copper

Foods Richest in copper

About copper

Basic description

Copper is a cofactor in numerous enzymatic reactions across multiple body systems. It is required for connective tissue synthesis, iron metabolism, and mitochondrial energy production. The total copper content of the adult human body is only about 75-100 mg, and modern U.S. pennies are only 2.5% copper by weight.

In the foods we commonly eat, there are only very small amounts of copper. Dietary copper intake correlates strongly with consumption of minimally processed plant foods.

Of the WHF, 12 are rated as excellent sources of copper, 37 are very good, and 42 are rated as good.

Role in health support

Antioxidant protection

Copper is a cofactor for copper-zinc superoxide dismutase (Cu/Zn-SOD), one of the body’s primary antioxidant enzymes. Cu/Zn-SOD converts superoxide radicals to hydrogen peroxide, which is then neutralized by catalase. Mutations in the SOD1 gene encoding this enzyme are associated with familial amyotrophic lateral sclerosis (ALS).

From recent studies where young volunteers were fed a copper-depleted diet, reduced SOD function was an early result. In fact, these changes were apparent within the first month of the experimental diet.

In more advanced cases of copper deficiency, including people who have undergone gastric bypass surgery, this loss of antioxidant protection over a period of years can lead to irreversible damage to the nervous system. However, this does not appear to occur without the types of unusual deficiency risks detailed below.

Bone and tissue integrity

Copper is required to manufacture collagen, a major structural protein in the body. When copper deficiency becomes severe, tissue integrity (particularly bones and blood vessels) can deteriorate.

Current evidence indicates that severe and prolonged dietary copper deficiency is necessary to produce overt clinical problems. For example, premature babies with immature gastrointestinal tracts can develop bone problems related to copper deficiency.

At least one recent author has speculated that the marginal copper status of the diets of about one-quarter of adults in the U.S. is related to eventual development of osteoporosis in some members of this group. For adults with borderline copper intake from food, deficient intake of nutrients like calcium and vitamin D is still likely to put them at greater risk than borderline intake of copper. Still, this low copper intake may be increasing their risk of osteoporosis and is very likely to be the subject of future research.

Energy support

Copper participates in energy production through two mechanisms. As a component of ceruloplasmin, it oxidizes ferrous iron (Fe2+) to ferric iron (Fe3+), enabling iron incorporation into transferrin for red blood cell production. It also serves as a cofactor in cytochrome c oxidase, the terminal enzyme in the mitochondrial electron transport chain.

Both functions also require iron, which is why copper deficiency symptoms often mimic iron deficiency. Lentils and sesame seeds provide both minerals in significant amounts.

Cholesterol balance

Animal studies have demonstrated that copper-deficient diets lead to increases in blood cholesterol levels. In humans, this appears to be true in some situations, but not all. This should not be a surprise, as human diets are much more varied than those of laboratory animals. The mechanism appears to involve increased activity of HMG-CoA reductase, the rate-limiting enzyme in cholesterol biosynthesis and the same target of statin medications.

Summary of food sources

With the single exception of shrimp, all of the very good or excellent sources of copper among the WHF are plant foods. These best copper sources are varied, however, and come from many different food groups.

The top three sources of copper are sesame seeds, cashews, and soybeans, each providing at least 75% of the daily copper requirement per serving. Shiitake and crimini mushrooms are also excellent copper sources, covering 40 to 75% of the daily requirement.

Many of the excellent food sources of copper are leafy greens, including turnip greens, spinach, Swiss chard, kale, and mustard greens. Asparagus and summer squash are two other excellent vegetable sources of copper.

The good and very good sources of copper include many legumes, whole grains, nuts, and seeds. For example, flax seeds, walnuts, and garbanzo beans are rated as very good sources of copper.

Combining a grain- or legume-based dish with an excellent vegetable source of copper can provide the entire daily requirement. A serving of sauteed crimini mushrooms alone meets or exceeds the Recommended Dietary Allowance (RDA) for copper.

