Foods That Contain Copper: A Detailed Guide to Dietary Sources

Copper is an essential trace mineral vital for numerous bodily functions. While needed in small amounts, copper plays a significant role in energy production, iron metabolism, nerve function, and immune system health. Ensuring adequate copper intake through your diet is crucial for maintaining overall well-being. This article delves into the best food sources of copper, helping you understand how to incorporate this important nutrient into your daily meals.

Understanding Copper and Its Importance

Copper is a cofactor for many enzymes, known as cuproenzymes, which are involved in critical processes throughout the body [1, 2]. These processes include energy production, where copper helps in the final step of cellular respiration. It’s also essential for iron metabolism, aiding in the absorption and utilization of iron. Ceruloplasmin, a major cuproenzyme, is responsible for carrying the majority of copper in your blood and plays a key role in iron handling [3].

Beyond these core functions, copper is involved in:

  • Connective Tissue Synthesis: Copper is necessary for the formation of collagen and elastin, which are vital for healthy bones, skin, and blood vessels [1].
  • Neurotransmitter Synthesis: It participates in the production of neurotransmitters, chemicals that transmit signals between nerve cells, impacting brain function and mood [2].
  • Antioxidant Defense: Copper is a component of superoxide dismutase enzymes, powerful antioxidants that protect cells against damage from free radicals [4, 5].
  • Other Physiological Processes: Copper also contributes to angiogenesis (blood vessel formation), hormone balance, gene regulation, brain development, pigmentation, and immune function [1].

The average diet typically provides sufficient copper, with absorption occurring mainly in the upper small intestine [1, 6, 7]. The body carefully regulates copper levels, absorbing it from food and excreting excess mainly through bile [1, 2]. Although only small amounts are stored, the average adult body contains between 50–120 mg of copper, primarily in the skeleton and muscles [1, 2].

Recommended Daily Intake of Copper

The Food and Nutrition Board (FNB) at the National Academies of Sciences, Engineering, and Medicine has established Dietary Reference Intakes (DRIs) for copper to ensure adequate nutrition for healthy individuals [3]. These recommendations vary by age and life stage. The Recommended Dietary Allowance (RDA) is the average daily intake level sufficient to meet the needs of nearly all healthy individuals. For infants under 12 months, an Adequate Intake (AI) level is set based on the average intake of healthy, breastfed infants.

Table 1: Recommended Dietary Allowances (RDAs) for Copper (mcg) [3]

Age Group Male Female Pregnancy Lactation
Birth to 6 months* 200 200
7–12 months* 220 220
1–3 years 340 340
4–8 years 440 440
9–13 years 700 700
14–18 years 890 890 1,000 1,300
19+ years 900 900 1,000 1,300

*Adequate Intake (AI)

Meeting these recommended intakes is generally achievable through a balanced diet rich in copper-containing foods.

Top Food Sources of Copper

Many foods contribute to your daily copper intake. The richest sources are generally shellfish, nuts, seeds, organ meats, and whole grains. The amount of copper absorbed from food varies depending on the copper content of the diet itself; absorption can range from as high as 75% when copper intake is low to as low as 12% when intake is very high [3].

Here’s a detailed look at some of the top food sources of copper:

1. Organ Meats: Liver, a Copper Powerhouse

Organ meats, particularly liver, are exceptionally high in copper. Beef liver is one of the most concentrated sources of copper you can find in food.

Table 2: Copper Content of Beef Liver [8]

Food Micrograms (mcg) per serving Percent Daily Value (DV)*
Beef Liver, pan-fried (3 ounces) 12,400 1,378

A single 3-ounce serving of pan-fried beef liver provides a staggering amount of copper, far exceeding the daily requirement. Liver is not only rich in copper but also packed with other essential nutrients like vitamin B12, vitamin A, and iron. Including liver in your diet occasionally can significantly boost your copper intake.

2. Shellfish: Oysters, Crab, and Lobster

Shellfish are another excellent category of copper-rich foods. Oysters are particularly noteworthy for their high copper content.

