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Coconut  water: Is it good for you?

Coconut woman is calling out, and everyday you can hear her shout,

"Get you coconut water  it’s good for your daughter
Coco got a lot of iron, make you strong like a lion"

Words from a Harry Belafonte song

Two recent articles, one a front page news item appearing in The Daily News of 2nd March titled "Coconut water improves HDL" and the other in the Island of 8th March titled "Sugary soft drinks lead to diabetes, research finds" prompted me to write this article. In it, as a medical academic turned coconut grower I will endeavour to discuss whether coconut water has any health benefits and to discuss the economics of growing coconut for producing coconut water.

King coconuts or young green coconuts "Kurumba" have to be harvested when the nuts are about 6 months old if they are to provide coconut water that can be used as a drink whereas to harvest the coconut kernel, mature nuts are plucked once a year. As the coconut matures, the "water" is gradually replaced by the coconut kernel (also called meat) and air. King coconuts are mostly plucked when immature. Once they have matured the little kernel in them can be converted to oil but the market for such oil is very limited and hence many mature king coconuts are left to fall off and decay.

The chemical composition of coconut water (CW) is affected by several factors. Published studies have shown that CW from different coconut varieties contains varying concentrations of the main constituents. The chemical composition of CW also changes as the nut matures. Soil and environmental conditions also affect the chemical profile of CW. The most comprehensive review of the composition, uses and possible medicinal applications for CW comes, of all places, from Singapore where today coconut is grown for landscaping and not as an agricultural crop (Jean W.H. Wong & colleagues published in Molecules 2009, 14, 5144-5164 ). Sadly in it, not a single paper authored by a Sri Lankan is cited. This paper publishes a detailed account of the various constituents found in coconut water. The data quoted from several sources are for green young and as well as mature coconuts. No mention is made of King Coconut water (KCW). Coconut water is made up of about 95% water. The energy value is low at between about 16 to 19 calories per 100g. Coconut water has relatively high amounts of potassium, calcium and magnesium but is comparatively deficient in sodium, chloride and bicarbonate. The biochemical profile of coconut water varies as nuts mature, resulting in reductions in the concentration of potassium, calcium, magnesium, chloride and osmolarity.

CW has been a thirst quencher and a refreshing drink over the ages. According to the Wikipedia web site, CW has long been a popular drink in the tropics, especially in Southeast Asia, the Pacific Islands like Hawaii and the Caribbean, where it is available fresh, canned or bottled. In Brazil, coconut water is the second best-selling juice after orange juice. While it is still consumed in our village areas and KCW is an essential component of the Buddhist mid day ‘dane’, in urban areas it has been replaced by the bottled sugary soft drinks and sweetened fruit drinks. In fact, I believe that the youth think it is fashionable to drink a bottle of Coke rather than a have a Thambili! There also seems to be a seasonal variation in the demand for CW or KCW. I have found that during the rainy season it is difficult to sell king coconuts. In many countries CW is also marketed as a sports drink because of its high potassium and mineral content. One cup-full of coconut water contains more electrolytes than most sports drinks and has more potassium than a banana. So, should we be serving CW in addition to "Anamalu or Ambung" at the next Cricket World cup? Interestingly, a booklet in Sinhala published by the Coconut Research Institute (CRI) titled "coconut based products" mentions the methods for producing three coconut water based products. They all refer to the uses for CW from mature nuts. The first is for the manufacture of coconut vinegar a long held practice. The second refers to bottling CW for sale as a sweetened drink (by adding 60g of sugar to a litre of mature CW along with preservatives etc.) This will only add to our diabetic population. The third is for the manufacture of ‘wine’ from CW. This goes against the ‘Mathata Thitha’ policy! The CRI has not paid any attention to KCW or CW from green nuts.

Coconut water is said to be isotonic with plasma and if the covering husk is not damaged is sterile. Hence it can be infused safely directly into the blood stream. The idea for its use as an intravenous rehydration fluid was proposed, I believe, by Prof. K. Rajasuriya in the 1950s. A 1979 study from New Zealand found that compared to oral rehydration fluids known to be effective in cholera, coconut water was found to have adequate potassium and glucose content, but was relatively deficient in sodium, chloride and bicarbonate. The addition of table salt to the coconut water was suggested to compensate for the sodium and chloride deficiency. The study concluded that in areas of the world where coconuts are plentiful, the advantages of sterility, availability and acceptability make coconut water theoretically feasible for the oral rehydration of patients with severe gastroenteritis when conventional fluids are unavailable. Other authors have questioned the wisdom of using coconut water as an oral rehydration solution given the great variation in concentration of sodium, glucose and tonicity. Then there is the question as to whether a litre of King Coconut water which, in my opinion, requires at least one and a half coconuts is cheaper than a packet of ‘Jeevani’? However, when one considers the fact that The Island report claimed that 130,000 new cases of diabetes may be attributed to consumption of sweetened drinks, drinking coconut water as a thirst quencher is to be recommended. Today, the cost of a king coconut from a road side stall may be around Rs. 20 to 30 compared to the cost of a bottle of a "spritely" drink (40 calories per 100 ml or double that of CW) at around Rs.70 for half that amount. Merely having young coconuts for sale by the wayside will not suffice. There is the need to develop proper packaging and marketing strategies based on consumer behaviour (seasonal demand and how it impacts on the variation in nut production etc.) in order to compete successfully with the large multinationals that produce the soft drinks. There is also the question of waste disposal that will need to be addressed. What does one do with the leftover husks? Though I could not find any hard data, in young coconuts the fibre content of the husk is low (one can cut through the husk quite easily) and thus cannot be turned in to coir products. At present they only contribute towards mosquito breeding unless disposed of properly.

