Monday, July 26, 2010

Are genetically modified foods safe?

Suman Sahai

GM crops are promoted as the answer to global hunger, to combat climate change, to produce renewable energy; it appears that if there is a problem anywhere, GM crops have the answer. Apart from this hyperbole, a fundamental question remains: does GM technology produce safe foods or should we be apprehensive about negative health impacts?

There is a substantial body of scientific data that demonstrates that the process of genetic engineering itself can cause changes in the cell that can lead to new and unpredictable changes in it.
Adverse health effects from GM food can result from the over-expression of an existing protein or activation of a dormant toxic substance, resulting in cell products that could be dangerous to human and animal health.
In addition to this, the genetic engineering of plants may result in the expression of totally new substances, which are not found in the natural plant species or, genes brought in from plants having known allergy provoking properties would bring the allergenic property along with them into the new transgenic plant.

The mere act of inserting alien genes into the chromosome of the host plant can create unintended effects and the formation of new and unknown toxic or allergy provoking compounds which are almost impossible to analyse and detect.
This can be a special problem in the case of plants like brinjal, which belong to the Solanacea family. This plant family to which nightshade, dhatura and tobacco (all highly poisonous) also belong has several natural toxins.

The chance of natural toxins being recreated through genetic engineering is high and therefore the genetic engineering of plants of this kind is more risky and more likely to produce foods that could be a threat to human health. Our regulatory system for GM crops have no provisions to conduct specific safety tests of this kind. Such tests, for instance, were not done for Bt brinjal.

It is known that allergenic proteins can be transferred by genetic engineering from one organism to another. The potential for development of toxic or allergic reactions to GM foods is likely to increase with advances in the scope and range of genetic modifications, increasingly radical transgenic combinations and the introduction of a greater variety of GM foods into the market, the last resulting in an increased exposure among people to foods carrying novel proteins.
With the widespread penetration of GM food in the market, food-allergic people will have to contend with new sources of allergens. The danger will be compounded by the difficulties of implementing labeling in India and making such labels intelligible to a large section of Indian people, particularly in rural areas. Allergic consumers will not even know what to avoid, resulting in a great risk to their health.

Children will be particularly vulnerable because their young immune systems will be less able to fight the allergen and also because their exposure to such novel proteins will be of longer duration, increasing their risk. The use of GM food products as food additives and processed foods, including baby foods, will lead to earlier exposure, especially for infants either directly or via breast milk. Maternal dietary food proteins are regularly detected in breast milk, and cow milk.

A particularly controversial area in the application of GM technology has been the use of marker genes which are introduced along with the gene for the desired trait as part of the gene construct that is inserted. The marker gene is just that, a marker to identify if the gene transfer has been successful.

Historically, the most common marker genes have been those that code for resistance to antibiotics. The concern is that these genes could find their way into pathogenic microbes, potentially compromising the clinical efficacy of antibiotics used in human medicine or livestock production. The indiscriminate use of antibiotics in human medicine is a large enough risk for giving rise to antibiotic resistant bacteria.

Testing can be done when the protein created by the foreign gene is known but problems arise when the toxicological hazard results from newly formed proteins which can not be predicted. It is not possible to test for what you do not know and the hazardous proteins can remain undetected. The problem is made worse by the fact that induction of food allergies by increasing dietary exposure may be difficult to detect because of low frequency in the population to start with and because years of ingestion may be required to provoke an allergic response. This has special implications in the case of proteins where allergies are likely to show up years later.
There is plenty of evidence about the health dangers of GM foods, from animal tests.

Studies done at the Russian Academy of sciences, on rats fed with GM soya showed high rates of mortality, severe stunting of pups and high levels of sterility in the surviving litter. The startling results showed that 36% of the litter born to emales fed GE soya were stunted at the age of two weeks, by the third week over 55% had died. The mortality was six to eight times higher than in the control group which had been fed non GE soya.

Data on the health damage caused by eating GM foods comes from Monsanto's own labs. Results from a secret study conducted on their GM maize Mon 863 which were accidentally leaked, showed that rats fed on Mon 863 developed organ abnormalities, changes in the blood profile and collapse of the immune system.

Earlier studies on rats have also shown that rodents appear to be averse to GM foods and reject them in laboratory tests. When the first genetically altered tomato "Flavr Savr" was fed to rodents in the labs in 1994, data revealed that many of the rats developed lesions in the stomach. Seven of the forty rats that were fed with GM tomatoes died within two weeks. There have been numerous other reports of stomach lesions in rats, false pregnancies in cows, excessive cell growth and damage to animal immune systems, following feeding studies conducted with GM foods.

Adequate testing procedures for allergenicity are not available in India. At present food toxicity is tested merely by the chemical analysis of nutrients and known toxins. This may fail to uncover several categories of toxins and allergens. This means that animals and humans could be exposed to allergens which are not being detected. Before any further commercialization is allowed, testing procedures of sufficiently stringent standards should be put in place.

Dr Suman Sahai, trained in genetics, is the chairperson of the Gene Campaign, She has served on the faculty of the Universities of Chicago and Heidelberg. She can be contacted at


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  2. If you want to know about what are genetically modified foods are, Genetically engineered foods have had foreign genes (genes from other plants or animals) inserted into their genetic codes.Genetic engineering can be done with plants, animals, or microorganisms. Historically, farmers bred plants and animals for thousands of years to produce the desired traits. For example, they produced dogs ranging from poodles to Great Danes, and roses from sweet-smelling miniatures to today's long-lasting, but scent-free reds. May be you are find a clear concept about what are genetically modified foods are ....

  3. Nice post, But I want to know weather Genetic food is natural or not ?? as my dietitian snuggest to have natural always,