Genetically Modified Foods and Their Impact on Human Health

Introduction

Genetically modified foods can be described as foods whose genetic material has been modified in a particular way that does not happen naturally. In genetic modification, the intended gene is inserted into the genome of a crop. A genome can be defined as the entire set of DNA instructions found in a cell. Determining whether genetically modifying foods is a safe process is extremely controversial. We will look at a few experiments throughout the article like, FLAVR SAVR tomatoes as well as T2A-1 rice on the GI health of rats after 90-day supplement. Some researchers also believe that genetically modified foods(GMF) can lead to gut health issues and some diseases. Due to GMFs being extremely controversial, this leads to many social disparities among environmentalists as well as social activists. Throughout the article we will also look at the genetics that are involved while modifying foods.

Genetics

Figure 1. Recombinant DNA being inserted into bacteria so that foreign DNA will replicate naturally.[1].

The history of genetic modification dates back to 1944 when scientists discovered DNA modification technology. Scientists discovered that genetic material can be transferred between different species. Then in 1973, Stanley Cohen developed DNA recombination technology which showed that genetically engineered DNA molecules are able to be transferred among different species. The beginning of genetically modifying plants started in 1983 with antibiotic resistant tobacco and petunias. Later in 1994, the US market created the first genetically modified tomato that was approved by the Food and Drug Administration (FDA). Today there are many crops that have received FDA approval and are consumed by many people across the globe.

One common gene that is inserted into crops is the Bacillus thuringiensis insecticidal toxin (Bt) gene. The Bacillus thuringiensis insecticidal toxin gene includes a range of different cry1Ac genes, expresses gram-positive spore-Bt toxins that have been used in insect-resistant biotechnology for many years and have a long history of safe use. The cry1Ac gene encodes a protein that is poisonous to certain types of insects. Scientists will cut the Bacillus thuringiensis gene from the bacterium DNA and insert the gene into a vector that has a selectable antibiotic resistance marker gene. Scientists then load the vector-coated particles onto a teflon bullet which is then loaded into a gene gun. A gene gun then shoots the particles at a very high velocity which penetrates the plant. Only the cells that have incorporated the vector will grow and the result will be insect resistant plants.

Microbiome

Figure 2. The complex interaction between the human gut microbiome and other organs of the host.[2].

To understand the effects that genetically modified foods can have on the human body, we must first understand the gut microbiome. The human gut microbiome is a complex part of the human body. Around 60 tonnes of food pasases through the GI tract or gut microbiota along with an abundance of microorganisms that create a huge threat to the gut. The gut is one of the largest interfaces between the host, environmental factors and antigens within the human body. The microbiota benefits the ghost by strengthening gut integrity and shaping the intestinal epithelium, harvesting energy, protecting against pathogens, and regulating host immunity. These mechanisms can be disrupted due to altered microbial composition, dysbiosis. Dysbiosis can be defined as an imbalance in the gut microbial community that is associated with disease.

Now that we understand the human gut microbiome in normal conditions, we are able to compare the microbiome to when genetically modified foods have been consumed. It has been observed by many researchers that there is a connection between genetically modified foods and the gut microbiome. The use of glyphosate in genetically modified food environments may cause imbalances of gut bacteria and promote gastrointestinal health in humans like cardiovascular disease, depletion of nutrients, birth defects, and many more. Glyphosate can be defined as a synthetic compound which is a nonselective systemic herbicide, particularly effective against perennial weeds.

Social Disparities

While biotechnology has tremendously helped the world prosper, it has also created social and ethical contradictions. The debate if biotechnology can be used for creating high quality crops while still protecting the ecosystem and human’s health is discussed by many environmentalists and social activists. Many people are concerned about their health as some health risks pertinent to unapproved GMFs include antibiotic resistance, aller-genicity,nutritional changes, and the formation of many toxins. Many social activists claim that biotech companies insist on producing genetically modified crops because they can be privatized, while ordinary crops are a part of the natural property of all humanity. Many environmentalists claim that there is a possibility for long term consequences. Environmentalists are concerned that genetically modified crops could create superweeds and superpests. The superweeds and superpests could potentially disturb the balance of nature as well as affect insects.

Experiments

Figure 3. Graphs A and C show the weight growth for males. Graphs B and D show the weight growth for females over a 14 week period.[3].

We are able to look past experiments to better understand if genetically modified foods have an effect on humans. Due to the ethical problem that testing on humans can lead to, most experiments have been performed on rats to better understand any effects. We will look at a 90-day-rat-feeding study where we will look at GMO-treated rats as well as control rats that will be fed an equivalent diet. The GMO-treated rats were fed with MON863 which is a genetically engineered variety of maize that contains nptII. NptII is a marker gene for antibiotic resistance. In the male rats that consumed MON863, there was a weight decrease of 3.3% while in females there was a 3.7% weight increase in females. Chemical measurements revealed signs of hepatorenal toxicity. Hepatorenal toxicity occurs when the kidneys stop working well in people who suffer from liver problems. The data also showed 24-40% increase in triglycerides while urine phosphorus and sodium excretions diminished in males by 31-35%.Triglycerides are a type of fat that circulates in your blood. Though the studies results are factual, it is tricky to understand all of the data due to the trial only being 90 days. If the experiment lasts longer than 90 days then the results would be more helpful for human knowledge as humans live way beyond 90 days.

Why or why not modify Food?

There are many pros and cons to genetically modifying foods. Some advantages would be added nutrients, fewer pesticides, and cheaper prices. When you are able to engineer a crop, you can create a product that has all of the correct aspects. Fast-growing, healthier, and extra resistant to weather or pests. Science has helped to put food on many families tables because of genetic modification. Another advantage to genetically modified foods is that prices are lowered. By changing the gene sequences in a crop, scientists are able to speed up production rate using less land, water, and pesticides. The saved time and resources is able to lower the prices for consumers. Genetically modified foods are proven to also improve some factors of human health. Scientists are able to modify some crops so there are more vitamins and minerals. Providing more positive health benefits helps the human health system tremendously by giving the body the nutrients that it is not always given as well as having more substance making you full faster.

While there are many benefits to genetically modifying foods, there are also many disadvantages. Some modified foods can cause allergic reactions as well as increase antibiotic resistance. There can be fatal risks when genetically modifying foods due to the transferring of DNA from other organisms. The unexpected DNA could trigger some allergic reactions that would not normally occur if the food was organic. When inserting new DNA into plant cells, scientists will often also add additional genes that make the cells resistant to antibiotics. By then using an antibiotic, scientists can kill off the plant cells that did not successfully take in the new DNA. The problem with inserting genes resistant to antibiotics is they do not always go away when you digest your foods. Occasionally the genes can be passed through your feces into the sewage systems. Many experts believe that these genes could be absorbed into harmful bacteria which could be detrimental to your health. Staph infections can also be caused from the gene being found in your gut which can lead to usual antibiotic treatments becoming powerless against new super-bacteria.

Conclusion

Though there have been many experiments performed to better understand genetically modified foods, there is still uncertainty whether or not there is an effect on humans. We have looked at tests done on rats which have shown some evidence regarding an effect on the body. In the big scheme of life, the experiment still leaves us with uncertainty as rats do not have the exact same structure as humans as well as the fact the study only lasted for 90 days. Though some have suggested a correlation between GMOs and human disease, scientists at the FDA have still approved the crops that are consumed.

References

Edited by Matthew Nguyen, student of Joan Slonczewski for BIOL 116 Information in Living Systems, 2022, Kenyon College.