Health effects

[edit] Historical

Coconut oil has a long history of use as both a food and as a medicine throughout the world. It holds a high place of respect in Ayurvedic medicine in India. Ayurvedic literature is full of praise for the coconut. The Council of Maharishi Ayurveda Physicians considers coconut a divine plant in the Vedic tradition. Whenever a sacred ceremony is performed, a coconut must grace the occasion. Thus, the coconut enjoys a hallowed status in the Vedic tradition. Ayurveda’s revered ancient healer, Sushruta, noted that coconuts strengthen muscles, the cardiovascular system, cleanse the urinary tract, and the seven body tissues. Coconut improves the complexion and is considered a wound healer, especially effective in preventing the formation of scars when applied topically.^[8]

Many populations within the tropics have used coconut for generations and recognize its healing value. In folk remedies around the world coconut is use to treat a wide assortment of ailments among which include abscesses, alopecia, amenorrhea, asthma, blenorrhagia, bronchitis, bruises, burns, cachexia, calculus, colds, constipation, cough, debility, dropsy, dysentery, dysmenorrhea, earache, erysipelas, fever, flu, gingivitis, gonorrhea, hematemesis, hemoptysis, jaundice, menorrhagia, nausea, phthisis, pregnancy, rash, scabies, scurvy, sore throat, stomachache, swelling, syphilis, toothache, tuberculosis, tumors, typhoid, venereal diseases, and wounds.^[9]

[edit] Digestion and Nutrient Absorption

The fatty acids in all dietary fats and oils are in the form of triglycerides. Triglycerides are simply three fatty acid molecules joined together by a glycerol molecule. Most of the triglycerides in dietary fats and oils contain only LCFA and are referred to as long chain triglycerides (LCT). Coconut oil is composed predominately of medium chain triglycerides (MCT).

One of the major differences between MCT in coconut oil and other fats is the way in which they are digested and metabolized. Most all fats in our diet, whether they are saturated or unsaturated, are in the form of LCT. Both vegetable oils and animal fats are composed almost entirely of LCT. The MCT in coconut are much smaller in size. The size makes a big difference.

When consumed, the large LCT pass through the stomach and into the intestinal tract where the majority of fat digestion takes place. Here they are digested and broken down into individual fatty acids with the aid of pancreatic digestive enzymes and bile. As individual fatty acids are released from the triglyceride molecule they are absorbed into the intestinal wall. Here they are combined into bundles of fat and protein called chylomicrons (a form of lipoprotein). These lipoproteins are sent into the bloodstream to be distributed throughout the body. Lipoproteins are the source of the fats that are packed away into our fat cells and the fat that ends up clinging to artery walls as a part of plaque.

MCT, on the other hand, are metabolized differently. When consumed, they are broken down into individual fatty acids in the stomach, before being released into the intestinal tract. Therefore, they do not need pancreatic digestive enzymes or bile for digestion and put little strain of the enzyme and digestive systems of the body. Since no further digestion is required, the individual medium chain fatty acids are immediately absorbed into the portal vein and channeled directly to the liver. In the liver MCFA they are used preferentially as a source of fuel to produce energy. They act as a more efficient source of fuel than glucose, the body’s normal energy source. Consequently, MCFA do not circulate in the bloodstream to the degree that other fats do. As a result, they are much less likely to be incorporated into fat cells and do not collect in artery walls or contribute to hardening of the arteries.^[10]MCFA are utilized primarily by the body to produce energy rather than body fat or arterial plaque.

Because of the ease at which coconut oil is digested, it has proven useful in the treatment of malnutrition. Coconut oil has shown to be superior to other vegetable oils for promoting growth and improving nutritional status in malnourished children. ^[1]

For this same reason, coconut oil is recommended over other oils for people who have digestive problems or who have trouble digesting fats. Coconut oil or MCT are routinely added to commercial and hospital infant formulas because they are better tolerated by newborns whose digestive systems are still developing. Likewise, they are added to adult hospital feeding formulas to improve patients’ nutritional status.^[11]

MCT are essential in infant formulas. They are required nutrients for proper growth and development. Nature itself utilizes MCT for this purpose. Next to coconut and palm kernel oils, breast milk is the richest source of MCT in the human diet. Adding coconut oil or MCT to infant formulas creates a food that most closely resembles natural breast milk in function and nutritional content.

