Organic-fed flies have more offspring and live 25 percent longer, researchers say. (Photo: digicla/Flickr)
After listening to her parents debate the benefits of buying organic food, Ria Chhabra decided to take matters into her own hands. The Texas high-school student — along with biology researchers from Southern Methodist University — began studying how an organic diet affects the health of fruit flies, hoping to shed light on potential benefits for people.
Fruit flies and humans have lots of obvious physiological differences, but the insects are still common test subjects for studying human health, since about 77 percent of known human disease genes have a relevant match in the fruit-fly genome. And based on Chhabra's research, both species may have a lot to gain by eating more organic food.
"To our surprise, in the majority of our tests of flies on organic foods, the flies fed organic diets did much better on our health tests than the flies fed conventional food," says SMU biologist Johannes Bauer, who served as Chhabra's mentor, in a press release. "Longevity and fertility are the two most important aspects of fly life. On both of these tests, flies fed organic diets performed much better than flies fed conventional diets. They lived longer, had higher fertility, and had a much higher lifetime reproductive output."
That's a promising result, but as Chhabra points out, it's still unclear why exactly the organic-fed flies turned out healthier.
"We don't know why the flies on the organic diet did better," says Chhabra, a student at Clark High School in Plano, Texas. "That will require further research. But this is a start toward understanding potential health benefits."
Lifespans of fruit flies fed organic vs. non-organic food extracts. (Image: PLoS One)
Egg production of fruit flies fed organic vs. non-organic food extracts. (Image: PLoS One)
According to SMU, Chhabra had the idea for this study after overhearing her parents discuss whether organic food is worth the money. And as an intern at SMU's biology department, she knew about Bauer's human health research on fruit flies. Before long, they and SMU researcher Santharam Kolli had published a peer-reviewed study on organic diets — all while Chhabra was still in high school. "It's rare for a high school student to have such a prominent position in the lab," Bauer says. "But Ria has tremendous energy and curiosity, and that convinced me to give this research project a try."
Scientists have struggled in recent years to determine the health outcomes of organic and non-organic diets. Many studies have shown higher nutrient levels and lower pesticide contamination in organic food, for example, but a recent analysis by Stanford University seemed to undermine some of those findings.
In hopes of clearing things up, Chhabra, Bauer and Kolli fed their fruit flies an array of organic and non-organic produce from "a leading national grocery retailer." The flies were fed extracts made from potatoes, soybeans, raisins and bananas, with no other nutritional supplements, and the researchers tested the effects of each food type separately to avoid muddling their results with a mixed diet.
Although the organic outcomes were generally positive, they did vary depending on food type. A diet of organic raisins, for instance, led to some neutral and even some negative health effects. That might help explain the disparities in previous research, but Bauer echoes Chhabra's sentiment that more research will be needed to pin down which organic foods trump their non-organic counterparts and which ones don't.
"While these findings are certainly intriguing," he says, "what we now need to determine is why the flies on the organic diets did better, especially since not all the organic diets we tested provided the same positive health outcomes."
For more information about the research, including a possible explanation for why organic-fed flies are healthier, check out this SMU video featuring Bauer and Chhabra:
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