Next to tomatoes, cabbage, and onions, cucumbers are the fourth most widely cultivated vegetable in the world. They are enjoyed on virtually all continents and you will find them being incorporated into all types of cuisine.
Cucumbers are scientifically known as Cucumis sativus and belong to the same botanical family as melons (including watermelon and cantaloupe) and squashes (including summer squash, winter squash, zucchini and pumpkin). Commercial production of cucumbers is usually divided into two types. “Slicing cucumbers” are produced for fresh consumption. “Pickling cucumbers” are produced for eventual processing into pickles. Slicing cucumbers are usually larger and have thicker skins, while pickling cucumbers are usually smaller and have thinner skins.
What’s New and Beneficial About Cucumbers
- Researchers have long been familiar with the presence of unique polyphenols in plants called lignans, and these health-benefiting substances have been studied extensively in cruciferous vegetables (like broccoli or cabbage) and allium vegetables (like onion or garlic). Recent studies, however, have begun to pay more attention to the lignan content of other vegetables, including cucumbers. Cucumbers are now known to contain lariciresinol, pinoresinol, and secoisolariciresinol–three lignans that have a strong history of research in connection with reduced risk of cardiovascular disease as well as several cancer types, including breast, uterine, ovarian, and prostate cancers.
- Fresh extracts from cucumbers have recently been show to have both antioxidant and anti-inflammatory properties. While research in this area must still be considered preliminary–since it’s only been conducted on animals in a lab setting–the findings are clear and consistent. Substances in fresh cucumber extracts help scavenge free radicals, help improve antioxidant status, inhibit the activity of pro-inflammatory enzymes like cyclo-oxygenase 2 (COX-2), and prevent overproduction of nitric oxide in situations where it could pose health risks. It’s highly likely that cucumber phytonutrients play a key role in providing these antioxidant and anti-inflammatory benefits, supporting health alongside of the conventional antioxidant nutrients–including vitamin C, beta-carotene, and manganeseâ”of which cucumbers are an important source.
- As a member of the Cucurbitaceae family of plants, cucumbers are a rich source of triterpene phytonutrients called cucurbitacins. Cucurbitacins A, B, C, D and E are all contained in fresh cucumber. They have been the subject of active and ongoing research to determine the extent and nature of their anti-cancer properties. Scientists have already determined that several different signaling pathways (for example, the JAK-STAT and MAPK pathways) required for cancer cell development and survival can be blocked by activity of cucurbitacins. We expect to see human studies that confirm the anti-cancer benefits of cucumbers in the everyday diet.
This chart graphically details the %DV that a serving of Cucumbers provides for each of the nutrients of which it is a good, very good, or excellent source according to our Food Rating System. Additional information about the amount of these nutrients provided by Cucumbers can be found in the Food Rating System Chart. A link that takes you to the In-Depth Nutritional Profile for Cucumbers, featuring information over 80 nutrients, can be found under the Food Rating System Chart.
Cucumbers have not received as much press as other vegetables in terms of health benefits, but this widely-cultivated food provides us with a unique combination of nutrients. At the top of the phytonutrient list for cucumbers are its cucurbitacins, lignans, and flavonoids. These three types of phytonutrients found in cucumbers provide us with valuable antioxidant, anti-inflammatory, and anti-cancer benefits. Specific phytonutrients provided by cucumbers include
- a luleolin
- a quercetin
- a kaempferol
- cucurbitacin A
- cucurbitacin B
- cucurbitacin C
- cucurbitacin D
Details about the best-researched health benefits of cucumbers are provided in the paragraphs below.
Antioxidant & Anti-Inflammatory Benefits
Cucumbers are a valuable source of conventional antioxidant nutrients including vitamin C, beta-carotene, and manganese. In addition, cucumbers contain numerous flavonoid antioxidants, including quercetin, apigenin, luteolin, and kaempferol. In animal studies, fresh extracts from cucumber have been shown to provide specific antioxidant benefits, including increased scavenging of free radicals and increased overall antioxidant capacity. Fresh cucumber extracts have also been shown to reduce unwanted inflammation in animal studies. Cucumber accomplishes this task by inhibiting activity of pro-inflammatory enzymes like cyclo-oxygenase 2 (COX-2), and by preventing overproduction of nitric oxide in situations where it could increase the likelihood of excessive inflammation.
Research on the anti-cancer benefits of cucumber is still in its preliminary stage and has been restricted thus far to lab and animal studies. Interestingly, however, many pharmaceutical companies are actively studying one group of compounds found in cucumber–called cucurbitacins–in the hope that their research may lead to development of new anti-cancer drugs. Cucurbitacins belong to a large family of phytonutrients called triterpenes. Cucurbitacins A, B, C, D and E have all been identified within fresh cucumber. Researchers have determined that several different signaling pathways (for example, the JAK-STAT and MAPK pathways) required for cancer cell development and cancer cell survival can be blocked by activity of cucurbitacins. Eventually, we expect to see human studies that confirm the anti-cancer benefits of cucumbers when consumed in a normal, everyday meal plan.
