According to Dr Paul Eck, “Heavy metals serve as a back-up system. When the primary nutritional minerals are insufficient to protect the person, Nature uses substitutes. For example, lead can substitute for some of the functions of calcium. In bones, lead can substitute for calcium if calcium is deficient or cannot be utilized. Of course, lead will also make the bones brittle, but this is just a price that must be paid for using a back-up system. Then there is cadmium. Few realize that cadmium raises sodium levels. It is a toxic metal. Nevertheless, it is frequently retained in the body to support adrenal activity. In this way, it helps the individual avoid a burnout.”
We know this to be especially true of the thyroid gland, that when it faces iodine deficiency, desperately absorbs anything that even looks like iodine including fluoride, bromide, radioactive iodine and mercury. All nuclear scientists know the same is true for many radioactive elements that substitute for minerals in the body.
If preferred elements are inadequate in the diet, long-term high-quality health is sacrificed due to the accumulation of less preferred elements for short-term survival. So, when an organism does not maintain adequate nutrition to thrive, it makes sense that compensations are made with less preferred elements so that organisms maintain their life and survives.
A heavier element can displace a lighter one in the same group in biological tissues and alter the reactions of the lighter one… tissues with an affinity for a certain element have an affinity for all other elements of the same group. Some elements are bone-seekers. Some are thyroid-seekers. All elements in two groups are liver- and kidney-seekers... In this way, niobium can displace vanadium, tungsten can displace molybdenum, … silver displaces copper, gold will displace copper under certain circumstances, cadmium avidly displaces zinc and changes or inactivates zinc enzymes, causing disease; arsenic displaces phosphorus, causing disease; bromine displaces chlorine; beryllium displaces magnesium; magnesium and calcium interact; strontium displaces calcium; lithium displaces sodium.
Dr Henry A. Schroeder in "Trace Elements and Man"
As long as there chronic poor nutritional status and nutritional deficiencies are present, the body will not be able to properly perform its innate cellular functions adequately enough for the whole body to experience a state of positive health.