The Little Watermelon Pill

Watermelon Viagra?

Who could possibly resist writing about such a concoction... er... uh... ridiculing such a juxtaposition:

Watermelon may have Viagra-effect

COLLEGE STATION -- A cold slice of watermelon has long been a Fourth of July holiday staple. But according to recent studies, the juicy fruit may be better suited for Valentine's Day.

That's because scientists say watermelon has ingredients that deliver Viagra-like effects to the body's blood vessels and may even increase libido.

Does the press release cite any papers proving that watermelon is an aphrodisiac? Need I even ask this question? Try typing watermelon libido in PubMed. No items found. Same result for watermelon aphrodisiac. And "citrullus" was automatically included as a search term.

The Texas A&M University - Agricultural Communications department doesn't seem to care, so they continue:

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."

But here's the Alternative Medicine Review on citrulline:

...some supplement companies are marketing L-citruilline--a by-product of the arginine-to-nitric oxide pathway--as a substance to increase nitric oxide synthesis in vascular endothelial cells. Although safe, citrulline does not directly convert to nitric oxide, but instead is recycled to L-arginine (an ATP-dependent process), which then converts to nitric oxide. Ferid Murad, MD, PhD, Nobel-prize winner for his research on nitric oxide, has said the use of L-citrulline to increase nitric oxide is only marginally effective.

Nevertheless, an increase in watermelon sales is predicted...