Watermelon Watermelon

Watermelon Watermelon

No other fruit says summer like the subtly crunchy, thirst quenching watermelon. Although watermelons can now be found in the markets throughout the year, the season for watermelon is in the summer when they are sweet and of the best quality.

As a member of the Cucurbitaceae family, the watermelon is related to the cantaloupe, squash and pumpkin, other plants that also grow on vines on the ground. Watermelons can be round, oblong or spherical in shape and feature thick green rinds that are often spotted or striped. They range in size from a few pounds to upward of ninety pounds.

Food Chart
This chart graphically details the %DV that a serving of Watermelon 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 Watermelon can be found in the Food Rating System Chart. A link that takes you to the In-Depth Nutritional Profile for Watermelon, featuring information over 80 nutrients, can be found under the Food Rating System Chart.

Health Benefits
Description
History
How to Select and Store
How to Enjoy
Individual Concerns
Nutritional Profile
References

Health Benefits

Watermelon is not only great on a hot summer day, this delectable thirst-quencher may also help quench the inflammation that contributes to conditions like asthma, atherosclerosis, diabetes, colon cancer, and arthritis.

Concentrated in Powerful Antioxidants

Sweet, juicy watermelon is actually packed with some of the most important antioxidants in nature. Watermelon is an excellent source of vitamin C and a very good source of vitamin A, notably through its concentration of beta-carotene. Pink watermelon is also a source of the potent carotenoid antioxidant, lycopene. These powerful antioxidants travel through the body neutralizing free radicals. Free radicals are substances in the body that can cause a great deal of damage. They are able to oxidize cholesterol, making it stick to blood vessel walls, where it can lead to heart attack or stroke. They can add to the severity of asthma attacks by causing airways to clamp down and close. They can increase the inflammation that occurs in osteoarthritis and rheumatoid arthritis and cause most of the joint damage that occurs in these conditions, and they can damage cells lining the colon, turning them into cancer cells. Fortunately, vitamin C and beta-carotene are very good at getting rid of these harmful molecules and can therefore prevent the damage they would otherwise cause. As a matter of fact, high intakes of vitamin C and beta-carotene have been shown in a number of scientific studies to reduce the risk of heart disease, reduce the airway spasm that occurs in asthma, reduce the risk of colon cancer, and alleviate some of the symptoms of osteoarthritis and rheumatoid arthritis. A cup of watermelon provides 24.3% of the daily value for vitamin C, and, through its beta-carotene, 11.1% of the DV for vitamin A.

More on Watermelon's Lycopene

Watermelon is also a very concentrated source of the carotenoid, lycopene. Well known for being abundant in tomatoes and particularly well absorbed from cooked tomato products containing a little fat such as olive oil, lycopene is also present in high amounts in watermelon and mangoes. Lycopene has been extensively studied for its antioxidant and cancer-preventing properties. In contrast to many other food phytonutrients, whose effects have only been studied in animals, lycopene has been repeatedly studied in humans and found to be protective against a growing list of cancers. These cancers now include prostate cancer, breast cancer, endometrial cancer, lung cancer and colorectal cancers. A study published in the American Journal of Clinical Nutrition found that in patients with colorectal adenomas, a type of polyp that is the precursor for most colorectal cancers, blood levels of lycopene were 35% lower compared to study subjects with no polyps. Blood levels of beta-carotene also tended to be 25.5% lower, although according to researchers, this difference was not significant. In their final (multiple logistic regression) analysis, only low levels of plasma lycopene (less than 70 microgram per liter) and smoking increased the likelihood of colorectal adenomas, but the increase in risk was quite substantial: low levels of lycopene increased risk by 230% and smoking by 302%. The antioxidant function of lycopene—its ability to help protect cells and other structures in the body from oxygen damage—has been linked in human research to prevention of heart disease. Protection of DNA (our genetic material) inside of white blood cells has also been shown to be an antioxidant role of lycopene.

Watermelon and Green Tea Team Up to Prevent Prostate Cancer

Choosing to regularly eat lycopene-rich fruits, such as watermelon, and drink green tea may greatly reduce a man's risk of developing prostate cancer, suggests research published the Asia Pacific Journal of Clinical Nutrition (Jian L, Lee AH, et al.)

In this case-control study involving 130 prostate cancer patients and 274 hospital controls, men drinking the most green tea were found to have an 86% reduced risk of prostate cancer compared, to those drinking the least.

