New Study Suggests We Really Are What We Eat

Illustration for article titled New Study Suggests We Really Are What We Eat

Scientists at Nanjing University made a startling discovery about the food we eat. Not only do we ingest the nutrients from our food, we incorporate some of the genetic material as well.

The research team discovered abundant levels of rice microRNA in the bloodstream of Chinese test subjects. And this miRNA isn't just sitting there idly, it may have an effect on our genes. In earlier laboratory trials, this rice miRNA had an effect on gene expression in mice and changed the liver's ability to filter LDL cholesterol.

The possibility that the food we eat may regulate gene expression is an exciting discovery, but it brings up as many questions as answers. Does this explain the medicinal qualities of some foods? Could our food be used as a vector to treat disease? And what does this mean for genetically modified foods? [Popsci; Image from Valentyn Volkov/Shutterstock]

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DISCUSSION

Perhaps a little bit more detail will clarify what this article is attempting to convey. We do not actually end up with "food DNA" in our genome such that testing one of our cells would reveal part hamburger. Instead, the miRNA from the food interacts downstream with gene expression.

(Caution: A little long, and a lot of rudimentary genetics information for the lay geneticists who want to learn a little something more about this. Last paragraph for the conclusion.)

The collection of our own human DNA within each cell of our bodies contains all of the information necessary to build an entire human body. That collection of DNA can be thought of as an instruction manual for building and repairing any and every cell (with rare exception not worth interjecting here).

Let's stick with the hackneyed but effective "instruction manual" analogy. Each cell in our body is programmed to know which chapter of the manual in which to turn. So Eye Cell will know to look at the Eye chapter, and Liver Cell will know to turn to the Liver chapter. However, just like the reference materials at the local library, the DNA manual cannot be taken outside of a certain restricted area of the cell (called the nucleus). So if, say, Liver Cell wants to actually build something from what it reads in the DNA manual, Liver Cell has to write down the instrucitons and then take those instructions outside of the restricted area. Liver Cell can then take those instructions to another part of the cell and use them to build the thing it needs to build. (In our bodies, the instructions tell the cell how to build proteins). While we might make a photocopy of a reference manual in a library and carry that out with us, Liver Cell makes an RNA copy which it carries outside of the nucleus.

So, Liver Cell has gone to his DNA manual and copied down the instructions (i.e. a strand of RNA) which tell him how to build a protein which will manage cholesterol. Liver Cell takes those instructions out of the restricted area and goes to build the protein. But before Liver Cell can get the chance to read one of the steps for building the protein, one of the steps is scratched out and illegible. Without this step, Liver Cell is no longer able to build the thing that he needs to build.

This seems to be what the Popsci article is telling us. The RNA taken outside of the cell - the copied down instructions for building proteins - is being bound up by miRNA which was introduced into our bodies from our food. The binding by the miRNA makes it impossible for the cell to build the protein which it needs and thus the miRNA is inhibiting gene expression. In other words, the miRNA, while involved with gene expression, is not actually incorporated into our DNA since it does not interact inside the nucleus, or at least it does not interact with DNA directly. While this is a REALLY cool discovery and fascinating new way of considering the level of our interaction with our food, I would think that this is hardly alarming since living things have been ingesting the nucleic acids of other things forever. In other words, whether we knew it or not (it appears we didn't) this has been happening forever.