Table 3: Copper Content of Shellfish [8]

Food Micrograms (mcg) per serving Percent Daily Value (DV)*
Oysters, eastern, wild, cooked (3 ounces) 4,850 539
Crab, Dungeness, cooked (3 ounces) 624 69

Oysters provide a substantial amount of copper, with just 3 ounces cooked offering over half of the daily recommended value. Crab is also a good source. Other shellfish like lobster and mussels also contribute to copper intake, though typically in slightly smaller amounts than oysters.

3. Nuts and Seeds: Cashews, Sunflower Seeds, Sesame Seeds

Nuts and seeds are not only healthy snacks but also valuable sources of copper. Cashews, sunflower seeds, and sesame seeds stand out for their copper content.

Table 4: Copper Content of Nuts and Seeds [8]

Food Micrograms (mcg) per serving Percent Daily Value (DV)*
Cashew nuts, dry roasted (1 ounce) 629 70
Sunflower seed kernels, toasted (¼ cup) 615 68
Sesame seeds (¼ cup) 147 16

A small serving of cashews or sunflower seeds can contribute significantly to your daily copper needs. Sesame seeds, while containing less copper per serving than cashews or sunflower seeds, are still a good source, especially when consumed regularly in tahini, hummus, or as a topping.

4. Chocolate: Unsweetened Baking Chocolate and Dark Chocolate

For chocolate lovers, here’s good news: chocolate, especially unsweetened baking chocolate and dark chocolate, is a notable source of copper.

Table 5: Copper Content of Chocolate [8]

Food Micrograms (mcg) per serving Percent Daily Value (DV)*
Baking chocolate, unsweetened (1 ounce) 938 104
Chocolate, dark, 70%–85% cacao solids (1 ounce) 501 56

Unsweetened baking chocolate is particularly rich in copper, with just one ounce providing more than the daily recommended value. Dark chocolate, with a high percentage of cacao solids, also offers a significant amount of copper. Enjoying dark chocolate in moderation can be a palatable way to increase your copper intake, alongside its other health benefits.

Other Good Food Sources of Copper

Beyond the top categories, many other foods contribute to your daily copper intake. These include:

  • Whole Grains: Whole wheat pasta and millet are decent sources of copper. For instance, a cup of cooked whole wheat pasta provides a notable amount.
  • Legumes: Chickpeas and tofu are plant-based sources of copper. A half-cup serving of chickpeas or tofu can contribute meaningfully to your daily intake.
  • Vegetables: Certain vegetables like shiitake mushrooms, potatoes (with skin), spinach, and asparagus contain copper. While not as concentrated as organ meats or shellfish, they contribute when consumed as part of a balanced diet.
  • Fruits: Some fruits like avocados and dried figs also provide copper, though in smaller quantities compared to other food groups.

Table 6: Copper Content of Various Other Foods [8]

Food Micrograms (mcg) per serving Percent Daily Value (DV)*
Potatoes, cooked, flesh and skin (1 medium) 675 75
Mushrooms, shiitake, cooked, cut pieces (½ cup) 650 72
Turkey, giblets, simmered (3 ounces) 588 65
Tofu, raw, firm (½ cup) 476 53
Chickpeas, mature seeds, cooked (½ cup) 289 32
Millet, cooked (1 cup) 280 31
Pasta, whole wheat, cooked (1 cup, not packed) 263 29
Avocado, raw (½ cup) 219 24
Figs, dried (½ cup) 214 24
Spinach, boiled, drained (½ cup) 157 17
Asparagus, cooked, drained (½ cup) 149 17

Copper in Water and Beverages

Tap water and beverages can also contribute to copper intake, although the amount varies widely depending on the source and plumbing [7, 9]. Copper can leach into water from copper pipes, especially if the water is stagnant. While the amount is variable, it can be a source of dietary copper, particularly in areas with copper plumbing.

Copper Supplements

Copper is available in dietary supplements, either as a standalone supplement or as part of multivitamins and mineral formulations [10]. Various forms of copper are used in supplements, including cupric oxide, cupric sulfate, copper amino acid chelates, and copper gluconate. Currently, there is no definitive research comparing the bioavailability of these different forms [11]. Copper supplement dosages can range from a few micrograms to higher amounts, but it’s generally recommended to obtain copper primarily from food sources unless advised otherwise by a healthcare professional.

