Water Chestnuts

Water chestnuts, sometimes known as Chinese water chestnuts, are small, white vegetables with a crunchy texture and a fresh, mild taste similar to apples. They’re often used in Asian cooking, specifically Chinese cuisine. In the West, most people who use the small, round “corms” (the short and slightly bulbous stem bases that grow underwater) in their culinary endeavors will either buy them whole or sliced in a can.

Water chestnuts are perennials from a plant family called sedge, a type of marshy grass with the edible part at the bottom appearing very much like a real chestnut in shape and color. They come from the Cyperaceae family, and despite their name, aren’t actually nuts — they’re an aquatic vegetable.

While they are somewhat subdued into blandness when canned, fresh water chestnuts are sweeter, firmer and crunchier. Usually available in specialty groceries or supermarkets, they should be washed thoroughly and peeled with a sharp knife, especially if they’re being eaten raw. Immersing them in water with a few drops of lemon juice keeps them from turning brown prior to steaming or sautéing. Once peeled, they’ll only remain fresh in water for a few days. It’s best to store water chestnuts in the refrigerator.

Because water chestnuts are so popular in tropical countries like Thailand, Vietnam, China and Japan, as well as Australia, they are often rotated with rice in paddy fields. Whether thinly sliced in soups, minced as an egg roll ingredient or sautéed in a stir-fry with snow peas, coconut oil and ginger, water chestnuts remain crispy even after cooking. They’re the main ingredient in a popular Thai dessert, tabtim krob.In the West, they’re sometimes wrapped with bacon strips and served as an hors d’oeuvre. In Indonesia, water chestnuts are blended into a drink.

Chinese water chestnuts shouldn’t be confused with the European water chestnut of the genus Lythraceae, as they are a completely different species. Also called water caltrop (trapa natans – trapa for the Latin “thistle”) or horned water chestnut, this aquatic plant was imported to the U.S. from Asia in the mid-1800s. Because of their thorny spikes and invasive nature (not to mention their toxins), this plant is the bane of the East Coast tourism trade, so selling any type of water chestnut plant species is reportedly banned from most southern states, including Maryland.

Health Benefits of Water Chestnuts

While water chestnuts don’t have an overwhelming amount of detailed nutritional information, they seem to have a reputation in traditional Asian and aboriginal medicine. They’ve been ground into powder, juiced, sliced, boiled and eaten raw, steamed, or steeped in rice wine and used as a curative and food supplement.

Drinking water chestnut juice has been touted to alleviate nausea, relieve suffering from jaundice and detoxify the body from impurities. The powder is made into a paste and used as a remedy for inflammation. It’s said to be useful as a cough elixir, stirred up in water, and for easing the symptoms of measles.

Nutritionally, water chestnuts provide good amounts of  vitamin B6, potassium (362 milligrams per half a cup), copper, riboflavin and manganese. The corms are a rich source of carbohydrates, which relates itself in a starchy texture. Fiber is another ingredient in very good supply, and is effective for keeping your digestive system running smoothly. Fresh, raw water chestnuts contain slightly more fat than the canned variety, but it’s the good kind.

Studies have found water chestnuts to contain flavonoid antioxidants like catechins, specifically epicatechins (the same type found in dark chocolate, red wine and green tea). Early aboriginal men crushed the outsides of the bulb for wound application and healing, which science now knows releases antimicrobial effects. Inside water chestnuts is an antibiotic compound called puchin, which can influence immune function, similar to how penicillin works. Check out the other nutrition facts of water chestnuts below:

Water Chestnuts Nutrition Facts Serving Size: 3.5 ounces (100 grams), raw
	Amt. Per Serving	% Daily Value*
Calories	97
Calories from Fat	1
Total Fat	0.1 g	0%
Saturated Fat	0.26 g	0%
Trans Fat
Cholesterol	0 mg	0%
Sodium	14 mg	1%
Total Carbohydrates	24 g	8%
Dietary Fiber	3 g	12%
Sugar	5 g
Protein	1 g
Vitamin E1.2 mg	Vitamin C	4 mg
Calcium11 mg	Iron	0.06 mg

*Percent Daily Values are based on a 2,000 calorie diet. Your daily values may be higher or lower depending on your calorie needs.

Studies on Water Chestnuts

Experiments on water chestnuts were conducted to determine what antioxidant activity and major phenolic compounds they contain. Extracts were found to strongly inhibit linoleic acid oxidation and free radicals, superoxide anions (negatively charged ions) and hydroxyl radicals, which is superior to ascorbic acid and butylated hydroxytoluene (BHT), two commercially used antioxidants, as well as a relatively higher reducing power compared with BHT. Major phenolic presence found in water chestnuts exhibited abundant potential for antioxidant activity, which scientists reported could be useful for nutritional and medicinal functions.

A very detailed study listed a number of useful phenolics contained in water chestnuts, including gallic acid and vanillin, hydrocinnamic acids such as ferulic, caffeic and p-coumaric acids, the flavonoids quercetin and kaempferol, the flavonols apigenin and luteolin, along with catechins and epicatechins.  These are just a few of the compounds that may have positive effects on numerous diseases.

Water Chestnuts Fun Facts

Eleocharis dulcis (water chestnut) is used for making salt in Zimbabwe.

Summary:

It’s important to remember that water chestnuts can refer to two distinct plant species. The edible kind is Eleocharis dulcis, a corm shaped like a small chestnut from the Cyperaceae family of plants, while Trapa natans (from the Lythraceae plant family) is thorny and invasive.

The firm, white, crunchy water chestnut is often purchased canned, but sweeter when obtained fresh. It can be eaten raw and peeled (after thorough washing) or steamed and used in stir-fries, soups or salads.

Nutritionally, water chestnuts have a considerable number of vitamins and minerals such as fiber, vitamin B6, copper, riboflavin and manganese, but the phenolics are what set this food apart. Free radical-scavenging activity and disease-fighting capability comes with phenolics and flavonoids, such as vanillin, hydrocinnamic acids, quercetin and kaempferol, and apigenin, luteolin, catechins and epicatechins. These compounds have the potential to fight numerous diseases, making water chestnuts much more than just a crunchy ingredient for chop suey.