As a kid in a traditional Italian family, I was raised on olive oil. And I now consume generous quantities of extra-virgin olive oil (EVOO) just about every day. For one thing, I love its taste. I am so hooked on EVOO that I shudder when a friend serves me a wonderful meal with a great salad, but sets out bottles of commercial salad dressing instead of dressing it with EVOO. I am particularly bothered by bottled dressings with big labels saying MADE WITH REAL ITALIAN OLIVE OIL and showing ladies in colorful dresses carrying baskets of olives while the very fine print on the back of the bottle lists the amount of olive oil as only 15%, and it’s not even extra-virgin oil. I have always known that olive oil is good for me. But for most of my life I could not respond intelligently if somebody asked me “why?” I thought here, as a break from heavy stuff in molecular biology, I would addresses that question and review some of the research on olive oil. I particularly focus on EVOO.
Olive oil and the Mediterranean Diet
There is a two-part generic argument often heard for olive oil. The first part is that a Mediterranean Diet contributes significantly to health and longevity. The second part is that olive oil is an essential component of a Mediterranean diet and therefore must be one of the key “good for you” components. There seems to be good research evidence for the first-part argument as outlined in my August 2009 blog post Recent research on the Mediterranean diet. The second part of the argument by itself does not meet the “beyond a reasonable doubt” test needed to convict somebody in a court trial. What if something else in the Mediterranean Diet is providing most of the benefits, like the tomatoes? The rest of this blog entry will establish the value of EVOO beyond a reasonable doubt.
Olive oil and heart disease risk
A good place to start is with a carefully controlled and fairly-large international 2006 study that directly relates phenolic content of olive oils to familiar lipid levels like HDL and triglycerides: The effect of polyphenols in olive oil on heart disease risk factors: a randomized trial “BACKGROUND: Virgin olive oils are richer in phenolic content than refined olive oil. — OBJECTIVE: To evaluate whether the phenolic content of olive oil further benefits plasma lipid levels and lipid oxidative damage compared with monounsaturated acid content. DESIGN: Randomized, crossover, controlled trial. SETTING: 6 research centers from 5 European countries. PARTICIPANTS: 200 healthy male volunteers. MEASUREMENTS: Glucose levels, plasma lipid levels, oxidative damage to lipid levels, and endogenous and exogenous antioxidants at baseline and before and after each intervention. INTERVENTION: In a crossover study, participants were randomly assigned to 3 sequences of daily administration of 25 mL of 3 olive oils. Olive oils had low (2.7 mg/kg of olive oil), medium (164 mg/kg), or high (366 mg/kg) phenolic content but were otherwise similar. Intervention periods were 3 weeks preceded by 2-week washout periods. RESULTS: A linear increase in high-density lipoprotein (HDL) cholesterol levels was observed for low-, medium-, and high-polyphenol olive oil: mean change, 0.025 mmol/L (95% CI, 0.003 to 0.05 mmol/L), 0.032 mmol/L (CI, 0.005 to 0.05 mmol/L), and 0.045 mmol/L (CI, 0.02 to 0.06 mmol/L), respectively. Total cholesterol-HDL cholesterol ratio decreased linearly with the phenolic content of the olive oil. Triglyceride levels decreased by an average of 0.05 mmol/L for all olive oils. Oxidative stress markers decreased linearly with increasing phenolic content. Mean changes for oxidized low-density lipoprotein levels were 1.21 U/L (CI, -0.8 to 3.6 U/L), -1.48 U/L (-3.6 to 0.6 U/L), and -3.21 U/L (-5.1 to -0.8 U/L) for the low-, medium-, and high-polyphenol olive oil, respectively. LIMITATIONS: The olive oil may have interacted with other dietary components, participants’ dietary intake was self-reported, and the intervention periods were short. CONCLUSIONS: Olive oil is more than a monounsaturated fat. Its phenolic content can also provide benefits for plasma lipid levels and oxidative damage. International Standard Randomised Controlled Trial number: ISRCTN09220811”. So, in only three weeks cholesterol and triglyceride scores improved in the olive oil takers and the scores increased most markedly in those taking the olive oil with the most phenolic content, i.e., the extra-virgin olive oil. And the result is not just because the olive oil is a “good fat.”