Nutrient rating chart

Introduction to nutrient rating system chart

Read more background information and details of our rating system

WHF ranked as quality sources of
copper

Food

Serving
Size

Cals

Amount
(mg)

DRI/DV
(%)

Nutrient
Density

World’s
Healthiest
Foods Rating

Sesame Seeds

0.25 cup

206.3

1.47

163

14.3

excellent

Cashews

0.25 cup

221.2

0.88

98

8.0

excellent

Soybeans

1 cup

297.6

0.70

78

4.7

excellent

Mushrooms, Shiitake

0.50 cup

40.6

0.65

72

32.0

excellent

Beet Greens

1 cup

38.9

0.36

40

18.5

excellent

Turnip Greens

1 cup

28.8

0.36

40

25.0

excellent

Mushrooms, Crimini

1 cup

15.8

0.36

40

45.5

excellent

Spinach

1 cup

41.4

0.31

34

15.0

excellent

Asparagus

1 cup

39.6

0.30

33

15.2

excellent

Swiss Chard

1 cup

35.0

0.29

32

16.6

excellent

Kale

1 cup

36.4

0.20

22

11.0

excellent

Mustard Greens

1 cup

36.4

0.20

22

11.0

excellent

Summer Squash

1 cup

36.0

0.19

21

10.6

excellent

Sunflower Seeds

0.25 cup

204.4

0.63

70

6.2

very good

Tempeh

4 oz

222.3

0.61

68

5.5

very good

Garbanzo Beans

1 cup

269.0

0.58

64

4.3

very good

Lentils

1 cup

229.7

0.50

56

4.4

very good

Walnuts

0.25 cup

196.2

0.48

53

4.9

very good

Lima Beans

1 cup

216.2

0.44

49

4.1

very good

Pumpkin Seeds

0.25 cup

180.3

0.43

48

4.8

very good

Tofu

4 oz

164.4

0.43

48

5.2

very good

Peanuts

0.25 cup

206.9

0.42

47

4.1

very good

Kidney Beans

1 cup

224.8

0.38

42

3.4

very good

Olives

1 cup

154.6

0.34

38

4.4

very good

Sweet Potato

1 cup

180.0

0.32

36

3.6

very good

Shrimp

4 oz

134.9

0.29

32

4.3

very good

Green Peas

1 cup

115.7

0.24

27

4.1

very good

Almonds

0.25 cup

132.2

0.23

26

3.5

very good

Grapes

1 cup

104.2

0.19

21

3.6

very good

Pineapple

1 cup

82.5

0.18

20

4.4

very good

Winter Squash

1 cup

75.8

0.17

19

4.5

very good

Flaxseeds

2 TBS

74.8

0.17

19

4.5

very good

Brussels Sprouts

1 cup

56.2

0.13

14

4.6

very good

Beets

1 cup

74.8

0.13

14

3.5

very good

Raspberries

1 cup

64.0

0.11

12

3.4

very good

Tomatoes

1 cup

32.4

0.11

12

6.8

very good

Broccoli

1 cup

54.6

0.10

11

3.7

very good

Kiwifruit

1 2 inches

42.1

0.09

10

4.3

very good

Basil

0.50 cup

4.9

0.08

9

32.8

very good

Cabbage

1 cup

43.5

0.08

9

3.7

very good

Sea Vegetables

1 TBS

10.8

0.08

9

14.7

very good

Black Pepper

2 tsp

14.6

0.08

9

11.0

very good

Miso

1 TBS

34.2

0.07

8

4.1

very good

Eggplant

1 cup

34.6

0.06

7

3.5

very good

Fennel

1 cup

27.0

0.06

7

4.4

very good

Leeks

1 cup

32.2

0.06

7

3.7

very good

Parsley

0.50 cup

10.9

0.05

6

9.1

very good

Chili Peppers

2 tsp

15.2

0.05

6

6.6

very good

Romaine Lettuce

2 cups

16.0

0.05

6

6.3

very good

Garlic

6 cloves

26.8

0.05

6

3.7

very good

Navy Beans

1 cup

254.8

0.38

42

3.0

good

Pinto Beans

1 cup

244.5

0.37

41

3.0

good

Black Beans

1 cup

227.0

0.36

40

3.2

good

Quinoa

0.75 cup

222.0

0.36

40

3.2

good

Dried Peas

1 cup

231.3

0.35

39

3.0

good

Barley

0.33 cup

217.1

0.31

34

2.9

good

Millet

1 cup

207.1

0.28

31

2.7

good

Avocado

1 cup

240.0

0.28

31

2.3

good

Buckwheat

1 cup

154.6

0.25

