Coconut water burst onto the scene – and into the fridge – a couple of years ago, touted as an all-round miracle drink. But is there any science to back up the health claims? Nutritionist Jo Lewin explains…
What is coconut water?
Coconut water is the clear liquid found inside green, immature coconuts. Young coconuts are favoured for their water as it is tastier, plentiful in volume and easier to access by chopping the top off the softer shell. More mature coconuts have a harder husk and less water inside because it gradually solidifies to form the flesh.
Different varieties of coconut yield slightly different-tasting water depending on where they are grown.
In taste and nutrition, coconut water is different to coconut milk and coconut oil, both of which are made from the flesh of the coconut. Read more about the health benefits of coconut milk and find out how healthy coconut oil really is.
What are the nutritional benefits of coconut water?
In 100ml of fresh coconut water extracted from the nut you’d expect about 2.7mg of sugar, but be aware that the branded versions on supermarket shelves are likely to be higher in sugar, ranging from 3g to 6g (about 1 tsp) per 100ml. So, in a 330ml serving of branded coconut water, there may be over 15g of sugar (roughly 3 tsps). It does have less sugar and fewer calories compared to many juices, soft drinks and sports drinks but still the sugars are ‘free’, which means they’re not bound to fibre and will be quickly absorbed into the bloodstream.
Coconut water also contains some potassium, which is essential for heart health and good skeletal and muscular function. Approximately 185-207mg of potassium is contained within a 100ml serving. However, in comparison to an average banana (330mg) or potato (715mg), it is not a large amount. There are plenty of potassium-rich foods that are likely to be cheaper and more locally sourced than coconut water.
What are some of the health claims made about coconut water?
Can coconut water help with weight loss?
Coconut water is a relatively low-calorie drink compared to sugary fizzy drinks or juices, but it is not calorie-free like plain water. The claims that drinking coconut water increases metabolism are not yet backed up by research. As the NHS notes, there is very little evidence to support the idea that certain foods and drinks can have a significant effect on your metabolism.
Can coconut water boost athletic performance?
It has been suggested that consuming coconut water after exercise improves endurance and athletic performance. This is because it contains carbohydrate in the form of glucose (a simple sugar) and the electrolytes sodium and potassium – the crucial components in commercial sports drinks. One study found that coconut water helped to rehydrate in a similar way to a carbohydrate-electrolyte sports drink, but didn’t have any significant impact on exercise performance. Another small study found no significant difference to athletic performance when drinking coconut water in comparison to plain water. Therefore there is not enough evidence to support the claim that coconut water can improve athletic performance any more than drinking plain water during exercise.
Read more about how to stay hydrated when exercising.
Can coconut water lower blood pressure?
Coconut water is claimed to be a heart healthy drink because of its potassium content. Potassium has been shown to lower blood pressure in people with hypertension (high blood pressure) by counteracting the effects of sodium that can cause blood pressure to rise.
However, there are plenty of fruits and vegetables that are high in potassium which also contain fibre, vitamins and minerals. Potassium-rich foods include bananas, apricots, green leafy vegetables and citrus fruits such as oranges. While potassium is beneficial for lowering blood pressure, guzzling lots of coconut water is not the best source; a balanced and varied diet high in fruits and vegetables will suffice.
Find out more about how diet and lifestyle can affect blood pressure.
Can coconut water help to lower cholesterol?
Some small studies carried out on rats suggest that drinking coconut water might lower cholesterol. However, the evidence in humans is incomplete, and even the studies on rats were carried out on a small sample size. Other lifestyle factors such as eating a balanced diet, maintaining a healthy weight, stopping smoking and increasing activity are more likely to have a beneficial impact on your cholesterol levels.
Discover more about how diet and lifestyle can affect cholesterol levels.
How do I choose the healthiest coconut water?
Coconut water is a relatively low-calorie drink with far less sugar compared to many soft or fizzy drinks. Natural coconut water that has been harvested straight from the nut is the best choice. Canned and cartoned versions have generally been processed by heat treatment or pasteurisation to extend their shelf life. Always check the label and look for pure coconut water. Avoid flavoured varietes as they tend to have a higher sugar content and so will be higher in calories too.
When reading a label, look per 100g/ml. For a product to be low-sugar, it should be less than 2.5g per 100g/ml. For it to be low-salt, under 0.3g or 0.1g of sodium is ideal.
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This article was last updated on 8 August 2018 by Kerry Torrens.
Kerry Torrens is a qualified Nutritionist (MBANT) with a post graduate diploma in Personalised Nutrition & Nutritional Therapy. She is a member of the British Association for Nutrition and Lifestyle Medicine (BANT) and a member of the Guild of Food Writers. Over the last 15 years she has been a contributing author to a number of nutritional and cookery publications including BBC Good Food.
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