Medium-chain fatty acids also improve the absorption of many other nutrients. The absorption of minerals (particularly calcium and magnesium), B vitamins, fat soluble vitamins (A, D, E, K and beta-carotene) and also amino acids have been found to increase when infants are fed a diet containing coconut oil. ^[12]

[edit] Energy and Weight Management

The fact that the fatty acids in coconut oil are used as fuel to generate energy, rather than being put into storage like other fats, provides many health benefits. The most obvious is a boost in energy. The energy boost is not like the kick you get from caffeine, it’s more subtle but longer lasting. It is most noticeable as an increase in endurance. ^[13] This effect is accumulative, that is, energy level increases with daily use. Some studies have shown when athletes are given MCFA during training their performance and endurance improves.^[14] For this reason, coconut oil or MCT oil, is added to many sports drinks and energy bars.

Because coconut oil produces energy, it stimulates the metabolism. This thermogenic or metabolic stimulating effect causes the body to burn more calories, thus leaving fewer calories to be converted into body fat. For this reason, coconut oil is believed to promote weight loss in overweight individuals.^[15]Studies have shown that replacing LCFA with MCFA in the diet yield meals having a lower effective calorie content.^[16]

In one study, the thermogenic (fat-burning) effect of a high-calorie diet containing 40 percent fat as MCFA was compared to one containing 40 percent fat as LCFA. The thermogenic effect of the MCFA was almost twice as high as the LCFA. The researchers concluded that the excess energy provided by fats in the form of MCFA would not be efficiently stored as fat, but rather would be burned. A follow-up study demonstrated that MCFA given over a six-day period can increase diet-induced thermogenesis by 50 percent.^{[17] [18]}

In another study, researchers compared single meals of 400 calories composed entirely of MCFA and of LCFA. The thermogenic effect of MCFA over six hours was three times greater than that of LCFA. Researchers concluded that substituting MCFA for LCFA would produce weight loss as long as the calorie level remained the same.^[19]

[edit] Antimicrobial Effects

Jon J Kabara^[20] and other researchers have reported that certain fatty acids, primarily MCFA, and their derivatives (e.g., monoglycerides) have potent antibacterial, antiviral, antifungal, and antiprotozoal properties. When coconut oil is consumed, the MCT are broken down into individual medium chain fatty acids and monoglycerides which can kill or inactivate disease-causing microorganisms inside the body. This is another reason why MCT are so important in human breast milk. They help protect newborns from infections for the first few months of their lives while their immune systems are still developing.^[21]

Unlike antibiotics which are only effective against bacteria, MCFA and monoglycerides can kill bacteria as well as viruses, fungi, and protozoa, which makes coconut oil a potentially useful aid in fighting infections.

It is reported that the fatty acids and monoglycerides produce their killing/inactivating effect by lysing the plasma membrane lipid bilayer of the microorganisms. This causes the organisms to essentially fall apart and die. The antiviral action attributed to monolaurin (the monoglyceride of lauric acid) is that of solubilizing the lipids and phospholipids in the envelope of the organisms causing the disintegration of their outer membrane. There is also evidence that MCFA interfere with the organism’s signal transduction ^[22] and another antimicrobial effect in viruses is due to interference with virus assembly and viral maturation.^[23]

Research has shown that MCFA and monoglycerides are effective in killing a number of disease-causing microorganisms among which include streptococcus, staphylococcus, H. pylori, Chalamydia trachomatis, Neisseria, candida, giardia, herpes virus, influenza, Epstein-Barr virus, hepatitis C virus, human immunodeficiency virus (HIV), and others.^[24][25].^[26]

Coconut oil has been shown to be useful either by itself or in combination with antimicrobial medications in fighting infectious illnesses.^[27][28][29]

[edit] Cardiovascular Disease

One of the major issues regarding coconut oil consumption is its effect on the heart and circulatory system. Because coconut oil contains a high amount of saturated fat, it has been believed to raise blood cholesterol levels and promote heart disease.

Some studies have shown that in laboratory controlled diets, coconut oil may increase total cholesterol levels, but most of these studies used hydrogenated coconut oil, not natural coconut oil, or the studies were designed in such a way as to create an essential fatty acid deficiency, both of these scenarios would cause a rise in total cholesterol regardless of the type of oil used.^[30]

Coconut oil may increase total cholesterol levels slightly in some individuals, but the rise in total cholesterol is due primarily to an increase in HDL (the so-called good) cholesterol. HDL cholesterol is believed to be protective against heart disease and the higher the HDL the better. Total cholesterol is a poor indicator of heart disease risk. ^{[31] [32]} The reason for this is that total cholesterol includes both HDL (good) cholesterol and LDL (bad) cholesterol and there is no indication of how much of each make up the total. This may explain why 75% of those people who experience heart attacks have normal to below normal total cholesterol values. ^[33] A far more accurate indicator of heart disease risk is the cholesterol ratio (Total cholesterol/HDL cholesterol). The cholesterol ratio takes into account the amount of HDL in the total cholesterol reading.