The 2007 publication Changes in the phenolic content of low density lipoprotein after olive oil consumption in men. A randomized crossover controlled trial reports on a trial cohort of 30 men, and my impression is that this cohort may have been part of the larger cohort of the first study mentioned above. The writeup has a somewhat different focus, however, focusing on the antioxidant properties of virgin olive oil. “Olive oil decreases the risk of CVD (cardiovascular disease). This effect may be due to the fatty acid profile of the oil, but it may also be due to its antioxidant content which differs depending on the type of olive oil. In this study, the concentrations of oleic acid and antioxidants (phenolic compounds and vitamin E) in plasma and LDL were compared after consumption of three similar olive oils, but with differences in their phenolic content. Thirty healthy volunteers participated in a placebo-controlled, double-blind, crossover, randomized supplementation trial. Virgin, common, and refined olive oils were administered during three periods of 3 weeks separated by a 2-week washout period. Participants were requested to ingest a daily dose of 25 ml raw olive oil, distributed over the three meals of the day, during intervention periods. All three olive oils caused an increase in plasma and LDL oleic acid (P < 0.05) content. Olive oils rich in phenolic compounds led to an increase in phenolic compounds in LDL (P < 0.005). The concentration of phenolic compounds in LDL was directly correlated with the phenolic concentration in the olive oils. The increase in the phenolic content of LDL could account for the increase of the resistance of LDL to oxidation, and the decrease of the in vivo oxidized LDL, observed in the frame of this trial. Our results support the hypothesis that a daily intake of virgin olive oil promotes protective LDL changes ahead of its oxidation.”
Coming back to the Mediterranean Diet, the 2005 review article The phenolic compounds of olive oil: structure, biological activity and beneficial effects on human health relates the phenolic content of olive oil to the diet’s salutary benefits. “The Mediterranean diet is rich in vegetables, cereals, fruit, fish, milk, wine and olive oil and has salutary biological functions. Epidemiological studies have shown a lower incidence of atherosclerosis, cardiovascular diseases and certain kinds of cancer in the Mediterranean area. Olive oil is the main source of fat, and the Mediterranean diet’s healthy effects can in particular be attributed not only to the high relationship between unsaturated and saturated fatty acids in olive oil but also to the antioxidant property of its phenolic compounds. The main phenolic compounds, hydroxytyrosol and oleuropein, which give extra-virgin olive oil its bitter, pungent taste, have powerful antioxidant activity both in vivo and in vitro.”
Again, the messages appear to be that it is the phenolic ingredients in olive oil that are important, that their antioxidant activities are important and that the most healthful olive oil is the one with the most concentration of the polyphenols, namely first-press extra-virgin olive oil (EVOO).
Further, though olive oil seems to be a simple substance the biochemical activities of olive oil polyphenols is not simple, as discussed in the 2008 paper Nutritional benefit of olive oil: the biological effects of hydroxytyrosol and its arylating quinone adducts. “A unique characteristic of olive oil is its enrichment in oleuropein, a member of the secoiridoid family, which hydrolyzes to the catechol hydroxytyrosol and functions as a hydrophilic phenolic antioxidant that is oxidized to its catechol quinone during redox cycling. Little effort has been spent on exploring the biological properties of the catechol hydroxytyrosol quinone, a strong arylating electrophile that forms Michael adducts with thiol nucleophiles in glutathione and proteins. This study compares the chemical and biological characteristics of hydroxytyrosol with those of the tocopherol family in which Michael adducts of arylating desmethyltocopherol quinones have been identified and correlated with biologic properties including cytotoxicity and induction of endoplasmic reticulum stress. It is noted that hydroxytyrosol and desmethyltocopherols share many similarities, suggesting that Michael adduct formation by an arylating quinone electrophile may contribute to the biological properties of both families, including the unique nutritional benefit of olive oil.”
