Hey Susan,
i was recently reading that menstruation is in fact not natural or healthy. It is considered normal because of our lifestyles. From what i read, if a lady was to revert to a very pure, natural diet, then she would no longer menstruate but still be able to bear children. What can you tell me about this?

No, I don't think you have that exactly right.

In the olden days, women were mostly pregnant or breast feeding. They didn't need birth control as breast feeding acts as birth control somewhat effectively. So women didn't put hormones in their body to control pregnancy - their lifestyle did. And they had babies as long as their bodies let them have babies. And this also meant that women very rarely menstruated.

There are diets that essentially stop your menstrual period. But I am not about to say these are healthy or not.

Here's some info you might find interesting: http://www.cwhn.ca/resources/menstruation/obsolete.html