A similar inverse association was found between the men's consumption of lycopene-rich fruits and vegetables such as tomatoes, apricots, pink grapefruit, watermelon, papaya, and guava. Men who most frequently enjoyed these foods were 82% less likely to have prostate cancer compared to those consuming the least lycopene-rich foods.

Regular consumption of both green tea and foods rich in lycopene resulted in a synergistic protective effect, stronger than the protection afforded by either, the researchers also noted.

Practical Tips: Get in the habit of drinking green tea and eating lycopene-rich foods such as watermelon.

Take a quart of iced green tea to work and sip throughout the day or take it to the gym to provide prostate protection while replenishing fluids after your workout.
Start your breakfast with a half grapefruit or a glass of papaya or guava juice.
For a great summer thirst-quencher, blend chunks of watermelon with a few ice cubes and a splash of lime juice. Serve with a fresh mint leaf.
Serve cooling watermelon chunks as a side dish to balance the flavor of spicy black beans or other fiery Mexican dishes.

Energy Production

Watermelon is rich in the B vitamins necessary for energy production. Our food ranking system also qualified watermelon as a very good source of vitamin B6 and a good source of vitamin B1, magnesium, and potassium. Part of this high ranking was due to the higher nutrient richness of watermelon. Because this food has a higher water content and lower calorie content than many other fruits (a whole cup of watermelon contains only 48 calories), it delivers more nutrients per calorie—an outstanding health benefit!

Protection against Macular Degeneration

Your mother may have told you carrots would keep your eyes bright as a child, but as an adult, it looks like fruit is even more important for keeping your sight. Data reported in a study published in the Archives of Ophthalmology indicates that eating 3 or more servings of fruit per day may lower your risk of age-related macular degeneration (ARMD), the primary cause of vision loss in older adults, by 36%, compared to persons who consume less than 1.5 servings of fruit daily.

In this study, which involved over 110,000 women and men, researchers evaluated the effect of study participants' consumption of fruits; vegetables; the antioxidant vitamins A, C, and E; and carotenoids on the development of early ARMD or neovascular ARMD, a more severe form of the illness associated with vision loss. While, surprisingly, intakes of vegetables, antioxidant vitamins and carotenoids were not strongly related to incidence of either form of ARMD, fruit intake was definitely protective against the severe form of this vision-destroying disease. Three servings of fruit may sound like a lot to eat each day, but watermelon can help you reach this goal. What could be more delicious on a hot summer's day than a slice of sweet, refreshing watermelon? For a great summer spritzer, blend watermelon with a spoonful of honey and a splash of lemon or lime, then stir in seltzer water and decorate with a sprig of mint. If you didn't experience the fun of a seed spitting contest as a child, it's not too late to introduce this summer ritual to your children or the child in you!

Arginine to Prevent Erectile Dysfunction, Lower Blood Pressure, Improve Insulin Sensitivity
One more reason to enjoy watermelon before summer ends: this sweet, crunchy, cooling fruit is exceptionally high in citrulline, an amino acid our bodies use to make another amino acid, arginine, which is used in the urea cycle to remove ammonia from the body, and by the cells lining our blood vessels to make nitric oxide. Nitric oxide not only relaxes blood vessels, lowering high blood pressure, it is the compound whose production is enhanced by Viagra to prevent erectile dysfunction. Arginine has been shown to improve insulin sensitivity in obese type 2 diabetic patients with insulin resistance. Am J Physiol Endocrinol Metab. 2006 Nov;291(5):E906-12. In volunteers drinking three 8-ounce glasses of watermelon juice each day for three weeks, blood levels of arginine (synthesized from citrulline provided by the watermelon) were 11% higher than in controls. Volunteers who drank six daily 8-ounce glasses of watermelon juice for 3 weeks had arginine levels 18% higher than controls. Nutrition. 2007 Mar;23(3):261-6.

Description

If you have ever tasted a watermelon, it is probably no surprise to you why this juicy, refreshing fruit has this name. Watermelon has an extremely high water content, approximately 92%, giving its flesh a crumbly and subtly crunchy texture and making it a favorite thirst-quenching fruit.

