Coconut water is the liquid inside a young coconut.
In the Solomon Islands the coconut is an essential part of their diet. The locals describe six distinct stages of the coconut as it develops. But to make it easy, let’s say a young coconut is about seven months old - that’s when they have the maximum amount of water relative to the coconut flesh. (By the way, coconut water is very different from coconut milk. Coconut milk is the emulsion of the freshly grated coconut combined with the coconut water.)
If the shell of the coconut has not been cracked, the coconut water inside is usually sterile - that is, free of bacteria and the like. So if its constituents are very similar to blood, could it be injected safely into people, to replace fluid loss?
Back in 1942, Dr Pradera in Havana, Cuba filtered coconut water and injected it into the veins of 12 children, at rates of around one-to-two litres per 24 hours. He reported no adverse reactions.
It is also claimed that, during World War Two, both the British in Sri Lanka and the Japanese in Sumatra regularly used coconut water when the standard intravenous fluids ran out. However, this is just anecdotal - it was never reported formally in the peer-reviewed medical literature.
In 1954, three doctors - Eisman, Lozano and Hager - combined the findings from their research. Between them, they had administered coconut water intravenously to 157 patients in Thailand, the USA and in Honduras - the majority, 136, being in Honduras. Out of 157 patients, 11 (that’s about 7 per cent) had reactions to the coconut water. These reactions included fever, itchiness, headache and tingling in the hands. Some unspecified number of patients also suffered aching sensations along the veins into which the coconut water was infused. This was thought to be due to the high potassium levels of coconut water.
And this brings us to the claim that coconut water is identical to blood plasma. It isn’t.
(There are two different “lots” of water in your body - the water inside your cells, and the water outside your cells.)
Human blood is about 55 per cent salty water, and about 45 per cent cells - overwhelmingly red blood cells with a tiny sprinkling of white blood cells and the like. The red blood cells give blood its red colour.
The salty water, called plasma, is a clear slightly yellowish liquid, with high levels of sodium, low levels of potassium, and trace amounts of other minerals. Genuine intravenous fluids are manufactured to have high sodium and low potassium.
Coconut water is not identical to the plasma. Instead, it is closer to the liquid inside the red blood cells, with low sodium and high potassium - the exact opposite. Everywhere in your body, when you compare the liquid inside your hundreds of trillions of cells with the liquid outside these cells, the levels of sodium and potassium are opposite. In fact, each cell has myriads of sodium and potassium pumps to shove the sodium outside, and the potassium inside.
Coconut water has about one-fortieth the sodium level of plasma, while the potassium level is about 10-15 times higher. But besides the high potassium, coconut water is also loaded with calcium and magnesium, which means it’s definitely not suitable for patients with kidney failure, severe burns, etc. Another problem is that it is much more acidic than human plasma. The bottom line is that coconut water is not identical to human plasma.
However, in an emergency, coconut water can be used. One case in the recent medical literature involved a man who had recently suffered a stroke - in the remote Solomon Islands. He had difficulty in swallowing, choked on both liquids and solids and repeatedly vomited them up. He was rehydrated with regular IV fluids, and fed via a tube directly into his stomach. After 36 days in hospital, he could no longer tolerate the feeding tube. Unfortunately, the hospital had run out of IV fluids, and because of its remoteness, would not get supplies for two days.