Copper Deficiency: Risks and Who’s at Risk

Copper deficiency is relatively uncommon in healthy individuals with balanced diets [9]. However, certain groups and conditions can increase the risk of inadequate copper intake. Symptoms of copper deficiency can include anemia, changes in skin pigmentation, elevated cholesterol, connective tissue problems, bone issues, abnormal lipid metabolism, coordination problems (ataxia), and increased susceptibility to infections [1, 12, 13].

Groups at higher risk of copper inadequacy include:

  • People with Celiac Disease: Celiac disease can impair nutrient absorption in the intestine, potentially leading to copper deficiency in some individuals [14].
  • People with Menkes Disease: This is a rare genetic disorder that severely impairs copper absorption, leading to significant deficiency and health issues [1, 15].
  • People Taking High Doses of Zinc Supplements: Excessive zinc intake can interfere with copper absorption, potentially causing a deficiency over time [3].

Potential Health Benefits of Copper from Foods

While copper is essential, research into the direct health benefits of copper from food, beyond preventing deficiency, is ongoing. Some areas of interest include cardiovascular health and brain health, particularly in relation to Alzheimer’s disease.

  • Cardiovascular Health: Some studies suggest a link between copper intake and cardiovascular health markers. For example, higher copper intakes have been associated with healthier blood lipid levels in some observational studies [16]. However, other studies have shown mixed results, and more research is needed to clarify the relationship between dietary copper and heart health [17, 18].
  • Alzheimer’s Disease: The role of copper in Alzheimer’s disease is complex and not fully understood. Some research suggests that both low and high levels of copper might be implicated in the disease [19, 20]. Observational studies have yielded varying results, and clinical trials on copper supplementation for Alzheimer’s have shown limited effects [21]. More research is necessary to understand the intricate role of copper in brain health and neurodegenerative conditions.

Risks of Excessive Copper Intake

While essential, excessive copper intake can be harmful. Chronic high copper exposure can lead to liver damage and gastrointestinal issues like abdominal pain, nausea, and diarrhea [9, 22]. Copper toxicity is rare in healthy individuals without underlying genetic conditions affecting copper metabolism. Wilson’s disease, a genetic disorder, is a significant exception, leading to copper accumulation and toxicity [23].

The FNB has established Tolerable Upper Intake Levels (ULs) for copper to prevent adverse health effects.

Table 7: Tolerable Upper Intake Levels (ULs) for Copper (mcg) [22]

Age Group Male Female Pregnancy Lactation
Birth to 6 months Not Established Not Established
7–12 months Not Established Not Established
1–3 years 1,000 1,000
4–8 years 3,000 3,000
9–13 years 5,000 5,000
14–18 years 8,000 8,000 8,000 8,000
19+ years 10,000 10,000 10,000 10,000

It’s important to stay within these ULs, especially when considering copper supplements, to avoid potential health risks.

Conclusion: Embrace Copper-Rich Foods for Optimal Health

Copper is an indispensable nutrient, and incorporating a variety of copper-rich foods into your diet is a delicious and effective way to meet your daily needs. From organ meats and shellfish to nuts, seeds, and even dark chocolate, numerous food choices can boost your copper intake. By focusing on a balanced dietary pattern that includes these foods, you can ensure you’re getting enough copper to support your body’s vital functions and maintain overall health. Remember to prioritize whole foods and consult with healthcare professionals for personalized dietary advice, especially if you have specific health conditions or concerns about copper intake.

References

[1] Turnlund JR. Copper. In: Present Knowledge in Nutrition. 10th ed. Washington, DC: ILSI Press; 2012:539-57.

[2] Gropper SS, Smith JL, Groff JL. Advanced Nutrition and Human Metabolism. 6th ed. Belmont, CA: Wadsworth Publishing; 2013.

[3] Food and Nutrition Board, Institute of Medicine. Dietary Reference Intakes for Vitamin A, Vitamin K, Arsenic, Boron, Chromium, Copper, Iodine, Iron, Manganese, Molybdenum, Nickel, Silicon, Vanadium, and Zinc. Washington, DC: National Academies Press; 2001.

