While the link between grape juice polyphenols to age related diseases like various cancers and heart disease, the mechanism by which polyphneols help reduce bad cholesterol levels is yet unknown.

Until Spanish researchers from the CSIC and the University of Alcala proposed a possible mechanism:

In the presence of LDL it was observed that the grape concentrate increased the activity and cell surface expression of the LDL receptor. The sterol regulating element-binding protein-1 was also increased in the presence of both LDL and the grape extract.

These processes also result in less free cholesterol reaching the endoplasmic reticulum (ER), an organelle found in eukaryotic cells.

"Taken together, these results suggest that red grape juice compromises the availability of LDL-derived free cholesterol in the ER, thus explaining the counteracting effect of red grape juice in the response of ER," wrote lead author Alberto Dávalos.

However, the researchers were not able to identify which polyphenol(s) were the active species (flavonols, anthocyanins, flavan-3-ols, procyanidins and phenolics acids) in the process.

The more polyphenols are understood, the more that consumers are becoming aware and looking for this beneficial ingredient in their food products.

Read more at NutraIngedients.