A single hormone seems to be responsible for the extended life span produced by a low protein diet. A new study from Pennington biomedical research center, recently published in nature, found that reducing the amount of protein in the diet can produce a range of beneficial health outcomes - including prolonging life , and these effects depend on a liver derived metabolic hormone called fibroblast growth factor 21 (FGF21).
It has long been recognized that reducing food intake can improve health and prolong life, and there is growing interest in the possibility that reducing protein or amino acid intake can contribute to this beneficial effect. Several recent studies have shown that a low protein diet, but not low enough to produce malnutrition, can improve health. In contrast, excessive intake of a high protein diet is associated with increased mortality in some age groups.
A few years ago, Pennington biomedical's neural signaling laboratory found that the metabolic hormone FGF21 is a key signal connecting the body and brain during protein restriction. Without this signal, young mice cannot change their eating behavior or metabolism when they are placed on a low protein diet.
"Our data show that FGF21 talks to the brain, and without this signal, the mouse would not 'know' that it is eating a low protein diet. Therefore, the mouse failed to adaptively change its metabolism or eating behavior," said Dr. Christopher Morrison, professor and director of the neurosignaling laboratory.
The latest research led by Dr. Cristal M. Hill shows that a low protein diet has beneficial metabolic effects on elderly mice, which can improve metabolic health, reduce weakness and prolong life. When the protein intake of middle-aged mice decreases, these beneficial effects are also very obvious. In addition, it can even prevent the harm of obesity. Importantly, these beneficial effects disappeared in mice lacking FGF21, suggesting that its role in the brain is essential for health and increased longevity.
"We previously found that FGF21 plays a role in the brain to improve the metabolic health of young mice fed a low protein diet. These new data expand this work and demonstrate that FGF21 can also improve metabolic health and prolong life," Dr. Hill said, "Overall, these data provide clear evidence that FGF21 is the first known hormone that coordinates eating behavior and metabolic health during protein restriction to improve longevity."
However, Dr Hill pointed out that there are still several problems to be solved. It is unclear how these observations will translate into aging humans, but it is hoped that this work will discover new molecular and neural pathways that researchers can use to improve people's health.
"This groundbreaking study is of great significance for prolonging people's health and life expectancy. If scientists can better understand how dietary and nutritional hormones such as FGF21 act to prolong life, these findings can offset many health problems in middle age and later," said Dr. John Kirwan, executive director of Pennington biomedicine.