​​​​​​The claim: Drinking water from a copper cup can bring a number of health benefits, including killing bacteria, slowing down aging and lowering the risk of cancer. 

Copper is one of the body’s essential micronutrients, as well as a naturally occurring metal. The human body needs copper to survive. The recommended dietary allowance of copper for men and women older than 18 is 900 mcg, according to the Office of Dietary Supplements. 

It is used in electrical wiring, plumbing and pesticides. Copper as a metal may appear in construction, home decor and household items. Moscow mule lovers know that the vodka-based cocktail is traditionally served in a copper mug, topped with a fresh lime. But copper cups are far from a new fad –– humans have been drinking water from copper vessels for thousands of years. 

One Facebook user recently posted a list of supposed health benefits attributed to copper cups, including killing bacteria, slowing down aging, getting rid of anemia, lowering the risk of cancer and heart disease and more. 

Tamra jal: Copper’s history in India for thousands of years

Copper drinking vessels have historical roots that extend back thousands of years. Bill Keevil, director of the Environmental Healthcare Unit at the University of Southampton, said that the practice of “tamra jal” in India has existed for thousands of years. Water is stored in brass or copper vessels overnight and drunk the next morning. 

This practice stems from an ancient system of medicine called Ayurveda, which translates to “knowledge of life” and promotes natural remedies. According to Johns Hopkins Medicine, Ayurvedic medicine can have positive effects “when used as a complementary therapy in combination with standard, conventional medical care,” but its claims have not been studied extensively in the scientific field. 

Health benefits from copper, as they are known 

Some health benefits of copper have been the subject of scientific study. Copper’s antimicrobial effects, in particular, appear supported in scientific research. Keevil pointed to studies connecting copper intake to fecal bacteria that live in the intestines. One from the Journal of Nutrition demonstrated “higher fecal free radical production, fecal water cytotoxicity and alkaline phosphatase activity when consuming low dietary copper,” all of which are considered risk factors for colon cancer. Proper quantities of copper, therefore, may make a positive difference in health. 

“It’s possible that if you live in countries where you don’t get much copper in the diet, then having copper in the drinking water could be a good thing,” Keevil said. In more developed countries, traces of copper may still enter drinking water, but just how much depends on “the types and amounts of minerals in the water, how long water stays in the pipes, the water temperature and acidity,” according to the Washington State Department of Health. Keevil said that copper can be found especially in nuts, chocolate and red wine.  

Terry Gordon, professor for the department of environmental medicine at New York University, noted copper’s biological function.

“Copper is actually in certain proteins in our body … and it does kill bacteria,” Gordon said, adding that of all the health claims in this post, copper’s ability to kill bacteria seems by far the most plausible.

“But what does it mean to ‘kill bacteria?’ We’ve got trillions of bacteria in our gut that we live with. We don’t necessarily want to change your gut microbiome,” Gordon said. 

Keevil studied solid copper surfaces and bacteria, and in his article for The Conversation, he cited results from a study that demonstrated a 58% reduction in infection rates in hospital rooms with copper components. 

“Certainly when bacteria and viruses land on copper, they’re killed very quickly. And that includes the new coronavirus, by the way,” Keevil said. Copper’s bacteria-fighting properties could increase its usage in public spaces, especially hospitals, going forward. 

Too much copper can be poisonous

While copper in water could be helpful for individuals who do not consume enough copper, high concentrations of copper can be dangerous. The Iowa Alcoholic Beverages Division issued an advisory bulletin in 2017 to address copper cups used to serve alcoholic beverages. 

Depending on the acidity of the food, copper could be leached through copper cups. The bulletin warns that food with a pH level below 6.0 may not be consumed with a cup with a copper interior, as stipulated by the federal Food and Drug Administration’s Model Food Code.

If drinking water is of a standard pH, leaching should not occur –– but there may be other ways that copper could leach into water, like through copper pipes. The CDC calls corrosion of copper pipes the greatest cause for concern, in addition to contamination of well water, wastewater releases and more. 

The Agency for Toxic Substances & Diseases Registry reports that ingesting high levels of copper could lead to harmful effects, from “nausea, vomiting, and diarrhea” to kidney and liver damage or even death, in extreme cases. 

Many copper cups are lined with silver or stainless steel, however, so liquid does not make contact with the copper itself. 

Despite some studies, copper’s benefits remain underresearched 

Copper has certainly been the subject of some scientific research, but the claims included in the Facebook post have yet to be substantially corroborated or accepted in the scientific field. A number of studies indicate the need for further research. 

For instance, one study from Journal of Health, Population and Nutrition demonstrates that copper “holds potential to provide microbially safe drinking water to the rural masses in developing countries,” but includes that this and other supposed benefits of copper have not been widely studied.

Keevil said many of copper’s alleged benefits stem from oral history rather than scientific research.

“Many people wear copper jewelry –– bangles, for example –– and they claim that it’s good for their arthritis, the argument being that copper is absorbed through the skin,” Keevil said. “I’m not aware that there’s ever been a proper study done, but anecdotally, many people claim that there are health benefits.”

Without the help of further scientific study, copper’s supposed health benefits remain under-researched and therefore difficult to sufficiently support or deny. 

“It’s a challenge for scientists to rebut these claims,” Gordon said. 

Our rating: Needs more information

The health benefits included in this post, on the whole, have not been sufficiently demonstrated as true or untrue. Copper represents an essential micronutrient, but any extraordinary health benefits brought from drinking out of copper vessels are, at this point, rooted in anecdotes. Until a stronger body of research emerges to provide scientific insight to these claims, they cannot be demonstrated as substantially true or false. Most likely, drinking from copper cups has a negligible impact on health, though that can depend on the type of cup and the pH of the liquid.  

Our fact-checked sources:

• Centers for Disease Control and Prevention, Copper and Drinking Water from Private Wells
• Office of Dietary Supplements, Copper 
• Abigail Brice, Facebook post
• Johns Hopkins Medicine, Ayurveda 
• The Journal of Nutrition, “Production, Fecal Water Alkaline Phosphatase Activity and Cytotoxicity in Healthy Men”
• The Conversation, Feb. 24, 2017 – “Copper is great at killing superbugs – so why don’t hospitals use it?”
• Health Environments Research & Design Journal, “From Laboratory Research to a Clinical Trial: Copper Alloy Surfaces Kill Bacteria and Reduce Hospital-Acquired Infections”
• Agency for Toxic Substance & Disease Registry, Toxic Substances Portal – Copper
• Iowa Alcoholic Beverages Division, Use of Copper Mugs in the Serving of Alcoholic Beverages
• Journal of Health, Population and Nutrition, “Storing Drinking-water in Copper pots Kills Contaminating Diarrhoeagenic Bacteria”
• Washington State Department of Health, “Copper in Drinking Water” 

Sarah Lynch is an intern for the Asbury Park Press and the editor-in-chief for the Marist Circle at Marist College. Reach her at SDLynch@gannett.com or via Twitter at @sarahdlynch. 

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