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Cucumbers: Nutrition facts and health benefits

A cucumber on a chopping board, surrounded by slices
There are hundreds of varieties of cucumber, and they come in dozens of colors. (Image credit: Getty/ Alberto Rojas Garcia)

Few foods, as they say, are as cool as a cucumber. A cucumber's nutritional benefits are ideal for healthy eating, because these low-calorie veggies contain many hydrating properties and valuable nutrients. In 2019, the cucumber was even elevated to the status of superfood, according to Men's Health (opens in new tab)

There are hundreds of varieties of cucumber, and they come in dozens of colors (including white, yellow and orange according to Nutritional Outlook (opens in new tab)), but the edible types are classified as being for either slicing or pickling, according to Cornell University's Growing Guide (opens in new tab). Slicing cucumbers are cultivated to be eaten fresh, while pickling cucumbers are intended for the brine jar — the former are also usually larger and thicker-skinned than the pickling variety.

In the United States, commonly planted varieties of slicing cucumber include Dasher, Conquistador, Slicemaster, Victory, Comet, Burpee Hybrid and Sprint, according to Gardener's Path (opens in new tab)  website. Commonly planted varieties of pickling cucumber include Royal, Calypso, Pioneer, Bounty, Regal, Duke and Blitz.

While most people think of cucumbers as vegetables, they are actually a fruit. They contain seeds and grow from the ovaries of flowering plants. Cucumbers are members of the plant family Cucurbitaceae (opens in new tab), which also includes squashes and melons. The most common type of slicing cucumber found in a grocery store is the garden cucumber, Cucumis sativus, according to Plants For a Future (opens in new tab)

Nutritional profile

Cucumbers are good sources of phytonutrients (plant chemicals that have protective or disease preventive properties) such flavonoids, lignans and triterpenes, which have antioxidant, anti-inflammatory and anti-cancer benefits. "We should definitely seek out foods that are nutrient-rich, using the positive approach of what to put on your plate vs. what to keep off," said Angela Lemond (opens in new tab), a Plano, Texas-based registered dietitian nutritionist. The peel and seeds are the most nutrient-dense parts of the cucumber. They contain fiber and beta-carotene. "Beta carotene is an antioxidant that helps with immunity, skin, eye and the prevention of cancer," said Lemond. A study published in the Pakistan Journal of Nutrition (opens in new tab) found that cucumber seeds were a good source of minerals, and contained calcium.

"Cucumbers are naturally low in calories, carbohydrates, sodium, fat and cholesterol," said Megan Ware (opens in new tab), a registered dietitian nutritionist in Orlando, Florida. There are just 16 calories in a cup of cucumber with its peel (15 without). You will get about 4% of your daily potassium, 3% of your daily fiber and 4% of your daily vitamin C. They also "provide small amounts of vitamin K, vitamin C, magnesium, potassium, manganese and vitamin A," Ware said.

Here is everything you need to know about cucumber nutrition, according to the U.S. Food and Drug Administration (opens in new tab), which regulates food labeling through the Nutritional Labeling and Education Act, :

Nutrition Facts Cucumber, with peel, raw Serving size: 1/2 cup, sliced (52 g) Calories 8   Calories from Fat 0 *Percent Daily Values (%DV) are based on a 2,000 calorie diet.
Amt per Serving%DV*Amt per Serving%DV*
Total Fat 0g0%Total Carbohydrate 2g1%
Cholesterol 0mg0%Dietary Fiber 0g0%
Sodium 1mg2%Sugars 0g
Protein 0g
Vitamin A1%Calcium1%
Vitamin C2%Iron1%

Hydration

Cucumbers are 95% water, according to WebMD (opens in new tab) . This makes cucumbers a great way to stay hydrated, especially during the summer. 

"They say we can get 20-30 percent of our fluid needs through our diet alone, and foods like these certainly help," added Lemond. "Not only are they high in water content, they also contain important nutrients that play a part in hydration like magnesium and potassium." 

