Food sources and absorption of copper

Copper, an essential mineral, is naturally present in some foods and is available as a dietary supplement. A small amount is needed for the body to function, but the body cannot make its own copper. Human body uses copper to form red blood cells, bone, connective tissue and some important enzymes. Copper also aids in iron absorption.

A wide variety of plant and animal foods contain copper, and the average human diet provides approximately 1,400 mcg/day for men and 1,100 mcg/day for women. Organ meats, shellfish, nuts, seeds, wheat-bran cereals, chocolate and whole-grain products are good sources of copper. Oysters are a good source of copper, providing 7.6 mg per 3.5 ounces (100 grams) — or 844% of the RDI.

Liver is also an excellent source of copper. One slice (67 grams) of calf liver gives you 10.3 mg of copper — a whopping 1,144% of the Reference Daily Intake.

Copper is primarily absorbed in the upper small intestine. Proteins and soluble carbohydrates tend to improve copper absorption and bioavailability by enhancing its solubility and intestinal bulk flow. Organic acids, other than ascorbic acid, or agents that form low-molecular-weight chelates, are likely to have a positive effect on overall copper absorption.

Copper deficiency can result from malnutrition, malabsorption, or excessive zinc intake and can be acquired or inherited. Many times, copper deficiency is the result of stomach surgery that can affect absorption. Zinc supplementation is also a common cause of copper deficiency. This is because zinc and copper compete for absorption in the stomach, with zinc being the usual winner.

Almost two-thirds of the body’s copper is located in the skeleton and muscle. Copper is a critical functional component of several essential enzymes known as cuproenzymes.
Food sources and absorption of copper