Having a candida overgrowth, let's say because of Antibiotics use, will make you more prone to parasites, because what protects you from them is compromised over time: gut flora, immune system, liver health, stomach acid, enzyme secretions... And same goes the other way, parasites can help candida proliferate.
I don't know about candida, but i know that helminths have the ability to weaken the immune system response and activity, there are several reports on pubmed which describe this phenomena, and unfortunately some doctors use helminths to "treat" "auto immune disease".
But let me correct that for you: if you have a compromised gut, kidney, infection or whatever, well you have a compromised liver, because the liver has to filter the blood and if you're having one of those conditions you mentionned, well your blood is overloaded with toxins.
I partially agree with you on that, the liver is an important organ because it is one of the main ways of assimilation and elimination, but dark circles in the eyes are not necessarily linked to a poor liver state. The kidneys can be completely destroyed when the liver is still ok.
The spleen filters the blood too.
The brain can be infected or intoxicated when the liver is still ok.
Also there are several hollow areas in the body where deposits and infections can grow and even if the liver can participate in the elimination, his state has nothing to do with the state of the local area. Well, there can be a relation of cause and effect, but not necessarily.
Restore proper gut flora and proper digestion>> no more infections, kidney issues, dark circles, or whatever disease you like that is related.
Propaganda at best.
There are several parameters which can greatly impact the body state, the diet and the digestion power is only a parameter.
Strong genes and weak genes don't seem to exist in your world. All humans don't have the same immune system, the immune system efficiency (weapons and defense mechanisms) is a product of evolution, but even if i have a weak immune system (meaning less weapons and defense mechanisms) against some helminths, i don't want to die, so i use external weapons. Can your immune system learn new defense mechanisms and build new weapons to kill new helminths (i mean new in my region) in a human lifetime ? Probably.
Will i take the risk to die in order to become immune if i catch a systemic infection ? Me, no, i prefer to use herbs. But you do what you want.
Study the concepts of Herbert Shelton and in which state he has finished his life. My interpreation is that he probably had an hidden infection in the brain. Hygienists have good concepts but are dogmatic, the human body has its strengths and weaknesses.
Restore proper gut flora and proper digestion and have chronic entries of toxic substances (toxic gazs, VOC) through the lungs, be chronicly dehydrated and you will have a polluted blood and probably deposits in the blood pipes and in others organs.
I appreciate your points but please consider that it is more complicated than it seems.
There are many concepts and advices which make no sense concerning the immune system.
Clearly if the immune system of humans was so efficient, we would all be immortal. It is not the case...