Possible human health impacts of Monsanto's transgenic glyphosate-resistant soybeans

Attempts by Monsanto to market a soybean which has been genetically engineered to make it resistant to a glyphosate herbicide produced by the US multinational under the brand name 'Roundup', have provoked world-wide protests. In the following critique, Dr Beatrix Tappeser and Christine von Weizsacker reveal why the studies carried out by Monsanto to assertain the safety of its Round-up Ready Soybeans are fatally flawed.


NUMEROUS studies have been carried out by Monsanto on the transgenic soybean and its potential impact on human health. However, going through the reports, one can easily identify a blatant scientific omission in the design of these tests:

Consumers will ingest transgenic soybeans that will be grown on glyphosate-sprayed fields. However, the tests were done on transgenic soybeans that were grown without the application of glyphosate.

This is a scientific error of major proportion which makes the results void. The beans tested are not the transgenic beans from glyphosate-sprayed fields which will be consumed.

Four problem areas associated with the use of glyphosate on legumes and with the impacts of transgenic food crops in general have already been identified:

1. Glyphosate was ranked third worst among all pesticides causing severe health problems among those working in agriculture in the State of California.

2. The application of glyphosate causes the production of phyto-oestrogens in legumes. These phyto-oestrogens mimic the role of hormones in the bodies of mammals who ingest them. Hence, they may cause severe reproductive system disruptions. The data on estrogen-content of the plants submitted by Monsanto does not reflect the real scope of this problem, because the tested plants were grown in a glyphosate-free environment (see above).

3. The adequacy of Monsanto's testing for allergenic potential is questionable. Rendering a plant herbicide-resistant, as in the case of the glyphosate-resistant bean, means that a new protein (or enzyme) is introduced into the plant. The presence of a new protein in the plant and in the foods the plant produces has potential for causing allergic reactions. Monsanto only tested people known to be allergic to soybeans. However, they cannot test for the reaction to new proteins with the test design they used. Every researcher active in the field knows that you cannot adequately test in advance for allergic reaction to proteins never before consumed by humans. Moreover, recent studies published by Swiss scientists have evaluated the differences in allergy potential between traditionally bred and genetically engineered crops. The scientists concluded that the use of genetic engineering techniques causes a higher incidence of allergy problems.

4. A further problem consists in the fact that genetic engineering produces 'position effects'. In living organisms, genes are intricately linked in finely balanced networks. The introduction of new gene constructs (often consisting of parts of genetic material of four to five different types of organisms) at a random place on the long stretch of the DNA-molecule is known to change the fine-tuning of the balanced network.The 'position effect' may lead to unintended shifts in the concentration of plant metabolic products. This seems to be the case in Monsanto's transgenic soybeans. The beans show some differences in oil-composition compared to non-transgenic beans, but not all data has been included in Monsanto's European application file. There are also differences in the level of trypsin-inhibitors, proteins that inhibit the degrading activities of proteases - the first step in the digestive pathway. Trypsin-inhibitors have been characterised as anti-nutritive. Again however, figures given in the application file are incomplete.

Governments, farmers and consumers should consider these problems carefully. They may not want to take a course of action which turns people into experimental guinea pigs.

Possible Environmental Impacts of Monsanto's transgenic Glyphosate-Resistant Soybeans

Glyphosate, like other herbicides, is meant for weed control, i.e. it is meant to reduce biological plant diversity in and around fields. Herbicides do so with devastating success. Unlike other herbicides, glyphosate could not be used in fields with growing crops since it kills not only a selected group but all green plants. The introduction of a glyphosate-resistance-gene now allows a widened range of application.

A very different aspect of herbicide use should also not be forgotten: Many plants that are called 'weeds' by those promoting high-input monoculture for the world market are called 'salad', 'medicine', 'animal feed', 'compost' and 'flower-bed' by many farmers in the world. Loss of plant diversity also invariably means loss of animal diversity and diversity of soil organisms. Herbicides are known to be self-abolishing technologies: Invariably, weeds learn to cope, and the herbicide has to be replaced by yet another one. Rye-grass in Australia already has asserted its weedy vitality by becoming glyphosate-resistant.

Transgenic soybeans, like all other transgenic plants, are associated with a specific biosafety risk if planted in centres of origin. Scientific studies have shown that transgenes are transmitted to wild relatives with potentially disruptive effects on the endemic flora and on agriculture.

Other adverse effects

Besides its plant-killing potential, glyphosate was shown to have other direct impacts on biological diversity: It is poisonous to fish. It persists in the soil for long periods of time: Salad, barley and carrots planted on soil one year after the application of glyphosate have been shown to have incorporated small quantities of this chemical. The degradation of glyphosate leads to metabolites like AMPA (amino-methyl-phosphonic acid) which can persist in the soil for three years.

Governments, farmers and consumers should consider these problems carefully. They may not want to take a course of action which:

* causes an increase in the use of the herbicide glyphosate

* may add to biosafety problems and

* are associated with the accumulation of largely unstudied metabolites with have already demonstrated some toxic effects in our soils and waters.

Dr Beatrix Tappeser is Head of Department on Risk Assessment in Genetic Engineering at the Institute for Applied Ecology, Freiburg, Germany.

Christine von Weizsaecker is Head of Ecoropa's Biodiversity/Biotechnology/Biosafety Programme, Vice-Chair of the Advisory Council of the German Consumer Testing Group.