clear Signs of

Toxicity linked with GM crops

Revealed by GM vs isogenic non-GM comparison

Feeding studies conducted by industryRats fed commercialised insecticide-producing MON863 Bt corn:Grew more slowlySex differencesShowed higher levels of certain fats (triglycerides) in their bloodProblems with liver and kidney function (Séralini et al., 2007).

Note: * & ** indicatestatisticalsignificance

Feeding studies conducted by industryRats fed commercialised GM Bt corn varieties MON863 and MON810 and Roundup tolerant NK603: signs of toxic effects on liver and kidneys. (de Vendomois et al., 2009).

Differences in NK603 fed rats andcontrol animals fed isogenic non-GMmaize.

Note: * & ** indicate statisticalsignificance

Heath Risk Evaluation of GM Crops

Industry position and accepted by regulators:

Accepts statistically significant differences between GM and non-GM feeding groups

But claims not biologically significant!

Feeding studies conducted by academics:commercialised crops

Rats fed GM Bt corn over three generations: areas of necrosis to liver and kidneys and alterations in blood biochemistry (Kilic & Akay, 2008).

Old and young mice fed GM Bt corn MON810: marked disturbance in immune system cells and in biochemical (cytokine) activity (Finamore et al., 2008).

Pigs fed GM Bt corn variety MON810 for 31 days: differences in immune cell type numbers (e.g. CD4+ T cells, B cells, macrophages) and biochemistry (cytokine levels; e.g. IL-12, IFNg, IL-6, IL-4, IL-8) (Walsh et al., 2011).

Ewes and their lambs fed GM Bt corn variety Bt176 over three generations: hyperplasia of ruminal epithelial basal cells in ewes and a disturbed gene functioning of liver and pancreas in lambs (Trabalza-Marinucci et al., 2008).

Feeding studies conducted by academics:commercialised crops

Rabbits fed GM soy: enzyme function disturbances in kidney and heart (Tudisco et al., 2006).Mice fed GM soy: disturbed liver, pancreas and testes function; abnormally formed cell nuclei and nucleoli in liver cells, indicating increased metabolism and potentially altered patterns of gene expression (Malatesta et al., 2002; Malatesta et al., 2003; Vecchio et al., 2004).Mice fed GM soy over their lifetime (24 months): more acute signs of ageing in the liver (Malatesta et al., 2008); significant changes in the expression of 49 proteins; 39 proteins more expressed in GM-fed mice, 10 proteins decreased. Significant decrease in senescence markers (e.g. regucalcin, HSPs); lower metabolism. Structure of liver cell nuclei suggest marked lowering of gene function: GM Non-GM

Feeding studies conducted by academics:non-commercialised crops

Mitogenic effect on gut mucosa of rats fed GM potatoes containing snowdropGNA insecticide protein (Ewen SWB and Pusztai A, Lancet, 354, 1353-1354, 1999):

GM Non-GM Rat Colon

Rats fed GM Bt rice: significant differences in gut bacterial populations and organ weights (adrenals, testis, uterus) (Schrøder et al., 2007).

“GM peas cause surprise allergic reaction”; unexpected post-translationalmodifications on bean -amylase inhibitor in peas caused marked immuneresponse and allergic type reactions in mice (Prescott VE et al. J Agri Food Chem., 53: 9023-9030, 2005).

Industry and academic led animal feeding studies show:

Commercialised GM soy and corn show consistent signs of toxic effects in liver and kidney structure and function as well as some immune system disturbances.

Such effects may be markers of the onset of chronic disease, requiring long-term rather than these reported short- and medium-term studies, to assess this more thoroughly.

Unfortunately, such long-term feeding trials on GM foods are neither required nor requested by regulators anywhere in the world.

What could be causing these signs of toxicity?

1. The introduced foreign GM gene (“transgene”):GM gene product directly (e.g. Bt toxin)Altered plant biochemistry caused by GM gene product (e.g. enzymes conferring herbicide tolerance)

2. Higher exposures to herbicides used in conjunction with the cultivation of GM crops (e.g. glyphosate formulations)

3. Altered plant biochemistry caused by mutagenic effect of the GM transformation process

Bt toxin

Crystalline protein complex (“Cry protein”) Occurs naturally in the common soil bacterium Bacillus thuringiensis Some types of Bt toxins are effective insecticides Used as agricultural spray

Bt toxin in its native crystalline form is inactive as an insecticide; converted to insecticide active form in the digestive tract of certain insects

Bt toxin activation procedure: highly selective insecticide Activated Bt toxin: inserts into and causes lesions in the insect’s gut

epithelium; death either through a disrupted digestion or systemic bacterial infection

 

Native Bt toxin sprays vs. Bt toxin engineered into GM crops

GM Bt toxins: truncated active form Bt toxin present throughout GM crop GM Bt toxin approximately only 45% identical to the native form

GM Bt toxin in crops significantly different from that used as an agricultural spray Insect target specificity is compromised (e.g. see Schmidt et al., 2009)

Poses new health risks that need evaluating

Bt toxin insecticides in GM Crops:artificial and novel, coming from modified genes of a soil

bacteria, a reservoir of more than 100 Bt toxin insecticides

Ex. 44% difference in GM Bt176 maize

Why is Bt toxin a health concern?