A second group of cucumber phytonutrients known to provide anti-cancer benefits are its lignans. The lignans pinoresinol, lariciresinol, and secoisolariciresinol have all been identified within cucumber. Interestingly, the role of these plant lignans in cancer protection involves the role of bacteria in our digestive tract. When we consume plant lignans like those found in cucumber, bacteria in our digestive tract take hold of these lignans and convert them into enterolignans like enterodiol and enterolactone. Enterolignans have the ability to bind onto estrogen receptors and can have both pro-estrogenic and anti-estrogenic effects. Reduced risk of estrogen-related cancers, including cancers of the breast, ovary, uterus, and prostate has been associated with intake of dietary lignans from plant foods like cucumber.
Even though long, dark green, smooth-skinned garden cucumbers are familiar vegetables in the produce sections of most groceries, cucumbers actually come in a wide variety of colors, sizes, shapes and textures. You’ll find white, yellow, and even orange-colored cucumbers, and they may be short, slightly oval, or even round in shape. Their skins can be smooth and thin, or thick and rough. In a technical sense, cucumbers are actually fruits, not vegetables. (Fruits are parts of flowering plants that come from the ovary.) But we’ve become accustomed to thinking and referring to cucumbers as vegetables.
All cucumbers belong to the botanical plant family called Curcubitaceae. This broad family of plants includes melons and squashes. The cucumbers we’re most familiar with in the grocery store belong to the specific genus/species group, Cucumis sativus.
While there are literally hundreds of different varieties of Cucumis sativus, virtually all can be divided into two basic types: slicing and pickling. Slicing cucumbers include all varieties that are cultivated for consumption in fresh form. In the United States, commonly planted varieties of slicing cucumber include Dasher, Conquistador, Slicemaster, Victory, Comet, Burpee Hybrid, and Sprint. These varieties tend to be fairly large in size and thick-skinned. Their size makes them easier for slicing, and their thick skin makes them easier to transport in whole food form without damage. (In many other countries, however, slicing cucumbers may be smaller in size and may be much more thinly skinned.)
Pickling cucumbers include all varieties that are cultivated not for consumption in fresh form, but for processing into pickles. In the United States, commonly planted varieties of pickling cucumber include Royal, Calypso, Pioneer, Bounty, Regal, Duke, and Blitz. Some of these pickling varieties are black-spine types (in reference to the texture of their outer skin) and some are white-spine. While pickling cucumbers can always be eaten fresh, their smaller size and generally thinner skins make them easier to ferment and preserve/jar.
Pickling is a process than can be used for many different foods. It’s not limited to cucumbers and or even to the vegetable food group. In general, the word “pickling” refers to a method of preventing food spoilage that involves soaking in a liquid and/or fermenting.
While the language used to describe pickles can be very confusing, there are only two basic types of pickles: fermented and non-fermented. Fermenting is a process in which fresh foods (in this case cucumbers) are allowed to soak in a solution for an extended period of time that allows microorganisms to make changes in the food. Among these changes is a build-up of lactic acid that serves to protect the pickles from spoilage. When fermented in an appropriate solution, fresh foods like cucumbers can be transformed in a way that greatly increases their shelf life. Cucumbers are typically fermented in brine (water that’s been highly saturated in salt). In fact, the word “pickle” actually comes from the Dutch “pekel” meaning brine. Alongside of salt, pickling brines often contain other ingredients, including vinegar, dill seed, garlic, and lime (calcium hydroxide or calcium oxide). “Dill pickles” get their name from the addition of dill seed to the brine. “Kosher dills” are brined not only with dill, but also with garlic. (One important note in this regard: “kosher dills” are not necessarily pickled cucumbers that have been prepared according to kosher dietary laws. The word “kosher” in their name often refers to a general style of preparation in which a good bit of garlic has been used in the brining process. If you are seeking pickles that have been prepared according to kosher dietary laws, look for “certified kosher” on the label, not just “kosher” or “kosher-style.”)
Fermented pickles are often called “brined pickles,” but here’s where confusion can set it. These two terms aren’t truly interchangeable since some brined pickles are “quick brined” and haven’t been given time for fermentation. When pickles are “quick brined,” the brining solution usually contains a significant amount of vinegar, and it’s this added vinegar that prevents the pickles from spoiling, not build up of lactic acid through the microbial fermentation process. Non-fermented pickles of all kinds – often referred to as “quick pickled” – rely on the addition of vinegar or another highly-acidic solution to prevent spoilage. “Quick pickling” with the use of vinegar can be accomplished in a matter of days. Pickling by fermentation usually takes a minimum of several weeks. If you would like to learn more about how pickled cucumbers compare in nutritional value to raw cucumbers, see this Q+A .