28

3.2

good

Oats

0.25 cup

151.7

0.24

27

3.2

good

Potatoes

1 cup

160.9

0.20

22

2.5

good

Rye

0.33 cup

188.5

0.20

22

2.1

good

Brown Rice

1 cup

216.4

0.19

21

1.8

good

Sardines

3.20 oz

188.7

0.17

19

1.8

good

Pear

1 medium

101.5

0.15

17

3.0

good

Onions

1 cup

92.4

0.14

16

3.0

good

Wheat

1 cup

151.1

0.14

16

1.9

good

Raisins

0.25 cup

108.4

0.12

13

2.2

good

Papaya

1 medium

118.7

0.12

13

2.0

good

Collard Greens

1 cup

62.7

0.10

11

3.2

good

Banana

1 medium

105.0

0.09

10

1.7

good

Blueberries

1 cup

84.4

0.08

9

1.9

good

Cantaloupe

1 cup

54.4

0.07

8

2.6

good

Green Beans

1 cup

43.8

0.07

8

3.2

good

Strawberries

1 cup

46.1

0.07

8

3.0

good

Watermelon

1 cup

45.6

0.06

7

2.6

good

Grapefruit

0.50 medium

41.0

0.06

7

2.9

good

Cranberries

1 cup

46.0

0.06

7

2.6

good

Oranges

1 medium

61.6

0.06

7

1.9

good

Carrots

1 cup

50.0

0.05

6

2.0

good

Plum

1 2-1/8 inches

30.4

0.04

4

2.6

good

Cucumber

1 cup

15.6

0.04

4

5.1

good

Celery

1 cup

16.2

0.04

4

5.0

good

Cumin

2 tsp

15.8

0.04

4

5.1

good

Bok Choy

1 cup

20.4

0.03

3

2.9

good

Mustard Seeds

2 tsp

20.3

0.03

3

3.0

good

Apricot

1 whole

16.8

0.03

3

3.6

good

Figs

1 medium

37.0

0.03

3

1.6

good

Peppermint

2 TBS

5.3

0.03

3

11.3

good

Thyme

2 TBS

4.8

0.03

3

12.4

good

Turmeric

2 tsp

15.6

0.03

3

3.9

good

World’s Healthiest
Foods Rating

Rule

excellent

DRI/DV>=75% OR
Density>=7.6 AND DRI/DV>=10%

very good

DRI/DV>=50% OR
Density>=3.4 AND DRI/DV>=5%

good

DRI/DV>=25% OR
Density>=1.5 AND DRI/DV>=2.5%

Impact of cooking, storage and processing

Storage of foods does not significantly affect their copper content. Like other minerals, copper will stay available in your foods as long as they are properly stored for recommended periods of time.

Processing whole grains into refined ones by removing the outer layers will significantly reduce copper content. For example, refined white flour has less than half the copper content of the whole wheat kernel. This is a large price to pay nutritionally.

Foods cooked at high temperatures for extended periods develop Maillard browning reactions that can substantially reduce copper bioavailability. Shorter cooking times at lower temperatures help preserve mineral availability.

Cooking vegetables reduces copper content in a manner that increases with both the volume of cooking water and the heating time. Lightly cooking vegetables by steaming should therefore help to minimize copper losses. For example, lightly boiling spinach only reduces the copper content by an insignificant fraction.

Risk of dietary deficiency

Between one-quarter to one-half of Americans fail to reach Dietary Reference Intake (DRI) recommendations for copper on a daily basis. In fact, in experimental research where scientists intentionally created copper-deficient diets, the composition of those diets was quite similar to the average U.S. diet. These copper-depleted diets were based largely around meats, refined grains, and dairy foods. As noted above, this common diet pattern was low enough in copper to cause significant detrimental effects to antioxidant enzymes within weeks.

