Copper and vegetarians. (Scientific update: a review of recent scientific papers related to vegetarianism).

Copper, an essential mineral for humans, is found in many vegetarian foods like whole grains, cocoa, nuts, and seeds, as well in non-vegetarian foods like organ meats and seafood. Researchers at the USDA set out to answer whether or not copper absorption would also be lower on a vegetarian diet.

They had 18 young women eat a lacto-ovo vegetarian diet for eight weeks and a non-vegetarian diet for eight weeks. The women's copper absorption and the levels of copper in their blood were measured while they were on each diet. The women did absorb somewhat less copper from the vegetarian diet (about one-third of copper was absorbed compared to 42% on the non-vegetarian diet). However, because the vegetarian diet was considerably higher in copper than the non-vegetarian diet, the total amount of copper absorbed was higher on the vegetarian diet. Blood levels of copper were not affected by either diet. We don't have to eat meat or seafood to get enough copper; foods like whole grains, legumes, nuts, and seeds can be used to meet the copper requirement.

Hunt JR, Vanderpool RA. 2001. Apparent copper absorption from a vegetarian diet. Am J Clin Nutr 74:803-807.