The anti-inflammatory compounds in cucumbers help remove waste from the body (opens in new tab) and reduce skin irritation, according to the Cleveland Clinic. Preliminary research also suggests cucumbers promote anti-wrinkling and anti-aging activity, according to an article in the journal Filoterapia. 

Cancer prevention

Cucumbers contain two phytonutrient compounds associated with anti-cancer benefits: lignans and cucurbitacins. In recent years, pharmaceutical companies have been paying special attention to cucurbitacins, hoping to use them in new cancer drugs. According to a 2010 research review published in Scientific World Journal (opens in new tab), scientists have found that cucurbitacins can help block the signaling pathways that are important for cancer cell proliferation and survival. 

Cucurbitacins can also inhibits the growth of pancreatic cancer cells, according to a 2009 study published in the Journal of Cancer Research (opens in new tab) looked at cucurbitacin B (which cucumber contains) on human pancreatic cancer cells and found that cucurbitacin supplements inhibited the growth of seven pancreatic cancer cell lines by 50%, and also increased apoptosis, or "death by suicide," of pancreatic cancer cells. 

However, in 2021 Health Feedback (opens in new tab) assessed a claim made by Ethan Evans in his medical thriller, "The Eden Prescription (opens in new tab)" (BookSurge Publishing, 2010) that: "Cucumber kills lung cancer cells" and  "cucurbitacin B suppressed growth of human lung cancer cells by 90%, reduced their ability to invade surrounding tissues by 75% and reduced migration ability by 88%." Health Feedback stated that: "Some scientific studies found that cucurbitacin B, a biochemical compound in cucumbers, promotes regulated cell death" and "these studies were conducted on laboratory cell cultures and mice" meaning "there isn’t evidence showing that cucumber or cucurbitacin B kills tumor cells in people." In short, whilst previous studies are certainly hopeful — the current evidence does not suggest that Cucumber kills or reduces lung cancer cells. 

Skin

A woman relaxing in a spa with cucumber over her eyes

Putting cucumber on your eyes during a pampering routine is backed up by scientific fact. (Image credit: Getty/ Jupiterimages)

You've probably seen pictures of people at a spa relaxing with cucumber slices over their eyes. It turns out there's science behind this pampering ritual. Ware explained, "Cucumbers have a cooling and soothing effect that decreases swelling, irritation and inflammation when used topically. Cucumber slices can be placed on the eyes can decrease morning puffiness or alleviate and treat sunburn when placed on the affected areas." She also noted that high vegetable intake is associated with a healthy complexion in general. 

Bone health

In the past few decades, it has become clear that vitamin K is important to bone health, according to Cleveland Clinic Health Essentials (opens in new tab) and one cup of cucumber contains about 19% of the recommended daily intake of vitamin K. One review published in Nutrition (opens in new tab) noted that vitamin K intake might reduce fracture rates, work with vitamin D to increase bone density and positively affect calcium balance. 

The human body uses vitamin K when building bones, and the effects seem to be especially important for women. Over the past two decades a number of studies were released which assessed the role of low-Vitamin K levels, particularly in relation to the risk of fracturing. A large 2003study conducted by American Journal of Clinical Nutrition (opens in new tab) (AJCN) showed that low vitamin K levels were associated with low bone density in women, but not in men. Another study published in the AJCN in 1999 found that low intakes of vitamin K were associated with an increased risk of hip fractures in middle-age women. This is especially interesting because the women saw results from eating lettuce, showing that dietary consumption of vitamin K via eating vegetables (not supplements) is beneficial. When it comes to men, the effects of vitamin K and bone health may become more apparent as they age: A 2000 study published in the AJCN saw reduced risk of hip fracture among both elderly women and elderly men who consumed more vitamin K.

