- Alongside of tomatoes,
watermelon has moved up to the front of the line in recent research
studies on high-lycopene foods. Lycopene is a carotenoid phytonutrient
that's especially important for our cardiovascular health, and an
increasing number of scientists now believe that lycopene is important for
bone health as well. Among whole, fresh fruits that are commonly eaten in
the U.S., watermelon now accounts for more U.S. intake of lycopene (by
weight of fruit eaten) than any other fruit. Pink grapefruit and guava are
two other important fruit sources of lycopene, although in the U.S., these
fruits are more often consumed in the form of juice.
- Health scientists are becoming more and more interested in the citrulline content of watermelon. Citrulline is an amino acid that is commonly converted by our kidneys and other organ systems into arginine (another amino acid). The flesh of a watermelon contains about 250 millligrams of citrulline per cup. When our body absorbs this citrulline, one of the steps it can take is conversion of citrulline into arginine. Particularly if a person's body is not making enough arginine, higher levels of arginine can help improve blood flow and other aspects of our cardiovascular health. There's also some preliminary evidence from animal studies that greater conversion of citrulline into arginine may help prevent excess accumulation of fat in fat cells due to blocked activity of an enzyme called tissue-nonspecific alkaline phosphatase, or TNAP.
- If you've gotten used to thinking about the juicy red flesh at the center of a watermelon as its only nutrient-rich area—and far more nutrient-rich than the more lightly-colored flesh that is farther out near the watermelon rind—it is time to change your thinking. In a recent study, food scientists compared the nutrient content of flesh from different parts of a watermelon: flesh from the center, the stem end, the blossom end (opposite from the stem), and the periphery (the part nearest to the rind). What they've discovered were impressive concentrations of phenolic antioxidants, flavonoids, lycopene, and vitamin C in all of these different areas. The exact distribution of nutrients was also highly dependent on the variety of watermelon. But there was no area in any of the watermelon varieties that came out badly in terms of nutrients, and in many of the watermelon varieties, the flesh's outer periphery contained impressive concentrations of most nutrients.
- Recent studies have
confirmed the nutritional importance of allowing a watermelon to fully ripen.
For example, research has shown that the biggest jump in lycopene content
occurs at the time when a watermelon's flesh turns from white-pink to
pink. Yet when that flesh continues to ripen, resulting in a color change
from pink to red, the lycopene content becomes even more concentrated.
Prior to ripening, when the flesh of a watermelon is primarily white in
color, its beta-carotene content is near zero. Even when allowed to ripen
to the white-pink stage, a watermelon still contains very little of its
eventual beta-carotene content. But as it moves from white-pink to pink to
red, the beta-carotene content of a watermelon steadily increases. Like
lycopene and beta-carotene, total phenolic antioxidants in a watermelon
also increase consistently during ripening, all the way up until the
appearance of fully red flesh. The bottom line: eating a fully ripe
watermelon can really pay off in terms of nutrient benefits. Please see
our section called "How to Select and Store" to learn about
determining a watermelon's ripeness before you purchase it.
Reasons why you should eat water melon
1. It soothes sore muscles.
According
to a new study in the Journal of Agricultural
Food and Chemistry, drinking watermelon juice before a hard workout helped reduce
athletes' heart rate and next-day muscle soreness. That's because watermelon is
rich in an amino acid called L-citrulline, which the body converts to L-arginine, an essential
amino acid that helps relax blood
vessels and improve circulation.
The
study's seven participants, all men, were given 17 ounces (500 mL) of either
natural watermelon juice, watermelon juice enriched with additional citrulline,
or a placebo drink an hour before their workouts. Interestingly, the natural
juice was just as effective as the enriched juice. The researchers also
determined that intestinal cells can absorb more citrulline from watermelon
juice than from citrulline supplements, especially when the juice is
unpasteurized.
2. It helps heart health.
Postmenopausal
women experienced improved
cardiovascular health after six weeks of taking commercially available
watermelon extract supplements containing citrulline and arginine, according to
a study published earlier this year by Florida State University physiologist Arturo Figueroa.
And
in a 2012 study—also led by Figueroa—such supplements helped alleviate high blood pressure in
obese, middle-aged adults. (Not surprisingly, he's received two grants from the Watermelon Promotion Board.)
3. It could be a natural Viagra.
Improved
circulation can benefit more than just the heart, as at least one watermelon
researcher has pointed out. But you'd probably have to eat an awful lot to
achieve the desired effect--and eating too much could cause unfortunate side
effects, since watermelon has long had areputation as a natural diuretic.
4. It's rich in vitamins and minerals, but low in calories.
Given
its name, you might assume the fruit has little nutritional value—and it is more than 90 percent water. But a
10-ounce (300-mL) wedge of watermelon packs in about one-third of the
recommended daily value of vitamins A and C, as well as a modest amount of
potassium (9 percent of the daily value).
5. It could even combat cancer.
Watermelon
is among the best dietary sources of lycopene, an
antioxidant linked to both the prevention and treatment of prostate cancer, although
scientists are still investigating the details of that connection.
0 blogger-facebook:
Post a Comment