Coconut oil, WADL Amarasiri, AS Dissanayake,

Title page

Title                                                                 :           Coconut fats - a perspective

Authors                                                           :           1. Dr. W. A. D. L. Amarasiri ¹

                                                                                    2. Dr. A. S. Dissanayake ²

                                   

Author for correspondence

                                    :           Dr. W. A. D. L. Amarasiri

                                                Lecturer

                                                Department of Physiology

                                                Faculty of Medicine

                                                University of Kelaniya

                                                P.O. Box 6, Thalagolla Road,

Ragama.

                                      

        Tel: 0777 449 866, 0112 958219 ext 28

All reprint requests could be directed to the above address.

Number of words in manuscript                    :           2026

Abstract

In many areas of Sri Lanka the coconut tree and its products have been an integral part of rural life and it come to be called the “Tree of Life”.

Coconut fats (CF) account for 80% of the fat intake among Sri Lankans. Around 92% of coconut fats are saturated fats. This has lead to the belief that coconut fats are ‘bad for health’ particularly in relation to ischaemic heart disease. Yet, most of the saturated fats in coconut are medium chain fatty acids whose properties and metabolism are different to those of animal origin.  The relationship between coconut fats and health has been the subject of much debate and misinformation.

The main fatty acid in CF is lauric acid (LA).  The only other naturally occurring fat with high LA content is human breast milk. This begs the question whether CFs  do have beneficial effects. 

There is the need to clarify issues relating to intake of coconut fats and health more particularly for populations that still depend on coconut fats for much of their fat intake. This paper describes the metabolism of coconut fats and its potential benefits, and attempts to highlight its benefits in order to remove certain misconceptions regarding its use. …

…Coconut trees were known to have existed as far back as 161 BC and the existence of coconut plantations was first recorded in the 2^nd Century AD. Coconut kernel and kernel products such as coconut milk and coconut oil (CO) are eaten mainly for the exquisite taste that the fats in coconut convey to food.

Fats make up less than 25% of the total energy expenditure among Sri Lankans. Studies done more than 20-30 years back have shown that coconut fats constitutes about 80% or more of the total fat intake of Sri Lankans [1].

Over 95% of coconut oil is fat while the fat content of scraped coconut is around 34% and that of coconut milk around 20%. It is also true that around 92% of the coconut fat is saturated fat [2].  However, the saturated fats in coconut and palm-kernel oil also called “tropical oils” differ from saturated fats in animal fats. Over 50% of the fats in coconut are medium chain triglycerides that are formed from fatty acids of chain length 8:0 to 14:0. It is primarily the 14:0 fatty acids that are thought to be atherogenic.  When digested in the small intestine, these yield saturated medium chain free fatty acids and monoglycerides. Lauric acid and monolaurin constitute around 50% of CF derived lipid.  However unlike long chain fatty acids, these medium chain free fatty acids and monoglycerides are absorbed intact from the small intestine and do not undergo degradation and re-esterification processes.

They are directly utilized in the body to produce energy and are therefore widely used in infant formulas, nutritional drinks for athletes and in intravenous lipid infusions. Animal and human studies have shown that the fast rate of oxidation of medium chain free fatty acids leads to greater energy expenditure. Animal studies have also demonstrated that this greater energy expenditure results in less body weight gain and decreased size of fat depots after several months of consumption. Furthermore, both animal and human trials suggest a greater satiating effect of medium-chain triglycerides compared with long-chain triglycerides [3].  In fact, administration of medium-chain triglycerides in the form of coconut oil along with a saturated fat diet increased oxidation of long-chain fatty acids in the body [4].

Current understanding based on the effect of dietary lipid manipulation upon immune system function indicates that fatty acids are involved in the modulation of the immune response through different and complex pathways. The problem with many animal studies is that they use hydrogenated coconut oil. One study where non hydrogenated coconut oil was used showed that lipopolysaccharide-stimulated TNF-alpha production by macrophages decreased with increasing unsaturated fatty acid content of the diet [24]. There are anecdotal claims to the effect that using coconut oil improves the action of anti-HIV drugs. Many other unsubstantiated claims on the benefits of coconut products such as its anti-oxidant effects etc, are gaining popularity among health food enthusiasts.

Clearly more work both of an epidemiological and experimental nature need to be done to establish whether coconut fats are indeed associated with the atherogenesis, ischaemic heart disease and cerebro-vascular disease. Population studies should attempt to remove the possible effect of other confounding variables such as increased consumption of animal fats along with coconut, smoking, alcohol more particularly illicit brews that could contribute to the increasing incidence of ischaemic heart disease and cerebro-vascular disease in Sri Lanka. In the absence of convincing evidence both epidemiological and experimental against the continued use of coconut fats in relation to atherosclerosis and ischaemic heart disease, one has to ask whether the recommendation of the Asian Heart Assoication issued in 1996, “An intake of 400 g/day fruit, vegetables and legumes, mustard or soybean oil (25 g/day) instead of hydrogenated fat, coconut oil or butter in conjunction with moderate physical activity (1255 kJ/day), cessation of tobacco consumption and moderation of alcohol intake may be an effective package of remedies for prevention of coronary artery disease in Asians” is valid in toto[25]. Should we be encouraging the use of mustard, soybean, corn or sunflower oils all of which will need to be imported or emphasize the need for eliminating smoking, excessive use of alcohol, animal fats and other life-style changes instead?