The latest health claim says that drinking water from a copper cup boosts health by reducing inflammation, bolstering brain functioning, aiding in weight loss, slowing aging, fighting cancer, and acting like an anti- microbial.
Whoa, does this mean people should toss out their glasses and buy a supply of copper mugs? Is it even possible that drinking from a certain type of cup can do anything other than make a Moscow Mule taste better? Or is this just the latest health fad?
“Drinking out of a copper mug is neither healthy or not healthy,” says Dr. Michael Lynch, medical director for the Pittsburgh Poison Center and assistant professor in the department of emergency medicine at the University of Pittsburgh School of Medicine.
Or, to put another way:
“I don’t think it is harmful, but it is not a magic bullet,” says Lauren Blake, a registered dietitian at the Ohio State University Wexner Medical Center.
There are no studies that find drinking from a copper cup helps with weight loss, improves brain function, slows aging, fights cancer, or reduces inflammation. But a study did find that leaving water in a copper vessel kills off bacteria.
“I still don’t know how much it would kill,” says Blake. “That would probably be a good space to use it, but I wouldn’t trust it to kill all the bacteria.”
Copper plays an important role in overall health and many of these overblown claims about copper cups seem to originate from what’s known about that mineral. It helps with brain function, can partner with other enzymes to work as an antioxidant, encourages red blood cell production, and maintains collagen and elastin, aiding in bone health.
“It is important because it helps in terms of iron absorption," says Leslie Bonci, a nutritionist and owner of Active Eating Advice.
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But most of us get plenty of copper from our diets. People need small amounts of copper — 900 micrograms a day. Foods such as mushrooms, cashews, almonds, beef liver, legumes, whole grains, and oysters are rich in copper. Cashews have about 500 micrograms per ounce; a few tablespoons of the nuts make up half of what a person needs.
“There are so few people out there who would ever have a necessity to take [a copper supplement]. Nobody should be self supplementing with copper unless they have a medical reason to do,” says Bonci.
Copper is a heavy metal and there's a danger of ingesting too much. Lynch has treated people who attempted suicide by drinking copper, though it’s rare. Too much copper causes people to experience nausea, diarrhea, and stomach bleeding. Prolonged exposure could cause neurological problems.
But he thinks it would be unlikely for people to get too much copper from supplements to experience negative effects.
“A copper supplement is probably not dangerous,” he says. “A copper supplement, like all supplements, is largely unnecessary.”
As for copper mugs, Lynch says most of them are lined so people drinking from them aren’t getting any extra copper from them.
"If you enjoy drinking from a copper mug ... you have no significant risk. But there is no significant health benefit," he says.
The experts agree that the best way to get copper is through a balanced diet.
“Copper, as well as any other nutrient, is best … from food,” says Blake.