Fuss and Worry about Nutrient Enriched Animal Feed - GM corn LY038.

Food regulator criticised over new GM corn
Anna Salleh, ABC Science Online
Friday, 4 August 2006

A GM corn that could soon be approved for human consumption in Australia and New Zealand might produce similar toxins to those of concern in cooked red meat, say some scientists.

Australia and New Zealand's food regulator is failing to apply its own safety standards, or those of international guidelines, in assessing a new-generation GM corn for human consumption, critics say.

But Food Standards Australia New Zealand (FSANZ) defends its so-far favourable assessment of the high-lysine corn, which it says is intended for animal feed and is unlikely to enter the human food chain.

The Centre for Integrated Research on Biosafety at the University of Canterbury has twice formally notified FSANZ of its concerns about the GM corn, LY038, which has been engineered to contain a bacterial gene that allows the accumulation of high levels of lysine.

"Among the types of potential hazards that this food poses are the creation of compounds that are known to be associated with important diseases like diabetes, Alzheimer's, heart disease and cancer," says centre director Associate Professor Jack Heinemann.

Heinemann says while the compounds, advanced glycoxidation endproducts (AGEs), are also produced when cooking conventional foods, he is concerned about potential levels in LY038 corn.

He says corn is normally extremely low in the compounds that combine to create AGEs.

But he says higher-than-normal levels of lysine in the LY038 and high sugar levels, combining under heat, have the potential to raise AGE levels.

"[LY038] has the potential to produce 100 times more [AGEs] than normal corn," says Heinemann.

Pundit has done a little digging on this topic and has chatted with his biochemically literate colleagues (Bruce Chassey in particular, in Illinois), and come to the conclusion that this story is a beat-up. All fried, browned, roasted or grilled snacks suffer to some extent from the risks raised in the ABC news item, but a balanced person can continue to eat them without getting sick.

Provided of course, they snack in moderation and don't imitate Elvis Presley in his last years.

Yes folks, cooking itself may be intrinsically hazardous, and it certainly produces a vast range of toxic compounds, which could be used to put anyone off their food in the interest of a dramatic but misleading news story. Charred meat and fried snacks are a mixed niutritional blessing. A marriage of heaven with a little bit of hell. But on the other hand, raw food can be dangerous too, and cooked food tastes really nice.

The lysine mentioned in the story- and implied to be a source of hazard - is actually an essential amino acid for humans, so all diets should have some of it. The interaction of amino acids, such as lysine, with sugars during the process of cooking is well known. Most people recognize this as the browning process that occurs with breads, meats and other foods.

Chemical reactions and risks ("AGEs") mentioned by Heinemann as possible hazardous consequences of heating the lysine enriched corn are very similar to those that come from cooking almost any food and particularly from frying it.

The following quotes from my “Food Bible” On Food and Cooking: The Science and Lore of The Kitchen (Completely Revised and Updated), 2004, Harold McGee, Scribner, might help restore a saner context for fears about reactions between sugars and proteins and the lysine they contain naturally that occur when you heat foods.

BROWNING REACTIONS AND FLAVOR (starts page 777.)
While the chemical changes caused by moderate heat modify or intensify flavors that are intrinsic to a food, the browning reactions produce new flavors, flavors that are characteristic of the cooking process. These reactions are named for the typical colors that they also create, which may actually range from yellow to red to black, depending on the conditions.

CARAMELIZATION
The simplest browning reaction is the caramelization of sugar, and it's not simple at all (p 656). When we heat plain table sugar, essentially just molecules of sucrose, it first melts into a thick syrup, then slowly changes color, becoming light yellow and progressively deepening to a dark brown. At the same time, its flavor, initially sweet and odorless, develops acidity, some bitterness, and a rich aroma. The chemical reactions involved in this transformation are many, and they result in the formation of hundreds of different reaction products, among them sour organic acids, sweet and bitter derivatives, many fragrant volatile molecules, and brown-colored polymers.
It's a remarkable change, and a fortunate one: it contributes to the pleasures of many candies and other sweets.