As a member of the Cucurbitaceae family, the watermelon is related to the cantaloupe, squash and pumpkin, other plants that also grow on vines on the ground. Watermelons can be round, oblong or spherical in shape and feature thick green rinds that are often spotted or striped. They range in size from a few pounds to upward of ninety pounds.

While we often associate a deep red-pink color with watermelons, in fact there are varieties that feature orange, yellow, or white flesh. While most watermelons have seeds that are black, brown, white, green or yellow, a few varities are actually seedless.

The scientific name for watermelon is Citrullis lanatus.

History

Originating in Africa, watermelons were first cultivated in Egypt where testaments to their legacy were recorded in hieroglyphics painted on building walls. The fruit was held is such regard that it was placed in the tombs of many Egyptian kings. It is not surprising that watermelon played such an important role in this country, and subsequently in countries in the Mediterranean region, since water was often in short supply in these areas, and people could depend upon watermelon for its thirst-quenching properties.

Watermelons were brought to China around the 10th century and then to the Western Hemisphere shortly after the discovery of the New World. In Russia, where much of the commercial supply of watermelons is grown, there is a popular wine made from this fruit. In addition to Russia, the leading commercial growers of watermelon include China, Turkey, Iran and the United States.

How to Select and Store

The best way to choose a flavorful melon is to look at the color and quality of the flesh, which should be a deep color and absent from white streaks. If it features seeds, they should be deep in color.

Oftentimes, however, we do not have this liberty when purchasing watermelon since it is more common to buy a whole, uncut fruit. When choosing a whole watermelon, look for one that is heavy for its size with a rind that is relatively smooth and that is neither overly shiny nor overly dull. In addition, one side of the melon should have an area that is distinct in color from the rest of the rind, displaying a yellowish or creamy tone. This is the underbelly, the place that was resting on the ground during ripening, and if the fruit does not have this marking, it may have been harvested prematurely, which will negatively affect its taste, texture and juiciness.

For the most antioxidants, choose fully ripened watermelon:

Research conducted at the University of Innsbruck in Austria suggests that as fruits fully ripen, almost to the point of spoilage, their antioxidant levels actually increase.

Key to the process is the change in color that occurs as fruits ripen, a similar process to that seen in the fall when leaves turn from green to red to yellow to brown—a color change caused by the breakdown and disappearance of chlorophyll, which gives leaves and fruits their green color.

Until now, no one really knew what happened to chlorophyll during this process, but lead researcher, Bernard Kreutler, and his team, working together with botanists over the past several years, has identified the first decomposition products in leaves: colorless, polar NCCs (nonfluorescing chlorophyll catabolytes), that contain four pyrrole rings - like chlorophyll and heme.

After examining apples and pears, the scientists discovered that NCCs replace the chlorophyll not only in the leaves of fruit trees, but in their very ripe fruits, especially in the peel and flesh immediately below it.

"When chlorophyll is released from its protein complexes in the decomposition process, it has a phototoxic effect: when irradiated with light, it absorbs energy and can transfer it to other substances. For example, it can transform oxygen into a highly reactive, destructive form," report the researchers. However, NCCs have just the opposite effect. Extremely powerful antioxidants, they play an important protective role for the plant, and when consumed as part of the human diet, NCCs deliver the same potent antioxidant protection within our bodies. . Angew Chem Int Ed Engl. 2007 Nov 19;46(45):8699-8702.

The quantity of carotenoids from watermelon, particularly lycopene and beta-carotene, increases if this melon is stored at room temperature, indicates a recent U.S. Department of Agriculture study published in the Journal of Agricultural and Food Chemistry.

Recent studies have linked lycopene to reducing the risk of prostate cancer and lowering inflammation that may cause hypertension and heart disease. A 180 gram (6.3 ounce) serving of watermelon is said to provide between 8 and 20 mg of lycopene, making it a rich source of the carotenoid.

The USDA research looked at the effect of storage on the carotenoid levels of three types of watermelon (open-pollinated seeded, hybrid seeded, and seedless) at 41°F(5°C), 55.4°F(13°C), and 69.8F(21°C) for 14 days.

Carotenoid levels increased in watermelons stored at 69.8°F(21°C). Compared to fresh fruit, watermelons stored at this temperature gained between 11-40% in lycopene, and beta-carotene content increased by between 50-139%. Fruit stored at 41°F(5°C) and 55.4°F(13°C), however, showed only very small changes in carotenoid content.

