Svetlana Lutsenko of Physiology on the importance of copper metabolism:
People don’t usually think of copper as a nutrient to include in their diet. Does copper play a big role in the body?
LUTSENKO: The vital importance of trace elements is often underappreciated. Copper is needed for many reactions in the body: respiration, hair and skin coloring, neurotransmitter formation, iron metabolism and blood vessel formation.
Should people be worried about getting enough copper in their diet?
LUTSENKO: There is good news for both health conscious and undisciplined individuals, because there is a lot of copper in spinach and grain, but there is also copper in chocolate and nuts. One can develop a copper deficiency, but it is not likely get too much copper through the diet.
Is there ever a case when healthy is too healthy?
LUTSENKO: I was talking to a doctor who had a patient come in with neurological symptoms--problems walking and keeping balance-- and over time she deteriorated. They didn’t figure out what was going on until they did very extensive blood work. They found out she was copper-deficient, but all the genetic tests for copper diseases came out normal. It turns out that this person was a fan of supplements. She would go to Costco and get the big bottle of zinc and she would eat 400 mg of zinc every day, which is a lot. When one consumes a lot of zinc, the body responds by producing specific proteins which bind zinc, but this protein bound copper too. She ate too much zinc, depleted her body of copper and developed copper deficiency.
Ok, no excessive zinc supplements. Check. Are there other causes of copper deficiency?
LUTSENKO: Well, there have been potential problems identified with patients that have bariatric surgery, which is a way to treat morbidly obese patients. In bariatric surgery, a part of the stomach and a piece of the intestine is removed and it just happens to be the piece where most of the copper is absorbed. If these patients are not monitored closely and if one doesn’t supply a necessary amount of copper in the body, these patients 2 or 3 years down the road can start developing neurological symptoms because of copper deficiency.
How did you get interested in copper metabolism?
LUTSENKO: I became interested in this about 15 years ago when the first copper transport genes were discovered. I was working on sodium and calcium transport in mammals. A colleague and former classmate was sequencing the human genome, specifically chromosome 13 at the Wilson’s disease gene locus. He called me up and said he was getting pieces that looked like one of the transporters I was working with and he wanted to know if I’d like to take a look at it. I was very excited because it was new and it was related to human disease.
What specific aspects of copper metabolism does your lab study?
LUTSENKO: We are interested in how copper gets in cells, how it’s distributed and how excess is removed out of the cell. In the body, copper ions do not float freely, like sodium or potassium. Copper is always carried by proteins. It gets into the cell through special protein transporters and once it’s in the cell, it’s immediately bound by proteins called copper chaperones. These chaperones make sure that copper behaves, so it’s not reacting with oxygen making reactive oxygen that bombards and damages the cell. The chaperones deliver copper to the right destinations in the cell. Another class of transporters export copper and deliver it to other cells. Several genetic diseases like Menkes and Wilson’s disease result from problems with copper transporters. We study Wilson’s disease in a mouse model.
--Interviewed by Vanessa McMains