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Coconut oil, also known as coconut butter, is a tropical oil extracted from copra (the dried inner flesh of coconuts) with many applications. Coconut oil constitutes seven percent of the total export income of the Philippines, the world's largest exporter of the product.
Coconut oil was developed as a commercial product by merchants in the South Seas and South Asia in the 1860s.
Physical properties
Coconut oil is a fat consisting of about 90% saturated fat. The oil contains predominantly medium chain triglycerides, with 86.5% saturated fatty acids, 5.8% monounsaturated fatty acids, and 1.8% polyunsaturated fatty acids. Of the saturated fatty acids, coconut oil is primarily 44.6% lauric acid, 16.8% myristic acid and 8.2% palmitic acid, although it contains seven different saturated fatty acids in total. Its only monounsaturated fatty acid is oleic acid while its only polyunsaturated fatty acid is linoleic acid.
Unrefined coconut oil melts at 20-25 °C and smokes at 170 °C (350 °F)., while refined coconut oil has a higher smoke point of 232 °C (450 °F).
Coconut oil has a long shelf life compared to other oils, lasting up to two years due to its resilience to high temperatures. Coconut oil is best stored in solid form - i.e. at temperatures lower than 24.5 °C (76°F) in order to extend shelf life. However, unlike most oils, coconut oil will not be damaged by warmer temperatures.
Chemical properties
Among the most stable of all oils, coconut oil is slow to oxidize and thus resistant to rancidity.
Types of oil available
Unrefined oil
Otherwise known as raw oil, this is oil that has been obtained simply through mechanical pressing and without further treatment apart from (possibly) filtration. Raw oil retains the compounds that provide its distinctive taste and smell. For marketing purposes, raw oil may also be called "virgin" or "extra virgin".
Raw oil is extracted by crushing and pressing copra. Traditionally, the oil was obtained by grating or grinding copra, then boiling it in water.
Refined oil
Various treatments can be given to the raw oil to produce different products each with their own characteristics and hence applications. Refined oil is virtually tasteless and odourless.
Hydrogenated oil
Hydrogenated coconut oil may either be fully or partially hydrogenated.
Fractionated oil
Fractionated coconut oil" is a fraction of the whole oil, in which most of the long-chain triglycerides are removed so that only saturated fats remain. It may also referred to as "caprylic/capric triglyceride" or MCT oil because mostly the medium-chain triglycerides caprylic and capric acid) are left in the oil.
Because it is completely saturated, fractionated oil is even more heat stable than other forms of coconut oil and has a nearly indefinite shelf life.
Effects on health
During the 1980s, the American Heart Association issued statements indicating that coconut oil's high saturated fat content was detrimental to cardiovascular health and promoted heart disease . The American Soybean Association in the 1980s also claimed that coconut oil is a saturated fat and can cause heart attacks. Twenty years later, however, the hydrogenated and partially hydrogenated vegetable oils that were supposedly more "heart friendly" than traditional saturated fats such as butter and coconut oil have been shown to have their own health risks because they cause trans fatty acids. This has caused many to question the anti-saturated fat bias, as a study published in the American Journal of Clinical Nutrition in 2004 carries the title: "Saturated fat prevents coronary artery disease? An American paradox"
A research study at the Heart Research Institute in Sydney, Australia used coconut oil and safflower oil (high in polyunsaturated fat) in two otherwise identical meals for the study's participants . The study found the following:
“...three hours after eating the coconut oil meal, the lining of the arteries was hindered from expanding to increase blood flow. After six hours, the anti-inflammatory qualities of the good cholesterol were reduced.
“...the safflower oil meal seemed to improve those anti-inflammatory qualities. Also, fewer inflammatory agents were found in the arteries than before the meal.”
The above study involved only 14 subjects, and it is unclear how the coconut oil used for the study was processed. The "meal" in this study consisted of a slice of carrot cake and a milk shake. The conclusion (as reported by the media covering the study) that coconut oil is unhealthy is consistent with prior concerns raised by the AHA. The actual quote from the authors of the study states: "A nonsignificant trend toward impairment of endothelium-dependent vascular reactivity in conduit arteries was also demonstrated after the saturated fat meal."
