In an article published online in the Nature journal, researchers from the U.S. Salk Institute for Biological Studies, La Jolla, California, reported the discovery of the gene PHA-4/Foxa, whose activity is necessary for an increase in longevity in experimental animals subjected to a restriction of diet ("eating less favors living longer").
The relationship between the reduction of diet and increased longevity was known since the 30s of last century, when it was shown that laboratory mice subjected to a sharp reduction in their diets lived longer than that following the diet.
Since then, this effect (reduction of diet = increased longevity) has been observed in organisms as yeast, flies, worms and dogs.
However, the consequences for humans to reduce the calories supplied in the diet by 60% while maintaining the vital nutrients are still unclear. By reducing calories too much, the slump could be the result (final grade of a state of malnutrition in which the individual loses more than 10% of their body mass and presents significant shortfall in reserves of protein and fat, with a very modest increase of water outside the cells and plasma albumin concentrations within the normal "Pera. C. Surgery., Masson, 1996) and increases over the result is obesity, so the so-called dietary restriction is on the razor's edge, as a signatory of the article.
PHA-4/Foxa discovery of the gene implicated in increased longevity associated with dietary restriction has been made in the worm Caenorhabditis elegans.
Research group has found that worms in which the PHA-4/Foxa gene is removed does not increase longevity, despite being under severe restriction of diet. Also show that the opposite experiment, increasing the expression of the gene in worms PHA-a/Foxa subject to a restriction in the diet, further increases in longevity. In conclusion, the PHA-a/Foxa gene is the first gene absolutely essential for increased longevity in response to a restriction in the diet.
Although the study was conducted in a worm, the authors argue that these findings may be relevant to other species. Mammals, including humans, have genes similar to gene PHA-a/Foxa. These genes play a key role in embryonic development and subsequently in the regulation of a hormone, antagonizes insulin, glucagon, which plays a key role in maintaining appropriate levels of blood glucose (blood sugar) in a special way during fasting.
PHA-a/Foxa gene could play a key role by allowing the animals subjected to intense stress situations survive in conditions of extreme food shortages.