About 5% of U.S. adults eat a diet with less copper than was used in these studies. In fact, this 5% of U.S. adults obtain less copper from their diets on a daily basis than would be found in a single serving of navy beans, a food not even close to the highest-rated copper source.

According to a statistical analysis published in 2011, copper deficiency risk has risen substantially over the past 75 years. This is probably most related to modern food processing methods, although copper depletion of soils may also contribute to some extent.

Other circumstances that might contribute to deficiency

Most of the non-dietary factors that contribute to copper deficiency tend to involve somewhat uncommon medical conditions. Gastric by-pass surgery stomach surgeries are two examples. Certain cancers (such as pancreatic cancer) can increase risk of copper deficiency, as can celiac disease when it is poorly managed or untreated.

Relationship with other nutrients

Prolonged supplementation with doses of zinc that go beyond normal dietary intake ranges can interfere with copper absorption and utilization, leading to copper deficiency.

Risk of dietary toxicity

Because most U.S. adults struggle to reach the DRI for copper, dietary toxicity risk is generally limited to two circumstances.

The first issue would be a genetic condition that impairs the ability to clear copper from the body, leading to a buildup to toxic levels. The most likely reason for this is a condition called Wilson’s disease, an inherited genetic mutation. Wilson’s disease is both rare (as few as one case per 100,000 people) and very severe. People with Wilson’s disease and similar genetic mutations affecting copper metabolism are usually diagnosed by adulthood.

A more common reason to see risk of copper toxicity is due to excessive exposure from the water supply. This is not generally caused by municipal water supplies (monitored by the EPA) but by leaching from old copper pipes and fittings.

The amount of copper that is leached into water from old pipes can be significant, but it varies widely. Several measures can reduce copper exposure from old pipes. Flushing the first gallon of water each morning (using it for non-cooking tasks) removes water that has sat in copper piping overnight. Running the tap until the water temperature drops noticeably also helps. Using cold water for cooking and heating it separately reduces leaching, since hot water extracts more copper. Activated charcoal and reverse osmosis filters can remove significant copper from tap water. However, given that most Americans consume less copper than recommended, reducing water copper exposure should only be considered when toxicity risk genuinely outweighs deficiency risk.

Disease checklist

• Anemia
• High cholesterol
• Fatigue
• Low immune function
• Osteoporosis
• Wound healing
• Cardiac arrhythmia
• Arthritis

Public health recommendations

In 2001, the Food and Nutrition Board of the National Academy of Sciences published a set of Dietary Reference Intakes (DRIs) that established both Recommended Dietary Allowances (RDAs) and Adequate Intakes (AIs) for copper. (The recommendations for children under one year of age below are AIs, and all other recommendations are RDAs.)

• 0-6 months: 0.2 mg
• 6-12 months: 0.22 mg
• 1-3 years: 0.34 mg
• 4-8 years: 0.4 mg
• 9-13 years: 0.7 mg
• 14-18 years: 0.89 mg
• 19+ years: 0.9 mg
• Pregnant women: 1.0 mg
• Lactating women: 1.3 mg

The DRI report also established a Tolerable Upper Intake Level (UL) of 10 mg per day for adult men and women.

The Daily Value (DV) for copper is 2 mg per 2000 calories. This is the value that you will see on nutrition labels on foods.

At WHF, we use the DRI of 0.9 milligrams for adult men and women 19 years and older as our recommended daily intake level for copper.

