BERKELEY, Calif., Feb. 18 (UPI) -- Two dietary supplements appear to restore some youthful, peppy energy in aging rats but do not seem to guarantee a longer life, according to a new study released Monday.
Researchers at the University of California at Berkeley and at Oregon State University in Corvallis, conducted a trio of studies to test acetyl L-carnitine and alpha-lipoic acid on old rats. These two compounds are easily accessible and sold in a variety of health food stores.
In the first study, researchers looked at mitochondria, a substance found in all cells that plays a critical role in the aging process. Mitochondria is mainly responsible for converting fuel in the diet into energy for the body, so if mitochondria breaks down, the entire cell is affected. Researchers say their first study showed when free radicals -- molecules that are a normal byproduct of metabolism but also harm cells -- build up, this can cause deterioration of mitochondria.
The second study examined giving acetyl-L carnitine and alpha-lipoic acid to rats. Acetyl-L carnitine is commonly found in meat, particularly pork and beef, and alpha-lipoic acid exists in green leafy vegetables, such as spinach and kale. For one month, researchers placed acetyl-L carnitine in the rats' water and alpha lipoic acid in their food. These rats were about 24 to 28 months old, the equivalent of a human around age 75. They were compared to young rats ages 2 to 4 months old.
The older rats quickly started behaving more like their younger counterparts, showing signs of more energy and physical activity.
"We were amazed in fact," co-researcher Dr. Tory Hagen, an assistant professor of biochemistry and biophysics at Oregon State and a principal investigator at the Linus Pauling Institute at the university, told United Press International. "We just did not expect this type of thing to happen."
Hagen and colleagues said it appeared the two compounds rejuvenated the mitochondria in the rats' cells by increasing chemicals known to decline with age, including ascorbic acid, a key antioxidant.
In the third study, researchers fed old rats a similar diet of acetyl-L carnitine and alpha-liopic acid to determine the effect on memory, another element vulnerable to aging. The rats underwent a series of tests and results showed the supplements significantly improved the animals' memory. Microscope images showed the mitochondria in the hippocampus, a region in the brain, suffered less decay among rats fed the supplements.
The findings are published in the Feb. 19 issue of Proceedings of the National Academy of Sciences. The work was funded by the National Institute on Aging and other private and university foundations.
"The brain stuff is pretty impressive, we didn't quite know what was going to happen there," co-researcher Bruce Ames of the University of California, told UPI. "There's every reason to think there's going be same thing in people."
Clinical trials involving elderly people are underway, Hagen said, though currently there are only 15 healthy subjects and researchers are not testing yet to see whether these supplements combat serious, chronic age-related diseases.
While these two supplements are not the fountain of youth, researchers said, they do offer some promise in restoring nutrients the body needs to remain energetic. However, there is nothing to suggest the compound can extend lifespan, Hagen explained. They only appear to improve overall well-being.
Lona Sandon, an assistant professor of clinical nutrition at University of Texas Southwestern Medical Center in Dallas and a registered dietitian, said scientists do not know enough about how acetyl-L carnitine and alpha-lipoic acid work to recommend particular dosages to thwart aging.
"They're trying to dig deeper to find out what is the mechanism or what is the result of taking some of these supplements," she told UPI. So far, these studies have involved only mice and Sandon said it is too premature to apply what is seen in rodents to what could happen in humans. "It's very, very preliminary," she said.
(Reported by Katrina Woznicki in Washington)