Researchers at Harvard Medical School have shown that coconut oil consumption increases HDL levels and in so doing improves the cholesterol ratio, thus reducing risk of heart disease. ^[34]

They also demonstrated that coconut oil does not significantly affect total cholesterol levels even when up to half of the total daily fat consumption (up to 37% of total calories) consists of coconut oil. The researchers state, “Two conclusions are solidly based. The first is that consumption of up to 50% of dietary fat as coconut oil does not significantly alter either total cholesterol or LDL cholesterol in otherwise healthy young men. More importantly, HDL levels seemed to increase significantly with coconut oil consumption. In fact, coconut oil was the only fat ^[35] which raised HDL.” They went so far as to suggest using coconut oil as an aid in preventing heart disease in high risk patients and said, “This observation is very significant since it raises the possibility of beneficial effects from coconut oil in subjects with increased cardiovascular risk due to low HDL levels…coconut oil may significantly improve blood lipid profiles in at-risk patients.”

Other researchers, after studying coconut oil, have come to similar conclusions. Kurup and Rajmohan^[36] conducted a study on 64 volunteers and found no statistically significant alteration in the serum total cholesterol or LDL cholesterol from baseline values.

Kaunitz and Dayrit reviewed epidemiological and experimental data regarding coconut-eating peoples and noted that the “population studies show that dietary coconut oil does not lead to high serum cholesterol nor to high coronary heart disease mortality or morbidity.” .^[37]

Mendis^[38] reported undesirable changes in blood cholesterol values when young adult Sri Lankan males substituted corn oil (a polyunsaturated oil) for their customary coconut oil. When these subjects switched from coconut oil to corn oil their total serum cholesterol decreased by 18.7% and their LDL (bad) cholesterol decreased 23.8%. Both of these changes are considered good, however when you take into account the HDL values a different picture emerges. The HDL cholesterol also decreased, from 41.4%, from an average of 43.4 to 25.4 mg/dL (putting the HDL values very much below the acceptable lower limit of 35 mg/dL) and the cholesterol ratio increased from 4.14 to 5.75. These cholesterol values indicate that coconut oil is more protective against heart disease than corn oil (a polyunsaturated oil).

Prior and colleagues^[39] showed that Pacific islanders with high intakes of fat, mostly from coconut, comprising up to 50% of total daily calories indicated “no evidence of the high saturated fat intake having a harmful effect in these populations.” When these people migrated to New Zealand, however, and lowered their intake of coconut oil and total fat, their cholesterol increased, and their HDL cholesterol decreased.

In Pacific Island counties rural communities generally consume more coconut and more saturated fat (from coconut) than urban communities which are more educated and in general more conscious about avoiding saturated fat. Yet, total blood cholesterol levels are generally lower in rural areas than in urban areas.^[40] The incidence of heart disease is also much lower in urban areas in Pacific Island communities where coconut oil is the predominate source of dietary fat.^[1]

The modernization of American Samoa over the past several decades has brought about a significant change in the diet and a marked increase in coronary heart disease. In the nearby island of Samoa the diet has remained less modernized. Traditional foods are still favored. Coconut cream, which is rich in fat, contributes 37% of their fat intake. In American Samoa the diet has increasingly relied on imported foods and oils. In American Samoa fat consumption is 36% of total calories, with 16% of calories as saturated fat. In Samoa total fat consumption is 46% of calories with 30% of calories coming from saturated fat, mostly from coconut. Despite the much higher total fat and saturated fat intake, the death rate from coronary heart disease in Samoa is only a third that of American Samoa (7.7% vs 21.0%). The prevalence of hypertension follows the same trend (7.7% vs 18.7% in men and 13.3% vs 37.3% in women).Samoans consume twice as much saturated fat (mostly from coconut) as American Samoans, yet have a much lower incidence of heart disease. This strongly suggests that coconut oil consumption does not increase risk of coronary heart disease and as the Harvard researchers have noted,^[41] may be protective.