Letters to the Editor
View(s):Coconut oil: We need a well planned clinical trial
There I was relaxing with my copy of the Sunday Times on October 25 when I was struck by the headline, ‘Coconut is bad for your heart”! Now I wondered were scientists from Sri Lanka announcing the outcome of a well-planned, long-term double blind controlled clinical trial of coconut oil versus other edible vegetable oils especially palm oil that is freely available in the marketplace. Something I have been advocating for many years and the scientists and clinicians in Sri Lanka are quite capable of carrying out.
It was not to be. The article’s conclusions were based on what is termed a “meta-analysis”. This is said to be a scientific method of obtaining a sort of weighted average from the results of individual studies. The study quoted however, is not the first such meta-analysis published recently on coconut oil and ischaemic heart disease (IHD). Several such analyses have been published in the last few years and this is the second this year.
When it comes to meta-analyses looking at coconut oil and effects on blood lipids, LDL-cholesterol in particular, a publication by Eyers and colleagues in 2016, identified for inclusion in the review: eight clinical trials and 13 observational studies that examined the effect of coconut oil or coconut products on serum lipid profiles. They concluded “Coconut oil generally raised total and low-density lipoprotein cholesterol to a greater extent than cis unsaturated plant oils, but to a lesser extent than butter”. They also mentioned that “observational evidence suggests that consumption of coconut flesh or squeezed coconut in the context of traditional dietary patterns does not lead to adverse cardiovascular outcomes”.
A study that appeared in the prestigious journal Circulation in March 2020 was an important advance over this systematic review in that it included a total of 17 published trials. This meta-analysis found that coconut oil significantly increased plasma LDL cholesterol and high-density lipoprotein (HDL) cholesterol, but had little effect on Triglycerides. In an editorial in the same journal Frank Sachs of the T.H. Chan School of Public Health at Harvard came out with a scathing attack stating coconut oil may be viewed as one of the most deleterious cooking oils that increases risk for cardiovascular disease. The article stated further that “even in comparison with palm oil (another tropical oil with high saturated fat content), coconut oil increased LDL cholesterol”. Thus the most recently quoted study has little to add to such a categorical statement, if it were to be accepted as the last word on the whole question of IHD and serum lipids.
How much emphasis should be placed on LDL cholesterol levels when assessing IHD risk is open to debate. In a 2009 study, “Relationship of Insulin Resistance and Related Metabolic Variables to Coronary Artery Disease: A Mathematical Analysis” Diabetes Care 2009 Feb; 32(2): 361-366, the authors concluded “Mathematical modelling has demonstrated that correcting insulin resistance in young adults could prevent 42% of episodes of myocardial infarction. The study reported the next most important determinant of CVD is systolic hypertension, prevention of which would reduce myocardial infarctions by 36%, followed by low HDL-C (31%), high BMI (21%) and lastly LDL-cholesterol.
In an extensive review titled “Saturated Fats and Health: A Reassessment and Proposal for Food-Based Recommendations: JACC State-of-the-Art Review” the authors question the whole concept of the role of lipids in the development of IHD and they are certainly not the first to do so. They state that “Most recent meta-analyses of randomized trials and observational studies found no beneficial effects of reducing Short chain fatty acid intake on cardiovascular disease (CVD) and total mortality”. They also state that “It is also apparent that the health effects of foods cannot be predicted by their content in any nutrient group without considering the overall macronutrient distribution.” Their article goes on further to suggest that even genetics may play a role. Well before this article appeared others like Glen Lawrence in his 2013 publication have questioned the scientific basis the emphasis placed on plasma lipids especially LDL –cholesterol as the prime measure of risk of IHD.
Jayawardena and colleagues have drawn their conclusions based on their meta-analysis but what of the 2015 retrospective study by Athauda and colleagues which suggested that “The results do not provide evidence at the population level that consumption of coconut products increases mortality due to cardiovascular diseases”. This latter finding suggests that the steep rise in non-communicable disease in our country may be due to causes other than consumption of coconut. Per capita consumption of coconut has not increased, however, based on import data our population may be consuming more palm oil. That too an oil of poor quality.
It was only the other day, a grocery store owner in a town close to where I live, from where I purchase goods, was lamenting how some coconut oil millers sell coconut oil adulterated with cheaper imported crude palm oil as “coconut oil” in the loose form! Little or no research has been done on the types of so-called coconut oils available in the market even though the Coconut Development Authority advises consumers to purchase C.O. or V.C.O. with their certification. Various types are seen in the market e.g. “White oil” – this is neither an RBD oil (Refined bleached and deodorized) nor V.C.O. Another is what is commonly labelled as “Kurutu thel” extracted from the “refuse” sold by virgin oil millers. How good or bad quality wise are they?
The Sunday Times article also quotes the researchers stating that there is a very high incidence of hyperlipidemia and indirectly attempting to implicate it to coconut oil consumption. However, studies from the same group have shown that Sri Lankans consume a disproportionately high percentage of carbohydrate in their diet. A disproportionately high value of around 72% of the diet, is carbohydrate compared to just 19% fat and 9% protein. Studies seem to show a complex and predominantly unfavourable effect of increased intake of highly processed carbohydrate on lipid profile. This may have implications for metabolic syndrome, diabetes and IHD. Thus blaming coconut oil for the lipid profile and the increase in IHD. may be called into question.