Epidemiological studies of tropical cultures that get a majority of their caloric intake from coconut oil shows a different result. The most popular study was conducted in the early 1980s on the Polynesian islands of Pukapuka and Tokelau - two cultures relatively untouched by western food (like carrot cake and milk shakes) at the time. The study was published in the American Journal of Clinical Nutriion in 1981. Both cultures had and extremely high intake of saturated fat, with one of the island's population consuming a whopping 63% of their caloric intake from coconut. The people were found to be very healthy, and the authors of the study concluded: "Vascular disease is uncommon in both populations and there is no evidence of the high saturated fat intake having a harmful effect in these populations."
Another study by coconut oil advocates suggested that coconut oil reduces LDL and improves HDL.
A study done by the Lazaro Hospital showed that coconut oil reduced the viral load on HIV patients. 15 participants were involved in the study and 7 of them showed substantial improvement after consuming coconut oil daily for six months. Participants in the study who consumed more coconut oil lowered their viral loads quicker than those who consumed less coconut oil. Furthermore, there have been instances where people have consumed as much as 1 cup of coconut oil a day and have lowered their viral loads to undetectable amounts.
Whereas consumption of most fats typically results in storage in the human body (as fat tissue), the fatty acids in coconut oil are broken down and are used primarily for energy production, seldom being stored as fat tissue . It has been discovered that these fatty acids do not have a negative effect on blood cholesterol; in fact, they help protect against heart disease.
Applications
Cooking
Coconut oil is commonly used in cooking, especially when frying, and it has a high smoke point temperature which makes it good for this purpose. In communities where coconut oil is widely used in cooking, the refined oil is the one most commonly used.
Coconut oil is often used in making a curry.
In Malaysia, coconut oil is used for making Nasi Lemak.
Manufacturing
Coconut oil is used in volume quantities for making margarine, soap and cosmetics.
Hydrogenated or partially-hydrogenated coconut oil is often used in non-dairy creamers, and snack foods.
Fractionated coconut oil is also used in the manufacture of essences, massage oils and cosmetics
Cosmetics and skin treatments
Coconut oil is excellent as a skin moisturiser. A study shows that extra virgin coconut oil is as effective and safe as mineral oil when used as a moisturiser, with absence of adverse reactions .
Coconut oil can also help in healing Keratosis pilaris by moisturising the affected area. The coconut oil should be applied in the shower, and may cause the KP bumps to disappear.
In India and Sri Lanka, coconut oil is commonly used for styling hair, and cooling or soothing the head (stress relief). People of coastal districts of Karnataka and Kerala bathe in warm water after applying coconut oil all over the body and leaving it as is for an hour. It is suggested by elders that this ritual must be done at least once in a week, to keep body, skin, and hair healthy.
As a fuel
Traditional use
Coconut oil is used in oil lamps.
In diesel engines
Coconut oil has been tested for use as a feedstock for biodiesel to be used as a diesel engine fuel. In this manner it can be applied to power generation and transport using diesel engines.
Coconut oil is blended to make biodiesel but can also be used straight, without blending. However, only blends with 10% or less of coconut oil can be safely used in unmodified engines. The oil needs to meet the Weihenstephan standard for pure vegetable oil used as a fuel since otherwise moderate to severe damage from coking and clogging will occur in an unmodified engine . Stationary engines that are continuously loaded (>70%) may possibly be used without engine modifications but there is divergent opinion about this.
The physical constraints of using raw coconut oil in a diesel engine are formed by:
- higher viscosity of coconut oil (up to 10 times as high as diesel), leading to altered spray pattern of injected fuel, additional stress on injection pump
- minimum combustion chamber temperature of 500 °C to avoid polymerisation of the fuel, leading to clogged injectors, sticking piston rings and lubrication oil deterioration
- solidification point between 22-25 °C requires an additional fuel tank heater in temperate climates.
