Watermelon is a fruit native to tropical Africa. It was cultivated centuries ago along the banks of the Nile River. From Europe, it reached the Americas and began to be cultivated throughout the continent. The wandering Israelites, after their flight from Egypt 3,500 years ago, also left behind the watermelons they ate in the land of the pyramids. It was brought to the Americas by Spanish priests in the mid-16th century.

Today, it is one of the most widespread fruits in the world, and the main producing countries are Turkey, Greece, Italy, Spain, China, and Japan.

More than fifty varieties of watermelon are known, classified according to the shape of their fruit, the color of the pulp, the color of the skin, the weight, the ripening period, etc.

20 years ago, a Japanese farmer on the island of Shikoku designed glass boxes in which he enclosed the germinating plants so that, as they grew, they would adapt to the cubicle, giving rise to square watermelons, which facilitates their packaging.

In the United States, there has been experimentation with the production of seedless watermelons, and in Chile, individual round watermelons are already known.

But in this delicious fruit, there is more than just flavor and color.

The lycopene richness of watermelon makes it a worthy rival to the tomato in the prevention of prostate cancer and against cellular aging.

American experts confirm that its juice could be a very rich natural source of L-citrulline, which is a precursor to L-arginine, an amino acid that dilates blood vessels, with properties similar to Viagra.

Citrulline is a non-essential amino acid that has the ability to produce relaxation of the capillaries. It is formed in the human body inside the mitochondria, starting from ornithine or glutamine. Once citrulline is formed, it moves outside the mitochondria to form arginine and finally transform ammonia into urea. This process is of vital importance for eliminating nitrogenous waste products from the body.

Citrulline relaxes the capillaries by producing nitric oxide, since nitric oxide relaxes blood vessels, which prevents erectile dysfunction. It is suggested that a good serving of watermelon could have effects similar to the drug Viagra.

In addition, citrulline increases blood flow to the muscles, which translates into delivering more oxygen and nutrients to these tissues, reducing muscle pain, and improving recovery and physical performance. Furthermore, due to its composition, watermelon is an ideal fruit for athletes because of its hydrating effects and electrolyte contribution.

Lycopene is a carotenoid that gives it its red color, with antioxidant and anti-aging capacity, which is present in the blood, along with other beta-carotenes.

It is also part of the prostate, testicles, and adrenal glands. It intervenes in the mechanisms of cell growth control. In the absence of lycopene, cells grow in a disordered manner.

This phytochemical has been associated with the prevention of prostate cancer. Its main source is the tomato, being higher in cooked tomato, and it is also found in grapefruit.

The bioavailability of this compound in the tomato is lower if consumed raw. In cooked products, such as soups, sauces, or stews, lycopene is better absorbed.

Watermelon is a fruit with a high lycopene content. Studies by nutrition specialists Beverly A. Clevidence and Alison J. Edwards of the Phytonutrient Laboratory in Beltsville, Maryland, in a 19-week study with 23 volunteers, confirmed good bioavailability of lycopene from raw watermelon.

Numerous scientific studies have proven that lycopene has antioxidant properties and reduces the risk of certain types of cancer, such as pancreatic, lung, colon, and prostate cancer in particular. A high level of lycopene in blood plasma is especially associated with a lower incidence of the latter type of cancer.

Lycopene, due to its antioxidant activity, acts against free radicals, which justifies the role of watermelon consumption in reducing the risk of cardiovascular and degenerative diseases.

Scientists from the Agricultural Research Service (ARS), the main scientific research agency of the U.S. Department of Agriculture, have discovered that in addition to containing abundant amounts of the antioxidant lycopene, watermelon is an excellent source of the amino acid L-citrulline.

Watermelon is the only food that contains L-citrulline in significant amounts, especially in the rind, but also in the pulp.

Researchers at the ARS in Lane, Oklahoma, have found that the citrulline reserves in watermelon are not only abundant but also readily available. Their findings are reported in a 2007 issue of the journal "Nutrition".

Unlike arginine, citrulline is NOT metabolized in the liver or intestines. It does not activate the arginase enzyme; in fact, citrulline inhibits it. Citrulline can safely regulate the delivery of arginine to the liver.