The 2007 document The olive oil antioxidant hydroxytyrosol efficiently protects against the oxidative stress-induced impairment of the NObullet response of isolated rat aorta reports “Moreover, hydroxytyrosol was found to be a potent OH(*) scavenger, which can be attributed to its catechol moiety. Because of its amphiphilic characteristics (octanol-water partitioning coefficient = 1.1), hydroxytyrosol will readily cross membranes and provide protection in the cytosol and membranes, including the water-lipid interface. The present study provides a molecular basis for the contribution of hydroxytyrosol to the benefits of the Mediterranean diet.”
A number of other published studies confirm these messages like the 2004 publication Effects of differing phenolic content in dietary olive oils on lipids and LDL oxidation–a randomized controlled trial and the 2010 publication Biological activities of phenolic compounds present in virgin olive oil, the 2005 report International conference on the healthy effect of virgin olive oil, the 2009 report Chemistry and health of olive oil phenolics, and a number of others.
Olive oil and cancers
A number of studies relate the effects of the active polyphenols in olive oil to killing (induction of apoptosis in) cancer cells. For example the 2009 study Anti-proliferative and apoptotic effects of oleuropein and hydroxytyrosol on human breast cancer MCF-7 cells reports “Olive oil intake has been shown to induce significant levels of apoptosis in various cancer cells. These anti-cancer properties are thought to be mediated by phenolic compounds present in olive. These beneficial health effects of olive have been attributed, at least in part, to the presence of oleuropein and hydroxytyrosol. In this study, oleuropein and hydroxytyrosol, major phenolic compound of olive oil, was studied for its effects on growth in MCF-7 human breast cancer cells using assays for proliferation (MTT assay), cell viability (Guava ViaCount assay), cell apoptosis, cellcycle (flow cytometry). Oleuropein or hydroxytyrosol decreased cell viability, inhibited cell proliferation, and induced cell apoptosis in MCF-7 cells. Result of MTT assay showed that 200 mug/mL of oleuropein or 50 mug/mL of hydroxytyrosol remarkably reduced cell viability of MCF-7 cells. Oleuropein or hydroxytyrosol decrease of the number of MCF-7 cells by inhibiting the rate of cell proliferation and inducing cell apoptosis. Also hydroxytyrosol and oleuropein exhibited statistically significant block of G(1) to S phase transition manifested by the increase of cell number in G(0)/G(1) phase.”
The 2009 study Extra-virgin olive oil polyphenols inhibit HER2 (erbB-2)-induced malignant transformation in human breast epithelial cells: relationship between the chemical structures of extra-virgin olive oil secoiridoids and lignans and their inhibitory activities on the tyrosine kinase activity of HER2 reports “Extra-virgin olive oil (EVOO – the juice of the olive obtained solely by pressing and consumed without any further refining process) is unique among other vegetable oils because of the high level of naturally occurring phenolic compounds. We explored the ability of EVOO polyphenols to modulate HER2 tyrosine kinase receptor-induced in vitro transformed phenotype in human breast epithelial cells. — EVOO polyphenols induced strong tumoricidal effects by selectively triggering high levels of apoptotic cell death in HER2-positive MCF10A/HER2 cells but not in MCF10A/pBABE matched control cells. EVOO lignans and secoiridoids prevented HER2-induced in vitro transformed phenotype as they inhibited colony formation of MCF10A/HER2 cells in soft-agar. Our current findings not only molecularly support recent epidemiological evidence revealing that EVOO-related anti-breast cancer effects primarily affect the occurrence of breast tumors over-expressing the type I receptor tyrosine kinase HER2 but further suggest that the stereochemistry of EVOO-derived lignans and secoiridoids might provide an excellent and safe platform for the design of new HER2 targeted anti-breast cancer drugs.”
The 2008 paper Analyzing effects of extra-virgin olive oil polyphenols on breast cancer-associated fatty acid synthase protein expression using reverse-phase protein microarrays is another of several more relating EVOO to breast cancer. “These findings reveal for the first time that phenolic fractions, directly extracted from EVOO, may induce anti-cancer effects by suppressing the expression of the lipogenic enzyme FASN in HER2-overexpressing breast carcinoma cells, thus offering a previously unrecognized mechanism for EVOO-related cancer preventive effects.”