What of its iron content that Belafonte sang about? The iron content is rather low at around 0.25 mg/100g compared to the amount of calcium or magnesium around 20mg/100g or more. Furthermore, there is no evidence that CW increases muscle mass or strength as claimed in the song. Another part of the song says "coconut water and rice curry can take any sweet man away". I do know of households where the CW is not thrown away but is added to curries possibly to improve the taste. Maybe some of the readers can contribute CW based recipes that will enable housewives to keep their husbands happy!

Coconut water is traditionally used as a growth supplement in plant tissue-culture / micro propagation. This may be attributable to the phytohormones (plant hormones) present in coconut water. There is increasing scientific evidence that supports a possible role for coconut water in health and medicinal applications. One of the groups of phytohormones found in coconut water is the cytokinins. To quote from Wong’s paper, "Significant advances have made in understanding the biological functions of the various cytokinins in both plant and human systems. The potential anti-cancer properties of specific cytokinins could bring encouraging and novel perspectives in finding cures for the different types of cancers. Kinetin has been known to retard senescence in plants and it has been suggested that it has anti-ageing and anti cancer effects."

What of its cholesterol lowering effect? A group very active in the area of research into beneficial effects of CW, the Coconut Research Unit in the Department of Biochemistry, University of Kerala, has reported that that both tender and mature coconut water feeding significantly reduced blood lipids in cholesterol fed rats. In a 2008 study they reported that coconut water had lipid lowering effect similar to the commonly used cholesterol lowering drug lovastatin in rats fed fat-cholesterol enriched diet. It is this study that was probably quoted in the Indian Coconut Journal referred to in the DN article. The same group showed that CW may offer protection against myocardial infarction (heart attacks) in rats. It has been suggested that CW can help in the control of high blood pressure. The Kerala group has also claimed that CW can protect against chemically induced liver damage in rats. Claims have been made for its efficacy in the treatment of kidney stones, urinary infections and as antidote for mineral poisoning. However, much more work involving both animal and human studies need to be done before we can extrapolate from a few rat experiments to man to give credence to the myriad of claims.

Let me turn to the question of economic viability of growing coconut to produce green coconuts. The writer of the DN article claims that there is likely to be an excess of nuts produced in Sri Lanka. Available data do not support this contention. The predicted yield for 2010 is 2791 million nuts. This is 2.4% lower than that predicted for 2009 (data from Coconut Research Institute web site). Of the annual production, about two third is consumed for cooking and only about one third is available for value addition. I cannot understand how the writer came to the conclusion that there would be a significant excess of nuts! Even if we were to produce well above the total current annual production which has averaged about 2.5 to 3.0 billion nuts per year for the last 5 or more years, would it be profitable for the grower to sell the young nuts and make a reasonable profit? On the one hand, I believe that producing nuts for drinking purposes is not going to significantly reduce the labour inputs for weeding, fertilizing and gathering the nuts and there is no real possibility of reducing fertilizer inputs. On the other, the green nuts have to be plucked by hand by climbing the tree and lowering the bunch on a rope so as to prevent them from being damaged. This will cost around Rs. 35-50 per tree per pluck as compared to plucking mature nuts using bamboo poles which today works out at about Rs. 5-6 per tree per pluck. Thus plucking young nuts will add a further Rs. 1.50 to 2 to the cost of production. Today it costs us between Rs. 11 and 12 to produce a mature nut and if tree climbers are used it will increase to about Rs. 14. We sell our king coconuts at around Rs. 10 per nut, the farm gate price for green nuts will definitely be not more than 50% of that for mature nuts i.e. Rs 10 compared to Rs. 20 at current prices. Thus to me it seems that growing nuts mainly to provide the coconut water is not a viable proposition. The "bad name" that coconut oil had in the West is slowly dissipating and what the State should be doing is to encourage the production of higher value virgin coconut oil, look for more markets for our coconut oil and desiccated coconut and increase the demand for our mature coconut. I have made a plea before in my article titled, "The Coconut Fat controversy. A plea for more research and a medical consensus" published in The Island of May 20, 2006 for the State to encourage research into the medicinal applications of coconut. I have yet to learn of any support being given for such research. Quality research will not only bring kudos to Sri Lanka but open new avenues for marketing our coconut products. This, I am sure would be more beneficial to our economy than for instance opening a coconut auction in Gampola which is not a coconut growing area but the current minister’s home borough! g

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