interesting looking paper I didn't read yet.

[Lindsay]

http://www.nature.com/cr/journal/vaop/ncurrent/full/cr2011158a.html

Abstract: Our previous studies have demonstrated that stable microRNAs
(miRNAs) in mammalian serum and plasma are actively secreted from
tissues and cells and can serve as a novel class of biomarkers for
diseases, and act as signaling molecules in intercellular
communication. Here, we report the surprising finding that exogenous
plant miRNAs are present in the sera and tissues of various animals
and that these exogenous plant miRNAs are primarily acquired orally,
through food intake. MIR168a is abundant in rice and is one of the
most highly enriched exogenous plant miRNAs in the sera of Chinese
subjects. Functional studies in vitro and in vivo demonstrated that
MIR168a could bind to the human/mouse low-density lipoprotein receptor
adapter protein 1 (LDLRAP1) mRNA, inhibit LDLRAP1 expression in liver,
and consequently decrease LDL removal from mouse plasma. These
findings demonstrate that exogenous plant miRNAs in food can regulate
the expression of target genes in mammals.