Experiments with mice suggest that life span may be related to what your mother ate during pregnancy.
The new study at Cambridge University in England shows that pregnant mice fed a well-balanced diet had babies that lived longer, healthier lives. Mice that were undernourished in the womb and ate a poor diet as adults died prematurely.
Researchers caution the mouse results cannot be directly applied to human health. But they said the results published in Thursday’s issue of the journal Nature bolster the notion that low-birth weight babies are more likely to develop life-threatening cardiovascular disease and other illnesses as they mature.
“Growth during prenatal life has a very powerful impact on longevity,” said Kent Thornburg, a fetal physiologist at Oregon Health Sciences University who did not contribute to the new study.
However, other researchers said they remain unconvinced.
Rachel Huxley of the Institute for International Health in Sydney, Australia, said a mother’s diet is likely to have very little effect on how long her offspring lives when compared to known health risks in adulthood, such as cigarette smoking.
“Even if a causal association could be demonstrated between diet in early life and longevity, its actual influence is likely to be small when compared with known environmental determinants of longevity,” Huxley said.
Protein-rich vs. low-protein
Pregnant mice in the study were fed either a protein-rich diet or a low-protein regimen. After the babies were born, researchers swapped the mothers so that undernourished babies were nursed by mothers on a standard diet to catch up on their growth, and vice versa.
The control animals had mothers that were fed a standard diet and they nursed normally after they were born. They lived for about two years.
Mice that were well-nourished in the womb lived on average two months longer than the control group, the researchers reported. The mice that were undernourished in the womb died six months earlier than the control group.
In a second round of experiments, half of the babies from each litter were weaned at 21 days on a high-calorie, high-sugar diet, similar to a diet that contributes to obesity in humans. The rest were fed a standard diet.
Mice that had poor maternal nutrition in the womb and weaned on the unhealthy diet survived only a year, or about half as long as other mice in the study.
Diseases later in life
The high-calorie diet did not have a noticeable effect on the life span of well-fed mice weaned on a restricted diet after birth, the researchers reported.
In the late 1980s, David Barker of the University of Southampton in England published research demonstrating that low-birth weight babies are more likely to develop heart disease and high blood pressure in later stages of life, leading some scientists to believe that poor nutrition in the womb restricts the normal fetal development.
In the latest study, the Cambridge researchers suspected that the mice may have permanently increased appetite when forced to catch up on nutrients after birth. Critical organs such as the kidneys may also be damaged in cases where mice are not given the necessary nutrition in the womb, they said.
Over a lifetime — seven or eight decades in the case of humans — those differences become magnified, they suggested.
“There is, after all, a significant difference between living to be 50 years old and reaching the age of 75,” the researchers wrote in Nature.