Epigraph:
And it is He Who sends down water from the cloud; and We bring forth therewith every kind of growth; then We bring forth with that green foliage wherefrom We produce clustered grain. And from the date-palm, out of its sheaths, come forth bunches hanging low. And We produce therewith gardens of grapes, and the olive and the pomegranate — similar and dissimilar. Look at the fruit thereof when it bears fruit, and the ripening thereof. Surely, in this are Signs for a people who believe. (Al Quran 6:100)
By Nasir S.A. Malik (nmalik6254@yahoo.com), National Agriculture Secretary USA Jamaat
Olive is predominantly a Mediterranean evergreen fruit tree which is now cultivated in various countries in Asia, Australia, Africa, America and Europe. It is one of the oldest cultivated plants as some reports indicate its cultivation as far back as 5000-6000 years. In Bible (Gen.8:11) it is mentioned that when the dove returned to Noah she had olive branch in her beak symbolizing peace. Thus, the term “offering olive branch” was coined for peace. The “Great Seal of United States” has an olive branch held in the right talon of the eagle representing power of peace.
Great Seal of the United States
In the Holy Quran, olive is mentioned multiple times, and there is a Hadeth from al-Tirmidhi that the Prophet (saw) said: “Eat the oil and use it on your hair and skin, for it comes from a blessed tree.” Consistent with this Hadeth, modern research has now proven several health benefits of olive oil, and its usefulness on skin. Olive has also been mentioned numerous times in Bible and is considered a very holy tree. I recall that in December of 2009 I was invited to Nazareth in Israel for giving a presentation on my research on olives (1). In Nazareth, I asked to visit historical shrines. When we reached the “Church of Agony” in Jerusalem (where Jesus had his last supper) the door was closed because we were late in the evening. Our host, a Jewish scientist, however, described that the Pope had given him special privileges to visit the church anytime because he was responsible of reviving olive trees inside the church that were dying and the Pope was concerned about those holy trees. The doors were therefore especially opened for us. In fact, olives are holy for Jews too. For example, about 7 years ago I received a call from a local nurseryman in Weslaco TX to help him set up olive nursery from cuttings. The gardener informed me that he had received olive cuttings from Israel by a group of Israelis who want to produce holy plant so that Jewish homes could be blessed by growing small trees inside their homes. In Jerusalem, they showed me live olive trees elevated several feet high in the sky on pillars; perhaps a symbol of respect and art. [Everyone in southern US should grow olive in their backyard to harness health benefits from its leaves.]
Author: Nasir S.A. Malik
In America, missionaries with early settlers brought olive trees and planted them in California from where their cultivation started in US. However, consumption of olive oil in America remained minimal until 1983 when it started to take off significantly and continues to increase every year as the public becomes aware of its health benefits. For example, US imported 9.5 million gallons of olive oil in 1989 and now it is imports are reaching about 100 million gallons (i.e., multi-billion $ market). The potential for olive oil consumption in America based on per capita consumption is Greece is about 800-1000 million gallons; i.e. we still have a long way to go. Before 2007 less than 1% of olive oil consumed in US was produced in US; primarily in California. Production of olive in Texas was strongly discouraged by early scientist, but my research has shown that it would be feasible to grow along Texas coastline north of Corpus Christy all the way to Louisiana and beyond (1). And now thousands of trees are being planted there. Californian farmers have also boosted their plantation of olive trees and hence the contribution of US produced olive oil among total olive oil consumed has reached to about 3 percent which is still pretty low.
Most consumers consider olive oil as the primary product of olive tree for health benefits, but leaves of olive trees are also loaded with health benefiting compounds; i.e. specific polyphenols found in olive species. Even the major health benefits attributed to olive oil are mainly because of the presence of polyphenols (2). Strictly based on the quality of oil itself olive oil may not be better than some other oils such as soybean or canola. For example, edible oils are mixtures of fatty acids, and if an oil contains more saturated fatty acids (e.g., stearic acid and palmitic acid) than unsaturated fatty acids (e.g. oleic acid, linoleic acid) then it is less healthy compared to the one that has more unsaturated fatty acid; and of course, as far as linolenic acid (omega 3) is concerned the more the better. Now if we look at the levels of fatty acids in olive oil versus canola oil we will find that in both oils saturated fatty acids are equally low and unsaturated fatty acids are similarly higher, but the canola oil has the advantage of having 10 times more omega 3 oil compared to olive oil (1 and 3). Similarly, soybean oil is also rich in unsaturated fatty acids and almost as high in omega 3 oil as it is in canola. So, does this mean that soybean and canola are better oils than olive oil? The answer is a big NO. The reason is that olive oil is much more than just oil. In reality, olive oil is a juice whereas canola and soybean are simply oils. To understand the difference in the two terms I just mentioned you need to know the processes how these oils are obtained.
