Copper in Athletes: The Trace Element That Affects Energy, Iron, and Connective Tissue
Table of Contents
Key takeaways: Copper in Athletes
- Copper has important biological roles in mitochondrial energy production, antioxidant defense, iron metabolism, and connective tissue formation.
- True copper deficiency appears to be very rare in everyday clinical practice, and athlete status alone is not usually a reason to test or supplement copper.
- Exercise may alter copper concentrations or urinary excretion in some studies, but the clinical significance of these findings appears limited.
- Copper deficiency should mainly be considered when the clinical picture fits: unexplained anemia, leukopenia, poor response to iron therapy, malabsorption, gastrointestinal surgery, or high-dose zinc supplementation.
- High-dose zinc supplementation is one of the most important preventable risk factors, because excessive zinc intake can interfere with copper absorption.
- For most healthy athletes, copper intake is usually covered by a varied mixed diet. A special copper-focused diet is rarely necessary.
- The bigger dietary concern is a restrictive, one-sided, or chronically calorie-deficient diet, where overall micronutrient intake may become inadequate.
- Copper is best viewed as part of overall diet quality, not as a separate performance supplement for copper-replete athletes.
Introduction: Copper in Athletes
Most sports medicine discussions of micronutrient deficiency in athletes tend to focus on the same three minerals: iron, magnesium, and zinc. Copper rarely receives the same attention. From my clinical perspective, that is partly understandable. True copper deficiency appears to be very uncommon in everyday practice, and as a general physician, it is not something I expect to encounter regularly. In reality, copper is probably discussed more often in the supplement market than it is diagnosed and treated in routine clinical care. For that reason, I do not think copper should be presented as a common hidden cause of poor performance in otherwise healthy athletes.
At the same time, I would not dismiss copper completely. Biologically, it is involved in several key systems that matter to athletes, including energy production, iron metabolism, antioxidant defense, and connective tissue synthesis. When true deficiency does occur, it can contribute to clinically relevant problems such as anemia, impaired iron utilization, leukopenia, and connective tissue or bone abnormalities.
In my view, the practical message is not to screen every athlete for copper deficiency. I think about copper mainly when the clinical picture fits: unexplained anemia, leukopenia, poor response to iron therapy, a history of high-dose zinc supplementation, gastrointestinal surgery, or significant malabsorption risk. In my clinical experience, severe malabsorption states such as untreated celiac disease, Crohn’s disease, or post-gastrectomy states would increase my suspicion for copper deficiency. Even then, these situations often involve several nutrient deficiencies at once, which means copper deficiency can be difficult to isolate and may receive less attention than more commonly measured nutrients such as iron, vitamin B12, folate, or vitamin D. High-dose zinc supplementation is another important exception, because excessive zinc intake can interfere with copper absorption and lead to copper-deficiency anemia or leukopenia [3][8]. Very rare genetic disorders of copper metabolism, such as Menkes disease or Wilson disease, can also affect copper status, although these are not typical considerations in routine sports medicine [7].
In this article I will examine copper in athletes from a practical clinical perspective: what copper does, how exercise may affect its distribution, who is genuinely at risk, and when I think clinicians and practitioners should actually consider measuring it.
What Does Copper Do in Athletes?
Copper is not usually discussed as a classic performance supplement. Current evidence supports copper as an essential nutrient, not as an ergogenic supplement for copper-replete athletes [1]. What copper does, however, is contribute to important machinery in aerobic metabolism, antioxidant defense, iron utilization, and connective tissue integrity — functions that, when impaired, may contribute to clinically relevant problems such as anemia, impaired iron utilization, and connective tissue or bone abnormalities [1].
The biochemical role for copper is primarily catalytic, with many copper metalloenzymes acting as oxidases to achieve the reduction of molecular oxygen [1]. Four systems are particularly relevant to copper in athletes: the mitochondrial electron transport chain, the antioxidant enzyme copper-zinc superoxide dismutase (Cu,Zn-SOD), the iron-mobilizing protein ceruloplasmin, and the connective tissue enzyme lysyl oxidase. Each of these is addressed below.
Although copper has an important role in cellular metabolism, true copper deficiency fortunately appears to be extremely rare in clinical practice. Most clinicians will probably never encounter a clear copper deficiency during their medical career, and I have personally never diagnosed one.
Part of the challenge is that copper deficiency can be difficult to isolate clinically. When it occurs, it often appears in situations where several other nutrient deficiencies may coexist, and other deficiencies usually become apparent first. Copper is also not included in most routine laboratory panels, which means it is rarely measured unless the clinician specifically thinks to look for it.
