The University of Minnesota, through a study, demonstrate that environmental cues have control over longevity and reproductive timing
The study has significant implications for the improvement of human health
In accordance with a recent study conducted by the University of Minnesota, that was published by the researchers in the June issue of PLoS (Public Library of Science) One, when animals and human beings postpone reproduction as food or other resources have become scarce, they may possibly live longer in order to increase the effect of reproduction.
The finding, which gives explanation in relation to why starvation can lead to an extended lifetime, has significant implications for the improvement of human health as well as for lengthening the lifespan.
The basic idea is that people use environmental cues to forecast population drops, causing them to postpone reproduction till the decline has taken place, when every child will make a greater splash in the gene pool. On the other hand, if ever bad times revert to good times and the population becomes on the verge of a boom, reproducing earlier rather than later will assist their genes to thrive.
Will Ratcliff, a graduate student of the College of Biological Sciences, who proposed the idea for the research, explains that if the population is declining, future children make a larger contribution to the gene pool than actual children. Therefore, if ever there are tradeoffs between actual and future reproduction, postponing reproduction might prove to be a good idea, even if it will bring a reduction in the quantity of children a person will have during his lifetime.
Variations in the level of testosterone offer an example of the way the environment and organisms interact to direct reproduction explains the associate professor of the College of Biological Sciences, R. Ford Denison and the advisor of Ratcliff. The immune system is suppressed by testosterone. Therefore when environmental conditions initiate high levels, the reproduction is high, however, longevity drops.
Environmental factors have a control on the age of menarche too. In African countries that are characterised by food scarcity, young girls go through menarche much later compared to the girls in the US, where the rich diets initiate early menarche. Food shortage is a sign that the population is most probable to drop, therefore reproduction is postponed, whilst availability of rich foods is an indication of an increase, triggering reproductive age to fall.
Denison declares that their assumption may elucidate hormesis, the puzzling health advantages of low amounts of toxins – it includes those that plants such as broccoli use in order to defend themselves from insects. When their typical foods become scarce, organisms resort to plants that contain chemicals that can hold back reproduction and as a result increase longevity. Furthermore, these toxins may be plentiful in ‘famine foods’ that are consumed only when fruit and meat are unavailable.
Source: Eurekalert
Thu, Jun 3, 2010
Anti Aging, Gerontology, Lifestyle