The 2008 document tabAnti-HER2 (erbB-2) oncogene effects of phenolic compounds directly isolated from commercial Extra-Virgin Olive Oil (EVOO) relates to the same theme. “Among the fractions mainly containing the single phenols hydroxytyrosol and tyrosol, the polyphenol acid elenolic acid, the lignans (+)-pinoresinol and 1-(+)-acetoxypinoresinol, and the secoiridoids deacetoxy oleuropein aglycone, ligstroside aglycone, and oleuropein aglycone, all the major EVOO polyphenols (i.e. secoiridoids and lignans) were found to induce strong tumoricidal effects within a micromolar range by selectively triggering high levels of apoptotic cell death in HER2-overexpressors. Small interfering RNA-induced depletion of HER2 protein and lapatinib-induced blockade of HER2 tyrosine kinase activity both significantly prevented EVOO polyphenols-induced cytotoxicity. EVOO polyphenols drastically depleted HER2 protein and reduced HER2 tyrosine autophosphorylation in a dose- and time-dependent manner. EVOO polyphenols-induced HER2 downregulation occurred regardless the molecular mechanism contributing to HER2 overexpression (i.e. naturally by gene amplification and ectopically driven by a viral promoter). Pre-treatment with the proteasome inhibitor MG132 prevented EVOO polyphenols-induced HER2 depletion. CONCLUSION: The ability of EVOO-derived polyphenols to inhibit HER2 activity by promoting the proteasomal degradation of the HER2 protein itself, together with the fact that humans have safely been ingesting secoiridoids and lignans as long as they have been consuming olives and OO, support the notion that the stereochemistry of these phytochemicals might provide an excellent and safe platform for the design of new HER2-targeting agents.”
It is interesting to me that the emphasis in the last-mentioned study and in several other studies seems to be not on promoting the use of EVOO as an anti-cancer health measure but rather on identifying biochemical pathways on which to base new drug developments. Perhaps this is because the point of departure of most of these studies is acknowledging the health benefits of a Mediterranean diet and consuming lots of olive oil. And, perhaps cynically, I wonder if it reflects research funding sources for whom finding a new blockbuster drug may be more important than public health.
A 2010 study publication Extra-virgin olive oil-enriched diet modulates DSS-colitis-associated colon carcinogenesis in mice reports “RESULTS: Disease activity index (DAI) was significantly higher on SFO (sunflower oil) vs. EVOO diet at the end of the experimental period. EVOO-fed mice showed less incidence and multiplicity of tumors than in those SFO-fed mice. beta-catenin immunostaining was limited to cell membranes in control groups, whereas translocation from the cell membrane to the cytoplasm and/or nucleus was showed in DSS-treated groups and its expression was higher in SFO-fed animals. Cytokine production was significantly enhanced in SFO-fed mice, while this increase was not significant in EVOO-fed mice. Conversely, cyclooxigenase-2 (COX-2) and inducible nitric oxidase synthase (iNOS) expression were significantly lower in the animal group fed with EVOO than in the SFO group. CONCLUSIONS: These results confirm that EVOO diet has protective/preventive effect in the UC-associated CRC. This beneficial effect was correlated with a better DAI, a minor number of dysplastic lesions, a lower beta-catenin immunoreactivity, a proinflammatory cytokine levels reduction, a non modification of p53 expression and, COX-2 and iNOS reduction in the colonic tissue.”
Olive oil and inflammation
A study in done back 2001 Protective effects upon experimental inflammation models of a polyphenol-supplemented virgin olive oil diet again demonstrated a dose-dependent effect of olive oil polyphenols in protecting rats from induced inflammation damage. “CONCLUSIONS: This study demonstrates that virgin olive oil with a higher content of polyphenolic compounds, similar to that of extra virgin olive oil, shows protective effects in both models of inflammation and improves the disease associated loss of weight. This supplementation also augmented the effects of drug therapy.”
