The human body requires many minerals, among which copper is an important and indispensable one. We receive copper mostly from the food that we consume and to a much lesser extent, from foods stored in copper vessels, or the water we drink, if it flows through copper pipes. Normally, a regular diet with sources of copper, consisting of whole grains, seafood, leafy green vegetables, and nuts, may make-up for the body’s requirement of copper.

The body requires copper for a set of diverse functions, including the production of ATP (adenosine triphosphate, the ‘energy currency’ of the body), development of connective tissues (chiefly of those found in bones and blood circulation system), regulation and metabolism of iron, formation of melanin, and for proper brain and nervous system function. Certain body conditions, like cancers and rheumatoid arthritis, are known to increase copper levels in the blood. Excess copper in the body may cause copper toxicity, leading to vomiting, low blood pressure, and coma.

According to the US National Academy of Sciences, Food and Nutrition Board, the recommended dietary allowance (RDA) of copper for adults is 900 micrograms/day. The RDA during pregnancy is 1000 micrograms/day and higher at 1300 micrograms/day for lactating mothers.

Foods that contain copper in high levels include the following:

• Sesame seeds: Sesame is an oilseed crop, used to extract edible sesame oil. The sesame seed is also used in many Asian food preparations.
• Soybeans: The UN Food and Agricultural Organization classifies soybean as an oilseed. It is a significant source of protein, apart from being a food rich in copper
• Nuts such as cashews and walnuts
• Mushrooms, namely crimini and shiitake
• Organ meat: It refers to the internal organs of a slaughtered animal such as goat, lamb, sheep, pig, etc. The internal organs may include the heart, liver, intestines, tongue, and even the head. Organ meat is also known as offal and there are many health benefits to eating organ meat, besides it being a rich source of copper.
• Green leafy vegetables that include asparagus, spinach, and kale
• Whole grains

Any deficient or excess copper situation in the body can cause health issues, though it is quite rare. Apart from wide-ranging disorders that affect multiple body systems, deficient copper levels are thought to be linked to amyotrophic lateral sclerosis (ALS, or Lou Gehrig's disease) and excessive copper levels are known to affect the liver, causing Wilson’s disease. It is always recommended to take the advice of a suitable healthcare professional before bringing any alteration to your regular food habits and diet such as taking a copper supplement or incorporating foods highest in copper.

References:

http://www.nal.usda.gov/fnic/DRI//DRI_Vitamin_A/224-257_150.pdf (accessed on 11/16/2014)

Vuori E, Makinen SM, Kara R, Kuitunen P. 1980. The effects of the dietary intakes of copper, iron, manganese, and zinc on the trace element content of human milk. Am J Clin Nutr 33:227–231.

Pennington JA, Schoen SA, Salmon GD, Young B, Johnson RD, Marts RW. 1995. Composition of core foods of the U.S. food supply, 1982–1991. III. Copper, manganese, selenium, and iodine. J Food Comp Anal 8:171–217.

ATSDR (Agency for Toxic Substances and Disease Registry). 1990. Toxicological Profile for Copper. Atlanta, GA: U.S. Department of Health and Human Services, Public Health Service.

Helpful Peer-Reviewed Medical Articles:

Duffy, E. M., Meenagh, G. K., McMillan, S. A., Strain, J. J., Hannigan, B. M., & Bell, A. L. (2004). The clinical effect of dietary supplementation with omega-3 fish oils and/or copper in systemic lupus erythematosus. The Journal of rheumatology, 31(8), 1551-1556.

Shike, M. (2009). Copper in parenteral nutrition. Gastroenterology, 137(5), S13-S17.