However, a recent study by Celia Rodríguez-Olleros Rodríguez showed that "Vitamin K plays an important role in bone health. Low vitamin K intake, low serum vitamin K values, and high levels of ucOC are associated with risk of fracture (especially hip fracture) in observational studies. However, clinical trials do not achieve conclusive results, and there is still controversy over the use of vitamin K1 and K2 supplements. High-quality clinical trials involving patients with low serum vitamin K values and/or low dietary intake are needed to clarify the role of vitamin K in fracture risk."

Antioxidants

"Foods that are high in antioxidants allow your body to function optimally.  Antioxidants help prevent damage and cancer," Lemond said.

Cucumbers contain several antioxidants, including vitamin C, beta-carotene and manganese, as well as flavonoids, triterpenes and lignans that have anti-inflammatory properties. Vitamin C is well known for its immune system benefits, and beta-carotene has been shown to be beneficial for vision, according to the American Optometric Association (opens in new tab) . According to a 2010 animal study published in the Journal of Young Pharmacists (opens in new tab), fresh extracts from cucumber showed increased scavenging of free radicals. Free radicals are associated with a variety of human diseases, but can sometimes be held in check by antioxidants, according to the Pharmacognosy Review (opens in new tab)

Another study of cucumber extracts in animals, published in the Archives of Dermatological Research (opens in new tab), found increased overall antioxidant benefits. Though this study focused on the cosmetic applications of this use of cucumbers, decreased free radicals can improve your inside organs as well as your skin. 

An additional study published in Current Pharmaceutical Design (opens in new tab) found a positive association between the triterpene cucurbitacin and reduced inflammation, particularly in cancer cells. A review of triterpenes on the immune system, published in the Journal of Ethnopharmacology (opens in new tab), suggested that they can help with inflammation and encouraged future research.

Heart health

A doctor listening to a man's heart using a stethoscope

Eating cucumber, along with other fruits and vegetables, is associated with a reduced risk of many heart conditions. (Image credit: Getty/ Sarinya Pinngam / EyeEm)

"Eating a variety of fruits and vegetables of all kinds is associated with a reduced risk for many health conditions, such as heart disease, diabetes, stroke and obesity," said Ware. Cucumbers' potassium content may be especially helpful in this regard. One cup of sliced cukes contains only about 4% of the body's daily potassium needs, but it comes with significantly fewer calories than most high-potassium foods like bananas. Potassium is an essential part of heart health, according to the American Heart Association (opens in new tab). A 2012 study of 12,000 adults, published in Archives of Internal Medicine (opens in new tab), showed that those who consumed 4,069 mg of potassium each day lowered their risk of cardiovascular disease and ischemic heart disease by 37% and 49%, respectively, compared to those who took 1,793 mg per day. 

Several studies have linked cucumber consumption to reducing hypertension. Many studies have linked it with lower blood pressure because it promotes vasodilation (widening of the blood vessels), according to Today’s Dietitian (opens in new tab). A 2017 study published in Public Health of Indonesia (opens in new tab) found that elderly participants with hypertension saw a significant decrease in blood pressure after consuming cucumber juice for 12 days.

The vitamin K in cucumbers is also known to be essential in the blood-clotting process, according to the Harvard School of Public Health (opens in new tab)

Digestion

A 2013 review in Fitoterapia (opens in new tab) noted that cucumbers might help relieve constipation because they provide both fiber and water. Tufts University (opens in new tab) notes that cucumbers can pack even more of a digestive punch if they are turned into pickles during a home-fermentation process. Cucumber pickles contain probiotic bacteria that promote healthy digestion and cultivating beneficial gut flora. Store-bought pickles usually do not have these bacteria because they have been boiled out. 

