What is the amount of copper that can be absorbed from drinking water stored in copper vessels?

From the Guidelines

Drinking water from copper vessels can lead to the absorption of small amounts of copper, typically around 0.1 to 2 mg per day, which is generally safe and within the recommended dietary allowance for adults. The exact amount absorbed depends on several factors including water acidity, storage time, and temperature 1. For safety, it's recommended to store water in copper vessels for 8-12 hours maximum and avoid storing acidic beverages in them.

Key Considerations

• Copper is an essential mineral needed for various bodily functions including iron metabolism and enzymatic reactions 1.
• Excessive copper intake (above 10 mg daily) can cause adverse effects such as nausea, vomiting, and liver damage 1.
• People with Wilson's disease or other copper metabolism disorders should avoid using copper vessels altogether 1.
• The practice of storing water in copper vessels may offer antimicrobial benefits as copper ions can kill harmful bacteria 1.

Recommendations

• Store water in copper vessels for 8-12 hours maximum to minimize copper absorption.
• Avoid storing acidic beverages in copper vessels to prevent excessive copper leaching.
• Individuals with Wilson's disease or other copper metabolism disorders should avoid using copper vessels.
• Monitor copper intake from all sources, including diet and drinking water, to avoid exceeding the recommended daily allowance of 1.1 to 2 mg/day 1.

From the Research

Copper Absorption from Copper Water Vessels

• The amount of copper that can be absorbed from drinking water from copper vessels is not directly stated in the provided studies, but we can look at the effects of copper intake from water to understand the potential risks.
• A study published in 1999 2 found that a concentration of 2 mg Cu/L of potable water does not produce an increase in gastrointestinal symptoms in infants, and that in women, only concentrations greater than 3 mg Cu/L increase the number of episodes of nausea, vomiting, and abdominal pain, but not diarrhea.
• Another study from 1999 3 reported that the average daily intake of copper in the US is about 1 mg Cu, with the primary source being the diet, and that the bioavailability of copper from the diet is about 65-70%.
• A study published in 2003 4 found that gastrointestinal symptoms increased significantly in response to 6 mg Cu/L water, but no detectable changes were observed in indicators of copper status.
• A review published in 2020 5 suggested an oral reference dose (RfD) of 0.04 mg Cu/kg/day, which would be protective of acute or chronic toxicity in adults and children, but noted that this dose is not intended to be protective of patients with rare genetic disorders for copper sensitivity.

Factors Affecting Copper Absorption

• The bioavailability of copper from water is not explicitly stated in the provided studies, but it is known that the bioavailability of copper from the diet is about 65-70% 3.
• The form of copper in water, such as soluble copper salts, can affect its absorption and toxicity 5.
• Individual factors, such as genetic susceptibility to copper dysregulation, can also affect the risk of copper toxicity 5.

Gastrointestinal Symptoms and Copper Intake

• Gastrointestinal symptoms, such as nausea, vomiting, diarrhea, and abdominal pain, have been associated with elevated levels of copper in water or beverages 2, 6, 4.
• The severity and frequency of these symptoms can vary depending on the concentration of copper in the water and individual factors, such as age and health status 2, 4.