A group of Italian scientists has flipped the script and made fish drink like humans. The researchers administered a red-wine polyphenol, resveratrol, to tropical killifish and found that the fish lived longer and remained more active than those fish that did not consume the compound.
This is the first time that a test of resveratrol's impact on longevity has been performed on vertebrates, according to the researchers, who are based in Pisa and Rome. The compound has previously been shown to extend the lifespan of basic organisms such as earthworms and fruit flies, as well as of yeast.
However, a person who drinks like a fish isn't likely to see similar benefits, cautioned Alessandro Cellerino, coauthor of the study, which was published in the Feb. 7 issue of Current Biology. To consume the high levels of resveratrol served to the fish that lived longest, "it would take 22.5 liters of wine to reach that total daily intake quantity," he said.
The scientists hatched 157 killifish eggs and raised them to adulthood, which took about four weeks. Cellerino said they picked killifish for their relatively short lifespan. On average, a killifish lives three months, compared with laboratory mice, which can live for up to two and a half years.
To serve as a control group, 47 fish were fed their normal diet of gnat larvae. The remaining 110 fish were divided into three groups and fed a resveratrol-treated version of the larvae. One group was given a daily diet of 24 micrograms of resveratrol per gram of larvae, another 120 micrograms and the third 600 micrograms.
The scientists measured the aging process in a few ways. They filmed the tanks and used the frames to measure the distance travelled per second by each fish. As fish age and their mental acuity declines, they gradually become more sluggish, according to the study text. The team also darkened parts of the tanks during the course of their observations. Cellerino said that a fish's level of brain deterioration could be measured by how quickly it swam into illuminated areas of the tank, as part of its natural survival behavior.
Each fish was observed until its death. Predictably, the study said, the control group lived up to 12 weeks, the average age for killifish, as did the group that consumed the lowest level of resveratrol, 24 micrograms.
The fish that consumed a daily diet of 120 micrograms of resveratrol lived between 27 percent and 33 percent longer than the control group. At 600 micrograms, the fish lived between 56 percent and 59 percent longer.
In addition, the fish that lived longer also experienced greater "locomotor activity and cognitive performance," according to the study, pointing to the possibility that resveratrol "delays age-dependent decay." The fish in the 600-microgram group were still producing fertile eggs at 12 weeks—another indication that their overall health was greater, wrote the authors. Those eggs later hatched into normal killifish.
In human studies, resveratrol has been found to have numerous potential health benefits, including contributing to lower cholesterol levels, alleviating some lung diseases, fighting certain types of cancer and reducing the growth of skin melanomas and damage caused by sunburn.
While the study's results indicate that resveratrol is a potential clinical tool for prolonging people's health, Cellerino said that should not be used as an excuse to drink red wine. "Moderate consumption of red wine is not expected to replicate the results that we observed in the fish," he said, "and high consumption, obviously, would have very serious side effects."
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