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Watermelon: Health Benefits, Risks & Nutrition Facts

watermelon, nutrition
Credit: junyanjiang | Shutterstock

Watermelons may be mostly water — about 92 percent — but these refreshing fruits are soaked with nutrients. Each juicy bite gives you significant levels of vitamins A, B6 and C, lots of lycopene, antioxidants and amino acids, and even a modest amount of potassium. Plus, this quintessential summer snack is fat-free, very low in sodium, and has only 40 calories per cup.

Scientists have taken notice of watermelon’s high lycopene levels. Lycopene is the red pigment that gives watermelons, tomatoes, red grapefruits and guavas their color. It’s also a valuable carotenoid phytonutrient linked with heart health, bone health and prostate cancer prevention. Watermelon has some of the highest levels of lycopene of any type of fresh produce, at about 15 to 20 milligrams per 2-cup serving. To really maximize your lycopene intake, let your watermelon fully ripen. The redder your watermelon gets, the higher the concentration of lycopene becomes. Beta-carotene and phenolic antioxidant content also increase as the watermelon ripens. However, all parts of the watermelon —including the white flesh nearest the rind — contain lots of nutrients.

Watermelon also contains a significant amount of the amino acid citrulline, which converts to the amino acid arginine. These amino acids promote blood flow, leading to cardiovascular health, improved circulation, and as some scientists have suggested, erectile dysfunction improvement (you’d probably have to eat a lot of watermelon to get a Viagra-like effect, though).

Here are the nutrition facts for watermelon, according to the U.S. Food and Drug Administration, which regulates food labeling through the National Labeling and Education Act:

Nutrition Facts

Serving size:
2 cups diced
(10 oz / 280 g)

Calories 80
  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 0g 0%   Total Carbohydrate 21g 7%
Cholesterol 0mg 0%     Dietary Fiber 1g 4%
Sodium 0mg 0%      Sugars 20g  
Potassium 270mg 8%   Protein 1g  
Vitamin A 30%   Calcium 2%
Vitamin C 25%   Iron 4%

Watermelon health benefits

Heart health

In addition to watermelon’s high levels of lycopene, which is very effective at protecting cells from damage and may help lower the risk of heart disease, the fruit’s concentrations of citrulline and arginine are good for your heart. Arginine can help improve blood flow and may help reduce the accumulation of excess fat. One 2012 study found that watermelon extracts helped reduce hypertension and lower blood pressure in obese adults.

Anti-inflammatory properties

Reducing inflammation isn’t just good for people suffering from arthritis. Anti-inflammatory foods can help with overall immunity and general health. The benefits of watermelon’s lycopene continue with its abilities to reduce inflammation. Lycopene is an inhibitor for various inflammatory processes and also works as an antioxidant to neutralize free radicals. Additionally, watermelon’s choline content helps keep chronic inflammation down, while to helping to maintain cellular structure and absorb fats.

Hydration

Watermelons are 92 percent water, so it’s no coincidence that they’re so refreshing on a hot summer day. Their water content can help keep you hydrated, and their juice is full of good electrolytes. This can even help prevent heat stroke.

Digestion

Watermelon contains fiber, which encourages a healthy digestive tract and helps keep you regular.

Skin and hair benefits

Vitamin A is stellar for your skin, and just a cup of watermelon contains nearly one-quarter of your daily recommended intake of it. Vitamin A helps keep skin and hair moisturized, and it also encourages healthy growth of new cells. Vitamin C is also beneficial in this regard, as it promotes healthy collagen growth.

Muscle soreness

Watermelon-loving athletes are in luck: a 2013 study found that drinking watermelon juice before an intense workout helps reduce next-day muscle soreness and heart rate. This can be attributed to watermelon’s amino acids citrulline and arginine, which help improve circulation.

Cancer prevention

Like other fruits and vegetables, watermelons may be helpful in reducing the risk of cancer through their antioxidant properties. Lycopene in particular has been linked to reducing prostate cancer cell proliferation, according to the National Cancer Institute.

Watermelon health risks

If eaten in reasonable amounts, watermelon should produce no serious side effects. If you eat an abundance of watermelon daily, however, you may experience problems from having too much lycopene or potassium.

Consuming more than 30 mg of lycopene daily could potentially cause nausea, diarrhea, indigestion and bloating.

People with serious hyperkalemia, or too much potassium in their blood, should probably not consume more than about one cup of watermelon a day, which has less than 140 mg of potassium. Hyperkalemia can result in irregular heartbeats and other cardiovascular problems, as well as reduced muscle control.

Watermelon facts

Watermelon (Citrullus lanatus) is related to cucumbers, pumpkins and squash.

Watermelon probably originated in the Kalahari Desert in Africa.

Egyptians placed watermelons in the burial tombs of kings to nourish them in the afterlife. The first recorded watermelon harvest is depicted in Egyptian hieroglyphics from about 5,000 years ago.

Merchants spread watermelons along the Mediterranean Sea. By the 10th century, watermelon had found its way to China, which is now the world's top producer of watermelons.

The Moors in the 13th century spread watermelon to Europe.

Watermelon likely made its way to the United States with African slaves.

Early explorers used watermelons as canteens.

The first cookbook published in the United States in 1776 contained a recipe for watermelon rind pickles.

About 200 to 300 varieties are grown in the United States and Mexico, but only about 50 varieties are very popular.

By weight, watermelon is the most-consumed melon in the United States, followed by cantaloupe and honeydew.

The watermelon is the official state vegetable of Oklahoma.

All parts of a watermelon can be eaten, even the rind.

Guinness World Records says the world's heaviest watermelon was grown by Lloyd Bright of Arkadelphia, Arkansas, in 2005. It weighed 268.8 lbs. (121.93 kg).

The United States ranks fifth in worldwide production of watermelon. Forty-four states grow watermelons, with Florida, Texas, California, Georgia and Arizona leading the country in production.

A seedless watermelon is a sterile hybrid, which is created by crossing male pollen for a watermelon, containing 22 chromosomes per cell, with a female watermelon flower with 44 chromosomes per cell. When this seeded fruit matures, the small, white seed coats inside contain 33 chromosomes, rendering it sterile and incapable of producing seeds.

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