In Your Food

Nanjing University researchers recently reported in Cell Research that plant microRNAs could be found in the sera and tissues of animals that eat those plants. Further, they found that MIR168a, which is found in rice, can bind to the human/mouse low-density lipoprotein receptor adapter protein mRNA and prevent its expression in liver, decreasing LDL removal from the bloodstream. "Like vitamins and minerals, microRNA may represent a previously unrecognized type of functional molecule obtained from food," says Anne-Marie C. Hodge at Scientific American.


The more that I think about

The more that I think about this report describing how a rice µRNA can affect mRNA levels for a LDL receptor adapter protein 1 (LDLRAP1), the more skeptical I am about the conclusions of the study. The use of even anti-sense RNA to control mRNA translation in human and animals has been challenging and only in recent years have successful early stage clinical trials been achieved (for example, for treatment of prostate cancer). The ability of an plant oligonucleotide to survive acids, bases and nucleases in the stomach and gut, be absorbed into the circulation, travel to the liver and penetrate into hepaocytes is remarkable alone. However, when one contemplates the likely species differences in the primary nucleotide sequences of the rice and human µRNA's that target the mRNA for the LDL receptor adapter protein, this is even more incredible. If in fact the data from this Chinese study is correct, it is likely to be a rather isolated case of accidental post-transcription regulation. Moreover, it would certainly not be anything like a vitamin or mineral, which is required from the environment to maintain the health of human cells.