Drinking water is an important way to keep your body hydrated.
However, eating foods that have a high water content can also help. Interestingly, watermelon is 92% water (1Trusted Source).
What’s more, a high water content is one of the reasons why fruits and vegetables help you feel full.
The combination of water and fiber means you’re eating a good volume of food without a lot of calories.
As far as fruits go, watermelon is one of the lowest in calories — only 46 calories per cup (154 grams). That’s lower than even low-sugar fruits such as berries (2).
One cup (154 grams) of watermelon has many other nutrients as well, including these vitamins and minerals:
- Vitamin C: 21% of the Reference Daily Intake (RDI)
- Vitamin A: 18% of the RDI
- Potassium: 5% of the RDI
- Magnesium: 4% of the RDI
- Vitamins B1, B5 and B6: 3% of the RDI
Watermelon is also high in carotenoids, including beta-carotene and lycopene. Plus, it has citrulline, an important amino acid.
Here’s an overview of watermelon’s most important antioxidants:
Vitamin C is an antioxidant that helps prevent cell damage from free radicals.
Carotenoids are a class of plant compounds that includes alpha-carotene and beta-carotene, which your body converts to vitamin A.
Lycopene is a type of carotenoid that doesn’t change into vitamin A. This potent antioxidant gives a red color to plant foods such as tomatoes and watermelon and is linked to many health benefits.
Cucurbitacin E is a plant compound with antioxidant and anti-inflammatory effects. Bitter melon, a relative of watermelon, contains even more cucurbitacin E.
Researchers have studied lycopene and other individual plant compounds in watermelon for their anti-cancer effects.
Though lycopene intake is associated with a lower risk of some types of cancer, study results are mixed. The strongest link so far seems to be between lycopene and cancers of the digestive system (1Trusted Source).
It appears to reduce cancer risk by lowering insulin-like growth factor (IGF), a protein involved in cell division. High IGF levels are linked to cancer (3Trusted Source).
In addition, cucurbitacin E has been investigated for its ability to inhibit tumor growth (4Trusted Source, 5Trusted Source).
Heart disease is the number one cause of death worldwide (6Trusted Source).
Lifestyle factors, including diet, may lower your risk of heart attack and stroke by reducing blood pressure and cholesterol levels.
Several nutrients in watermelon have specific benefits for heart health.
Studies suggest that lycopene may help lower cholesterol and blood pressure. It can also help prevent oxidative damage to cholesterol (1Trusted Source).
According to studies in obese, postmenopausal women and Finnish men, lycopene may also reduce the stiffness and thickness of artery walls (7Trusted Source, 8Trusted Source).
Watermelon also contains citrulline, an amino acid that may increase nitric oxide levels in the body. Nitric oxide helps your blood vessels expand, which lowers blood pressure (9Trusted Source).
Other vitamins and minerals in watermelon are also good for your heart. These include vitamins A, B6, C, magnesium and potassium (1Trusted Source).
Inflammation is a key driver of many chronic diseases.
Watermelon may help lower inflammation and oxidative damage, as it’s rich in the anti-inflammatory antioxidants lycopene and vitamin C (1Trusted Source).
In a 2015 study, lab rats were fed watermelon powder to supplement an unhealthy diet. Compared to the control group, they developed lower levels of the inflammatory marker C-reactive protein and less oxidative stress (10Trusted Source).
In an earlier study, humans were given lycopene-rich tomato juice with added vitamin C. Overall, their markers of inflammation went down and antioxidants went up. Watermelon has both lycopene and vitamin C (11Trusted Source).
As an antioxidant, lycopene may also benefit brain health. For example, it may help delay the onset and progression of Alzheimer’s disease (12).
Lycopene is found in several parts of the eye where it helps protect against oxidative damage and inflammation.
It may also prevent age-related macular degeneration (AMD). This is a common eye problem that can cause blindness in older adults (1Trusted Source).
Lycopene’s role as an antioxidant and anti-inflammatory compound may help prevent AMD from developing and getting worse.
For more information on how to keep your eyes healthy, consider reading The 9 Most Important Vitamins for Eye Health.
Citrulline, an amino acid in watermelon, may reduce muscle soreness. It’s also available as a supplement.
Interestingly, watermelon juice appears to enhance the absorption of citrulline.
One small study gave athletes plain watermelon juice, watermelon juice mixed with citrulline or a citrulline drink. Both watermelon drinks led to less muscle soreness and quicker heart rate recovery, compared to citrulline on its own (13Trusted Source).
The researchers also conducted a test-tube experiment, investigating the absorption of citrulline. Their findings suggest that citrulline absorption is most effective when it’s consumed as a component of watermelon juice.
Other research has also looked at citrulline’s potential to improve exercise endurance and performance.
So far, citrulline doesn’t seem to improve exercise performance in the amounts studied, but it’s still an area of research interest (14Trusted Source).
Two vitamins in watermelon — A and C — are important for skin and hair health.
Vitamin C helps your body make collagen, a protein that keeps your skin supple and your hair strong.
Vitamin A is also important for healthy skin since it helps create and repair skin cells. Without enough vitamin A, your skin can look dry and flaky.
Both lycopene and beta-carotene may also help protect your skin from sunburn (15Trusted Source).
Watermelon contains lots of water and a small amount of fiber — both of which are important for healthy digestion.
Fiber can provide bulk for your stool, while water helps keep your digestive tract moving efficiently.
Eating water-rich and fiber-rich fruits and vegetables, including watermelon, can be very helpful for promoting normal bowel movements.
Watermelon is a surprisingly healthy fruit. It has a high water content and also delivers many other important nutrients, including lycopene and vitamin C.
These nutrients mean that watermelon isn’t only a tasty low-calorie treat — it’s also very good for your health.