The title of the Discover Magazine article is link bait bullshit. It suggests that what you eat affects your genes. What the authors of the Science paper really found is that plant microRNAs can survive digestion in mammals. These plant microRNAs where subsequently found in mammalian cells affecting expression of genes and cell chemistry.

I don't understand how what you said is different than the title.

Could you please explain the difference between "affects your genes" and "affecting expression of genes."

A process of genes expression is when information from your genes translates to the proteins which are primary regulatory entities in cells. "Affects your genes" implies that somehow your genes are changed permanently. MicroRNAs affect the process of gene expression not the genes itself. What the authors found is that microRNAs from rice can appear in cells of mammals if they eat a lot of rice. But if they stop eating rice the effect of these microRNAs will be lost.

If a miRNA alters the expression of transcription factors, chromatin remodeling agents, or other epigenome modifiers, the effect could last long after a person stops eating the miRNA-containing food.

To me, the title sounds like your genes are changed (pre-transcription), whereas the study finds ways the body operates on itself (post-transcription).

Quite a difference.

That said, it is already known that parental malnutrition can be detected in offspring that were never themselves malnurished.

So, does that mean that that the post-transcriptive changes will not affect descendants? If so, I agree that my impression of the title is at odds with the information trying to be conveyed.

EDIT: I think you edited your comment to basically say that maybe these changes can be passed on?

Nope. The malnutrition causes gene methilation, which can be passed to children.

I edited my comment to add the malnurishment part but that's not the same as the premise of the article.

Can the microRNAs really enter into mammalian cells? I feel like there should be some mechanism for blocking outside RNAs from entering a cell. Unless there's no selection for a defense mechanism because it's not harmful? Someone fill me in here.

That was my question as well. Skimming the paper on nature.com (http://www.nature.com/cr/journal/vaop/ncurrent/full/cr201115...) turns up this :

"We next characterized the possible carrier of circulating miRNAs. Microvesicles (MVs) are small vesicles that are shed from almost all cell types under both normal and pathological conditions 13, 14. They bear surface receptors/ligands of the original cells and have the potential to selectively interact with specific target cells and mediate intercellular communication by transporting bioactive lipids, mRNA, or proteins between cells... "

It looks like the miRNAs are trapped in tiny bits of the rice cells. These bits have receptors that can interact with mammal cells and transport RNA across the cell barrier. (This really sounds like a protovirus!) If this can happen from eating a plant, I wonder what miRNA is circulating after eating a nice rare steak.

Biology is weird. Frankly, if this pans out, I wouldn't be surprised if there were an active uptake mechanism.

Agreed. "What You Eat Affects Your Genes" and "What You Eat Affects Your Gene Expression" are subtle, but quite a big difference. The latter we already broadly know, the former would be a revolutionary discovery if true.

What You Eat Affects Your Genes (Expression)

The formatting of this article is AWESOME. There are so many articles that I'd love to read, but I simply don't have the time to parse through a gigantic wall of text. An outline with bolded text and bullet points is exactly what I love to see.