10 Common Genetically Modified Foods

While cotton may not be a food, it's such a ubiquitous crop that it's worth mentioning. China produces more cotton than any country in the world and for more than 15 years, it has been genetically modifying its cotton to help combat the effects of the bollworm. The boll is the protective shell that the soft cotton ball grows inside of, and it's at risk because of the bollworm's persistence.

With the advent of "Bt cotton," China, courtesy of Monsanto, the controversial biotech company headquartered in Missouri, has been able to cut back on spraying pesticides. The good news is that studies found a sharp reduction in bollworm infestation despite the lower amount of pesticides. It also increases overall yield. The bad news is that Bacillus thuringiensis, the specific pesticide that's actually bred into the cotton, isn't effective on a formerly lesser pest, the mirid bug. And what's worse, now that the cotton is infested, the mirid is becoming a problem for other nearby crops.

The tomato has the distinction of being the very first widespread genetically modified food available in the United States. Starting in 1994, the Flavr Savr tomato was bred with a deactivated gene that kept the plant from producing polygalacturonase, an enzyme that's the starting point for rot. Flavr Savr tomatoes were able to fully ripen on the vine and still be able to stick around for a while in stores. This helped stop the practice of harvesting the crop early and artificially ripening the tomato when it's closer to its final destination.

The tomatoes were a popular product for about four years, until the scientist who invented it went on television and expressed concern over whether the tomatoes could be carcinogenic. This led to bans of genetically modified foods at major food chains, as well as the end of the Flavr Savr tomato.

The ringspot virus was a big problem for the Hawaiian papaya industry for many years, until the 1980s, when they began to experiment with genetically modified versions that were resistant to the virus. It was the addition of the "viral capsid" protein that created the effect of an immune response.

It wasn't until 1999 that the first commercial papaya crops were grown in Hawaii. These papayas now make up about three-quarters of the total output in the Aloha State. Currently, the United States and Canada both give these transgenic papayas the stamp of approval, while the EU has not yet allowed them.

Like most genetically modified foods, rice is being experimented on to make it more resistant to pests. And since rice is the staple food for more than half of the world's population, it's a pretty big deal to keep the rice crops of the world healthy as an important part of preventing starvation.

China is ahead of the game in terms of research, and even though a strain of pest-resistant rice has been approved in the United States, it hasn't yet been used by farmers. Since there's no widespread use of GM rice yet, it's not known what kind of side effects the strains could potentially introduce, if any. The first returns on the Chinese research indicate that farmers could potentially not spray any pesticides on the crops, which would be a marked reduction from the typical four per-year rate on most rice farms.

While the potato industry is lagging behind as far as human consumption goes, the use of potatoes as a raw material is booming. In fact, three-quarters of all the potatoes grown in Europe are used for something other than your dinner plate. Many of the other potatoes are fed to livestock, and the rest are for the alcohol and starch industries. That's a lot of vodka and dry cleaned shirts.

Scientists are beginning to make GM potatoes specifically intended to be grown and sold as starch potatoes. As far as potatoes that you might find in your grocery store, about 10 percent could be genetically modified. These are not just the raw, whole potatoes you'll find in the veggie section. You can also find GM potatoes in processed products containing potatoes.

Corn is everywhere in the United States. In fact, the U.S. is the largest producer of corn in the world. Corn is a fixture of U.S. landscapes, food and even industrial chemicals. It's also one of the most heavily modified crops. In 2000, the U.S. Department of Agriculture estimated that 25 percent of corn crops growing in the United States contained genetically modified corn. Products containing corn include beer, salad dressing, margarine, flour and, of course, anything that has corn syrup.

So, are we eating genetically modified corn? That's a tough one. While most genetically modified corn isn't destined for human consumption, one of the biggest concerns in transgenic corn is the possibility of GM corn corrupting unmodified strains. Corn is wind-pollinated, which means that nearby fields can become unintentionally contaminated. The affected area can be great -- in 2001, for instance, scientists even found GM material in wild corn in Mexico.

Of all crops, soy is the most heavily modified. In 2007, more than half of the world's soy was made up of genetically modified strains. Soy is modified for a variety of purposes. Common modifications include increasing its resistance to insects and fungus, as well as enriching its vitamins or fat and protein content so it can be used for animal feed. Soy is also integral to creating chemicals for use in pharmaceuticals.

Since soy is one of the more heavily modified crops (and one of the most useful for additives), chances are in the United States that if the label says you're eating soy, you're eating genetically modified material. This isn't just tofu and soy milk either -- foods that include soy byproducts are very common and can be found in staples like bread, cereal, ice cream and chocolate.

One of the most controversial GM foods is rBGH, or recombinant bovine growth hormone. The hormone, which is synthesized from genetically modified bacteria, produces higher milk yields by keeping milk-producing cells alive in cows for longer than normal. Though there's no official difference between rBGH milk and regular milk, critics point out that rBGH cows are more prone to disease, which means higher concentrations of bovine antibiotics filtering down into the milk supply.

The world is divided on whether milk from cows that were injected with recombinant growth hormones is safe. Though it's banned in the European Union and Australia, rBGH is legal in the United States, and there are no FDA requirements about labeling milk as coming from rBGH cows. Because of the controversy, many dairies and supermarkets advertise that they accept milk only from farmers who do not use rBGH.

Canola oil, also known as rapeseed oil, is one of the most heavily used genetically modified crops. In Western Canada, 80 percent of canola crops are transgenic. In this case, rapeseed is modified to be more resistant to certain herbicides. This results in easier weed control, lower pesticide use and larger crops. However, there are also concerns that GM rapeseed could transfer its resistance to the pests around it, which would result in the pesticides being useless.

An interesting aspect of genetically modified rapeseed is that it produces one of the main pollens used to make honey. Scientists in Germany found that as much as one-third of the pollen in Canadian honey came from GM rapeseed, meaning that any honey coming out of Canada (unless labeled otherwise) could potentially qualify as a GM food.

Aspartame is an artificial sweetener that's about 200 times as potent as sugar. Although it's technically an artificial substance and doesn't occur in nature, aspartame is the result of a combination of two natural amino acids. Two different species of bacteria produce these acids, and in some cases, one of the bacteria is modified in order to boost the yield.

So is aspartame dangerous? If it is, it's not because of genetic manipulation -- aspartame itself contains no genetic material. However, debate still rages in the food world about how safe it is for human consumption. While there's no confirmed link to cancer in humans, female lab rats fed aspartame had higher rates of lymphoma and leukemia than those in the control group.