Unsuccessful detection of plant microRNAs in beer, extra virgin olive oil and human plasma after an acute ingestion of extra virgin olive oil

Authors: MICO, VICTOR - CAMPUS DE EXCELENCIA INTERNACIONAL, UNIVERSIDAD AUTÓNOMA DE MADRID & THE CONSEJO SUPERIOR DE INVESTIGACIONES CIENTÍFICAS (CEI UAM + CSIC); MARTIN, ROBERTO - CAMPUS DE EXCELENCIA INTERNACIONAL, UNIVERSIDAD AUTÓNOMA DE MADRID & THE CONSEJO SUPERIOR DE INVESTIGACIONES CIENTÍFICAS (CEI UAM + CSIC); LASUNCION, MIGUEL - INSTITUTO RAMON Y CAJAL DE INVESTIGACION SANITARIA (IRYCIS); ORDOVAS, JOSE - JEAN MAYER HUMAN NUTRITION RESEARCH CENTER ON AGING AT TUFTS UNIVERSITY; DAIMIEL, LIDIA - CAMPUS DE EXCELENCIA INTERNACIONAL, UNIVERSIDAD AUTÓNOMA DE MADRID & THE CONSEJO SUPERIOR DE INVESTIGACIONES CIENTÍFICAS (CEI UAM + CSIC)

Submitted to: Plant Foods for Human Nutrition
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 1/12/2016
Publication Date: 2/12/2016
Citation: Mico, V., Martin, R., Lasuncion, M., Ordovas, J.M., Daimiel, L. 2016. Unsuccessful detection of plant microRNAs in beer, extra virgin olive oil and human plasma after an acute ingestion of extra virgin olive oil. Plant Foods for Human Nutrition. doi: 10.1007/s11130-016-0534-9.

Interpretive Summary: Previous research by other investigators demonstrated the presence of active genetic material, known as microRNA, from rice in human plasma. Moreover, it was suggested that this microRNA was able to regulate gene expression. The presence of such exogenous plant microRNAs from rice in human plasma could have profound implications for the interpretation of food in human health. If validated, these findings would imply that food should not be considered only as the source of nutrients but also as a way of genomic interchange between kingdoms. Other studies have tried to replicate these results in rice and other plant foods, but most of them have failed to find plant microRNAs in human plasma. In this scenario, we aimed to detect plant microRNAs in beer and extra virgin olive oil (EVOO)--two plant-derived and frequently consumed products--as well as in human plasma after an acute ingestion of EVOO. Our hypothesis was that microRNAs present in beer and EVOO source material could survive the manufacturing processes, be part of these liquid products, be absorbed by human gut, and then circulate in human plasma. To test this hypothesis, we first optimized the microRNA extraction protocol to extract microRNAs from beer and EVOO and then tried to detect microRNAs in those samples and in plasma samples of healthy volunteers after an acute ingestion of EVOO. Our results add experimental evidence suggesting that plant-based processed products, like beer and EVOO, do not contain microRNAs. Furthermore, we did not detect plant microRNAs in the human plasma after the ingestion of an acute dose of EVOO.

Technical Abstract: The recent description of the presence of exogenous plant microRNAs from rice in human plasma had profound implications for the interpretation of microRNAs function in human health. If validated, these results suggest that food should not be considered only as a macronutrient and micronutrient supplier but it could also be a way of genomic interchange between kingdoms. Subsequently, several studies have tried to replicate these results in rice and other plant foods and most of them have failed to find plant microRNAs in human plasma. In this scenario, we aimed to detect plant microRNAs in beer and extra virgin olive oil (EVOO)--two plant-derived liquid products frequently consumed in Spain--as well as in human plasma after an acute ingestion of EVOO. Our hypothesis was that microRNAs present in beer and EVOO raw material could survive manufacturing processes, be part of these liquid products, be absorbed by human gut and circulate in human plasma. To test this hypothesis, we first optimized the microRNA extraction protocol to extract microRNAs from beer and EVOO, and then tried to detect microRNAs in those samples and in plasma samples of healthy volunteers after an acute ingestion of EVOO.