Monday, November 4, 2013

The Healthy Taste of Olive Oil. Would the Flavor Be Enough to Induce At Least Some of Its Health & Satiety Effects? Plus: Cholesterol Control - Pomace vs. Refined Olive Oil

What about an EVOO perfume, then?
I know, it sounds crazy, but in view of what you've learned in previous articles here at the SuppVersity about sweet taste receptors (learn more) and their far-reaching influence on our metabolism, it does not appear to far-fetched to assume that there is a receptor that "tastes" the flavor-active compounds of olive oil that's responsible for some of its beneficial health effects - right?

I guess, Sabine Frank and almost a dozen of other scientists from Germany and Austria must have had a similar idea, when they came up with the research question of their most recent study.

Olive oil flavored yoghurt?! Really?

I suppose, olive oil flavored, or, more specifically, low-fat yogurt mixed with a fat-free aroma extract from olive oil may not sound appealing to the average Western customer, but it would certainly deserve the label "functional food":
Figure 1: Only the olive oil enhanced yogurt will also enhance the activity of the frontal operculum (Frank. 2013)
As you can see in Figure 1, it's a functional food that has a statistically highly significant effect on the cerebral blood flow in the frontal operculum 30 and 120 min after a meal: This and the increased activity in the anterior insula of which the scientists found that it correlated positively with the postprandial change in bloos glucose change in the 11 healthy male subjects of the study, clearly suggest: The taste of olive oil alone has significant effects on the blood flow in parts of the brain that are involved in the control of energy intake and metabolic rate.

"What is the "frontal opercular" and why would I care about its blood supply?"

If the subheading to this paragraphs describes what you are thinking right now, it's about time to take a look at the little information we have about the frontal operculum:
  • Suggested read: "Pimp My Olive Oil! When Virgin is not Phenol-Rich Enough: The Pharmacokinetics of Phenol-Enriched Virgin Olive Oil." | read more
    We know from previous studies that the frontal operculum (FP) is sensitive to food intake.
  • The study at hand shows that the FP does not care about caloric values (the yogurts were isocaloric).
  • In task-related studies, the frontal operculum as part of the primary taste cortex, has shown pronounced activation to visual food cues and anticipation of food intake.
  • The activation of the frontal operculum appears to control the "this smells good" or "this looks good, I must have it" response that makes weight loss so difficult.
  • There is a telling relation between the sensitivity of the frontal operculum and the BMI of a person (Batterink. 2010; Yokum. 2011)
  • Earlier fMRI studies showed that oral delivery of a drop of fat leads to an immediate increase in insular and frontal opercular activity, which suggests that there are "fat taste receptors" somewhere in the oral cavity or digestive tract that are wired to the the frontal perculum (Small. 2012).
Now, in context of the results of the study at hand, it is obviously the last of these points, which is particularly interesting. The discovery Frank et al. made would after all suggest that we can get satisfactory "fat effect" without the fat - simply by having the right "aroma."
Figure 2: Modulating effect of the minor components of pomace olive oil (POMACE) on lipid composition in 10 healthy young men (Cabello-Moruno. 2013) - severs as illustration for the importance of the "non-fat" components for our health.
Frank et al. also point out that the fact that they measured the CBF not immediately but 30 min and 120 min after the consumption of the yogurt would make it quite unlikely that they had mistaken an acute aroma response for what they believe is the "association with fat" - in other words, the researchers believe that the ingestion of the olive oil flavor components "modifies later responses to achieve an appropriate sensory control." Effects just as we know them from glucose and artificial sweeteners which "prepare" the body to release insulin.
Per capita consumption of vegetable oils and fats in selected European countries in 2009 (Eurostat. 2011)
Bottom line: I guess it is too early to say, whether and what kind of applications the said olive oil extract could have in the future. What the study does however show is that focusing on macros and even micronutrients, only, is insufficient.

In fact, the "ideal" diet, with the perfect macros and 100% adherence could in the end turn out to produce inferior results to a "sub-optimal", but tasty diet with olive oil and other aromas triggering all-sorts of still to be elucidated beneficial downstream effects on our physiology and psychology.
  • Batterink L, Yokum S, Stice E. Body mass correlates inversely with inhibitory control in response to food among adolescent girls: an fMRI study. Neuroimage 2010;52:1696–703.
  • Cabello-Moruno R, Martinez-Force E, Montero E, Perona JS. Minor components of olive oil facilitate the triglyceride clearance from postprandial lipoproteins in a polarity-dependent manner in healthy men. Nutrition Research. Oct. 2013 [accepted manuscript]
  • Small DM, Green BG. A proposed model of a flavor modality. In: Murray MM, Wallace MT, eds. The neural bases of multisensory processes. Boca Raton, FL: 2012
  • Yokum S, Ng J, Stice E. Attentional bias to food images associated with elevated weight and future weight gain: an FMRI study. Obesity (Silver Spring) 2011;19:1775–83.