Genetic material from your food is not absorbed by your body

A report in 2012, published in the journal Cell Research, seemed to suggest that genetic material, specifically microRNA, could pass from a person’s small intestine and into their blood stream. These microRNAs are small pieces of genetic code that cells use to modify the expression of certain genes. Think of them as dimmer switches on a light, they can turn up or turn down the expression of certain genes by different amounts. This finding had the potential to revolutionize drug delivery and treatment options for many diseases since we could turn down the expression of unwanted genes. It also scared a lot of people because it meant that genetic material from what we ate could enter our bodies and interact with our cells. Specifically, people began to worry that the genes inserted into genetically modified organisms (GMO’s) could enter our cells and make us sick. There was a lot of press given to this story, not all of it true, and unfortunately it played right into many peoples fears about GMO’s. The problem with the original study that was never adequately answered was the question about contamination in the samples used for genetic testing. The techniques used to detect the presence of genetic material are exquisitely sensitive and so any amount of contamination could be picked up. Contamination is a big problem in DNA testing at crime scenes and great care must be taken not to contaminate the sample with any sort of genetic material. Investigating the potential of contamination, a team of researchers from Denmark, Sweden, and Spain set out to analyze previous data sets on human blood and tissue samples in a more careful manner.

Published in the journal RNA, the team of researchers found NO EVIDENCE that RNA material from other organisms or food sources could enter our blood stream or tissues. When reviewing previous 824 previous data sets containing information about the genetic make up of human tissues and bodily fluids they found that foreign DNA from other organisms, also called xenoDNA, made up less than 0.001% of all genetic material found in the samples. This is a very small percentage. Additionally, they hypothesized that if DNA from our food is being absorbed by the body then tissues that are involved in dietary intake should see a rise in the abundance of xenoDNA. When they looked at the liver, an organ involved in digestion, they found no such increase. When they looked at organs that are separate from normal blood circulation, like the brain and cerebrospinal fluid (separated by the blood brain barrier) they expected to see a dip in the amount of foreign RNA but did not. Most interestingly, 81% of the foreign DNA and RNA came from rodents. Rodent’s are not a common staple in human diets but are very common laboratory animals suggesting that these samples had been contaminated by exposure to lab equipment that has come in contact with the rodents. Finally, when the researchers carefully fed rats and cows food containing foreign DNA, being sure to avoid contamination, they could not detect any of food’s DNA being absorbed into the blood or milk of the animals. All of these results suggest that the presence of foreign DNA in human tissue and fluid samples is the result of contamination in experiments conducted in less than sterile environments.

These results should hopefully lay to rest some of the concerns about genes from GMO’s being absorbed into our bodies. When you step back and think about it logically it makes no sense that genetic material from our food is absorbed into our bodies. Your digestive system is an exquisite system of enzymes, acids, and molecules that break down all the macromolecules in your diet into their essential building blocks for absorption. Our body does not absorb whole proteins; it breaks them down into amino acids. Our body does not absorb whole carbohydrates; it breaks them down into simple sugars. There is no way our body or immune system would allow the absorption of any whole DNA. So rest assured that GMO’s are not going to poison you with their genes or turn you into a mutant. GMO’s are safe, stop listening to all the pseudoscience.

Image Credit: Alessandro Flickr

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