Watermelon is an excellent source of lycopene, with upwards of 6,500 micrograms (6.5 mg). Consumption of watermelon juice increases plasma concentrations of lycopene and beta-carotene in humans.
Also noteworthy, the lycopene in watermelon appears to be quite stable, with little deterioration occurring even after it’s been cut and stored in the refrigerator for more than two days. In one study, it took about seven days of storage for the lycopene to deteriorate, and then it was only by about 6 percent to 11 percent.
So what makes lycopene so important?
Lycopene’s antioxidant activity has long been suggested to be more powerful than that of other carotenoids, such as beta-carotene. Lycopene helps to protect you against UV rays, sunburn and skin cancer. In one study, after controlling for other stroke risk factors, such as older age and diabetes, they found that men with the highest blood levels of lycopene were 55 percent less likely to have a stroke than those with the lowest.