Soybean, corn, and canola oils are obtained by extracting with organic solvents such as hexane; and therefore, water soluble compounds (such as health benefitting polyphenols) do not get extracted in the oil. On the other hand, olive oil is a juice because it is extracted by simply pressing the ripe olive fruits; this is done in the cold to prevent oxidation of fatty acids. After malaxation of ripe olives, the oil mixed with water is centrifuged to separate oil and water layers and then the oil layer is syphoned off. During this extraction process small amount of water and the healthy compounds (i.e., polyphenols) remain mixed or dispersed within the olive oil. Almost all powerful health benefits that are attributed to olive oil are due to this class of compounds. Thus, olive oil is superior to soybean, corn, or canola oils because it contains polyphenols (many of which are unique to olive trees) that the other oil don’t contain. Here it is important to mention that it is advisable that consumers should always buy a good brand of extra virgin olive oil. Extra virgin grade signifies maximal inclusion of polyphenols. It is not a good idea to buy light or lower grade olive oil because usually those grades do not contain health benefitting polyphenols. Tests in my laboratory confirmed the absence of polyphenols in light and lower grade oils. After cold pressing extra virgin olive oil the remaining pulp or pomace is extracted with organic solvents that gives additional light oil which lacks polyphenols.
Of all the polyphenols unique to olive, oleuropein has been most extensively studied for its several health benefits. For example, this compound has been reported to reduce platelet aggregation and hence increase blood flow and reduce hypertension; clinical trials have demonstrated reduction in blood pressure via oleuropein administration. Being a strong antioxidant it prevents the oxidation of LDL and coupled with its anti-inflammatory effects it reduces the incidences of coronary diseases. Several studies show that oleuropein strongly decreases breast cancer. These antitumor effects were shown by both pure oleuropein as well as via crude olive extracts containing oleuropein. Claims have been made that oleuropein could also be a powerful antiviral agent, and a patent has been granted for the use of olive leaf extracts for this purpose. Thus, while preparations containing oleuropein can be useful for ailments like herpes and hepatitis, patients of AIDS have also used it to boost their immune system, reduce fatigue and enhance the effect of anti-HIV medicine. A group of scientist in New York and Harvard medical schools has obtained very encouraging results regarding the anti –HIV effects of olive leaf extracts.
Oleuropein is the most abundant polyphenol among all other polyphenols in various parts of the olive tree but it is not the major component of polyphenols in olive oil. This is because the levels of oleuropein increase with fruit development attaining maximum level in fully developed green olive fruits but when fruits begin to mature and change color to brown then oleuropein levels begin to decline drastically (5). Therefore, depending upon the proportion of green olives included in the harvest the levels of oleuropein will fluctuate in different oils; of course other factor such as processing would also influence oleuropein levels. Probably, decline in oleuropein levels in mature fruits and hence in oil is a good thing because oleuropein is very bitter and olive oil has to be palatable to eat it raw. Anyway, the decline in oleuropein levels is usually due to its conversion into tyrosol and hydroxytyrosol. These smaller molecules are not bitter but have similar beneficial effects for heart, blood pressure and have anti-inflammatory, anti-cancer, and anti-viral effects. When I travelled through Portugal and Spain I noticed that people of Mediterranean countries eat olive oil straight out of the bottle and pour it on their toasts, sprinkle on salads or apply topically on baked food; that is the best way to maximize the benefits from olive oil. So, select the brand of olive oil that suits your taste. Always avoid deep frying with olive oil, and try no more than stir frying.
Hadeth described above not only recommended eating olive oil but it also suggested applying on skin and hair. Again, this is because of the antioxidant and anti-aging effect of its specific polyphenols. Although, most of the olive polyphenols will benefit skin due to their anti-oxidant and ant-aging effect but the polyphenol named verbascoside in most prominent for dermatological uses. Studies have shown that verbascoside helps skin repair and improves skin inflammation, and therefore, in addition to be a good sunscreen it could actually repair skin damage.
Polyphenols, including oleuropein and verbascoside, are abundantly found in olive leaves. Therefore, I conducted several studies to find simple ways of extraction and use of olive leaf polyphenols for home consumers (4). First, do not freeze olive leaves before extracting health benefitting polyphenols. Thawing frozen olive leaves at room temperature for even a few minute would drastically degrade oleuropein. The best way to preserve polyphenols in olive leaves for extraction is to dry them at room temperature under shade; drying in sun or oven will also degrade polyphenols. Dried leaves then can be pulverized using home coffee grinder, or food processor with a few drops of olive oil to reduce dust production. The powdered olive leaves can be boiled for five minute to extract polyphenols in the form of olive tea. However, this extract could be bitter depending upon how much powder was used, so to make it pleasant one could dilute the extract with other health benefitting juices such as pomegranate or cranberry juices. The other method for daily use is to extract in coffee maker along with tea and coffee adjusted to one’s personal taste. I use olive leaf powder while making my tea in the office twice a day.
(1) My presentation as webinar http://texasoliveoilcouncil.org/conferences/2013/09/presentations/presentation1.html
(2) My interview with Washington Post http://www.star-telegram.com/2012/09/28/4296089/how-to-get-all-the-benefits-of.html.
(3) Lee et al 1998 Analytical Chemica Acta 358: 163-175).
(4) Malik, N. S. A and J. Bradford 2008, J. Food Agric. Environ. 6:8-13
(5) Malik, N. S. A. and J. Bradford 2006, Scientia. Hort. 110:274-278
Categories: Agriculture, Americas, Botany