Synergy of olive oil with other supplements
A 2006 study Intestinal anti-inflammatory activity of combined quercitrin and dietary olive oil supplemented with fish oil, rich in EPA and DHA (n-3) polyunsaturated fatty acids, in rats with DSS-induced colitis found synergy between administration of fish oil, quercetin and olive oil in a rat model of colitis. “In addition, a complete restoration of colonic glutathione content, which was depleted as a consequence of the colonic insult, was obtained in rats treated with QR plus FO diet; this content was even higher than that obtained when colitic rats were treated with FO diet alone. When compared with the control colitic group, the combined treatment was also associated with a lower colonic nitric oxide synthase and cyclooxygenase-2 expression as well as with a significant reduction in different colonic proinflammatory mediators assayed, i.e. leukotriene B(4), tumor necrosis factor alpha and interleukin 1beta, showing a significantly greater inhibitory effect of the latter in comparison with rats receiving FO diet without the flavonoids (quercetin). CONCLUSIONS: These results support the potential synergism between the administration of the flavonoid and the incorporation of olive oil and n-3 PUFA to the diet for the treatment of these intestinal inflammatory disorders.”
EVOO and gene expression
Finally, I want to mention that new studies are starting to look at the effects of EVOO on gene expression. For example, the 2010 publication Gene expression changes in mononuclear cells from patients with metabolic syndrome after acute intake of phenol-rich virgin olive oil. “BACKGROUND: Previous studies have shown that acute intake of high-phenol virgin olive oil reduces pro-inflammatory, pro-oxidant and pro-thrombotic markers compared with low phenols virgin olive oil, but it remains unclear if the effects attributed to its phenolic fraction are exerted at the transcriptional level in vivo. To achieve this goal, we aimed at identifying in humans those genes which undergo expression changes mediated by virgin olive oil phenolic compounds. RESULTS: Postprandial gene expression microarray analysis was performed on peripheral blood mononuclear cells at the postprandial period. Two virgin olive oil-based breakfasts with high (398 ppm) and low (70 ppm) content of phenolic compounds were administered to 20 patients with metabolic syndrome following a double-blinded random crossover design. To eliminate the potential effect that might exist in their usual dietary habits, all subjects followed a similar low-fat, carbohydrate rich diet during the study period. Microarray analysis identified 98 differentially expressed genes (79 underexpressed and 19 overexpressed) when comparing the intake of phenol-rich olive oil with the low-phenol olive oil. Many of those genes are linked to obesity, dyslipemia and type 2 diabetes mellitus. Among these, several genes are involved in inflammatory processes mediated by transcription factor NF-kappa B, activator protein-1 transcription factor complex AP-1, cytokines, mitogen-activated protein kinases MAPKs or arachidonic acid pathways. CONCLUSION: This study shows that intake of a breakfast based in virgin olive oil rich in phenol compounds is able to repress the in vivo expression of several pro-inflammatory genes, thereby switching the activity of peripheral blood mononuclear cells to a less deleterious inflammatory profile. These results provide at least a partial molecular basis for the reduced risk of cardiovascular disease observed in Mediterranean countries, where virgin olive oil represents the main source of dietary fat.”
I could continue this blog entry citing more and more studies but it should be clear by now that the old Italian folklore about the health value of olive oil is right-on and the pungent extra-virgin variety is by far the best. What I have to figure out now based on the final study quoted is how can I work extra virgin olive oil into my regular daily breakfast? I want to do that without adding carbs and confounding tastes like blueberries and EVOO. I will need to do some experimenting. Perhaps they will go together fine.
Please see the medical disclaimer for this blog.
Oleocanthal is a component of olive oil that doesn’t seem to get as much press as hydroxytyrosol. It helps protect against Alzheimer’s. Another good reason to consume EVOO.
One way I work extra EVOO into my diet is that I use it to take my powdered CoQ10. Q10 in capsule form is rather expensive so I buy bulk powder. Since Q10 is oil soluble and is absorbed better if taken with oil, EVOO is a perfect solvent. Warning- this does not improve the taste of EVOO! The combination is a bit horrid. So, I have my daily square of 88% cocoa dark chocolate at hand to pop into my mouth immediately after downing the EVOO/Q10 mixture to eliminate the taste. If you are brave, you might want to try this. It does involve about four grams of carbs but, for me anyway, doesn’t add to what I would normally consume. I think my taste buds are actually getting used to the EVOO/Q10 mixture (but I still pop the chocolate!)… or, you could just forget the Q10 and just take a swig of EVOO straight… especially if you love the taste. A bite of anything with a distinctive taste afterwards followed by a drink of water will “cleanse the palate” and not confound the taste of your other breakfast favorites.
