Health Benefits Of Watermelon

Watermelons 

Despite the popular belief that watermelon is just water and sugar, watermelon is a nutrient-dense food. It provides high levels of vitamins, minerals, and antioxidants and just a small number of calories.

Watermelons have become synonymous with summer and picnics, and for good reason. Their refreshing quality and sweet taste help to combat the heat and provide a guilt-free, low maintenance dessert.

Along with cantaloupe and honeydew, watermelons are a member of the botanical family Cucurbitaceae. There are five common types of watermelon: seeded, seedless, mini (also known as personal), yellow, and orange.

1. Hydrates You

Drinking water is an important way to keep your body hydrated.
However, eating foods that have high water content can also help. Interestingly, watermelon is 92% water. The combination of water and fiber means you're eating a good volume of food without a lot of calories.

It’s called watermelon for a reason. While refilling your S’well bottle is undeniably a good thing, what you eat also counts toward your hydration quota for the day, says Smith. (In fact, food makes up about 20 percent of your water intake.) Considering watermelon is drip-down-your-chin juicy, it should come as no surprise that it’s a great way to “drink” up in addition to your other healthy hydration habits.

Made up of 92 percent water and full of important electrolytes, watermelon is a great snack to have on hand during the hot summer months to prevent dehydration. It can also be frozen in slices for a tasty cold Popsicle-style snack.

2. Helps To Relieve Muscle Soreness

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.

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.

3. Helps Combat Cancer

Lycopene gets the credit, again. According to a study, lycopene in watermelons has been found to reduce the extent of cancer insurgence. Lycopene is the pigment that renders watermelons their characteristic red color, and since it is a powerful antioxidant, it prevents the onset of certain cancers.

A two-cup serving of watermelon contains about 20 mg of lycopene, which battles free radicals and protects against numerous types of cancer. According to a Chicago study, lycopene exhibits chemopreventive properties, especially in prostate cancer cells.

Lycopene has also been found useful in the treatment of HPV (human papillomavirus) infection, which might otherwise lead to uterine cancer.

4. Helps Treat Diabetes

Although watermelon has a high glycemic index, it has a lower glycemic load (the value by which a particular food will raise an individual’s blood glucose levels), and hence is suitable for Diabetes.

In a Nigerian study, watermelon was found to have anti-diabetic properties. Another study showed the beneficial effects of watermelon pomace juice – it increases the mass of brown adipose tissue and reduces excess white fat mass, which eventually helps treat diabetes.

5. Best Workout Snack

Not only are watermelons 92 percent water, but they’re also full of magnesium and potassium. We often lose these two minerals, along with sodium, in our sweat during exercise, and they need to be replenished immediately. Potassium and magnesium are known as electrolytes because they help carry the electrical signals in the body and allow our muscles to contract and relax.

6. Heart Health

Watermelons contain a unique amino acid called citrulline, which our bodies use to manufacture another amino acid called arginine. Arginine plays a direct role in the volume and direction of blood flow in the body. It’s currently being researched in treating erectile dysfunction, with promising results.

Other Benefits

It is the diversity of phytonutrients in watermelon—and some key players in this group—that make this fruit unique in terms of anti-inflammatory and antioxidant benefits. You will find many different types of phenolic phytonutrients in watermelon, including carotenoids, flavonoids, and triterpenoids. Among these phytonutrients, lycopene (a carotenoid) and cucurbitacin E (a triterpenoid) stand out from a research perspective as being most closely related to this fruit's antioxidant and anti-inflammatory benefits. In the case of lycopene, you can expect to receive an average amount of 4–5 mg of lycopene in every 100g (approximately two-thirds cup in volume) of red-fleshed watermelon. This amount makes red-fleshed watermelon–on average–more concentrated in lycopene than red tomatoes, which usually contain about 3–4 mg per 100g (approximately one-half cup in volume). 

