You catch (and kill) more flies with this sweetener

I wonder if it might be that the fruit flies are starving themselves to death by ignoring sugar for non-nutritive Truvia® , rather than the Truvia actually being toxic? I can't tell from the article.

http://www.eurekalert.org/pub_releases/2014-06/du-yc052814.php

PUBLIC RELEASE DATE: 4-Jun-2014
Contact: Rachel Ewing
Drexel University
You catch (and kill) more flies with this sweetener

Drexel researchers discover that erythritol, the main component of Truvia®, could be a safe and effective insecticide

PHILADELPHIA (June 4, 2014)— In a study that began as a sixth-grade science fair project, researchers at Drexel University have found that a popular non-nutritive sweetener, erythritol, may be an effective and human-safe insecticide.

Erythritol, the main component of the sweetener Truvia®, was toxic to Drosophila melanogaster fruit flies in a dose-dependent manner in the Drexel team's study, published in PLOS ONE. The flies consumed erythritol when sugar was available and even seemed to prefer it. No other sweeteners tested had these toxic effects.

Based on this discovery, Drexel and the researchers are pursuing a patent on erythritol as an insecticide and are continuing to study its effectiveness.

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Erythritol is a naturally occurring sugar alcohol that is present in small amounts in many fruits. It has been tested in humans at high doses and found safe to consume; it has been designated as a generally recognized safe food additive by the U.S. Food and Drug Administration since 2001 and is also approved as a food additive in many other countries.

And the new evidence that it is toxic to flies, which are drawn to its sweet flavor even when other foods are available, makes it a killer combination. It is particularly promising because it is safe for human consumption, unlike other pesticides that have caused tragic accidental poisonings such as one that killed 23 Indian school children last year.

This line of research would not have started without the curiosity of one of the paper's co-authors, Simon D. Kaschock-Marenda, who is now in the ninth grade. Three years ago, Kaschock-Marenda questioned why both of his parents had stopped eating white sugar when trying to eat healthier.

"He asked if he could test the effects of different sugars and sugar substitutes on fly health and longevity for his science fair, and I said, 'Sure!" recalled Daniel Marenda, PhD, Simon's father and an assistant professor of biology in Drexel's College of Arts and Sciences – and now co-senior author of the study. Father and son proceeded to buy supplies at their local supermarket – as many types of sugar and sugar substitutes as they could find. Marenda's lab supplied "baby" flies and growth medium for his son to raise flies in each of the different types of sweeteners at home, in preparation for the science fair at the Julia R. Masterman School in Philadelphia.

"After six days of testing these flies in our house, he came back to me and said, 'Dad, all the flies in the Truvia® vials are dead...'" Marenda said. "To which I responded, 'OK...we must have screwed up somehow. Let's repeat the experiment!'"

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Flies raised on food containing Truvia® lived for only 5.8 days on average, compared to 38.6 to 50.6 days for flies raised on control and experimental foods without Truvia®. Flies raised on food containing Truvia® also showed noticeable motor impairments prior to their deaths.

"Indeed what we found is that the main component of Truvia®, the sugar erythritol, appears to have pretty potent insecticidal activity in our flies," Marenda said.

They found that the toxic effect did not come from stevia plant extract, which is present in both Truvia® and the non-nutritive sweetener PureVia®. PureVia® was included in their experiments and had no toxic effect on the flies.

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