So, if those polyphenols are the "active ingredients" in olive oil, wouldn't it be nice if we had an oil that had even more of these beneficial healthy secondary plant metabolits in our oils, right?
Now we have tons of polyphenols, but does that make a difference?
The thought, that a souped up version of the already phenol-rich virgin olive oil would be an even more potent health promoter must have occurred to a group of researcher from Spain, as well. Back in 2010 already, Manual Suárez and his coworkers published a paper in the Journal of Argiculture and Food Chemistry in which they describe the development of a "phenol-enriched olive oil with phenolic compounds from olive cake" (Suárez. 2010). In essence, the scientists just put back some of the pulp (an extract to be precise) that is produced when the oil is squeezed from the olives into the end-product. In a more recent study the scientists did now try to evaluate how much of these (additional) health promoters in 30ml of regular virgin olive oil (VO) and the enhanced virgin olive oil (EVOO) actually make it into the blood of 16 (8 men, 8 women) healthy subjects in a randomized, controlled, cross-over trial (Suárez. 2011).
|Figure 1: Compositional differences (phenol-enriched vs. standard virgin olive oil) in polyphenol content (data calculated based on Suárez. 2011)|
The in vivo study showed that the concentration of fourteen of twenty-four compounds detected was higher in the plasma samples from the EVOO than after ingestion of VOO. Among these, two of them, hydroxytyrosol sulphate and vanil-lin sulphate, were statistically significant in attending their pharmacokinetic parameters, demonstrating the suitability of enrichment. In general, a displacement of the time to reach the maximum concentration is observed in the samples, which indicates that more time is needed to absorb the higher phenolic content. However, inter-individual variability in the concentration of the plasma phenol metabolites shows that it is difficult to show statistically significant differences between the VOO and the EVOO.The scientists thusly conclude that the "metabolism of phenols is affected first by the individual". So until we actually know which influence these are, the label "phenol-enriched" on olive oils and other products has little meaning for you as an individual. And even if you belong to the "lucky" high-absorbers, only two, namely vanillin sulphate and hydroxytyrosol sulphate will reach what the scientists call "pharmocokinetic" levels, if you ingest two tablespoons of the super-potent "phenol-enriched" virgin (and still relatively natural) olive oil.
|Figure 2: Changes in total antioxidant activity (TAA) of experimental oils subsequent to heat treatment (from Pellegrini. 2001)|