For this reason, I would not generally consider copper supplementation necessary for someone with a normal, varied diet and no known malabsorption issues. In that situation, the more practical approach is usually to maintain adequate dietary intake rather than adding copper as a separate supplement.
Copper in Athletes: Key Physiological Roles
All of copper’s known biological roles can make it sound like an especially attractive nutrient to athletes, and this is probably why it works well in supplement marketing. However, athletes are not automatically a special risk group for copper deficiency. In my clinical view, athlete status alone is not an indication for copper testing or supplementation, and it does not usually raise particular concern about copper balance.
Instead, the indications for measuring copper are generally the same as in the sedentary population: unexplained anemia, leukopenia, poor response to iron therapy, high-dose zinc supplementation, gastrointestinal surgery, significant malabsorption, or other clinical features that make copper deficiency plausible. In other words, copper may matter in selected clinical situations, but simply being an athlete is not enough to make copper deficiency likely.
1. Mitochondrial Energy Production
Copper is required for mitochondrial oxidative phosphorylation and protection against oxidative stress [2]. Specifically, copper is required for the assembly and function of cytochrome c oxidase (COX), the terminal enzyme of the mitochondrial respiratory chain. The catalytic core of COX contains three copper atoms [2]. Severe copper deficiency can impair COX-dependent oxidative metabolism, compromising aerobic energy production.
2. Antioxidant Defense
Exercise-induced reactive oxygen species (ROS) are an unavoidable byproduct of aerobic metabolism [9]. Copper-containing superoxide dismutase enzymes participate in antioxidant defense against superoxide radicals.
The pathophysiology of copper deficiency involves impairment of cytochrome c oxidase and superoxide dismutase [3], linking inadequate copper status directly to both impaired energy production and a weakened antioxidant defense system.
3. Iron Metabolism and Hematological Function
The copper–iron relationship is one of the most interesting aspects of copper status in athletes. Ferroxidases are copper enzymes found in plasma, with a function in ferrous iron oxidation (Fe²⁺→Fe³⁺) that is needed to achieve iron’s binding to transferrin [1]. Copper deficiency can lead to anemia, leukopenia, or thrombocytopenia, often mimicking vitamin B₁₂ deficiency or myelodysplastic syndrome [3]. The pathophysiology involves compromised ferroxidase activity, which hampers iron utilization [3].
Copper deficiency can impair iron utilization, and may be worth considering in cases of unexplained or iron-refractory anemia — including in athletes presenting with low ferritin that fails to respond to oral iron supplementation. Adequate copper intake permits normal utilization of dietary iron in that intestinal iron absorption, iron release from stores, and iron incorporation into hemoglobin are copper-dependent processes [1].
4. Connective Tissue Integrity
Lysyl oxidase uses lysine and hydroxylysine found in collagen and elastin as substrates for posttranslational processing to produce cross-linkages needed for the development of connective tissues, including those of bone, lung, and the circulatory system [1]. Without adequate copper, lysyl oxidase activity fails, and copper deficiency has been associated with connective tissue and bone abnormalities. For athletes under repeated mechanical loading — tendons, ligaments, bone — this may be worth considering when other causes of connective tissue problems have been excluded.
How Exercise Changes Copper Status in Athletes
Acute Exercise Response
In one study, incremental exercise to exhaustion in well-trained male athletes produced a decrease in Co and Cu serum concentrations, as well as a decrease in urinary Cu excretion post-exercise [4]. Notably, at baseline, urinary Cu concentrations were lower in the sedentary control group than in the athlete group — a difference the authors suggest may reflect adaptive responses to exercise [4].
Training Adaptation Over Time
In a six-month study of well-trained male middle-distance runners, the clearest copper-related change was not a confirmed fall in serum copper, but a decrease in urinary copper excretion after the training period [5]. Serum copper was numerically lower after training, but this change was not statistically significant. The authors suggested that the reduction in urinary copper excretion may reflect an adaptive response to retain copper during sustained aerobic training [5]. Training status may therefore be one factor to consider alongside reference ranges when interpreting copper measurements in trained athletes.
Dietary Inadequacy in Athletes
Despite the importance of copper in athletes, suboptimal dietary intake can occur and may be overlooked. Among 70 female collegiate athletes across seven sports (cross country track, tennis, softball, swimming, soccer, basketball, and gymnastics), 41% of athletes and 29% of controls failed to consume two thirds of the RDA for copper [6]. Notably, softball athletes consumed only 654 ± 420 µg/day (73 ± 47% of RDA) and soccer athletes only 695 ± 368 µg/day (77 ± 41% of RDA) [6]. These intake findings suggest that copper intake can be suboptimal in some athletes and may warrant dietary review.