Studies by the American team of Dr. Collins with 23 volunteers over three weeks found that L-arginine doses with a consumption of 1560 cc of watermelon juice had increased relative to baseline values by 22% the levels of ornithine, a catabolite of L-arginine in its synthesis of nitric oxide.

Ornithine supports liver function and reduces blood ammonia (especially in the form of L-ornithine L-aspartate or LOLA); it is recommended for treating hepatic encephalopathy, helps reduce fatigue, improves physical performance, and lowers stress, as it stimulates the release of growth hormone and modulates cortisol.

Studies by Julie K. Collins ¹, Guoyao Wu , Penélope Perkins-Veazie , Karen Spears , P. Larry Claypool , Robert A. Baker , Beverly A. Clevidence, conclude that the increase in fasting plasma concentrations of arginine and ornithine, as well as the stability of plasma citrulline concentrations in response to watermelon juice consumption, indicated that citrulline from this plant source was effectively converted into arginine. These results demonstrate that plasma arginine concentration can be increased through the ingestion of watermelon citrulline. The increase in fasting plasma concentrations of arginine and ornithine, as well as the stability of plasma citrulline concentrations in response to watermelon juice consumption, indicated that citrulline from this plant source was effectively converted into arginine.

Citrulline is found in greater quantities in the watermelon rind and is a potential substance for exploring numerous metabolic pathways in the human body related to the cardiovascular system.

According to nutritionist Julie Collins, consuming a glass of watermelon juice with every meal for a period of three weeks results in an 18% increase in nitric oxide synthesis, with a consequent decrease in blood pressure.

Medical researchers have evaluated arginine as a possible treatment for high blood pressure, elevated glucose levels, and vascular complications associated with sickle cell disease (a condition where red blood cells do not have their intended shape).

Clinical studies have verified that watermelon juice avoids the nausea, diarrhea, and gastrointestinal discomfort that sometimes occur with L-arginine, since in this case the amino acid is incorporated into the intestinal tract as L-citrulline, an amino acid with a neutral effect.

We know if a watermelon is ripe if the spot on the rind that has been in contact with the ground is a creamy yellow color. A white or greenish spot indicates that it was picked too early and will be tasteless, as watermelon is a non-climacteric fruit, which is why, for it to be of good quality, it must be harvested when it is fully ripe.

The trick to choosing a ripe watermelon is that it should sound "hollow" when you tap it with your fingers or the palms of your hands. Its surface should not show scars, sunburn, abrasions, or dirty areas.

Watermelon is a fruit that stays in perfect condition for two weeks if kept at about 15°C, and up to three weeks at 7-10°C. Because it is very sensitive to cold, it should not be kept at temperatures below 7-10ºC. Its thick rind allows it to last in good condition for many days at room temperature.

Once opened, it should be kept in the refrigerator covered with plastic wrap and consumed as soon as possible.

Composition per 100 grams of edible portion of watermelon

Calories : 20 - 32

Carbohydrates (g) : 4.5 - 6.7

Fiber (g) : 0.3 - 0.5

Potassium (mg) : 88.5 - 116

Magnesium (mg) : 11

Calcium (mg) : 7

Iron (mg) : 0.3

Folic acid (mcg) : 3

Sodium (mg) : 2

Beta-carotene (provitamin A) (mcg) : 18

Vit. A (mcg RE) : 37

Vit. B1 (mg) : 0.080

Vit. B3 (mg) : 0.317

Vit. B6 (mg) : 0.144

Vit. C (mg) : 9.6

mcg = micrograms

• Its seeds are rich in copper, manganese, and zinc. In natural medicine, it is recommended to chew the seeds to combat prostate problems.

• Watermelon is the fruit richest in water (93%), which is why it provides barely 20 calories per 100 grams.

• It has an interesting content of vitamins A, C, E, B1, and B6, which, together with potassium and fiber, make it an ideal food in weight-loss diets, and it is recommended for kidney patients and children.

• It does not provide a large amount of carbohydrates, so it can be consumed by diabetic people. It contains no fat, but its high water content gives it satiety power, which is why it is advisable for weight-loss, cardiovascular, and liver problems.

• Due to its good digestibility and low caloric content, it can be consumed in larger quantities than other fruits, allowing for a greater supply of vitamins and minerals. A 250 g serving provides 70 calories, covers 42% of the daily requirements for vitamin C, 15% for vitamin A, and 10% for vitamin B1.

