Copper is a trace mineral and is associated with a number of metalloproteins, whose major functions involve oxidation-reductions in many important enzymes. It is also associated with iron in red blood cell formation, energy release, and is important in the synthesis of melanin, nerve coverings, collagen and elastin. Copper is transported in the blood attached to ceruloplasmin. Deficiency symptoms of copper may include anemia, fatigue, fragile bones and blood vessels, and lower disease resistance. Copper toxicity results in nausea, vomiting, epigastric burning and diarrhea. Classic conditions associated with copper deficiency are Menke's syndrome and Wilson's disease. Estrogens (birth control pill or pregnancy) may cause an increase in blood copper by increasing the production of ceruloplasmin. Copper is widely distributed and may be found in shellfish, liver, cherries, nuts cocoa, gelatin, and from copper water pipes. With all minerals, the RDA may be different for children and pregnant or lactating women. A normal safe daily intake is 1.5 to 3.0 mg/day. Copper intake must be proportional with zinc and iron, if not, an imbalance of copper may occur.