Food compounds in grapefruit juice may optimize CoQ10 absorption
Coenzyme Q10 (CoQ10) is one of the most widely consumed supplements. Because of CoQ10’s key roles in energy metabolism and optimal cellular functioning it is used a therapeutic agent for a number of disorders, including cardiovascular and neuromuscular diseases, diabetes, immunologic impairments and cancer. Though humans naturally produce CoQ10, the rate of production declines with age, dropping significantly after age 40. While CoQ10 is widely consumed, researchers note that most forms of CoQ10 available on the market have a very low bioavailability. In this study, Itagaki et al attempted to improve intestinal absorption of C0Q10 by co-administration of a food supplement.
Like many other micronutrients, intestinal absorption is often enhanced by the presence of other compounds and food constituents. In the case of CoQ10, Itagaki et al sought to improve intestinal absorption with the introduction of grapefruit juice (GFJ). Though GFJ is known to ultimately have a net inhibitory effect on the intestinal absorption of many pharmaceutical drugs, it appears to have an opposite effect on the intake of CoQ10.
In prior research utilizing a cell line designed to mimic the human intestinal cells called Caco-2, Itagaki et al reported that efflux transport of CoQ10 is mediated by a widely investigated secretory transport system known as P-glycyprotein (P-gp). In this study they introduced CoQ10 and GFJ to cultured Caco-2 cells, postulating that a strategy “involving P-gp substrates with P-gp inhibitors may ultimately improve the absorption of P-gp substrates.” In other words, utilizing a food supplement such as GFJ, which is known to inhibit the extrusion of compounds outside cells, may result in a net increase of the uptake of CoQ10.
Itagaki et al observed that in the presence of GFJ, the efflux transport of CoQ10 was decreased by 50% while the cellular uptake of CoQ10 was, in turn, increased. Because the pharmacological effects of CoQ10 is contingent on sufficient intestinal absorption, investigators suspect that co-administration of GFJ and CoQ10 may ultimately improve clinical outcomes and/or prevent diseases. Itagaki et al note that further study is needed to confirm these presumptions and to further explore possible clinical applications of co-administration of GFJ and CoQ10.
Study: Itagaki, S., et al, Food Chemistry, 120: 552-555(2010)