Are the lifeforms unknown to science that are in water destroyed when distillation is used to purify water?

Unfortunately, this is the case. So this would come under the heading of harsh treatment and would remove this beneficial aspect of water. While it is highly effective at separating out many dissolved elements, and in other respects would be superb as drinking water given that there are more minerals present in solid food than in drinking water, per se, so that is not one reason alone to exclude distilled water. But we would recommend using a filtration mechanism that removes such dissolved solids as chemicals and other impurities through various filtration strategies, to extract them from the water without heating it to high temperature.