1. Introduction

Several dozen metallic elements have an important influence on human biochemistry and brain chemistry. The most important nutrient metals include zinc, copper, calcium, magnesium, iron, selenium, lithium, cobalt, manganese, and phosphorus and the electrolytes sodium and potassium. In addition, toxic heavy metals such as lead, cadmium and mercury can disrupt brain chemistry and human functioning. 

Serious problems can result if abnormal levels of any of the above metals are present. The body has several mechanisms which regulate and control these metal concentrations and cope with fluctuations in dietary intake. For example, proper calcium levels are critically important for heart functioning, skeletal structure, and the calcium energy pump. Blood levels of calcium are so well controlled that it is quite rare to find a patient with out-of-range levels, even in cases of serious calcium deficiency.

Divalent metals such as copper, zinc, and manganese would be very toxic to cells in elemental or ionic form. These metals are "enveloped" or "bound" to a small linear protein (61 amino acids) called metallothionein (MT), which supervises and regulates metal levels in blood, brain and the periphery.

The various metals in the body compete with each other for participation in chemical reactions and can displace each other depending on local concentration and their relative position in the chemical activity series. Thus, an overload or deficiency of one metal can alter the concentration and functioning of other metals.

2. Absorption

The stomach and intestines represent a highly efficient system for processing metal constituents in food. For example, dietary zinc is absorbed into the portal blood stream with an average efficiency of 38%. This zinc initially binds to albumin, globulin, or histidine for transport to the liver, where it is converted to zinc metallothionein and sent to every cell in the body. Absorption can be inhibited by certain medications, foods rich in trace metals or phytates (such as cereals) and a variety of digestive disorders. 

3. Copper/Zinc Imbalance

Genetic errors and environmental insults can result in abnormal metal levels and cause problems ranging from poor immune function to mental illness. The large HRI database suggests that copper overload and zinc depletion are the most common metal-metabolism abnormalities in behavior, ADHD, autism, depression, bipolar disorders, and schizophrenia. 

Zinc and copper are present in high concentrations in brain hippocampus which is involved in mood regulation, short-term memory, and behavior control. In most cases, this chemical imbalance appears to be genetic in nature and related to MT disfunction. This condition may be seriously aggravated by a poor diet, malabsorption, emotional stress, physical injury, or exposure to environmental sources of copper or toxic heavy metals.

Most children with elevated Cu/Zn ratios exhibit hyperactivity, attention deficit disorder, and/or poor behavior control. In addition they are unusually sensitive to lead, cadmium, mercury and other toxic metals which they tend to accumulate rather than eliminate. Puberty is an especially difficult time for children with Cu/Zn imbalance since (a) copper levels are sensitive to estrogen levels which increase during puberty, and (b) zinc is depleted by the rapid cell divisions which occur during the puberty growth spurt.

Many adult males with Cu/Zn imbalance become "late bloomers" who surprise friends and relatives with striking improvements in intellectual capability and behavior control after the age of 20. This may be due to the fact that they have stopped growing, in effect reducing the severity of the Cu/Zn imbalance.

Adult females with Cu/Zn imbalances benefit from the cessation of growth but are prone to severe depression and irritability if estrogen levels become elevated. Their depression can be aggravated by (a) estrogen medications, (b) birth of a child, (c) a hysterectomy, (d) menopause, or (e) environmental exposures to copper. A Cu/Zn elevation is associated with many cases of PMS.

The primary environmental sources of copper are impurities in the water supply, "enriched" foods and nutritional supplements, mining operations, welding, brazing and other metal-joining processes, and swimming pools and jacuzzis using copper sulfate for algae control. Foods rich in copper include chocolate and carob. Also, certain food dyes and colorings have a high hydrazine content which causes zinc depletion. Persons with the Cu/Zn chemical imbalance need to be vigilant in limiting sources of copper exposure.

Treatment for this imbalance centers on stimulation of MT protein with divalent metals (such as Zn and Mn) which are in depletion and by providing cysteine, serine, and other constitituents of MT. In addition, vitamins B-6, C, and E are helpful in correcting this chemical imbalance. This treatment should be gradual during the first 4 weeks of treatment to avoid rapid release of copper from tissues which could cause a sudden worsening of symptoms.

4. Heavy Metal Toxics

The adverse effects of heavy metal toxics are well documented in the scientific literature. Persons with a metal-metabolism disorder can be especially at risk since they may tend to accumulate, rather than eliminate, these toxics. A sibling study of violent boys showed dramatically-higher lead and cadmium levels than was observed for their well-behaved brothers living in the same environment.

Heavy-metal overloads can effectively be treated using oral supplements of zinc, manganese, cysteine, serine, and vitamins B-6, C, and E. The initial treatment must be gradual to avoid a sudden dumping of metal toxics from tissues which could cause kidney damage and a worsening of symptoms. 

Many heavy metals are" bone seekers" and treatment is prolonged due to the slow kinetics of metal transport out of bone. For example, about 95% of long term lead in the body is stored in bone and the half-life for lead elimination is about 22 years, which is somewhat typical of the heavy metals. We prefer oral nutrient therapy to intervenous chelation, which (a) is more invasive, (b) disrupts the levels of zinc, calcium and other essential metals, and (c) must be continued for years to maintain toxic levels at acceptable levels.

Heavy-metal toxics can cause dramatic problems in physical health and brain function. High levels of lead in brain have been associated with (a) disruption of the calcium ion channel, (b) altered levels of essential trace metals, especially in hippocampus, (c) disruption of neurotransmitter synthesis, and (d) disruption of nerve transmission in the myelin sheath. The half-life of lead in the brain is measured in weeks, and nutrient treatment can be effective within that time frame. However, treatment must be continued for years to cope with lead which will gradually diffuse out of the skeletal structure.