Blood has two components; the liquid part (serum or plasma) which is a reflection of the health of all your organs and bones, and the second part being the formed elements of red cells, white cells and platelets. Healthy kidneys will do a lot of the work of maintaining proper electrolyte balance in the blood. Some herbs which benefit the liver and kidneys might optimize the working of those organs and show the right range of liver enzymes. I think milk thistle will benefit both the liver and kidneys to a small extent.
Once kidney function is lowered, very little, if anything, can be done to recover them, so it's best to not harm your kidneys in the first place with things like NSAIDs and acetaminophen. One can function very well with kidneys operating at only 50% efficiency. Kidney disease is usually something that accompanies old age, but they will still often function well enough into old age that they usually don't compromise health.
As far as the formed elements go, adequate red cells depend upon adequate B vitamin intake.
If you want a detailed supplement prescription for health, you might be interested in this:
http://www.lifeextension.com/Protocols/Lifestyle-Longevity/Prevention-Protocols/Page-les
If you become a member of Life Extension, you can speak to their staff of "Wellness Specialists."
http://www.lifeextension.com/Quest-Com
They do keep naturopaths on staff as part of the group of Wellness Specialists, but you may have to wait to speak to them. I think you may have to join as a Premier Member in order to speak to their Wellness Specialists:
http://www.lifeextension.com/Lpages/Premier/index
