Coconut water is one of the most refreshing drinks and, in its pure state, provides many unusual health benefits. Coconut water is used in traditional medicine systems in countries such as Sri Lanka, Jamaica and Brazil to promote digestion, treat urinary infections, heart problems, arthritis, kidney stones, dry eyes and hiccups, as well as to improve male fertility and assist childbirth.
Modern research shows that coconut water is more quenching than plain water for rehydration following exercise and, as a bonus, it tastes better too. Coconut water can lower blood pressure through several different actions, reduce inflammation and has antibacterial and antiviral properties to support immune function.
What’s more, as it represents the ‘life’ fluid of an actively growing fruit, coconut water contains growth regulators (auxins) and cytokinin plant hormones that – in the laboratory at least – appear to offer anti-aging and anti-cancer effects on human cells, too.
Not all coconut waters are created equal, however. Some manufacturers add sugar to their coconut water which will wipe out the health advantages, so check labels carefully. As long as you choose a coconut water with no added sugar, it is naturally low in calories, virtually fat-free, and is a good all-round healthy choice as a post-exercise drink. It also tastes delicious.
Nutritional benefits of coconut water
An immature green coconut contains around 750ml pure coconut water, which naturally forms as a clear, sterile liquid inside the shell. It is an excellent source of electrolytes and is classed as isotonic, meaning that its dissolved substances have the same osmotic pressure as body fluids.
Coconut water is a great source of potassium, containing around 15 times more of this vital electrolyte than most sports and energy drinks (250mg/100g versus 12.5mg/100ml).
Coconut water also supplies useful amounts of magnesium (25mg/100g), calcium (24mg/100ml), phosphorous (20mg/100ml) and manganese (142mcg/100ml).
It is relatively low in sodium (105mg/100ml) which is not a bad thing for most people, and naturally provides between 1g and 3g sugar per 100ml, depending on the maturity of the coconuts from which it is derived.
Small amounts of vitamin C (2.4mg/100ml), folate (30mcg/100ml) and other B vitamins are also present – although not enough to get excited about.
Rehydration with coconut water after exercise
Where coconut water really comes into its own is as a tasty, refreshing, sports drink. One study compared the effectiveness of four different rehydration drinks on whole body rehydration in ten healthy males who agreed to run for 90 minutes in a temperature of 32 degrees C, and a relative humidity 53%. They lost an incredible 3% of body weight as sweat and must have felt rubbish yet, astonishingly, each volunteered to do this on four separate occasions, at least 2 weeks apart. I hope they were getting paid!
Following each bout of intensive exercise, the exhausted volunteers drank one of the test fluids (selected in random order) over a two-hour period: either plain water, a sports drink, or two types of fresh young coconut water (one of which was sodium enriched).
A bevy of blood, respiratory and urine tests were then performed and, within two hours of drinking each type of fluid, the extent of rehydration was:
- 58% with plain water
- 68% with the commercial glucose/electrolyte sports drink
- 65% and 69% with the two different types of coconut water.
Researchers concluded that coconut water was more effective than pure water for rehydration after exercise-induced dehydration, and just as good as the commercial sports drink. The coconut water tasted better, however, and was easier and more pleasant to drink in the large volumes needed.
Overall, the coconut water was better tolerated and did not cause nausea, fullness or stomach upset. Although the sodium-enriched coconut water performed best, most people already obtain excess sodium in their diet and the amount of sodium naturally present within pure coconut water is likely to be sufficient for rehydration after typical levels of exercise.
Rehydration with coconut water during illness
In parts of the world where electrolyte solutions aren’t readily available for oral rehydration following bouts of vomiting and diarrhoea, coconut water is often used as a medicine to replace lost fluids and electrolytes. Within the coconut, it is sterile and ready-packaged for transportation, and has even been used during cholera epidemics. Coconut water is credited with saving thousands of lives – especially children in underdeveloped countries.
While the amount of sugar in coconut water (1.1 gm/100ml) is less than in alternative rehydrating fluids, such as cola (8.7 gm/100ml), it contains sufficient glucose and potassium for use even in people with cholera, although it is relatively deficient in sodium, chloride and bicarbonate. In fact, coconut water has even been infused intravenously to save lives when blood or saline was unavailable – not something I recommend you try at home!
In well-nourished children with mild diarrhoea, you can certainly offer coconut water, together with early refeeding, as a home glucose-electrolyte rehydration drink.
Drinking coconut water can lower your blood pressure
Researchers have found that drinking coconut water every day, for two weeks, results in a significantly lower blood pressure than in a similar group of people who drank plain bottled water. Significant systolic blood pressure reductions were seen in 71% of those drinking coconut water. Significant reductions in diastolic blood pressure were seen in 29% of those coconut water.
According to one published review, ‘The evidence is so convincing that the FDA allows coconut water to carry the claim that it may reduce the risk of high blood pressure and stroke.’ I’ve not been able to verify this specifically for coconut water, but the FDA do allow foods that provide at least 350mg potassium, and no more than 140mg sodium, per usual serving, to carry an authorised claim that: ‘Diets containing foods that are good sources of potassium and low in sodium may reduce the risk of high blood pressure and stroke.’
There are several different ways in which coconut water can lower blood pressure.
- Potassium helps to flush sodium and excess fluid through the kidneys, while calcium and magnesium also have blood pressure lowering actions.
- Coconut water contains low levels of medium chain fatty acids that have beneficial effects on the liver, reducing the production of inflammatory chemicals that are linked with hypertension.
- It is also a good source of the amino acid, L-arginine (300 mg/L) which is involved in the production of nitric oxide, which is a powerful blood vessel dilator known to lower blood pressure.
Coconut water can save lost teeth!
If a tooth is knocked out, traditional advice is to store it in pasteurised whole milk while waiting to have it re-implanted as soon as possible. A recent study involving 50 freshly extracted teeth compared tooth survival in milk, a balanced salt solution, or coconut water. The results suggested that significantly more cells survived for 8 hours in the teeth stored in coconut water than in the milk or saline.
Other health benefits
Ongoing research suggests that coconut water has protective effects on brain cells deprived of oestrogen, which might make it of benefit during the menopause, which it can improve heart failure and glucose control to protect against diabetes, and that growth factors in coconut water, such as kinetin, can prevent unwanted blood clots and aid wound healing. There is not yet enough evidence to verify these initial findings, however.
Coconut water tastes good, is more rehydrating than plain water, and is an excellent source of potassium to help improve blood pressure control. What’s not to like? We get through litres of coconut water at home – but do check labels for large amounts of added sugar. You definitely want to avoid those!
Make Healthy Lollies From Coconut Water And Fresh Tropical Fruit
Simply combine tropical fruit, coconut water, and a little agave nectar (I suggest using stevia instead) to make these tasty ice pops.