Bt toxin:Proven allergen and potent adjuvant in mammals (rats, sheep) even at low levels of exposure (Vázquez et al., 1999; Vázquez-Padrón et al., 1999 & 2000; Kroghsbo et al., 2008; Adel-Patient et al., 2011; Trabalza-Marinucci et al., 2008). Possesses properties, which with sufficient exposure could lead to allergic reactions caused directly by itself or against other ingested foodstuffs.Immunogenic properties may account for the disturbing effects on immune system function observed in animal feeding studies (Finamore et al., 2008; Walsh et al., 2011). Bt toxin type Cry1Ab:Present in commercialised GM crops (e.g. MON810 corn)Binds to human cells in tissue cultureDisturbances in cell energy production and exterior (plasma) membrane systems leading to cell death, albeit at relatively high levels (Mesnage et al., 2012).

Human incidences of Bt toxin exposure GM Cry9C Bt toxin “Starlink” corn, USA:Intended only for animal feed; accidental entry into human foodMany recorded instances of allergic type reactions following consumptionBt cotton, India:Severe skin rashes in Bt cotton field workers; some cases needed hospitalisation (Gupta et al., 2005)Farm animals feeding on the Bt cotton stubble suffering severe illness and death (Warangal District, Andhra Pradesh, 2006) Bt toxin in pregnant and non-pregnant women, Canada:Bt toxin found in the circulation of non-pregnant & pregnant women including blood supply to foetusSource and integrity of the Bt toxin-unknownStudy shows that Bt toxin can survive digestion and enter the circulation. (Aris and Leblanc, 2011) Consumption of Bt toxin GM food runs the risk of chronic systemic exposure.Animal feeding studies suggest this may contribute to adverse health effects especially with respect to liver, kidney and immune system function.

Therefore, further investigation is needed before Bt crops can be claimed to be safe for humans.

Conclusions Increasing evidence shows the disruptive effect of the GM: need for in-depth molecular profiling to identify alterations in composition. Clear signs of toxicity: (especially to liver & kidney function) in controlled animal feeding studies even of a short-term nature.

Cause of signs of toxicity: do they result from GM transgene function (Bt toxin, herbicide tolerance), herbicide residues, the mutagenic effect of the GM transformation process or combinations of these? Allergenicity: needs to be evaluated with human volunteers; no animal model systems available for this type of clinical investigation.  Toxicity needs to be confirmed or refuted in life-long animal feeding studies. Based on available evidence and inadequacy of the tests requested by regulators, at present no GM crop and food can be categorically stated as safe to consume, especially on a long-term, life-long basis.

Background to Study

Follow up to industry 90 day feeding trial Same experimental design: OECD, same strain &

numbers of rats analysed GLP conditions Longer (2 years) More parameters measured (e.g. endocrine hormone

levels) Three doses of GMO & Roundup More extensive test groups; GMO, GMO+R, R

NOTE: toxicity NOT carcinogenicity study

Summary of Study Findings

Escalation of signs of liver and kidney toxicity in Monsanto 90-day feeding trial leading liver / kidney failure and premature death especially in males

Unexpected increase in tumor incidence, especially via Roundup in females (mammary tumors)

Unexpected low dose toxicity from Roundup (10,000 times lower than that permitted in drinking water in USA)

Females: died prematurely from mammary tumors (& pituitary dysfunction).

Note: severe adverse effects started at 4 months and peaked during second year of life.

Criticisms from GM Crop Advocates

Wrong strain of rat: already cancer prone

Too few rats analysed

Wrong statistical methods of analysis

Not in accordance with OECD guidelines

But, Seralini study based on Monsanto study only longer and more comprehensive in analysis; either both are wrong or both are right as far as each goes!

Rebuttal of Criticisms

For detailed, evidence-based rebuttal of criticisms: see gmoseralini.org

ConclusionsRe-evaluate assessment of NK603 GM corn:Conduct carcinogenicity study with larger number of animals

Need to conduct life long (2-year) feeding studies for ALL GMO foods

Need to conduct life long (2 year) toxicity studies with complete pesticide formulations and not just active principle

The GM Transformation Process

(A) PDS/1000 biolistic device used for microprojectile bombardment.(B) Suspension cells of tall fescue plated on filter paper before microprojectile bombardment.(C) Hygromycin resistant calli obtained after selection.(D), (E) Transgenic plantlets regenerated from the hygromycin resistant calli.(F) Transgenic tall fescue plants growing in the greenhouse.

Increased Rates of Mortality in GMO & Roundup Fed Groups

Increase Tumor Incidence in GMO & Roundup Fed Groups

Most Frequent Anatomical Pathologies

Increased Incidence of mammary Tumors in Females

Kidney Failure in Females

Kidney Leakage & Hormone Imbalance in Females

33% GMO (solid line) vs Controls (dotted line): serum or urine measurements; at 15 month

Animals