Dangerous RNA in Food?

[Update Jan 13: The original article has been edited and extensively modified in response to reader feedback. The author has acknowledged several mistakes in the original and generally improved the clarity of his argument. However, the main point I make in response remains despite the changes to the original. —cw]

As I wrote about previously, a research group has shown that miRNA from rice is present in human blood and can influence gene expression in the liver. In response to this work, Ari Levaux (@arilevaux) has published a somewhat sensationalistic opinion for The Atlantic that concludes:

The news that we’re ingesting information as well as physical material should force the biotech industry to confront the possibility that new DNA can have dangerous implications far beyond the products it codes for.

Most of the article takes aim at the purported implications of this research for GMO foods. Specifically, he believes this finding contradicts the long-standing policy of “substantial equivalence” claimed by the pro-GMO producers. If I were an author of this study, I would be disappointed to have my work so badly misconstrued for the general public.

Clearly, LeVaux has an axe to grind with the large, multi-national agribusiness industry (who doesn’t, besides incumbent politicians?). And I don’t necessarily even support the concept of substantial equivalence, but I must point out that there is a major hole in the evidence between “the food we eat can regulate gene expression in a new way” (the new research) and “GMOs are dangerous to human diet because they contain new DNA” (LeVaux’s claim).

If the uptake of miRNA from food is widespread (which is not known yet), then potentially every food we eat of biological origin could have previously unknown effects on the cells of our body. Think about that for a moment and I think you will agree that to focus on GMO foods is to miss the potential scope of this finding. If widespread (again, a big if), then wouldn’t every food need to be reevaluated as a precaution? This is nothing short of the kind of shift in thinking that humanity underwent upon discovering the need for essential vitamins, maybe bigger.

The other big problem I have with LeVaux’s piece is that there is no reason to think that the miRNAs in GMO corn would be any different than those in nonGMO corn. Most GMO corn carries one of the Cry1 genes from soil bacteria, encoding a protein that is toxic to insect larvae. What is the proposed connection between the expression of this gene and any miRNA expression? None, as far as I know and as far as LeVaux informs me. Back to the quote above from his article, there is nothing new or known to be harmful in ‘ingesting information’, we have been doing it as long as we’ve been eating, apparently.

RNA in Food Alters Metabolism

In what I would consider a bombshell finding, researchers have demonstrated a new way that food can influence our metabolism. For the first time, researchers have identified microRNAs that originated in grains of rice circulating in the blood serum of research subjects. MicroRNAs are short sequences of RNA that can bind to messenger RNA sequences and cause their degradation, thus influencing gene expression. From the article:

Like vitamins, minerals and other essential nutrients derived from food sources, plant miRNAs may serve as a novel functional component of food and make a critical contribution to maintaining and shaping animal body structure and function.

Not only did the researchers simply identify miRNAs from plants in human blood plasma and serum, they also demonstrated a physiological effect in a mouse. Using bioinformatics, they identified a number of candidate targets that the specific miRNA may interact with. One of the candidates is involved in cholesterol metabolism, and by feeding the rice to mice, they were able to observe a change in cholesterol processing within 3 hours of feeding.

There are so many implications to this finding, I’m not sure where to start. One of the first thoughts that came to mind was the ongoing discussion surrounding organic foods. I have always been of the opinion that there could be only slight advantages, if any at all, to eating organic fruits and vegetables in terms of the actual food quality itself, assuming any potentially harmful substances had been removed from conventionally grown produce. But wouldn’t it stand to reason that there could be significant differences between the microRNAs actively expressed in organic crops compared to conventional ones? And if that’s the case, their influence on human health could be dramatically different.

I guess this same research group had shown several years ago that microRNAs that are secreted from cells can circulate in blood and influence expression elsewhere in the body, so in some ways this work is following on the same idea. Depending on where this work goes from here, and how wide-ranging the implications turn out to be, this seems like the kind of research that can attract serious attention from the Nobel folks. Makes me wonder why it’s in Cell Research and not the flagship of the same publisher, Nature.