One of the reasons that the population of Europe was hit so hard by the Black Plague was that is was not healthy, there was a shortage of most of the above. Then after the plague hit the Little Ice age set in which reduced the area under cultivation, took centuries to recover.
The western Roman Empire had a problem with a shrinking population and a reduction of cultivated land starting in about 200, plague (?) they can't find enough bodies to match the stories. Samething with the plague in Justinians' time (532), no bones. As Blam speculated there is evidence of and impact of some sort around that time.
400-425 AD Gohnerrhea (sp).
750 AD The plague
Yup. I read (somewhere, I think in the 1491 article) last night that greater than 50% of the worlds food supply today is dependent on plant crops that originated in the Americas. The discovery of the Americas caused a population explosion in Europe.
The plague first hit Europe in 1348, and returned every few decades for several hundred years. In that time, the Renaissance began in Northern Italy and spread to France and the low countries. If that isn't recovering, I don't know what is. Hell, the Decameron perhaps the most important work of fiction since the fall of the Western Empire, was written by Boccacio in the countryside around Florence, as the plague decimated its inhabitants. The Plague saved Europe, by concentrating its weakth and by upsetting its parasitic social fabric.