Researcher Retreats on Sexual Enhancement Claim for Watermelon

[Guest guest]

There goes the watermelon stampede!

Ralph Giarnella MD

Southington Ct USA

Researcher Retreats on Sexual Enhancement Claim for Watermelon

By Gever, Staff Writer, MedPage Today

Published: July 03, 2008

Reviewed by Zalman S. Agus, MD; Emeritus Professor

University of Pennsylvania School of Medicine.

COLLEGE STATION, Tex., July 3 -- Chalk up the widely publicized report that

watermelons can enhance erections, much like a certain PDE-5 inhibitor, to a

stretched version of the truth by a university PR officer seeking a good story

for the Fourth of July.

Action Points

Explain that media reports that watermelons may promote male erections were

based on a press release on limited research by plant scientists.

Explain that no clinical studies have confirmed such an effect and that medical

researchers were skeptical of the proposed mechanism.

A somewhat red-faced plant scientist, who was quoted extensively in a Texas A & M

press release, backed away from claims that the summer picnic staple actually

can promote erections. But he didn't abandon the notion entirely.

Bhimu Patil, Ph.D., director of the Fruit and Vegetable Improvement Center at

Texas A & M, said he was sorry that a press release, issued by the university,

referred to the well-known erectile dysfunction drug in its headline.

Hundreds of news outlets around the world picked up the release, which archly

suggested that watermelon " 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, "

according to the release.

In reality, studies at Texas A & M and a nearby U.S. Department of Agriculture lab

in Oklahoma have found that watermelon contains high levels of citrulline, which

is converted into arginine in the human body.

Arginine is the raw material from which nitric oxide, the powerful vasodilator

critical to penile erection, is generated in vivo.

But according to Dr. Patil, as well as physicians familiar with erectile

biology, no studies have shown that boosting arginine -- through high-citrulline

foods, arginine supplements, or other means -- promotes erectility.

Dr. Patil did not contribute to the studies of citrulline in watermelon, but his

laboratory is involved in watermelon breeding. He said he was approached to

suggest good things about watermelon for inclusion in the press release, a

publicity exercise intended to capitalize on the upcoming Independence Day.

Nevertheless, in an interview with MedPage Today, Dr. Patil reiterated that the

citrulline studies suggested eating watermelon could boost levels of arginine in

the blood and hence make it easier for men to develop erections.

But he said he was unaware of clinical evidence to confirm the connection.

" Until you have a clinical trial, it would be tough to [claim an erectile

effect], " he said.

Still, he said it was a strong possibility that should be evaluated with a

clinical study.

Jay I. Sandlow, M.D., of the Medical College of Wisconsin in Milwaukee,

cautiously agreed that a clinical study was worthwhile.

" We're always looking for nonprescription medications or supplements, " said Dr.

Sandlow, who is president of the Society for Male Reproduction and Urology.

" Everyone wants to do things naturally. If you could find foods that are

beneficial to overall health, that's always helpful. "

On the other hand, he was skeptical that such a study would really find that

high-citrulline foods such as watermelon make a difference in most men.

Such an effect, he said, presupposes that arginine levels in the blood are a

limiting factor to developing erections. He said there was little evidence to

suggest that is the case in most men.

But he said it hadn't been disproved either, to his knowledge.

Seftel, M.D., of Case Medical Center in Cleveland, and a spokesman for the

American Urological Association, said arginine is itself a vasodilator, but it

acts systemically.

It can lower blood pressure but has no specific effects in the penis, he said.

Dr. Sandlow pointed out that if watermelon does have a significant effect on

vasodilation, some people might find it a problem.

" If you're on nitrates, a medication like Viagra is contraindicated, " he said.

" Do those people have to worry about eating fruits and vegetables that are high

in these substances? "

Dr. Sandlow said the concept that high-citrulline foods would have health

benefits is attractive. " The problem is translating the concept into reality, "

he said.

Nevertheless, Dr. Patil said his laboratory is going ahead with a breeding

program to increase citrulline levels in watermelon, in confidence that it will

be beneficial.