For those of you with a New Scientist subscription, here is more information about Hormesis.
Dr Mercola expands on the topic: here
Here is a snippet:
Your body is a finely tuned instrument, and even seemingly insignificant changes can sometimes create major repercussions, for better or worse. Like a spider’s web, if you pluck one strand, the entire web vibrates. Pluck too hard and it breaks the strand, collapsing the intricate design of the whole.
Hormesis – To Impel Change
Hormesis — from the ancient Greek word hormáein, meaning “to set in motion, impel, urge on” — is the term for favorable biological responses resulting from low exposures to toxins and other stressors. A toxin showing hormesis thus has the opposite effect in small doses than in large doses.
Homeopathy could be considered as an example here, where even a highly toxic (natural) substance can be used to produce dramatic healing responses in your body because it is reduced to such a degree that only the energetic essence of it remains; there’s enough to impel a healing change, but not nearly enough to tip the scales too far to cause damage.
Hormesis then, is the biological phenomena where an otherwise adverse or detrimental influence is beneficial when applied at low levels – just enough to set something into motion.
The concept of biological hormesis is as important as that of homeostasis for the survival of an organism. Your body’s ability to resist and adapt appropriately to both internal and external stresses is essential for good health, and the hallmark of aging is your body’s inability to withstand stress, which starts to degrade it.