Anti-aging Strategy May be Pointless
For lean mice – and possibly for lean humans, the authors of a new study predict – the anti-aging strategy known as caloric restriction may be a pointless, frustrating and even dangerous exercise.
“Today there are a lot of very healthy people who look like skeletons because they bought into this,” said Raj Sohal, professor at the USC School of Pharmacy.
He and Michael Forster, of the University of North Texas Health Science Center, compared the life span and caloric intake of two genetically engineered strains of mice.
The “fat” strain, known as C57BL/6, roughly doubles in weight over its adult life. That strain benefited from caloric restriction, Sohal said.
The “lean” strain, DBA/2, does not become obese. Caloric restriction did not extend the life of these mice, confirming previous work by Forster and Sohal.
The results appeared online Jan. 13 in The Journal of Nutrition.
“Our study questions the paradigm that caloric restriction is universally beneficial,” Sohal said. “Contrary to what is widely believed, caloric restriction does not extend (the) life span of all strains of mice.”
By measuring the animals’ metabolic rate, Sohal and his colleagues came to a deceptively simple conclusion: Caloric restriction is only useful when, as in the case of the obese mice, an animal eats more than it can burn off.
“Your energy expenditure and your energy intake should be in balance,” Sohal said. “It’s as simple as that. And how do you know that? By gain or loss of weight.
“The whole thing is very commonsensical.”
For humans of normal weight, Sohal strongly cautions against caloric restriction. In a 2003 study, he and Forster found that caloric restriction begun in older mice – both in DBA and leaner C57 individuals – actually shortened life span.
However, Sohal said that obese individuals are probably better off cutting calories than increasing their exercise to make up for overeating. Overly vigorous exercise can lead to injuries and long-term wear and tear.
In other words, it is better to skip the double cheeseburger than to turn up the treadmill after binging at Carl’s Jr.
Sohal’s study is not the first to question the allegedly universal benefits of caloric restriction. A study by Ross et al. published in Nature in 1976 (“Dietary practices and growth responses as predictors of longevity”) found that caloric restriction works best in mice that gain weight rapidly in early adulthood, Sohal said.
Studies of caloric restriction in wild types of mouse strains have shown minimal life span extension, he added.
Next, the researchers want to understand why the obese mice have a lower metabolic rate that promotes weight gain.
The other members of the research team were Melissa Ferguson and Barbara Sohal of the USC School of Pharmacy.
Funding for the study came from the National Institute on Aging, part of the National Institutes of Health.
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The Chronicle of Higher Education mentioned USC’s $6 billion fundraising campaign. The story noted that USC had already raised $1 billion in a “quiet phase,” including the $200 million naming gift from USC Trustee and alumnus David Dornsife and wife Dana Dornsife to the USC Dornsife College.
The Guardian (U.K.) highlighted two major gifts to USC in a list of the 10 biggest philanthropic benefactors in America. The list included the $200 million naming gift from USC Trustee and alumnus David Dornsife and wife Dana Dornsife to the USC Dornsife College, and the $110 million gift from USC Trustee and USC Viterbi School alumnus John Mork and wife Julie to create the USC Mork Family Scholars Program.
The New York Times featured the USC U.S.-China Institute documentary “Assignment: China — The Week that Changed the World.” The documentary, part of a series, examines media coverage of the 1972 Nixon trip that reshaped U.S.-China relations after a quarter century of isolation and hostility. “People look back now and take it for granted that the outcome was preordained,” said the institute’s Mike Chinoy, who produced the documentary. Voice of America also featured the story.
Los Angeles Times featured the Oscar Senti-meter, a tool developed by the USC Annenberg School, Los Angeles Times and IBM that analyzes thousands of tweets about the Academy Awards nominees. The story noted that Mexican actor Demian Bechir received an enormous boost on Twitter the day of the nominations, with a total of 6,893 tweets mentioning him, a 47-fold increase from the day before. The story noted the tool uses language-recognition technology developed in collaboration with USC Viterbi School’s Signal Analysis and Interpretation Lab.
The Times of India (India) featured a three-day medical emergency training workshop organized in association with USC. At the workshop, held at GCS Medical College in India, 50 doctors and more than 100 paramedics learned how to improve emergency support systems. William Mallon of the Keck School of USC said that discussion topics included the use of portable ultrasonic devices to scan patients. “The ultrasound applications help physicians make accurate and timely decisions,” he noted. Daily News & Analysis (India) also featured the workshop.
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