There is then the question of lifestyle changes. To what extent are these contributing? Are they taken into account when looking at all the data? Living in a village, I know how life has changed. Take, for instance, paddy farming. We have just finished sowing the paddy. The tilling was done by a big four-wheel tractor driven by a man who rode a motorcycle up to the paddy field. The bunds “niyaras” were shaped and prepared by backhoe excavator –no “crocodile” mammoties in sight, grass on top of the niyaras will be cut with brush cutters and when it comes to harvesting a “boothaaya” or combined harvester will be hired to do the needful and finally all the farmer has to do is to carry the bags of paddy to the waiting tractor or truck. So where is all the physical activity that was associated with paddy cultivation! In the case of women, there is no threshing of paddy, no grinding curry stuffs on a grinding stone, no looking around for firewood. Now only the TV to view for hours on end!
I would like to suggest our researchers such as the very capable and competent team at Colombo University, carry out a well-designed controlled clinical trial, without quoting the two small trials conducted 20 or more years back, however good they may have been. It is unfortunate, to say the least that attempts to conduct well planned good quality clinical research at our universities such as at Kelaniya, have received inconsistent support from Government institutions such as the Coconut Research Institute.
I agree totally with the writer that research on coconut and health is of high national importance. Coconut sustains a vast majority of our population as a food supplement providing much of the calories from fat, is the third major source of foreign exchange from agri exports and provides employment for over hundreds of thousands of people. Thus it is incumbent on the government to provide the funding. Such funding should be on a long term basis not stop-start as happened in the past. If not as coconut growers, we have one of two choices – grow coconuts but use only coconut flesh and coconut milk in our diet. This, then begs the question, how thick should the milk be? It would call for more research and more money. That has to come from the Government. No pharma backing for such endeavours!
What oil should we use for frying – Palm oil? Then we may have to think of uprooting our coconut and growing oil palm and the President may have to rescind his decision to halt expansion of oil palm plantations. If not, should we be using a “healthy” polyunsaturated oil, importing it at great cost and selling it to the economically disadvantaged at subsidised prices? I believe there already is some scanty data to suggest urban dwellers are switching to oils other than coconut.
Dr. Asoka S. Dissanayake
(Former Professor of Physiology, Faculty of Medicine, Univ. of Kelaniya, Visiting Fellow and Member of Coconut Research Caucus, Wayamba University of Sri Lanka, Co-Chair now defunct C.R.I. Research Group on Coconut and Health (2011-2015)
A picture that might be of interest to both Ananda and Nalanda Colleges
Thank you on behalf of the two iconic schools Ananda and Nalanda for the coverage given in the Sunday Times Plus of November 1.
I am an old Nalandian, 1948-50, and I taught at Ananda from 1955-60. My father, D.T. Devendra was one of the original staff members of Nalanda Vidyalaya (which was its name even in my time). He went on to be Principal of Buddhist secondary schools and later of a Government Central College before he became Assistant Archaeological Commissioner and Deputy Editor of the Buddhist Encyclopaedia.
I write this only to post a photograph (seen below) of the Nalanda staff in 1928. The names were given to me by my centenarian uncle, the late Dr. D.W. Devendra, (1916-2017) who was a schoolboy in those days. I personally knew the following and those marked with an asterisk were on the staff in my time: Miss Alwis*, W.E.Fernando, D.F.Wijesinghe*, D.T. Devendra (my father), M.E. Dharmadasa, P.T. de Silva*, S.A. Wijayatilaka (my Principal in Ananda days), D.C. Lawris (my Principal when I was at school)*, W.D.E. Perera*, and V.I. Perera*.
If the Principal or any of the Old Boys’ Associations are interested, I can donate the restored original of the photo.
Somasiri Devendra
Via email
MEMBERS OF THE NALANDA
VIDYALAYA STAFF 1927-28
Front row (L-R)
1. Miss Roslyn
2. J.N.Jinendradasa
3. Miss Alwis
4. W.E.Fernando (Headmaster)
5. G.K.W.Perera (Principal)
6. C.E.Strange
7. Miss Kumarasingha
8. D.S.Gunasekera
9. Miss Suwaris
Middle row
1. C.E.P.Kumarasingha ?
2. ………..
3. D.F.Wijesingha
4. D.T.Devendra
5. ………..
6. M.E.Dharmadasa
7. ………..
8. P.T.de Silva
9. S.A.Wijayatilaka
10. D.C.Lawris,
11. A.Ariya Sumithtra
Back row Only three persons can be identified:
3. W.D.E.Perera
4. V.I.Perera
5. M.A.Mapalagama.
There are others in the group who should be there but, alas, cannot be identified. Among them are H. D.A.Wijesinghe, S.Jayasingha, M.T.Pieris, T.Kandasamy, D.M.Hettiarachchi