Hogs may shed light on human growth - Purdue Univ research on hogs shows that vaccines for chronic diseases are just as important as nutrition in improving human longevity - Brief Article

USA Today (Society for the Advancement of Education), August, 1997

It is common wisdom and accepted scientific thinking that today's generation of people is taller because of improved nutrition the 20th century. However, it may be that, by lessening the effects of chronic disease, vaccines play as important a part as nutrients, hypothesizes Allan Schinckel, an animal scientist at Purdue University, West Lafayette, Ind.

Research conducted on hog growth has found that chronic disease can slow the rate of growth by as much as 40 to 60%. Schinckel theorizes that it causes a genetic shift, which makes the animals divert resources from growth to fighting disease.

"This genetic shift may be due to changes in gene transcription and gene expression." he suggests."It may be that if the body is chronically fighting disease. that at some point it doesn't make RNA for a certain gene; that it activates a genetic switch and goes into a survival mode where it puts energy into fighting disease instead of into growth." RNA is the biochemical messenger that tells cells to produce new protein.

Schinckel is conducting an experimental trial that examines the RNA/DNA ratios in hogs. If the RNA levels are reduced in chronically diseased animals, it will lend support to his theory. "Already, we're seeing that differences in potential become smaller as the animal matures. In other words, chronic disease affects the growth of the animal less as it gets older."

Although hogs are quite different from humans, they do provide a mammalian model for studying growth, Schinckel maintains. "This gene switch may be why humans of generations past were shorter and smaller than people are today. This difference is normally attributed to better nutrition, but the smaller stature may have had as much to do with chronic disease as it did with differences in nutrition."