• Due to its beta-carotene and Vit. C content, it has antioxidant properties very useful for maintaining skin and epithelia in perfect condition.

• Its potassium content (88.5 mg/100 g) makes it an excellent diuretic (potassium is a mineral necessary for the transmission and generation of nerve impulses and for normal muscle activity; it is involved in the balance of water inside and outside the cell).

• Its low sodium content (8 mg/100 g) favors people who must follow low-sodium diets.

• Its fiber content is moderate but sufficient to combat constipation, combining its potential laxative effects with the high water content. One of the advantages of watermelon is that it provides fiber without causing gas or aerophagia problems like other fruits, making it suitable for more delicate stomachs.

• In general, it is easy to digest, although it can be indigestible for certain people if consumed after meals, because its high water content dilutes gastric juices and slows down food digestion, which causes a sensation of indigestion and bloating.

A powerful moisturizer, this fruit is especially indicated during the warm season for the elderly or for people who do not usually drink enough liquids. Two slices of watermelon are equivalent to a glass of water, with the added pleasure of enjoying a refreshing, sweet, and tasty fruit.

It is a magnificent diuretic that increases urine production, which is why its consumption is indicated for those who suffer from kidney stones, high uric acid, hypertension, and other diseases associated with fluid retention.

It promotes the elimination of waste substances through urine, making it a perfect aid as a detoxifier.

Ethnologist Leslie Spier of the University of Chicago, in her 1933 book *Yuman Tribes of the Gila River*, asserts that the Indians of the Southwestern United States prepared a syrup by boiling and filtering the pulp.

Anthropologist Daryll C. Ford reported in 1931 how women from various Hopi villages used this syrup to treat lung, gastrointestinal, and skin problems, as well as other organic dysfunctions.

Medical anthropologist John Heinerman, author of the book *The Encyclopedia of Healing Juices*, confirms the value of freshly squeezed watermelon juice in helping weak bodies recover, based on his observations among the Hopi people, who used it to give energy to elderly people and to treat headaches, infant colic, fever, and heartburn caused by eating too much "white man's food."

It is also mentioned among the Indians for its effect in helping to expel uremic poisons, gout, and arthritis from the body, by drinking fresh, seedless watermelon juice in the morning and at night.

According to J. Heinerman, the Mojave, Yuma, Cocopa, and Maricopa Indians consumed watermelon seeds, roasted or boiled, to prepare a tea that relieved their urogenital discomfort. (Castetter and Bell. Op. cit.)

Furthermore, it is indicated for kidney and urinary tract ailments, such as renal insufficiency, lithiasis, and infections.

This fruit is ideal for weight-loss diets, given that one can consume double the amount of watermelon compared to many other fruits without significantly increasing calories.

1. Cut the pulp including a little of the white part and the seeds and process it without adding water
2. Pass it through a strainer to remove the seed residue
3. Drink twice a day, for as long as necessary

1. John Heinerman. *The Encyclopedia of Healing Juices*. Prentice Hall. USA. 1997
2. Jorge Pamplona Rogers. *The Medicinal Power of Foods*. Ed. Safeliz. Aces. USA. 2003.
3. Jordi Montaner. "The dilating power of watermelon." Consumer.es
4. Erin Peabody. "Watermelon is a rich source of the amino acid citrulline." USDA. http://www.ars.usda.gov/is/AR/archive/jun02/lyco0602.htm
5. BBC. Science. "Forget Viagra, eat watermelon." http://news.bbc.co.uk/go/pr/fr/spanish/science/newsid_7483000/7483059.stm
6. Dr. Glenn S. Rothfeld. "Citrulline: the 'forgotten nutrient' that increases heart health, erectile function, and much more." *Nutrition & Healing*. Number 28 • JANUARY 2022 nutricion-curacion-n2801e.pdf (nutricionycuracion.com)
7. https://www.hsnstore.com/blog/nutricion/aminoacidos/l-ornitina/?srsltid=AfmBOorZzpChfi9szgj6TkVhmNWXz8Qmmoj-L5_nH4onYKzuJIVcydy2
8. https://pubmed.ncbi.nlm.nih.gov/17352962/ 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. doi: 10.1016/j.nut.2007.01.005. PMID: 17352962.
9. https://www.sciencedirect.com/science/article/pii/S2095254620300168