Saturday, July 5, 2008

Watermelon and Fireworks

Photo by Flickr user EricGjerde, used under a Creative Commons license.

Yesterday, I waxed downright sanctimonious about the deeper meanings of the Fourth of July. But let's be honest: For most of us - me too! - the Fourth is about fireworks and food, not FISA and fear (no matter how much fun it is to indulge in silly alliteration).

Last night, we got to see the big display of fireworks in town - the only legal one, since I'm still in California and El Dorado County outlaws freelance fireworks. This policy predates the recent wave of wildfires since much of the county is a forest fire waiting to happen. Given how dry California is, the prohibition ought to apply to the whole state.

Since it doesn't, though, we had a big family celebration on the third at my brother's house (he lives in a county where fireworks are legal) and that's the show we'll all remember. As fireworks displays go, this one had a real kinship with the Charlie Brown Christmas tree. Nothing was allowed to go airborne. But my brother-in-law provided hilarious patter and the kids loved waving sparklers in the air. The show's grand finale was something called the "Dixie Delight," which whistled, sprayed multicolored sparks skyward, and then seceded from the Union. (I'm not sure if this name is a bizarre marketing ploy or some Chinese manufacturer's notion of what Americans want. For all I know, it is what many Americans want.)

As for food, we had the usual American fare, including vast amounts of watermelon. You may have heard that watermelon was in the news a few days ago, with scientists at Texas A&M claiming it may have Viagra-like effects.
Beneficial ingredients in watermelon and other fruits and vegetables are known as phyto-nutrients, naturally occurring compounds that are bioactive, or able to react with the human body to trigger healthy reactions, [Dr. Bhimu] Patil said.

In watermelons, these include lycopene, beta carotene and the rising star among its phyto-nutrients – citrulline – whose beneficial functions are now being unraveled. Among them is the ability to relax blood vessels, much like Viagra does.

Scientists know that when watermelon is consumed, citrulline is converted to arginine through certain enzymes. Arginine is an amino acid that works wonders on the heart and circulation system and maintains a good immune system, Patil said.

"The citrulline-arginine relationship helps heart health, the immune system and may prove to be very helpful for those who suffer from obesity and type 2 diabetes," said Patil. "Arginine boosts nitric oxide, which relaxes blood vessels, the same basic effect that Viagra has, to treat erectile dysfunction and maybe even prevent it."

While there are many psychological and physiological problems that can cause impotence, extra nitric oxide could help those who need increased blood flow, which would also help treat angina, high blood pressure and other cardiovascular problems.

"Watermelon may not be as organ specific as Viagra," Patil said, "but it's a great way to relax blood vessels without any drug side-effects."

(Source: Texas A&M press release via Eurekalert)
Revere at Science Blogs' Effect Measure debunks this claim by noting that Viagra and its chemical cousins (Cialis and Levitra) don't just dilate blood vessels, they keep them open by interfering with an enzyme, phosphodiesterase type 5 (PDE5), that normally counteracts the effects of nitric oxide, causing the vessels to constrict again. Revere says:
Watermelon isn't a PDE5 ihibitor. It has a an ingredient that participates in the formation of NO (nitric oxide). So does pornography. It would have been more accurate to say that watermelon may have a pornography-like effect than that it has a Viagra-like effect.
But hey, that's no small thing! Finding a substance that enhances libido and eases arousal has been the holy grail of research on a "female Viagra" for women whose sexual responsiveness is flagging. This is both medically and politically tricky, as I discussed a few months ago. But imagine if one's libido could be amplified something as innocuous as watermelon - which won't cause headaches or blue vision, like Viagra does. You wouldn't need a prescription and you wouldn't have to order it from shady online pharmacies; you could just visit your local farmer's market.

Anyway, I think it is our patriotic duty this weekend - when we'll be eating lots of watermelon anyway - to test out this hypothesis, in the least scientific ways possible. Who knows? Maybe watermelon isn't just a preliminary to the fireworks; maybe it can help bring them on.

P.S. Notice to all PDE-5 spammers: Your comments will be deleted. Watermelon farmers are welcome to respond, however.

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