While genetically engineered cucumbers do exist, genetic engineering is not responsible for the existence of seedless varieties of cucumbers. Through a natural process called parthenogenesis, cucumber plants can fruit without pollen. In the absence of pollen, seeds do not develop in the fruit. While some people have a personal preference for seedless cucumbers, it’s worth remembering that cucumber seeds are rich source of cucumber nutrients that are sometimes absent in the pulp and skin.
Sometimes you will hear the word “gherkin” being used to refer to cucumbers and pickles. This word can be used to describe a variety of cucumber that comes from the same plant species (Cucumis sativus) that is the source of most other cucumber varieties found in the grocery. But the term “gherkin” can also be used to describe a cucumber variety that comes from a different species of plant (Cucumis anguiria).
Cucumber plants naturally thrive in both temperate and tropical environments, and generally require temperatures between 60-90°F/15-33°C. For this reason, they are native to many regions of the world. In evolutionary terms, the first cucumbers were likely to have originated in Western Asia (and perhaps more specifically in India) or parts of the Middle East. Cucumbers are mentioned in the legend of Gilgamesh–a Uruk king who lived around 2500 BC in what is now Iraq and Kuwait. It was approximately 3,300 years later when cucumber cultivation spread to parts of Europe, including France. And it was not until the time of the European colonists that cucumbers finally appeared in North America in the 1500’s.
Today, the states of Florida and California are able to provide U.S. consumers with fresh cucumbers for most of the year (from March through November). Imported cucumbers from Mexico are commonly found in groceries during the winter months of December, January, and February. In California alone, about 6,600 acres are planted with slicing cucumber varieties and 4,400 with pickling cucumbers. Worldwide, China is by far the largest producer of cucumbers, and provides about two-thirds of the global supply. Iran, Turkey, Russia, Egypt, Spain, Mexico, the Ukraine, Japan, Indonesia, and the U.S. all participate in the world cucumber market, with an especially high number of exports coming from Iran, Mexico, and Spain. Annual production of cucumbers worldwide is approximately 84 billion pounds.
How to Select and Store
Since cucumbers can be very sensitive to heat, you’ll be on safer grounds if you choose those that are displayed in refrigerated cases in the market. They should be firm, rounded at their edges, and their color should be a bright medium to dark green. Avoid cucumbers that are yellow, puffy, have sunken water-soaked areas, or are wrinkled at their tips.
We address the issue of seeds and skins in our “Healthiest Way of Preparing Cucumbers” section below. But during the selection process, you may find it helpful to know that thin-skinned cucumbers will generally have fewer seeds than those that are thick-skinned.
While we always recommend purchase of certified organic foods, cucumbers are a food that may merit special consideration when you are deciding whether to purchase conventional versus organic. Cucumbers do not appear on the Environmental Working Group’s 2011 list of conventionally grown fruits and vegetables that are most contaminated with pesticide residues, but recent research studies suggest that conventionally grown cucumbers may be more susceptible to heavy metal contamination than other vegetables.
Cucumbers should be stored in the refrigerator where they will keep for several days. If you do not use the entire cucumber during one meal, place it in a tightly sealed container so that it does not become dried out. For maximum quality, cucumber should be used within one or two days. Cucumbers should not be left out at room temperature for too long as this will cause them to wilt and become limp.
Tips for Preparing and Cooking
Tips for Preparing Cucumbers
Two common questions about cucumbers involve consumption of their skin and their seeds. There are several facts you need to know before making your decision about consumption of cucumber skins and seeds. First, it is important to remember that the skins and seeds of cucumbers are both rich in nutrients. In fact, the nutrient richness of both plant parts is significantly higher than the flesh. For this reason, consumption of both skins and seeds is desirable from a nutritional standpoint. Both conventionally grown and organically grown cucumbers may have been waxed. However, the only waxes that can be used on organically grown cucumbers are non-synthetic waxes, and these waxes must be free of all chemical contaminants that are prohibited under organic regulations. Conventionally grown cucumbers may be waxed with synthetic waxes that contain unwanted chemical contaminants. For these reasons, we recommend leaving the skin of organically grown cucumbers intact regardless of whether the organically grown cucumber has been waxed. For conventionally grown cucumbers, we recommend removal of the waxed skin. For conventionally grown cucumbers that have not been waxed, we don’t have a good research basis for recommending either removal or non-removal of the skin. However, if you do decide to consume the skin of a non-waxed, conventionally grown cucumber, we recommend thorough washing of the whole cucumber under cool running water while gently scrubbing with a natural bristle brush.
Some people have a personal preference for removal of cucumber seeds, and we respect this preference. The seeds can easily be removed from a cucumber if it’s cut lengthwise and the tip of a spoon is used to gently scoop out the seeds. Our general recommendation, however, is to keep and consume the seeds, since they are an unusually rich source of nutrients. Getting optimal nourishment from your cucumbers while minimizing your health risks will mean choosing organically grown cucumbers over conventionally grown varieties.