THE MAILLARD REACTIONS

Even more fortunate and complex are the reactions responsible for the cooked color and flavor of bread crusts, chocolate, coffee beans, dark beers, and roasted meats, all foods that are not primarily sugar. These are known as the Maillard reactions, after Louis Camille Maillard, a French physician, who discovered and described them around 1910. The sequence begins with the reaction of a carbohydrate molecule (a free sugar or one bound up in starch; glucose and fructose are more reactive than table sugar) and an amino acid (free or part of a protein chain). An unstable intermediate structure is formed, and this then undergoes further changes, producing hundreds of different by-products. Again, a brown coloration and full, intense flavor result. Maillard flavors are more complex and meaty than caramelized flavors, because the involvement of the amino acids adds nitrogen and sulfur atoms to the mix of carbon, hydrogen, and oxygen, and produces new families of molecules and new aromatic dimensions.
…
DRAWBACKS OF THE BROWNING REACTIONS
Browning reactions do have some drawbacks. First, many dehydrated fruits are prone to gradual browning over weeks or months at room temperature, because the carbohydrates and amine-containing mol ecules are especially concentrated (browning caused by enzymes can also be a factor).
Small amounts of sulfur dioxide are commonly added to these foods to block these unwanted changes in color and taste. Second, the nutritional value of the foods is slightly reduced because amino acids are altered or destroyed.
Finally, there's evidence that some products of the browning reactions can damage DNA and may cause cancer. In 2002, Swedish researchers found worrisome levels of acrylamide, a known carcinogen in rats, in potato chips, french fries, and other starchy fried foods, apparently the product of reactions between sugars and the amino acid asparagine. The health significance of this and similar findings remains unclear.
The ubiquity of browned foods, both today and through thousands of years of history, would suggest that they do not constitute a major threat to public health. And other browning-reaction products have been found to protect against DNA damage!
But it's probably prudent to make charred meats and fried snacks occasional pleasures, not everyday ones.

Moving on the the context in which this new crop will enter commerce, it's worth mentioning that the maize variety in question LY038, is not intended to enter the food chain, but is reserved as an animal feed that won't be cooked, and thus will have minimal opportunities to contain AGEs.

Furthermore, in order to capture value, growers will need to preserve identity of grain crops that are enriched in the nutrient lysine after they leave the farm gate. Thus very little will end up in the human food supply. Add that to the fact that most maize-derived products consumed by humans are free of protein (eg. oil and starch), coupled with the fact that very little whole field maize or its immediate products are consumed by humans, and you have a miniscule predicted human exposure. And the exposure that occurs will be infinitesimally increased exposure to an amino acid that is essential for human health, growth and development. After over 100 years of scientific effort spent trying to define and fulfill human nutritional requirements, it is truly amazing that anyone would be concerned about a small potential increase in lysine consumption.

Lysine is increased approximately 60 percent in LY038 grain, compared to conventional maize. Scientific studies have shown the lysine in LY038 is nutritionally the same as other conventional sources of lysine, and lysine is commonly added to livestock feed today. The level of lysine in LY038 similar to that found in foods like lentils. Higher levels of lysine are encountered in other commonly consumed foods, like fish, red meat, cheese and eggs, many of which are also safely browned during cooking.

There is a lot of medical literature about AGE compounds that are produced inside the human body. They are, in fact, one "natural" aspect of human ageing (no pun intended).

Prof. Heinemann's remarks about diabetes and AGEs need to be considered cautiously– AGEs do not “cause” diabetes (as he indicates), they are simply higher in diabetic patients because those individuals have higher circulating levels of sugars and are, therefore, more prone to formation of AGEs.

The chemical aminoguanidine has been one of several compounds touted as an inhibitor of AGE formation to treat complications of diabetes – it can be purchased through health food stores. Of course our bodies also have defenses against AGEs. Definitive clinical data has been hard to obtain because the levels of aminoguanidine needed to block all AGE formation is, as you might expect, very high. It never ceases to amaze me that people can on one hand worry about a 60% increase in an amino acid that is deficient in a crop (remember that this product was developed because maize is a poor source of lysine), while the will on the other hand go out an consume unphysiologically high levels of another compound whose safety has not been fully investigated and whose efficacy in preventing disease has not been demonstrated. I suppose they see aminoguanidine as natural but can't make that leap of faith that an essential amino acid--one required to be above a minimal level for humans--could be safe if introduced by genetic engineering.

The real argument here is that Heinemann and others are really saying that we should only eat raw foods; that cooking reduces nutrients and creates toxins. For what it's worth, food and nutritional scientists have decided that on balance cooking is far more beneficial than deleterious. That is not to say that there are not exceptions to this claim, but everything has pluses and minuses that must be balanced against one another and viewed in the big picture of overall diet composition. There are a lot of supposedly educated and intelligent people who could benefit from a good course in food science and nutrition, or reading Harold McGee's great book.

(Many comments and links thanks to Bruce Chassey.)