Copper is a mineral that occurs naturally in many foods and is present in small amounts in drinking water. Contributors of dietary copper include organ meats, seafood, nuts, wheat bran cereals and whole grain products. Copper is a component of multiple enzymes and is involved in numerous biochemical reactions in human cells, such as the reduction of molecular oxygen, the regulation of gene expression, mitochondrial function/cellular metabolism and the absorption, storage and metabolism of iron 1.
The U.S. Food and Drug Administration (FDA) has established a Reference Daily Intake (RDI) of 2.0 mg copper for adults and children 4 or more years of age (21CFR101.9). RDIs are a set of dietary references for essential vitamins and minerals that are considered amounts sufficient to meet the daily requirements of healthy individuals. RDIs serve as the basis for calculating the percent daily value (%DV) amounts found on dietary supplement and food labels.
The risk of adverse effects resulting from excess intake of copper from food, water and supplements appears to be very low in adults, but may be more likely in young children. Excess copper intake can lead to gastrointestinal disturbances and possible liver damage 1.
According to the FDA, copper sulfate is Generally Recognized as Safe (GRAS) (21CFR 184.1261).