Moreover, the bioavailability of lycopene from red-fleshed watermelon appears to be greater than its bioavailability from red tomato. This greater bioavailability may have to do with the presence of cis-isomeric lycopene in red-fleshed watermelon, which is a more readily available form of this carotenoid. (At WHFoods, our top lycopene sources include not only watermelon and tomato but also papaya and pink grapefruit.) Lycopene is a carotenoid that has been best studied about cardiovascular disease, where it has repeatedly been shown to lower disease risk through scavenging of lipid peroxyl radicals and reactive oxygen species (ROS). 

Deficiencies in lycopene throughout aging have also been associated with increased age-related cardiovascular disease. The lycopene richness in red-fleshed watermelon makes this fruit a logical choice for increased antioxidant protection, particularly as it relates to our cardiovascular system.

We think about cucurbitacin E as a second featured phytonutrient in watermelon that acts to complement the activities of lycopene. Cucurbitacin E is a triterpenoid that is known to lessen unwanted inflammation by inhibiting the activity of the enzyme cyclooxygenase-2 (COX-2). Unlike lycopene, however, it does not appear to be especially effective in the scavenging of ROS. However, it is very effective in the scavenging of RNS (which stands for reactive nitrogen species). By combining these two phytonutrients (lycopene and cucurbitacin E), watermelon can provide us with improved scavenging of both oxygen and nitrogen radicals, and lessen our risk of undesirable oxidative stress or chronic unwanted inflammation.

Within the context of cardiovascular benefits, it's important to recognize the third nutrient in watermelon present in unusual amounts. This nutrient is the amino acid citrulline. While the amount of citrulline in watermelon flesh can vary significantly, the cup of fresh watermelon that we profile on our website is estimated to contain between 200–300 milligrams of citrulline. One primary way in which citrulline can provide us with cardiovascular support is through its role in a metabolic process known as the urea cycle. In this cycle, three amino acids—citrulline, arginine, and ornithine—undergo interconversion. During this interconversion process, a key cell-signaling molecule—nitric oxide (NO) —can get produced. (NO) plays a key role in the regulation of blood pressure since it can increase the expansion of our blood vessel diameter, thus lowering the pressure at which our blood flows. Levels of NO have also been determined to play a key role in the regulation of our blood sugar. Since NO is directly produced from the conversion of arginine into citrulline, researchers have long been interested in the degree to which citrulline intake can affect the overall balance of citrulline, arginine, ornithine, and NO in this area of metabolism.

Similarly, researchers have wondered if a citrulline-rich food like watermelon might provide us with potential cardiovascular benefits. One recent study has looked at this exact set of questions in a group of participants who consumed between 3–6 cups of watermelon juice per day over several weeks. What the researchers found was a steady and well-maintained level of citrulline in the bloodstream of the participants, as well as an increased level of arginine. 

They concluded from these findings that citrulline from the watermelon juice had undergone conversion into arginine while leaving plenty of citrullines to stabilize blood levels. In other words, the citrulline from watermelon was viewed as improving balance in this area of metabolism. These findings add to the research evidence for watermelon as a fruit that can lower our risk of high blood pressure and type 2 diabetes especially since arginine deficiency—whether chronic and moderate or temporary and serve deficiency—has been linked to increased risk of both health problems.


When considering antioxidant benefits from watermelon, it would be wrong to overlook vitamin C and beta-carotene. In our Food Rating System, watermelon qualifies as a very good source of vitamin C, providing about 12 mg per fresh cup. Two cups' worth of this delicious fruit means that one-third of our daily recommended vitamin C intake has already been met. Watermelon ranks as a good source of vitamin A in our food rating system, and this rank is largely due to its beta-carotene content. 

While watermelon contains a far greater amount of lycopene than beta-carotene, researchers do not take lycopene into account when estimating vitamin A activity since lycopene is a carotenoid that cannot be converted into retinol. Beta-carotene, however, is the best non-retinol form of carotenoids for conversion into vitamin A. Beta-carotene is typically highest in red-fleshed varieties of watermelon, although amounts can vary greatly, in a range of approximately 5–325 micrograms per 100 grams. But even in the lower half of this range, we are getting valuable antioxidant benefits from the beta-carotene content of watermelon.