"The increased lycopene and beta-carotene contents of fruit held at 69.8 degrees Fahrenheit, but not at 55.4 or 41 degrees, indicate temperature sensitivity and enhancement of carotenoid pathway enzymes in watermelon," wrote the researchers.

Lycopene is produced by increased conversion of geranyl-geranyl diphosphate (GGPP) to phytoene by the enzyme, phytoene synthsase, which is then turned into lycopene by the enzyme, phytoene desaturase. So, increase the lycopene and beta-carotene your watermelon delivers by storing it at room temperature.

Yet, once cut, watermelons should be refrigerated in order to best preserve their freshness, taste and juiciness. If the whole watermelon does not fit in your refrigerator, cut it into pieces (as few as possible), and cover them with plastic wrap to prevent them from becoming dried out and from absorbing the odors of other foods.

How to Enjoy

For some of our favorite recipes, click Recipes.

Tips for Preparing Watermelon:

Wash the watermelon before cutting it. Due to its large size, you will probably not be able to run it under water in the sink. Instead, wash it with a wet cloth or paper towel.

Depending upon the size that you desire, there are many ways to cut a watermelon. The flesh can be sliced, cubed or scooped into balls. Watermelon is delicious to eat as is, while it also makes a delightful addition to a fruit salad. Jam, sorbet and juice are some nutritious and delicious things you can make with watermelon.

While many people are just accustomed to eating the juicy flesh of the watermelon, both the seeds and the rind are also edible. If you choose to eat the rind, we would highly suggest purchasing organic watermelon.

A Few Quick Serving Ideas:

Purée watermelon, cantaloupe and kiwi together. Swirl in a little plain yogurt and serve as refreshing cold soup.

In Asian countries, roasted watermelon seeds are either seasoned and eaten as a snack food or ground up into cereal and used to make bread.

A featured item of Southern American cooking, the rind of watermelon can be marinated, pickled or candied.

Watermelon mixed with thinly sliced red onion, salt and black pepper makes a great summer salad.

Watermelon is a wonderful addition to fruit salad.
And fruit salad can be made days ahead since cut fruit, if chilled, retains its nutrients for at least 6 days.

It's been thought that cut fruit rapidly degrades, so fruit salad, which can take 15 minutes to prepare, would have to be freshly prepared to be good.

Now, a study published in the Journal of Agricultural and Food Chemistry has found that minimal processing of fruit—cutting, packaging and chilling—does not significantly affect its nutritional content even after 6, and up to 9, days. This is great news for all who enjoy delicious, colorful fresh fruit salad—and who doesn't since it's a perfect addition to any meal and makes a great snack or dessert?

Researchers cut up pineapples, mangoes, cantaloupes, watermelons, strawberries and kiwi fruit. The freshly cut fruits were then rinsed in water, dried, packaged in clamshells (not gastight) and stored at 41°F(5°C).

After 6 days, losses in vitamin C were less than 5% in the watermelon, mango, and strawberry pieces, 10% in pineapple pieces, 12% in kiwifruit slices, and 25% in cantaloupe cubes.

No losses in carotenoids were found in the watermelon cubes and kiwifruit slices. Pineapples lost 25%, followed by 10-15% in cantaloupe, mango, and strawberry pieces.

No significant losses in phenolic phytonutrients were found in any of the fresh-cut fruit products.

"Contrary to expectations, it was clear that minimal processing had almost no effect on the main antioxidant constituents. The changes in nutrient antioxidants observed during nine days at five degrees Celsius would not significantly affect the nutrient quality of fresh cut fruit. In general, fresh-cut fruits visually spoil before any significant nutrient loss occurs," wrote lead researcher Maria Gil. In practical terms, this means that you can prepare a large bowl of fruit salad containing watermelon on the weekend, store it in the refrigerator, and enjoy it all week, receiving almost all the nutritional benefits of just prepared fruit salad. Before cutting up your watermelon, however, don't forget to store it at room temperature to maximize its carotenoid content (see Select and Store tips above).

Individual Concerns

Watermelon is not a commonly allergenic food, is not known to contain measurable amounts of oxalates or purines and is also not included in the Environmental Working Group's 2010 report "Shopper's Guide to Pesticides" as one of the 12 foods most frequently containing pesticide residues.

Nutritional Profile

Watermelon is an excellent source of vitamin C. It is also a very good source of vitamin A and vitamin B6. In addition, watermelon is a good source of thiamin, potassium and magnesium.

