Rhubarb is a good source of vitamin C, fiber, and calcium, and it also provides some potassium. Rhubarb is very low in calories, and half of its carbohydrates are dietary fiber. Since it is very tart, rhubarb is usually sweetened with sugar when cooked. Its unusual flavor has led to its use in traditional medicine in many regions. It is known for its laxative effect, and the roots were initially cultivated for use as a purgative or cathartic.
More recently, researchers have been investigating rhubarb’s potential as a cancer- fighting food. Anthraquinones in rhubarb appear to attack cancer cells in several different ways, including starving tumor cells by interfering with their ability to take in glucose, limiting their proliferation, and preventing metastasis (the traveling of cancer cells to other parts of the body). One rhubarb extract may also help relax blood vessels, lowering blood pressure. Another appears to help constrict blood vessels, useful for stopping bleeding. Rhubarb also appears to have antioxidant and anti-inflammatory properties.
Rhubarb, however, is a food that not only contains measurable amounts of oxalates, but is actually quite high in them. The leaves are so high in oxalic acid that they are regarded as poisonous, and although they were used in some traditional soups, it is better to avoid eating them altogether. The leaves also contain a second toxin, possibly anthraquinone glycoside, which is thought to be related to its laxative effect. The stalks contain much less oxalate, and these can be eaten by those who are not at risk. However, rhubarb can cause problems for those with kidney disease, gout, vulvar pain, rheumatoid arthritis, or other conditions that may require a low-oxalate diet.Nutritional Facts
One cup of frozen raw rhubarb provides 29 calories, 7 g carbohydrate, 0.8 g protein. 0.2 g fat, 2.5 g dietary fiber, 147 IU vitamin A, 7 mg vitamin C, 11 mcg folic acid, 148 mg potassium, 3 mg sodium, 266 mg calcium, 16 mg phosphorus, and 25 mg magnesium.