Weight loss

A woman in exercise clothing holding a glass of cucumber juice

A woman holds a glass of cucumber juice. (Image credit: Getty/ d3sign)

Cucumbers are a low-calorie food therefore a popular ingredient in diet meals. In 2018 NDTV (opens in new tab) described it as an "amazing veggie for weight loss" and stated that the fact it has "zero fat, low-calories"  makes "it an excellent snack for people looking to lose weight". A 2011 study in the journal Obesity found that greater water consumption correlated with more weight loss in middle-age and older adults. Participants who consumed 1 pint (500 milliliters) of water prior to eating a meal lost an average of 4 lbs. (2 kilograms) more than participants who did not. Snacking on water-dense foods like cucumbers can be an effective way to up water intake. 

But Lemond cautions against relying too much on water-dense foods like cucumber. "We know that people that eat higher quantities of fruits and vegetables typically have healthier body weights. However, I do not recommend eating only cucumber.  You will lose weight, but that weight will be mostly muscle," she said. 

Brain health and memory

Recently, scientists have taken interest in the flavonoid fisetin. Cucumbers are a good source of fisetin, which studies have associated with protecting nerve cells, improving memory and decreasing the risk of Alzheimer's in mice, according to a 2013 review in the journal of Antioxidants & Redox Signaling (opens in new tab). The same review found promising results for the relationship between fisetin and cancer prevention. 

Risks of eating cucumbers

There can be a few risks from eating cukes. Pesticide consumption is one concern. Ware explained, "The Environmental Working Group produces a list each year of fruits and vegetables with the highest levels of pesticide residue, known as the Dirty Dozen (opens in new tab). Cucumbers are one of the fruits and vegetables that the Environmental Working Group has placed on its Dirty Dozen list, meaning the exposure to pesticide residue is high." As of 2022, cucumber was still featured on the list, this time at number 17.

Additionally, cucumbers may be waxed to help protect them during shipping. According to World's Healthiest Foods, both organic and conventionally grown cukes may be waxed, but organic ones can only use non-synthetic waxes with chemicals approved under organic regulations. For this reason and the pesticide concerns, World's Healthiest Foods encourages buying organic cucumbers. But Ware stipulated, "This does not mean you should avoid cucumbers altogether if you can't find or afford organic. The nutritional benefit of eating conventionally grown produce outweighs the risk of not eating produce at all."

Healthy as they are, you don't want to overdo it on cucumbers, said Lemond. "My recommendation is always to vary your selections.  Cucumbers are great hydrating foods, so keep them in along with other plant foods that offer other benefits. Variety is always key."

Pickles

Fermented pickles in a jar

Gherkin pickles are usually just immature cucumbers (Image credit: Getty/ Yulia Naumenko)

Pickling is a method of preserving food — and not only cucumbers — to prevent spoiling. There are two basic types of pickles: fermented and non-fermented, according to the Exploratorium (opens in new tab)

Fermented pickles have been soaked in brine, which is water that has been saturated with salt. The word "pickle" comes from the Dutch word pekel, which means brine. Brines can also contain other ingredients, such as vinegar, dill seed, garlic and lime. 

Dill pickles are brined with dill added to the solution, obviously.  Kosher dills are brined with dill and garlic. "Kosher" in this case does not necessarily mean the cucumbers have been prepared according to kosher dietary laws, however; it just means garlic has been added to the brining process, according to Insane in the Brine (opens in new tab).

Gherkin pickles are usually just immature cucumbers, according to Masterclass (opens in new tab)

Additional Resources

For those wishing to grow their own cucumbers, Cornell University has a handyCucumber Growing Guide (opens in new tab). If you are looking for other foods with health benefits then check out Cleveland Clinic's list of  7 Foods That Will Satisfy Your Thirst and Hunger (opens in new tab).

Bibliography

Callum McKelvie
Features Editor

Callum McKelvie is features editor for All About History Magazine. He has a both a Bachelor and Master's degree in History and Media History from Aberystwyth University. He was previously employed as an Editorial Assistant publishing digital versions of historical documents, working alongside museums and archives such as the British Library. He has also previously volunteered for The Soldiers of Gloucestershire Museum, Gloucester Archives and Gloucester Cathedral