Half truth and untruth about coconut

Dr. Mahinda de Silva

REPLY: I refer to the letter (Daily News, 4.3.06) by Dr. D.P. Atukorale titled 'Coconut Oil used for over a thousand years'. What is implied by this cliche is untrue as what was said and done for, or a thousand years is not necessarily right or beneficial.

Evidence that animal fat, in the form of beef, pork, chicken and eggs, consumed by humans since time immemorial, when homo sapiens was a hunter, was shown to raise blood cholesterol and have detrimental effects on the heart and blood vessels (cardiovascular system) began to be evident only from the 1960s onwards. Tobacco smoking which to Europe by Sir Walter Raleigh, 500 years ago was shown to be detrimental to one's health only over the past 50 years.

There is little doubt that coconut in all its forms is specially suited to the Sri Lankan cuisine, and because it is a saturated and is chemically unreactive it is stable, can be heated without untoward effect as for frying .

Coconut contains mainly medium chain fatty acids (MCFAs) and is easily digested, absorbed and utilised by the body.

It is therefore useful in acute illnesses and in digestive diseases as a source of energy. However it is a saturated fat and has been shown in studies the world over to raise. Total cholesterol and the bad LDL cholesterol more than the good HDL cholesterol. Though in acute situations and in digestive diseases, its effect on blood lipids, as a constituent of long term diet is the same as any saturated coconut oil that contain mainly medium chain atty acids (MCA's) and is easily digested and utilised.

Polyunsaturated oils are more reactive to heat, light moisture and exposure to air. They therefor unstable with a short shelf life and when heated produce substances which are detrimental to health and its nutritional value.

They lower total cholesterol by lowering both good and bad cholesterol. Prof. Shanti Mendis, demonstrated both these effects in a small experimental study in Sri Lanka (1989), on young male participants. She showed that after consuming coconut oil, the LDL/HDL (bad to good) ratio had increased. When coconut oil is replaced by corn oil, TC, LDL and HDL all decreased and the LDL/HDL increased.

While a case for the use of coconut oil in the Sri Lankan diet cannot be disputed, its unlimited use, on the pretext that it has a neutral effect on serum lipids, cannot be entertained in the current state of knowledge. On the otherhand a diet which has been used for a thousand years by some Mediterenean cultures has shown to have a beneficial effect on all blood lipids and also other parameters of CV health such as blood pressure, antioxidant effect on LDL, anti-clotting, and resistance to insulin. This diet contains olive oil as its major source of fat.

However, it can be recommended only to those whom Dr. DPA categorises as "some who have migrated to the urban areas and want to imitate the rich," because of its expense.

Therefore it is prudent to supplement the use of coconut oil with other polyunsaturated and monounsaturated oils as far as possible.

In his zeal to promote, coconut consumption, Dr. DPA in his letter has found it necessary to misrepresent the findings and conclusions of researchers, misinterpret basic statistics, and quote obviously biased sources, in a rather simple minded fashion, and so, mislead a trusting public.

He quotes an article, (Atukorale T.M.S. and Jayawardane MIFB, Ceylon Medical Journal, 1991:31; 9-10). In this article Atukorale and Jayawardana (A&J) study the relationship between serum lipids and food habits in 168 subjects in urban, suburban areas and two rural areas in Kalutara and Kurunegala. He totally misrepresents their findings.

To summarise A&J's findings, they concluded that in urban, suburban and the rural areas of Kalutara (where coconut consumption in all its forms was highest, and occupational physical activity moderate (brick laying), there was no difference in blood lipid levels. In the Kalutara rural area where coconut consumption was high, but coconut consumption as oil was very low, and there was high occupational physical activity (agricultural work), the lipid levels were best.

First let me quote an easily understood passages from this article, which will make this clear to readers.

I quote A&J:

"The Total Cholesterol to/HDL (good) cholesterol, and LDL (bad) cholesterol to HDL cholesterol ratios were significantly lower in Kurunegala area in subjects who were agricultural workers with a high degree of physical activity, despite a higher consumption of coconut as saturated fat. It is possible that the hypercholesteroloemic (raising) effect of the saturated fat was mitigated by the high fibre content of their diets".

"The energy supplied by coconut oil was significantly lower (p less than 0.001) among subjects in this area" than in urban, suburban and rural Kalutara area".