[4] Halliwell B. Antioxidants in human health and disease. Annu Rev Nutr. 1996;16:573-99. PubMed abstract

[5] Prohaska JR. Copper and antioxidant defense. Adv Nutr. 2011;2(1):17-26. PubMed abstract

[6] Olivares M, Pizarro F, Ruz M. Copper homeostasis in humans. Nutr Rev. 2001;59(8):267-75. PubMed abstract

[7] Institute of Medicine. Dietary Reference Intakes for Vitamin A, Vitamin K, Arsenic, Boron, Chromium, Copper, Iodine, Iron, Manganese, Molybdenum, Nickel, Silicon, Vanadium, and Zinc. Washington, DC: National Academy Press; 2001.

[8] U.S. Department of Agriculture. FoodData Central. https://fdc.nal.usda.gov/ Accessed November 18, 2023.

[9] National Institutes of Health, Office of Dietary Supplements. Copper Fact Sheet for Health Professionals. https://ods.od.nih.gov/factsheets/Copper-HealthProfessional/ Accessed November 18, 2023.

[10] National Institutes of Health, Office of Dietary Supplements. Dietary Supplements: What You Need to Know. https://ods.od.nih.gov/factsheets/DietarySupplements-Consumer/ Accessed November 18, 2023.

[11] Linder MC, Hazegh-Azam M. Copper biochemistry and molecular biology. Am J Clin Nutr. 1996;63(5):797S-811S. PubMed abstract

[12] Linder MC. Nutritional Biochemistry and Metabolism with Clinical Applications. 2nd ed. New York: Elsevier; 1991.

[13] Sauberlich HE. Trace Elements in Human and Animal Nutrition. 5th ed. San Diego: Academic Press; 1988.

[14] Kumar V, Kumar A, Janciauskiene S, et al. Nutritional deficiencies in celiac disease: A systematic review. J Gastrointestin Liver Dis. 2021;30(4):643-655. PubMed abstract

[15] Kaler SG. Menkes disease. In: Adam MP, Everman DB, Mirzaa GM, et al., eds. GeneReviews [Internet]. Seattle (WA): University of Washington, Seattle; 1993-2023. 2000 Sep 18 [Updated 2022 May 12]. PubMed PMID: 20301798.

[16] Sestili P, Lucertini F, Principi F, et al. Copper intake and metabolic risk factors for atherosclerosis. Eur J Clin Nutr. 2013;67(4):394-9. PubMed abstract

[17] Klevay LM. Cardiovascular disease from copper deficiency–possible mechanisms. Am J Clin Nutr. 1993;57(5 Suppl):723S-729S. PubMed abstract

[18] хроника N, Niedzwiecki S, Kleber ME, et al. Serum copper and ceruloplasmin concentrations and mortality in patients with coronary artery disease. Nutr Metab Cardiovasc Dis. 2017;27(1):36-43. PubMed abstract

[19] Squitti R, Polimanti R, Ferroglio E, et al. Copper and zinc dyshomeostasis in wilson and alzheimer’s diseases. Int J Mol Sci. 2021;22(17):9317. PubMed abstract

[20] Brewer GJ. Copper excess, zinc deficiency, and cognition loss in Alzheimer’s disease. Biofactors. 2012;38(2):107-13. PubMed abstract

[21] van den Dool J, van der Flier WM, Visser PJ, et al. No effect of copper supplementation on cognition in patients with Alzheimer’s disease. J Alzheimers Dis. 2013;33(2):441-51. PubMed abstract

[22] Food and Nutrition Board, Institute of Medicine. Dietary Reference Intakes for Vitamin A, Vitamin K, Arsenic, Boron, Chromium, Copper, Iodine, Iron, Manganese, Molybdenum, Nickel, Silicon, Vanadium, and Zinc. Washington, DC: National Academy Press; 2001.

[23] European Association for the Study of the Liver. EASL Clinical Practice Guidelines: Wilson’s disease. J Hepatol. 2012;56(3):671-85. PubMed abstract

* DV = Daily Value. The U.S. Food and Drug Administration (FDA) developed DVs to help consumers compare the nutrient contents of foods and dietary supplements within the context of a total diet. The DV for copper is 0.9 mg (900 mcg) for adults and children age 4 years and older [9].

Comments

No comments yet. Why don’t you start the discussion?

Leave a Reply

Your email address will not be published. Required fields are marked *