Hi James,
I thought I would pass this one along: Intestinal Parasites May Be Causing Your Energy Slump. This article talks about intestinal parasites, many of which are found in our drinking water, and their effects on chronic fatigue and irritable bowel syndrome (IBS). This is one good reason for people to start using their Berkey filters on a regular basis and also start cleansing their bodies of these parasites.
I have my filter in the closet, but after reading this I think I will put it on the counter and start using it to filter my tap water. I never thought there was a link between fatigue and internal parasites. After TEOTWAWKI it would be even harder to maintain personal hygiene with no running water and public sources of water will quickly become contaminated with these and even more deadly parasites. Considering most prepared individuals would be doing a lot of physical labor at their retreats as well as performing guard duty the last thing one need is more fatigue. Regards, – Eric