An interesting and valuable contribution. Thanks.
An interesting idea! Next time I buy CoQ10 I will get some of the powdered version and try your approach. I have also been doing litle squares of 99% cocoa chocolate brought to me from Germany by a friend. You are tight. It is bitter in its own way and clears out any previous taste.
Yesterday morning I tried a variety of my usual breakfast main dish: a generous half-cup or more of blueberries, a quarter-cup of walnuts, a sliced half-banana, all topped with a small portion of rasin bran and 1% milk. This time I soaked the raisen bran with about a tablespoon of EVOO before adding the milk. Appearance in the bowl was weird with little oil-spill splotches of EVOO on the surface of the milk. And the taste mixing the pungent EVOO and the sweet rasins and blueberries was very strange. I could possibly get used to this combination or even like it but want to try something else first. Next I might try a thin slice of toast soaked with EVOO and sprinkled with cinamon.
Sometimes before bed I will soak a triscut in EVOO as a snack.
Works great as a butter substitute on old-fashioned oatmeal when you want it savory instead of sweet.
There’s an olive oil extract equivalent to taking 4-6oz:
Be aware that virtually all commercially available EVOO’s are diluted with hazelnut oil or sunflower oil. This is hard to detect for up to 2% (hazelnut) and/or 25% (sunflower), especially in Italy where adulteration is quite rampant. Geniune 100% EVOO can only be had from small, local suppliers (such as California Estate (Trader Joe’s), Bariani’s, Jaffee Bros, Eliki, etc.), or imported directly from Greece.
Great practical suggestions! The issue that is puzzling me now is how can I get a breakfast that combines the impacts of EVOO, blueberries and walnuts? Tomorrow morning I will see if the combination works with oatmeal. With rasin bran, it gets a D- for taste.
With regard to the Olivenol supplement product it sounds good but I have a few questions about it. First, I am a bit confused because the key polyphenols in EVOO are all clearly fat-soluable and Olivenol is made entirely out of the water extracted when making olive oil according to the website. Are these polyphenols both water and fat soluable? Second, I see claims but no data on the actual potency or bioavailability of Hydroxytyrosol as compared with oleuropein and other polyphenols in EVOO. Third, it is unclear whether Olivenol contains oleocanthal, another important polyphenol. See prophets’ post above. Nontheless, I will probably order some. Finally, I am already taking an olive leaf extract supplement and feel a need to cross-check the polyphenols in that and in Olivenol.
And thanks for your cules on undiluted olive oil. I get some of mine from a distant cousin in Calibria who raises his own olives and is a tiny commercial local supplier. But I often run out of that and have been doing what my grandparents did 70 years ago, namely buy Filippo Berio EVOO. Though this was first sold in 1850 and has won gold medals since 1872 it might not still be the best. I will check out the Trader Joe’s brand.
I looked at the Filippo Berio website, but right away I could tell it was commercial and likely to be adultered. High quality EVOO will be in dark green or amber bottles to protect the sensitive polyphenols and other important nutrients from degradation by light. If a company does not use a proper bottle, the obviously do not give two shits about the quality of their oil, all the marketing propaganda to the contrary.
Once when I was out, I bought a whole gallon of what seemed like a high quality, imported, cold pressed EVOO in metal tin from Ralphs (it was the best choice out of the available poor choices). It turned out to be the worst EVOO I had ever tasted and it smelled plenty weird too. Back it went and never again!
Let’s continue to exchange info on what the best available EVOOs are. I have a cousin in Calibria who has his own olive tree orchard and who presses EVOO and sells it only locally. Great stuff but very expensive to get it shipped here. Philippo Berio has a great tradition of quality but most likely is now run by corporate types. They do sell some EVOO in dark green bottles but I am not sure of its quality. It is hard for me to tell.
I recently purchased an expensive gallon of The Olive Harvest EVOO imported from Northern Lebanon. I was assured by the Leanese store proprietor that it is of the highest quality. The importer is local to where I live. I have not opened it yet but will report on it when I do.
