Coconut water: What’s all the hype?
VAIL CO, Colorado
Coconut water is showing up at gas stations, convenience stores and your local supermarket. If you shop at health food stores, they’ve been carrying the products for a long time. Celebrities are endorsing them, along with two major beverage companies that invested in coconut drinks in 2009: Coca-Cola with Zico and PepsiCo with Amacoco. They come in different flavors and with bits of coconut. But why the sudden upswing in interest and ubiquitousness? Are the health claims supported by research studies?
The scientific name for coconut water is Cocos nucifera. It is also known as coconut drink, coconut fruit water, coconut juice, coconut palm water, green coconut water, kabuaro water and young coconut water. It comes from immature, green coconuts and is the liquid found in the hollowed center. There can be up to one liter of fluid (composed of about 95 percent water) in an immature coconut. As the coconut matures, the amount of water declines and is replaced by coconut meat.
Coconut milk is different than coconut water. In the United States, coconut milk is sold in cans at the grocery store and may be more familiar to you as an ingredient in Indian and Thai curry dishes. It is about 50 percent fat and protein, and 50 percent water and made by grating mature coconut meat with water.
Coconut water contains electrolytes including potassium, sodium, magnesium and glucose. According to the U.S. Department of Agriculture, one cup of coconut water contains around 200 mg of potassium, 25 mg of sodium, 5 gm of natural sugar and 118 mg of chloride. Because of its natural electrolyte content, it is often used as a rehydrating solution. However, the amount of electrolytes in the water will vary based on the maturity of the coconut. Some experts do not consider it a true rehydration fluid due to this variation.
Coconut water is fat-free, cholesterol-free, caffeine-free and gluten-free. It is low in calories compared with other commercial drinks. It is lower in acidity than soft drinks and commercially available rehydration drinks, therefore less upsetting for your stomach and better for your teeth. It has a pH of 4.5-5.2 compared with a pH of 2.4-3.2 for soft drinks and pH 2.4-2.9 for Gatorade-type drinks. The sugar content is also significantly lower at an average of 1.1 gm/dl (for the unsweetened version) compared with 8 gm/dl for soft drinks.
So what are the health claims and are they supported by research studies? People have used coconut water for rehydration after athletic activity, to treat dehydration during an illness such as diarrhea, and for hypertension. It has even been used as an IV hydrating fluid, however there are no reliable clinical studies to support this. Claims for improved athletic performance, weight loss and heart health do not have adequate clinical studies to support them.
Coconut water has been studied at least since the mid-’60s as a rehydration fluid for severe diarrheal illnesses such as cholera and severe forms of gastroenteritis. When compared with other rehydration fluids known to be effective in these illnesses, coconut water had sufficient potassium and glucose, but was relatively deficient in sodium, chloride and bicarbonate. In areas of the world where coconuts are plentiful, the sterility and availability of coconut water, with the addition of table salt, can be as effective as an oral rehydration fluid when conventional rehydration fluids are not available.
For exercise induced dehydration, studies show it is comparable to sports drinks that contain carbohydrates and electrolytes, but it may not be more effective than drinking plain water. When compared with soft drink beverages such as Sprite and Coke, coconut water had more electrolytes, especially potassium. It was found that coconut water was more easily absorbed than soft drink beverages for hydration purposes. When used as a beverage for children and adults, there were no known safety concerns.
Drinking coconut water might lower systolic and diastolic blood pressure in people with hypertension, according to preliminary research studies. Theoretically, combining coconut water with antihypertensive drugs might cause additive blood pressure lowering effects and increase the risk of hypotension. However, there are no studies to support this yet.
Side effects and interactions
Some people may experience stomach upset or a feeling of fullness when coconut water is consumed as a rehydration fluid following exercise. However, this occurs at a lower rate when compared to drinking plain water or a carbohydrate-electrolyte rehydration fluid.
Combining coconut water with other herbs or supplements with blood pressure lowering effects theoretically might have additive effects and increase the risk of hypotension. Some of these herbs and supplements include andrographis, casein peptides, cat’s claw, coenzyme Q-10, fish oil, L-arginine, lyceum, stinging nettle and theanine.
Since coconut water is a significant source of potassium, drinking large amounts of coconut water might increase the risk of high potassium in people with kidney disease. If you’re a daily coconut water consumer, the current recommendation is to discontinue use at least 2 weeks before elective surgical procedures due to its theoretical blood pressure lowering effects.
The bottom line is coconut water may be an effective alternative for rehydration after exercise and mild forms of gastroenteritis. However, you can obtain the same electrolytes and minerals from other readily available sources, it’s just a matter of personal preference. If you’re thinking about replacing sports drinks with coconut water, be aware that sports drinks contain more sodium, while coconut water contains more potassium. If you sweat a lot during workouts, sodium is more important to replace than potassium.
Be sure to check the label for electrolyte and calorie content. Also check for any additives you probably don’t need. Flavored coconut water often has higher calories due to the addition of cane juice or other sugars. The addition of pulp or bits of coconut also increases calorie count. But if you’re just looking for a non-water alternative without the additional sugar, artificial colors and additives, coconut water is a better option than conventional sport drinks.
Dr. Susan Lan is a Preventive Medicine and Public Health specialist. She is co-owner of Apex Dental with her husband, Dr. Michael Harms. Visit Facebook.com/ApexDentalVail to learn more.
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