Carbs in Water Chestnuts

A Starchy Root Vegetable Rather Than a Nut

water chestnuts
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You may be surprised to find out that the water chestnut is not a nut (or even related to nuts), but rather a starchy root vegetable. If you are limiting your carbohydrates, knowing how many they contain is important so you can decide whether to make a substitution.

Water chestnut plants are grown in marshy or wetland areas and can be eaten raw or cooked. They are best knows as a popular ingredient in Chinese cooking. Their flavor is mild and slightly sweet. Perhaps the biggest selling point of water chestnuts is that they remain crunchy when cooked or canned, so they can add a nice texture to dishes. Although they are starchy, they are small, so a little chopped up in a stir-fry or salad can be a nice addition.

If you want a lower-carb substitute for water chestnuts, try jicama, which is also mild and crunchy, although it doesn't maintain its crunch on long cooking.

Carbohydrate and Fiber Counts for Water Chestnuts

The carbohydrate counts for raw and canned water chestnuts are different in the USDA database because the values for the canned variety include the weight of water they are packed in. The raw values are probably more typical for the use you will make of water chestnuts.

  • 1/2 cup raw water chestnut slices: 13 grams effective (net) carbohydrate, 2 grams fiber, 60 calories
  • 4 medium raw water chestnuts (about 1 1/2 ounce): 8 grams effective (net) carbohydrate, 1 gram fiber, 35 calories
  • 1/2 cup canned sliced water chestnut: 7 grams effective (net) carbohydrate, 2 grams fiber, 35 calories
  • 4 medium canned water chestnuts (about an ounce): 2 grams effective (net) carbohydrate, 1 gram fiber, 14 calories

Compared with jicama, canned water chestnuts have three times the effective (net) carbohydrates, while raw water chestnuts have over five times as much.

Glycemic Index for Water Chestnuts

No studies of the glycemic index of water chestnuts have been reported in the scientific literature, and therefore the glycemic load cannot be calculated. You may see glycemic index listed elsewhere for water chestnuts, but they do not appear on the reference table and a couple of such listings differed significantly. The glycemic index indicates how much a certain food raises blood glucose levels. The glycemic load takes the serving size into account. As water chestnuts are usually used in small amounts in recipes and salads, the serving size would be a factor.

Health Benefits of Water Chestnuts

A 1/2 cup serving of water chestnuts proves 4 percent of your daily value of vitamin C and 10 percent of the daily value of iron. Water chestnuts are a fairly good source of potassium, manganese, calcium, copper, and vitamin B6.

Water Chestnut Selection and Storage

Canned water chestnuts, which are obviously more commonly available, should be rinsed to remove the "canned" flavor.

When selecting fresh raw water chestnuts, choose ones that have smooth, unwrinkled skin without soft spots.  Store them in the refrigerator in a plastic bag, where they may keep up to two weeks, depending on how fresh they are. Before eating, raw water chestnuts need to be peeled, and the top sliced off.

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