Hypercharge said:
I was recently asked why the iron in our blood wasn't killing us while iron is poisonous to the body; and what would be if it was other metals than iron in our blood, what would happen?
Too much of any element is bad.
Transition metals are in trace quantities within the body.
Iron is part of hemoglobin.
Hemoglobin and Functions of Iron
Iron is an essential element for blood production. About 70 percent of your body's iron is found in the red blood cells of your blood called hemoglobin and in muscle cells called myoglobin. Hemoglobin is essential for transferring oxygen in your blood from the lungs to the tissues. Myoglobin, in muscle cells, accepts, stores, transports and releases oxygen.
About 6 percent of body iron is a component of certain proteins, essential for respiration and energy metabolism, and as a component of enzymes involved in the synthesis of collagen and some neurotransmitters. Iron also is needed for proper immune function.
About 25 percent of the iron in the body is stored as ferritin, found in cells and circulates in the blood. The average adult male has about 1,000 mg of stored iron (enough for about three years), whereas women on average have only about 300 mg (enough for about six months). When iron intake is chronically low, stores can become depleted, decreasing hemoglobin levels
. . .
http://www.ucsfhealth.org/education/hemoglobin_and_functions_of_iron/index.html
The element cobalt is essential to cobalamin (vitamin B12), a water-soluble vitamin with a key role in the normal functioning of the brain and nervous system, and for the formation of blood. It is one of the eight B vitamins.
http://en.wikipedia.org/wiki/Vitamin_B12
http://www.ucsfhealth.org/tests/003705.html
Manganese: Health Information Summary
http://des.nh.gov/organization/commissioner/pip/factsheets/ard/documents/ard-ehp-15.pdf
"Classes of enzymes that have manganese cofactors are broad, and include oxidoreductases, transferases, hydrolases, lyases, isomerases, ligases, lectins, and integrins."
http://en.wikipedia.org/wiki/Manganese#Biological_role
http://www-personal.umich.edu/~vlpec/mn/Mn.html
Ceruloplasmin is the major copper-carrying protein in the blood.
http://en.wikipedia.org/wiki/Metalloprotein#Copper
Chromium - "Chromium (III) is one of the trace elements, which are necessary for human and animal vital activity. It enters the organism from digestive tract and is transported to the tissues, where its accumulation takes place. The deficiency of chromium (III) causes the disturbances in metabolic processes. The primary reaction of organism on chromium (III) deficiency, is the lowered tolerance of glucose, which is the consequence of changes in insulin affinity to its receptors on cells. The considerable quantities of chromium (III) reveal in nucleic acids. It influences on their metabolism, replication and transcription. The ion decreases the content of corticosteroids in plasma and increases the functional activity of immune system of organism."
http://www.ncbi.nlm.nih.gov/pubmed/10609294
http://www.ncbi.nlm.nih.gov/pubmed/10913239
"Your body needs just small amounts of trace minerals. These include iron, manganese, copper, iodine, zinc, cobalt, fluoride and selenium."
http://www.nlm.nih.gov/medlineplus/minerals.html
http://www.nutrition.gov/dietary-supplements/vitamin-and-mineral-supplements
Silver has no known biological role.
http://en.wikipedia.org/wiki/Silver#Human_exposure_and_consumption