For an in-depth nutritional profile click here: Watermelon.

In-Depth Nutritional Profile
In addition to the nutrients highlighted in our ratings chart, an in-depth nutritional profile for Watermelon is also available. This profile includes information on a full array of nutrients, including carbohydrates, sugar, soluble and insoluble fiber, sodium, vitamins, minerals, fatty acids, amino acids and more.

Introduction to Food Rating System Chart
In order to better help you identify foods that feature a high concentration of nutrients for the calories they contain, we created a Food Rating System. This system allows us to highlight the foods that are especially rich in particular nutrients. The following chart shows the nutrients for which this food is either an excellent, very good, or good source (below the chart you will find a table that explains these qualifications). If a nutrient is not listed in the chart, it does not necessarily mean that the food doesn't contain it. It simply means that the nutrient is not provided in a sufficient amount or concentration to meet our rating criteria. (To view this food's in-depth nutritional profile that includes values for dozens of nutrients - not just the ones rated as excellent, very good, or good - please use the link below the chart.) To read this chart accurately, you'll need to glance up in the top left corner where you will find the name of the food and the serving size we used to calculate the food's nutrient composition. This serving size will tell you how much of the food you need to eat to obtain the amount of nutrients found in the chart. Now, returning to the chart itself, you can look next to the nutrient name in order to find the nutrient amount it offers, the percent Daily Value (DV%) that this amount represents, the nutrient density that we calculated for this food and nutrient, and the rating we established in our rating system. For most of our nutrient ratings, we adopted the government standards for food labeling that are found in the U.S. Food and Drug Administration's "Reference Values for Nutrition Labeling." Read more background information and details of our rating system.

Watermelon, diced
1.00 cup
152.00 grams
48.64 calories
Nutrient Amount DV
(%) Nutrient
Density World's Healthiest
Foods Rating
vitamin C 14.59 mg 24.3 9.0 excellent
vitamin A 556.32 IU 11.1 4.1 very good
vitamin B6 (pyridoxine) 0.22 mg 11.0 4.1 very good
vitamin B1 (thiamin) 0.12 mg 8.0 3.0 good
potassium 176.32 mg 5.0 1.9 good
magnesium 16.72 mg 4.2 1.5 good
World's Healthiest
Foods Rating Rule
excellent DV>=75% OR Density>=7.6 AND DV>=10%
very good DV>=50% OR Density>=3.4 AND DV>=5%
good DV>=25% OR Density>=1.5 AND DV>=2.5%

In-Depth Nutritional Profile for Watermelon

References

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Collins JK, Wu G, Perkins-Veazie P, Spears K, Claypool PL, Baker RA, Clevidence BA. Watermelon consumption increases plasma arginine concentrations in adults. Nutrition. 2007 Mar;23(3):261-6. 2007. PMID:17352962.
Edwards AJ, Vinyard BT, Wiley ER et al. Consumption of watermelon juice increases plasma concentrations of lycopene and beta-carotene in humans. J Nutr 2003 Apr;133(4):1043-50 2003.
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Gil MI, Aguayo E, Kader AA. Quality changes and nutrient retention in fresh-cut versus whole fruits during storage. J Agric Food Chem. 2006 Jun 14;54(12):4284-96. 2006. PMID:16756358.
Jian L, Lee AH, Binns CW. Tea and lycopene protect against prostate cancer. Asia Pac J Clin Nutr. 2007;16 Suppl 1:453-7. 2007. PMID:17392149.
Lucotti P, Setola E, Monti LD, Galluccio E, Costa S, Sandoli EP, Fermo I, Rabaiotti G, Gatti R, Piatti P. Beneficial effects of a long-term oral L-arginine treatment added to a hypocaloric diet and exercise training program in obese, insulin-resistant type 2 diabetic patients. Am J Physiol Endocrinol Metab. 2006 Nov;291(5):E906-12. Epub 2006 Jun 13. 2006. PMID:16772327.
Perkins-Veazie P, Collins JK. Carotenoid changes of intact watermelons after storage. J Agric Food Chem. 2006 Aug 9;54(16):5868-74. 2006. PMID:16881688.
Wood, Rebecca. The Whole Foods Encyclopedia. New York, NY: Prentice-Hall Press; 1988 1988. PMID:15220.