Going back to the Olivenol product, they make their product out of water extracted from olives which leads me to wonder about the pungent wattery liquid that bottled green olives are normally packed in. The liquid is strongly and plesantly olive-flavored and I sometimes secretly drink a little of it. I wonder if it is polyphenol-rich and should be consumed instead of thrown away as is normally done.
Long time… I was wondering if you know which variety of olive oil has a reputation for the highest polyphenol count?
Thanks a lot
Your question is a good one I wonder about myself. I am sure there are major differences. I try to buy good brands of extra-virgin olive oil but am not at all sure what I am getting except when I travel to Calabria and bring back cans of EVO packaged by my cousin who has an olive-tree orchard and olive oil extraction plant. He sells only locally.
Found a nicely layed out table with a Polyphenol index (see below)… I am wondering if its better as part of the anti aging-plan to consume the whole olive ‘instead of’ or aswell as the olive oil itself? In theory this would reduce oxidation further – or would I be missing out on some benefits of consuming the oil itself?
I understand time of year for harvest affects the level of polyphenols – I will continue my research and keep you informed.
Interesting publication and please do keep me informed. I have a cousin in Calabria Italy who is an agronomist. Last year while visiting in Calabria, he presented me with a copy of a book he has written all about olive oils and olive trees and olive oil production. I quickly scanned through the book which is written in Italian, and my impression is that it deals with the kinds of topics treated in the reference you cited. I will see if I can manage to find it on my shelves and see if it sheds any light on key issues such as shelf life and polyphenol content.
I looked at the table of olive oil polyphenol content according to cultivars of olives. Good first step of research. Next step is to see what blends of EVO are produced by cultivars with high polyphenol content such as Frantorio and Pictual. Final step is to determine where they are sold in the US. Then, to order and hope the data in the table is not too obsolete. A good clue for buying is probably the observation in the paper that the highest polyphenol-containing brands are the most bitter and pungent and have the shortest shelve lives.
Regarding your question of whether it is worthwhile to eat the whole olive, I have often wondered about that myself. I keep jars of three different kinds of olives in the frige and typically eat 4-6 every day. I also have an unusual habit which is to drink the water-based juice from jars of commercial olives when most of the oilves are eaten and nobody is looking. I like the stuff which has a strong flavor and imagine it could be possibly beneficial. I do recall reading once that it is high in polyphenols but don’t want to take the time now to track the quote down.
Be interested to hear how you get on foraging in your cousins book. I think if we iteratively find studies on the different cultivars – trends should start to emerge. Well I have made good progress learning how to leverage google to the maximum searching multi lingual queries: managed to stumble on this. Variety Coratina seems to be highest from my research so far…. In March 675 mg / kg in the Coratina variety. I have spoken to some farms in the region and they are sending me some samples.
Next, the taste test as per your last quote on seeing how pungent they are!
I am wondering if I am overdosing on olives now after seeing you only go through 4-6 per day. I personally consume 1 whole jar of olives per day but, that is instead of consuming any oil. I imagine the body has to work a lot harder to get any fat out of the olives though. Just a theory. My only fat sources come from avocado, olives and almonds and of course oily fish…. and lots of it!
See what you make of this piece (scroll down the page): http://translate.google.co.uk/translate?hl=en&langpair=es|en&u=http://www.inta.gov.ar/catamarca/info/documentos/caract_producc_olivo.pdf
I am also wondering if you have a function on your website where every time you post a reply people get an email update ? I am sure your traffic would sky rocket if you could embed this feature.
Hi, I can’t understand how to add your site in my rss reader. Can you Help me, please 🙂
First off I would like to say excellent blog! I had a quick question in which I’d like to ask if you do not mind. I was curious to find out how you center yourself and clear your head before writing. I’ve had a hard time clearing my thoughts in getting my thoughts out. I truly do enjoy writing however it just seems like the first 10 to 15 minutes are generally wasted simply just trying to figure out how to begin. Any suggestions or tips? Thank you!
What do you make of this? He is basically knocking olive oil, in an infuriating sort of way.
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