Living longer by eating less works at any age

Nutrition

It’s been known for decades that an animal’s lifespan could be extended by severely reducing its calorie intake, while avoiding malnourishment. Calorie restriction slows the rate of aging, as well as the development of age-related diseases. (A few hardy, if hungry, souls are testing calorie restriction on themselves to see if this holds true for humans.) But it was also thought that a restricted diet had to be started early in an animal’s life to work well.Nowa study on older mice in this week’s Proceedings of theNational Academy of Sciences Early Edition suggests otherwise. Stephen Spindler of the University of California at Riverside and colleagues started late middle-aged mice on a restricted diet and found the same benefits: The mice lived almost six months longer and the onset and progression of cancers were slowed. Genetic analysis revealed that the older calorie-restricted mice had patterns of genetic activity similar to those of mice on the diet from their youth. The researchers suggest that drugs that could mimic the same patterns of genetic activity might give the same beneficial effects.

AGNIESZKA BISKUP

Ecology

Is the world on the brinkof an extinction crisis?

British researchers have reported dramatic declines in plant and animal species in the United Kingdom and suggest it’s evidence that the earth may be experiencing ‘‘the sixth major extinction event in its history.’’ (Major extinction event number five is whatever wiped out the dinosaurs millions of years ago.) In the March 19 Science, Jeremy Thomas of the UK’sNatural Environment Research Council Centre for Ecology and Hydrology and colleagues report analyzing six surveys compiled by scientists and some 20,000 volunteers that stretched back 40 years and covered almost all of the UK’s plant, bird, and butterfly populations. The researchers found that 28 percent of native plant species decreased in Britain over the past 40 years and that 54 percent of bird species decreased over 20 years. Surprisingly, since insects were thought to be among the more resilient species, butterflies fared particularly poorly: Over 20 years, 71 percent of all butterfly species declined. If insects elsewhere are similarly sensitive, then ‘‘the world is indeed experiencing the extinction crisis many people have been suggesting and talking about for years,’’ Thomas stated.

AGNIESZKA BISKUP

Climatology

‘Grapes of Wrath’ drought explained

The Dust Bowl droughts that ruined millions of Great Plains farm families in the 1930s were triggered and sustained by barely perceptible temperature changes in oceans thousands of miles away, according to a new NASA study. Computerized climate simulations suggest that abnormally warm water in the tropical Atlantic set up wind circulation changes that cut off the flow of moisture from the Gulf of Mexico during the summer and fall. At the same time, unusually cool sea-surface temperatures in the tropical Pacific set up global patterns that suppressed storm development on the Plains. The combination, scientists said, led to persistent drought and what many observers regard as the worst US natural disaster of the 20th century. The pattern has not recurred, and no Great Plains drought since has been as severe. But that might be only a matter of time, said Siegfried D. Schubert ofNASA’s Goddard Space Flight Center. There’s no reason to believe we’re not going to have another drought like that, said Schubert, a co-author of the study published in the journal Science. There’s evidence going back at least 400 and even 1,000 years where they’ve been able to show these mega-droughts tend to occur once or twice a century.
THE BALTIMORE SUN

Bones

Strong case for osteoporosis drug

The widely used osteoporosis drug Fosamax keeps strengthening bones for at least a decade, a study in last week’sNew England Journal of Medicine found, easing fears that the medicine might eventually boomerang and start making hips and spines brittle and prone to break. The randomized study of 247 middle-aged and elderly women with the disease is the longest test yet of Fosamax, which was approved in 1995. It has gained quickly in popularity as an alternative to hormone supplements, which have been linked in recent years to heart disease and cancer. ‘‘This is a chronic condition and requires long-term treatment, so it’s really important to have the data,’’ said Dr. Henry Bone, the study’s lead author at St. John Medical Center in Detroit. About 8 million American women and 2 million men have osteoporosis and about 34 million others are at elevated risk. The disease is blamed for about 1.5 million broken bones a year. The blockbuster drug, generically known as alendronate, raked in $2.7 billion in world sales last year. The research was backed by the maker of Fosamax, Merck & Co. of Whitehouse Station,N.J. Several researchers disclosed ties to Merck.

ASSOCIATED PRESS