Rhubarb: Benefits, Nutrition, and Risks

Rhubarb (Rheum rhabarbarum) is a perennial plant part of the buckwheat family. The plant has long, fleshy stalks in bright pink and red hues and large, dark green leaves. Rhubarb stalks are edible and have a tart, acidic flavor that pairs well with sweet foods, such as in a fruit pie. The leaves of the plant are inedible as they are toxic to humans.

Traditional Chinese Medicine (TCM) practitioners have used rhubarb medicinally for an estimated 5,000 years. The unique vegetable contains vitamin K, fiber, and antioxidants that support bone, digestive, and heart health. However, taking supplemental versions of rhubarb in the long term may be harmful.

Up to 20% of people in the United States have chronic constipation, and rhubarb may help. The vegetable stalks are a good source of fiber—a key nutrient for preventing and managing constipation. Fiber draws in water and adds bulk to the stool, which can help it move through your system quicker and make it easier to pass. Make sure to drink enough water since fiber works better when it has plenty of liquid to absorb.

Traditional Chinese Medicine has used rhubarb to treat constipation for thousands of years. Modern research has found that rhubarb contains a large amount of anthraquinone chemical constituents. These compounds have a laxative effect, stimulating the intestines to push stool out. Since rhubarb is abundant in these compounds, it may be particularly helpful for constipation.

One small study found that, among critically ill people, taking powdered rhubarb effectively caused a bowel movement in less than two days, on average.

Rhubarb is an excellent source of antioxidants, which can help counteract free radicals and prevent oxidative stress. The body produces free radicals as a natural reaction to many elements, including exercise, smoking, sun exposure, and pollution.

Without enough antioxidants, free radicals can build up and lead to oxidative stress. This state of oxidative stress is linked to chronic diseases like cancer, cardiovascular disease, diabetes, depression, Alzheimer’s disease, and more.

One study analyzed 29 varieties of rhubarb and found they were all rich in antioxidants, specifically phenolic compounds. Seven varieties had even more antioxidants than kale. Rhubarb is especially rich in one type of phenolic compound called anthocyanins, which gives rhubarb stalks their red color.

These antioxidants help reduce inflammation and neutralize free radicals, making them helpful for preventing and managing conditions like diabetes, cancer, cardiovascular disease, and neurological diseases.

The most abundant vitamin in rhubarb is vitamin K. This nutrient helps add structure to bone and regulates bone growth. Studies have found that low dietary intake of vitamin K is linked with a higher risk of bone fractures and lower bone mineral density. To support this, other studies have found that supplementing with vitamin K when your dietary intake is low helps prevent bone fractures.

Getting enough vitamin K from foods like rhubarb, natto, dark leafy greens, soybean oil, edamame, and pomegranate juice can help your body reap these benefits without needing to add a supplement.

As stated above, rhubarb is a good source of fiber, vitamin K, and antioxidants. It also offers other beneficial vitamins and minerals, like vitamin C and manganese.

One cup of diced rhubarb contains:

  • Calories: 25
  • Fat: 0.2 grams (g)
  • Sodium: 5 milligrams (mg)
  • Carbohydrates: 5.5 g
  • Fiber: 2.2 g, or 8% of the Daily Value (DV)
  • Added sugars: 0 g
  • Protein: 1.1 g
  • Vitamin K: 36 micrograms (mcg), or 29% of the DV
  • Vitamin C: 9.7 mg, or 11% of the DV
  • Manganese: 0.24 mg, or 10% of the DV

Vitamin C is essential for tissue growth and repair in the body. It helps produce collagen. It’s also an antioxidant, making it beneficial for disease prevention.

Manganese is a mineral that helps the body break down starches for energy. Your body also uses this mineral for bone formation, protection against cell damage, immune health, and reproduction. Plus, manganese works with vitamin K to support blood clotting.

Vitamin K is important for blood clotting and bone health. However, people taking anticoagulant drugs like warfarin should be careful about eating rhubarb because vitamin K can interact with this type of medication.

A one-cup serving of rhubarb also provides about 8% of the DV for calcium and potassium, as well as smaller amounts of vitamin A, vitamin E, folate, thiamin, riboflavin, niacin, and more.

Rhubarb extract is available as a supplement because it has various purported medicinal uses, including treating chronic kidney failure, diabetic nephropathy, and constipation.

However, experts do not advise the long-term use of rhubarb supplements since rhubarb can be toxic to the gastrointestinal tract, kidneys, and liver when consumed in excess. Certain compounds in rhubarb have a laxative effect, so concentrated forms of rhubarb can cause serious diarrhea.

For safety reasons, it’s generally best to consume rhubarb as a food rather than a supplement.

While rhubarb stalks are generally safe, the leaves contain toxins that are unsafe for humans to eat. Some symptoms of rhubarb leaf poisoning include:

  • Breathing difficulty
  • Burning in the mouth and throat
  • Diarrhea
  • Hoarse voice
  • Nausea and vomiting
  • Kidney stones
  • Red-colored urine
  • Seizures
  • Stomach pain

Seek medical help immediately if you consume rhubarb leaves. 

Rhubarb is also a source of oxalates, which can contribute to the formation of calcium oxalate kidney stones—the most common type of kidney stones. To prevent these stones, pair high-oxalate foods with high-calcium foods like yogurt, leafy greens, or seeds and limit sodium consumption.

Rhubarb allergies are uncommon but possible. Seek immediate medical help if you experience allergy symptoms like tongue swelling, wheezing, or hives.

Rhubarb may be intimidating to work with if it’s new to you, but it’s a flavorful and unique vegetable you can use in many different ways. Here are a few ideas to add rhubarb to your diet:

  • Make a strawberry rhubarb pie
  • Dip raw rhubarb stalks (without the leaves) into honey to mellow its bitter flavor
  • Top yogurt with diced rhubarb
  • Add rhubarb to smoothies
  • Make a chutney, jelly, or sauce using rhubarb
  • Roast rhubarb and serve with ice cream or frozen yogurt

Rhubarb is a tart vegetable consisting of fleshy, pink-red stalks. It’s important to only eat the stalks of the rhubarb plant as the leaves are toxic to humans. Rhubarb is a good source of vitamin K, fiber, and antioxidants that can support overall health and help prevent chronic disease.

Supplement forms of rhubarb are available, but they may have harmful effects when taken long-term. For this reason, it’s best to consume this versatile vegetable as a food.


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