"Coconut fat contains high levels of lauric (47 per cent) myristic (17 per cent) and palmitic (9 per cent). However, unlike coconut milk or oil, the kernel used in food contains a high proportion of fibre, reducing the effect of saturated fats, therefore the cholesterol raising effect of saturated fat could be reduced by the complex polysaccharides."

It is interesting that the higher lipid levels were similar in urban areas suburban areas and rural areas in Kalutara. In Kalutara subjects were "engaged in bricklaying and occupations involving moderate physical activity."

Now to DPA's distortions and what A & J actually wrote. Dr. DPA says, I quote from his letter: "It has been proved by researchers like Professor Sunethra Atukorale (of Colombo Medical Faculty) and Jayawardena (Atukorale T. M. S. and Jayawardane MIFB, Ceylon Medical Journal, 1991:31;9-10 that:

1) Intake of coconut oil is significantly higher in rural areas of Sri Lanka than in urban areas (DPA Quote from authors, (A&J): "Although the energy supplied by coconut milk and coconut kernel was highest in rural area (Kurunegala), the energy supplied by coconut oil was significantly lower (p 0. 001) among subjects in this area" than in urban, suburban and rural Kalutara area.

2) People in rural areas have lower blood levels of cholesterol and better lipid profiles than those in urban areas. (DPA)

A&J's data indicate that in the Kalutara rural area where coconut consumption in all its forms was the highest, the ratios of bad to good cholesterol were also the highest.

The proportion of coconut fat to total fat consumed was also higher in Kalutara area, which may even suggest that coconut fat raises serum lipid levels more than other fats.

3) Adolescent school boys in rural areas have better lipid profiles. (DPA)

There is no reference to adolescent schoolboys by A&J

c) Ratio of total cholesterol (T.C.) to serum HDL (good) cholesterol level (T.C./HDL) is lower among people in rural areas than those in urban areas hich is false.

A&J: There was no difference in the ratio of TC/HDL between urban suburban and the Kalutara rural area.

A&J; "Data on comparison of prevalence of CHD in rural and urban areas not available." He states above that researchers like Prof. Sunethra..... have proven that..."One reference is a symposium on coconut oil in human nutrition, 27 March, Coconut Development Board, Kochik, India, and the other by Prof. Shanti Mendis.

The former source needs no comment, while the latter reference (which I was unable to obtain), is by the same individual whose study (1989) I referred to earlier.

In the Indian State of Kerala, there is a high rate of coronary disease. The following is the postscript from an exhaustive review by Dr. C.R. Soman, who is the Chairman, Helath Action by People, Trivandrum, which will give a more balanced and insightful view of the place of coconut in this situation (http://www.kerala.gov.in/keralacallmay04/p15-17.pdf.) Google will have the whole article in HTML format. The whole article is certainly worth reading.

"A prudent diet which maintains cholesterol in the desirable range shall provide one third of fat energy in the form of saturated fatty acids, another third from mono-unsaturated fatty acids and the remaining third from poly-unsaturated fatty acids. All international recommendations point to this fact.

In the Kerala diet however, over 60 per cent of fat energy will be from saturated fat. Despite some favourable contribution from fish, the diet of the Keralite is heavily atherogenic. The only practical approach is to moderate the consumption of coconut and coconut oil. Moderation is the key, not total abstinence. Talking about coconuts is a sensitive issue.

The emotional bonds that a Malayalee holds for the coconut palm and all its products are so strong that he believes that the nature's gift can do no harm. Examples of our ancestors living long on diets rich in coconut often cited Naturopathy proponents advocate coconut meat and milk as remedies.

Recent studies have been cited as evidence that coconut oil does no harm. Such claims are made in popular newspapers and meetings sponsored by the Coconut Board and similar agencies. No evidence has been published suggesting the beneficial effects of coconut consumption. On the contrary, thousands of publications in the 60s and 70s have clearly demonstrated the cholesterol raising property of coconut oil.

People of Kerala are in a dilemma. Whom shall they believe? In a land in which every one claims to be an expert in every other's field, informed choice is difficult. Scientific knowledge is often subordinated to political pragmatism. The medical communities of Kerala privately agree that saturated fats are harmful, but many hesitate to air their private convictions in public. I can only say one thing.

It would be prudent of Keralites to limit the intake of coconut and coconut oil to minimise potential threat from raised serum cholesterol. The other choice is to believe the quacks, continue to use coconut and oil with gay abandon and swallow "stating pills" costing ten rupees everyday throughout your life to keep cholesterol in check.

The author is the Chairman, Helath Action by People, Trivandrum.