In various areas of the human body, different pH values prevail. Nature ensures that water can adapt to the respective environment.
In the mouth (pH value 6.5-7.2), a different pH value prevails than in the stomach (pH value 2.2-2.4), a different one there than in the intestines (pH value 5.5-6.5), and a different one there again than in the blood (pH value 7.45). Water with a flexible pH value is therefore far more agreeable for the body than water with a fixed pH value. The pH value becomes more flexible when the water contains as few solid particles as possible, because without solid components, the pH value has nowhere to "attach". Its environment can then adapt most quickly and easily, through external influences (more acidic or more basic), without further exertion by the body.
As soon as solid components are present in a liquid, the pH value attaches to them and a change in the acid/base environment becomes more difficult and harder to achieve. This is why people speak of a "buffered" pH value. (Buffering means reducing the effect of something). A healthy body perceives the unbuffered pH value of 6.5 as agreeable, which nature also provides with natural rainwater. When this water encounters stomach acid with a pH value of 2-2.5, it shifts to this pH value without major resistance. In the intestines, there is again a completely different environment, the pH value must then be able to change again as quickly as possible.
The pH value of highly pure water is basically not a relevant statement, since the buffering capacity of such water is extremely low. This means the water has no strength to maintain the acidic pH value when it comes into an environment with a different pH value. As soon as slightly acidic reverse osmosis water enters a basic environment, it immediately becomes basic; it cannot maintain the acidity due to its weak buffering capacity.
Reverse osmosis water is also created through a very technical process and cannot be compared to completely natural water in all aspects. However, with regard to the pH value, the acid/base properties, and the purity, it is very similar to rainwater from primordial times and represents the best possible approximation to nature.