Raw coconut oil can be used as a fuel for generating electricity by remote communities that have an abundant supply of coconuts and milling capacity, provided diesel engines are adapted.
Coconut oil is currently used as a fuel for transport and electricity generation in the Philippines and India while research is being carried out in the islands of the Pacific . In the 1990s Bougainville conflict, islanders cut off from supplies due to a blockade used it to fuel their vehicles.
Availability to consumers
While coconut oil is widely available in some countries, it can be hard to find in others. In the UK it is not generally available in big supermarkets, but can be easily obtained from smaller convenience stores at very cheap prices (from £1 to £2 for 500ml). Some people are unaware of this and resort to buying it online or from health food shops, which generally charge a lot more (from £5 to £20 for 500ml). Some sellers explain their prices by saying that their product is not refined (eg. "extra virgin"). However, as saturated fats do not contain any double bonds, they are highly heat stable, and as coconut oil is about 90% saturated fat, the quality of the oil itself is not affected very much by the processing. Interestingly enough, some sellers even advertise their product as being both "made without heat processing" and as being heat stable. The main difference between these two oils is the amount of extra nutrients that may remain in the unrefined oil, and the taste which in the refined oil is nearly non-existent.
References
- http://www.nutritiondata.com/facts-C00001-01c208C.html
- Nutrient analysis of coconut oil - USDA
- Cooking For Engineers - Kitchen Notes: Smoke Points of Various Fats
- http://www.newstarget.com/001587.html
- http://www.mercola.com/2001/jul/28/coconut_health.htm
- The Coconut Oil Miracle, Bruce Fife, C.N., N.D, p 9 (2004)
- http://www.ajcn.org/cgi/content/full/80/5/1102
- J Am Coll Cardiol, 2006; 48:715-720, doi:10.1016/j.jacc.2006.04.080 (Published online 21 July 2006).
- http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?cmd=Retrieve&db=PubMed&list_uids=7270479&dopt=Abstract
- The Coconut Oil Miracle, Bruce Fife, C.N., N.D. (2004)
- http://www.newstarget.com/009701.html/ Hypothyroidism and Virgin Coconut Oil (press release)
- Dr. D. P. Athukorale, South Asia Research Institute for Policy and Development, "Coconut Oil: Latest Weapon Against Heart Disease", November 29, 2004
- Agero AL, Verallo-Rowell VM A randomized double-blind controlled trial comparing extra virgin coconut oil with mineral oil as a moisturizer for mild to moderate xerosis Dermatitis 2004 Sep;15(3):109-16
- Straight vegetable oil as diesel fuel
- Vegetable oil used as fuel
- Weihenstephan vegetable oil fuel standard (German Rapeseed Fuel Standard)
- Coconut Oil for Power Generation by EPC in Samoa - Jan Cloin
- The coconut revolution - a documentary film.
These were probably referenced in the text at one time but no longer are:
- Mohamed, Ali; Hussein, Ahmed; Bhathena, Sam; Hafez, Y Effect of Dietary Fatty Acid Unsaturation and Vitamin E Interaction on Serum and Liver Lipids in Rats. Journal of Nutritional Biochemistry. 4 April 2002.
- Kritschevsky D, Tepper SA, Biseg G, et al. Experimental atherosclerosis in rabbits fed cholesterol-free diets. Atherosclerosis. 1982;41:279-284.
- Reiser R, Probstfield JL, Silvers A, Scott LW, Shorney ML, Wood RD, O'Brien BC, Gotto AM Jr and Insull W Jr Plasma lipid and lipoprotein response of humans to beef fat, coconut oil and safflower oil. American Journal of Clinic Nutrition. 1985;42:190-197. (PDF reprint also available)
See also
External links
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- The Health Benefits of Coconuts & Coconut Oil by Mary G. Enig
- "Popcorn: Oil in a Day’s Work" from Center for Science in the Public Interest
- Coconut Oil for Power Generation by EPC in Samoa (CocoGen)
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