Rhubarb is a good source of antioxidants, vitamin K, and fiber. It’s also rich in calcium oxalate, so if you’re prone to kidney stones, it might be best to avoid. More importantly, the leaves are toxic and should never be eaten.

Rhubarb is a vegetable known for its reddish stalks and sour taste.

In Europe and North America, it’s cooked and often sweetened. In Asia, its roots are used medicinally.

This article provides a detailed overview of rhubarb, including its uses and potential health benefits.

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What is rhubarb?

Rhubarb is renowned for its sour taste and thick stalks, which are usually cooked with sugar.

The stalks range in color from red to pink to pale green and have a consistency that’s similar to celery.

This vegetable requires cold winters to grow. As a result, it’s mainly found in mountainous and temperate regions around the world, especially in Northeast Asia. It’s also a common garden plant in North America and Northern Europe.

Several varieties and species exist. In the West, the most common variety is called culinary or garden rhubarb (Rheum x hybridum).

How is it used?

Rhubarb is an unusual vegetable because it’s very sour and slightly sweet.

In fact, it’s easily mistaken for a fruit. Adding to the confusion, rhubarb is officially classified as a fruit by the U.S. Department of Agriculture (USDA).

Due to its sour taste, it’s rarely eaten raw. Instead, it’s normally cooked — either sweetened with sugar or used as an ingredient.

It wasn’t until the 18th century, when sugar became cheap and readily available, that rhubarb became a popular food.

Before that, it was mainly used medicinally. In fact, its dried roots have been utilized in traditional Chinese medicine for thousands of years.

Only the stalks are eaten, most commonly in sweet soups, jams, sauces, pies, tarts, crumbles, cocktails, and rhubarb wine.

As sweet rhubarb pies are a traditional dessert in the United Kingdom and North America, this vegetable is sometimes called “pie plant.”

Nutrient content of rhubarb

Rhubarb is not especially rich in essential nutrients, and its calorie content is low.

However, it is a very good source of vitamin K1, providing around 18% or 24% of the Daily Value (DV) in a 3.5-ounce (100-gram) serving depending on whether it’s cooked.

Like other fruits and vegetables, it’s also high in fiber, providing similar amounts as oranges, apples, or celery.

A 3.5-ounce (100-gram) serving of cooked rhubarb with added sugar contains:

• Calories: 116
• Carbs: 31.2 grams
• Fiber: 2 grams
• Protein: 0.4 grams
• Vitamin K1: 18% of the DV
• Calcium: 11% of the DV
• Vitamin C: 4% of the DV
• Potassium: 2% of the DV
• Folate: 1% of the DV

Although there are decent amounts of calcium in rhubarb, it’s mainly in the form of the antinutrient calcium oxalate. In this form, your body can’t absorb it efficiently.

It is also moderately high in vitamin C, boasting 4% of the DV in a 3.5-ounce (100-gram) serving.

Health benefits of rhubarb

Studies on the health benefits of rhubarb are limited.

However, a few studies have examined the effects of isolated rhubarb stalk components, such as its fiber.

May lower cholesterol levels

A 2023 review of studies found that resveratrol, emodin, and other chemicals in rhubarb also contribute to its role in regulating lipid metabolism and lowering bad cholesterol levels.

Rhubarb stalks are also a good source of fiber, which may affect your cholesterol. This beneficial effect is not exclusive to rhubarb fiber. Many other fiber sources are equally effective.

Provides antioxidants

Rhubarb is also a rich source of antioxidants.

One 2012 study suggests that its total polyphenol content may be even higher than that of kale.

The antioxidants in rhubarb include anthocyanins, which are responsible for its red color and thought to provide health benefits. Rhubarb is also high in proanthocyanidins, also known as condensed tannins.

These antioxidants may be responsible for some of the health benefits of fruits, red wine, and cocoa.

Why does it taste sour?

Rhubarb is probably the most sour-tasting vegetable you can find.

Its acidity is mainly due to its high levels of malic and oxalic acid. Malic acid is one of the most abundant acids in plants and contributes to the sour taste of many fruits and vegetables.

Interestingly, growing rhubarb in darkness makes it less sour and more tender. This variety is known as forced rhubarb, which is grown in spring or late winter.

Safety and side effects

Rhubarb is among the richest dietary sources of calcium oxalate, the most common form of oxalic acid in plants.

In fact, according to folk tradition, rhubarb should not be harvested past late June, as oxalic acid levels are said to rise from spring to summer.

This substance is particularly abundant in the leaves, but the stalks may also contain high amounts, depending on the variety.

Too much calcium oxalate can lead to hyperoxaluria, a serious condition characterized by the accumulation of calcium oxalate crystals in various organs.

These crystals may form kidney stones. Sustained hyperoxaluria can lead to kidney failure. In addition, a newer study has shown that long term consumption of the anthocyanins in rhubarb may actually harm the kidneys.

Not everyone responds to dietary oxalate in the same way. Some people are genetically predisposed to health problems associated with oxalates.

Vitamin B6 deficiency and high vitamin C intake may also increase your risk.

Additionally, growing evidence suggests this problem is worse for those who lack certain beneficial gut bacteria. Interestingly, some gut bacteria, such as Oxalobacter formigenes, degrade and neutralize dietary oxalates.

Although reports of rhubarb poisoning are rare, make sure you consume it in moderation and avoid the leaves. What’s more, cooking your rhubarb may reduce its oxalate content by 65.9% to 74.5%.

How to cook rhubarb

Rhubarb can be eaten in a number of ways. It is usually used in jams and desserts, which contain plenty of added sugar. Make sure to cut off the tops and bottoms of the stalks and discard the leaves before cooking.

That said, it’s easy to use in low-sugar recipes — or even cooked with no sugar at all.

A few creative ideas include rhubarb salad and healthy rhubarb crumble. You can also add this vegetable or its jam to your morning oatmeal.

Try this rhubarb crisp recipe.

The bottom line

Rhubarb is a unique vegetable that people use in cooking and baking.

Since it may be high in oxalate, you should avoid eating too much of it and try to select stalks from low-oxalate varieties. If you are prone to kidney stones, it might be best to avoid rhubarb altogether.

On the bright side, rhubarb is a good source of antioxidants, vitamin K, and fiber.

Additionally, its sour taste makes it a perfect ingredient in jams, crumbles, pies, and other desserts.