However, the relationship between exercise and copper status is still somewhat unclear. These studies suggest that exercise may alter copper concentrations or excretion, but the clinical relevance of these findings appears limited.
In practice, I would not consider athlete status alone to be a meaningful risk factor for copper deficiency. These findings are probably better understood as a matter of sports physiology and scientific curiosity rather than something with major clinical importance. From a clinical standpoint, copper deficiency should be considered based on the same kinds of risk factors seen in the general population.
Dietary Sources of Copper for Athletes
The Recommended Dietary Allowance (RDA) for adult men and women is 900 µg/day, with the Tolerable Upper Intake Level (UL) for adults at 10,000 µg/day (10 mg/day) [1]. For context, the median intake of copper from food in the United States is approximately 1.0 to 1.6 mg/day for adult men and women [1].
Rich food sources include shellfish, seeds and nuts, organ meats, wheat-bran cereals, whole-grain products, and chocolate [7]. Iron, vitamin C, and zinc have been reported to exert adverse effects on the bioavailability of copper [7].
Practical dietary priorities for copper in athletes:
- Include nuts and seeds such as cashews, almonds, sunflower seeds, and sesame seeds regularly, as they can contribute dietary copper in a practical, training-compatible way [7].
- Whole grains and legumes can also contribute copper as part of a varied diet [7].
- Shellfish such as oysters and lobster are among the most concentrated dietary copper sources, although they do not need to be daily staples [7].
- Beef liver is also among the most concentrated dietary copper sources available [7].
- Be cautious with high-dose zinc supplementation: review total zinc intake across all supplements and foods, and consider monitoring serum copper and ceruloplasmin if high-dose zinc is continued long-term [8].
In my view, most athletes do not need to think about copper as a separate dietary target. The main priority is simply to maintain a varied and adequate diet. In most cases, copper intake is covered through a normal mixed diet, unless the athlete has malabsorption, gastrointestinal disease, high-dose zinc exposure, or another condition that increases deficiency risk.
In practice, I would not usually recommend a special copper-focused diet for athletes. I would be more concerned about restrictive, one-sided, or chronically calorie-deficient eating patterns, where overall micronutrient intake may become inadequate. For most healthy athletes, I see copper as part of overall diet quality rather than as a nutrient that usually needs separate attention.
Conclusion: Copper in Athletes
Copper is biologically important, but clinically it should be kept in perspective. It plays real roles in mitochondrial energy production, antioxidant defense, iron metabolism, and connective tissue formation, and true deficiency can cause clinically relevant problems such as anemia, leukopenia, impaired iron utilization, and connective tissue or bone abnormalities [1][3]. However, in everyday practice, genuine copper deficiency appears to be very rare, and athlete status alone should not be treated as an indication for copper testing or supplementation.
The exercise studies on copper are interesting from a sports physiology perspective, but they do not show that healthy athletes commonly develop clinically meaningful copper deficiency simply because they train hard [4][5]. Some athletes may have suboptimal intake, especially if their diet is restrictive, one-sided, or chronically calorie-deficient [6], but for most healthy athletes, copper intake is usually covered by a varied mixed diet. In my clinical view, copper is best approached as part of overall diet quality rather than as a nutrient that usually needs separate attention.
The situations where copper becomes more clinically relevant are the same ones that matter in the general population: unexplained anemia, leukopenia, poor response to iron therapy, significant malabsorption, gastrointestinal surgery, or high-dose zinc supplementation. Zinc is especially important because excessive intake can interfere with copper absorption and lead to copper-deficiency hematological problems [8]. For most athletes, the practical message is simple: eat a varied diet, avoid unnecessary high-dose supplementation, and consider copper testing only when the clinical picture genuinely fits.
References
[1] https://www.ncbi.nlm.nih.gov/books/NBK222312/
[2] https://doi.org/10.1002/iub.50
[3] https://doi.org/10.1007/s12185-025-04036-7
[4] https://doi.org/10.1007/s12011-018-1500-1
[5] https://doi.org/10.1186/s12970-019-0322-7
[6] https://doi.org/10.1123/ijsnem.13.3.343
[7] https://pmc.ncbi.nlm.nih.gov/articles/PMC8970836/
