KATHMANDU — Putting just a bit less on your dinner plate each day reducing caloric intake might be key to a longer life, a preliminary research has suggested.
According to a small clinical trial, people who reduced their caloric intake by just 15 percent over two years experienced a significant decrease in their metabolism.
These people also saw improvements in biomarkers associated with slower aging and longer life span, said lead researcher Leanne Redman, an associate professor of clinical sciences at Pennington Biomedical Research in Baton Rouge, La.
For the study published March 22 in the journal Cell Metabolism, Redman’s team recruited 34 healthy people with an average age of 40 to follow a calorie-restricted diet for two years.
The researchers found that the participants developed a lower core body temperature, lower blood sugar and insulin levels, and significant drops in hormones that moderate metabolism.
“We know these things are lower in people who live longer lives,” Redman said.
Researchers taught the study participants how to cut 25 percent of their daily caloric intake using three different models of a healthy diet, Redman said.
The participants then were free to follow their diet by any means they chose.
“On their own, they achieved a 15 percent reduction in calorie intake that was sustained for the two years, which is pretty remarkable,” Redman said.
On average, the group lost about 20 pounds, mostly in the first year, even though half entered the study at normal weight and the rest were only modestly overweight, Redman said.
Aging studies in animals have tied lower calorie intake to longer lives, but this is the first clinical trial to bridge the gap between animals and humans, said Rozalyn Anderson, an expert with the American Federation for Aging Research who reviewed the findings.
“So much of what they’re reporting is entirely consistent with what we’ve seen in our monkey studies,” said Anderson, an associate professor who studies aging and calorie restriction at the University of Wisconsin School of Medicine and Public Health.
“We’ve got a match between the monkeys and the humans, and that’s absolutely brilliant. This is a really neat gap to have closed in terms of aging biology,” she said.
The researchers said this offers support to controversial theories linking high metabolism and increased oxidative stress to faster aging.
“When we make energy, we have byproducts of metabolism, and these byproducts called oxygen radicals accumulate in the body and cause damage to cells and tissues,” Redman said. Such damage can cause cells to age faster and contribute to diseases like cancer.
Anderson isn’t so sure that’s the best explanation. She noted that lab studies in mice have shown that damage done by oxidative stress has no effect on overall life span.
Anderson thinks lower calorie intake prompts the body to use energy more efficiently, and that somehow results in benefits for aging.
“We know, for example, there’s a really tight connection that we don’t understand between fasting and resilience — the ability to stand up against distress,” Anderson said.
People who want to try to eat less in an attempt to live longer should focus on portion size while following a healthy and well-balanced diet, Redman said.
They should aim for lowering calorie intake by 25 percent, with the understanding that they will probably fall short of the goal, Redman said. They shouldn’t be discouraged if they don’t keep losing weight long-term.
“The goal is not to lose weight. The goal is to have this sustained lower intake,” Redman said.
Suicide can’t be predicted by asking about suicidal thoughts : Study
Most people who died of suicide deny they experience suicidal thoughts when asked by doctors in the weeks and months leading up to their death, a major Australian study has found.
The findings, co-authored by clinical psychiatrist and Professor Matthew Large from UNSW’s School of Psychiatry, Sydney that published in the journal BJPsych Open The meta-analysis challenge the widely-held assumption that psychiatrists can predict who will suicide by asking if they are preoccupied with thoughts of killing themselves.
The study showed that 80% of patients who were not undergoing psychiatric treatment and who died of suicide reported not to have suicidal thoughts when asked by their psychiatrist or GP.
“If you meet someone who has suicidal ideation there is a 98 per cent chance that they are not going to suicide,” said Professor Large, an international expert on suicide risk assessment who also works in the emergency department of a major Sydney hospital.
“But what we didn’t know was how frequently people who go on to suicide have denied having suicidal thoughts when asked directly,” he added.
“This study proves we can no longer ration psychiatric care based on the presence of suicidal thoughts alone. We need to provide high-quality, patient-centred care for everyone experiencing mental illness, whether or not they reveal they are experiencing suicidal thoughts,” Professor Large said.
About one in 10 people will have suicidal ideation in their lifetime. But the study showed suicidal ideation alone was not rational grounds for deciding who gets treatment and who does not, Professor Large said.
“We know that suicide feeling is pretty common and that suicide is actually a rare event, even among people with severe mental illness,” Professor Large added.
Suicidal ideation tells us an awful lot about how a person is feeling, their psychological distress, sometimes their diagnosis and their need for treatment but it’s not a meaningful test of future behaviour.
Suicidal feelings can fluctuate rapidly and people may suicide very impulsively after only a short period of suicidal thoughts.
But, people had good reasons not to disclose thoughts of suicide, fearing stigma, triggering over-reactions or upsetting family and friends, and being involuntarily admitted for psychiatric treatment, Professor Large said.
Professor Large emphasized that clinicians should not assume that patients experiencing mental distress without reporting suicidal ideas were not at elevated risk of suicide.