Description

How it functions

Deficiency symptoms

Toxicity symptoms

Factors that affect function

Nutrient interactions

Health conditions

Food sources

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References

1. Amaro Lopez MA, Moreno Rojas R, Zurera Cosano G, et al. Nutritional changes in the essential trace elements content of asparagus during industrial processing. Food Res Int 1999;32:479-86. https://doi.org/10.1016/s0963-9969(99)00111-8
2. Doblado-Maldonado AF, Pike OA, Sweley JC, et al. Key issues and challenges in whole wheat flour milling and storage. J Cereal Sci 2012;56:119-26. https://doi.org/10.1016/j.jcs.2012.02.015
3. Georgopoulos PG, Wang SW, Georgopoulos IG, et al. Assessment of human exposure to copper: A case study using the NHEXAS database. J Expo Sci Environ Epidemiol 2006;16:397-409. https://doi.org/10.1038/sj.jea.7500462
4. Goodman BP, Mistry DH, Pasha SF, et al. Copper deficiency myeloneuropathy due to occult celiac disease. Neurologist 2009;15:355-6. https://doi.org/10.1097/nrl.0b013e31819428a8
5. Griffith DP, Liff D, Ziegler TR, et al. Acquired copper deficiency: a potentially serious and preventable complication following gastric bypass surgery. Obesity 2009;17:827-31. https://doi.org/10.1038/oby.2008.614
6. Hoyle GS, Schwartz RP, Auringer ST. Pseudoscurvy caused by copper deficiency. J Pediatr 1999;134:379. https://doi.org/10.1016/s0022-3476(99)70470-1
7. Hunt CD, Meacham SL. Aluminum, boron, calcium, copper, iron, magnesium, manganese, molybdenum, phosphorus, potassium, sodium, and zinc: Concentrations in common Western foods and estimated daily intakes by infants; toddlers; and male and female adolescents, adults, and seniors in the United States. J Am Diet Assoc 2001;101:1058-60. https://doi.org/10.1007/s12403-019-00324-w
8. Institute of Medicine. Dietary Reference Intakes for Vitamin A, Vitamin K, Arsenic, Boron, Chromium, Copper, Iodine, Iron, Manganese, Molybdenum, Nickel, Silicon, Vanadium, and Zinc. National Academy Press: Washington DC, 2001.
9. Klevay LM. Is the Western diet adequate in copper? J Trace Elem Med Biol 2011;25:2004-12. https://doi.org/10.4491/eer.2016.007
10. Marquardt ML, Done, SL, Sandrock M, et al. Copper deficiency presenting as metabolic bone disease in extremely low birth weight, short-gut infants. Pediatrics 2012;130:695-8. https://doi.org/10.1542/peds.2011-1295
11. Mesias M, Seiquer I, Navarro MP. Consumption of highly processed foods: Effects on bioavailability and status of zinc and copper in adolescents. Food Res Int 2012;45:184-90. https://doi.org/10.1016/j.foodres.2011.09.030
12. Nations SP, Boyer PJ, Love LA, et al. Denture cream: an unusual source of excess zinc, leading to hypocupremia and neurologic disease. Neurology 2008;71:639-43. https://doi.org/10.1212/01.wnl.0000349696.89948.b7
13. Turnlund JR, Scott KC, Peiffer GL, et al. Copper status of young men consuming a low-copper diet. Am J Clin Nutr 1997;65:72-8. https://doi.org/10.1093/ajcn/65.1.72
14. Burkitt MJ. A critical overview of the chemistry of copper-dependent low density lipoprotein oxidation: roles of lipid hydroperoxides, alpha-tocopherol, thiols, and ceruloplasmin. Arch Biochem Biophys 2001 Oct 1;394(1):117-35. 2001. PMID:15240.
15. Davis CD. Low dietary copper increases fecal free radical production, fecal water alkaline phosphatase activity and cytotoxicity in healthy men. J Nutr. 2003 Feb; 133(2):522-7. 2003. https://doi.org/10.1093/jn/133.2.522
16. Groff JL, Gropper SS, Hunt SM. Advanced Nutrition and Human Metabolism. West Publishing Company, New York, 1995. 1995.
17. Harris ED. Copper homeostasis: the role of cellular transporters. Nutr Rev 2001 Sep;59(9):281-5. 2001. PMID:15230.
18. Harris ED, Qian Y, Tiffany-Castiglioni E, et al. Functional analysis of copper homeostasis in cell culture models: a new perspective on internal copper transport. 0. PMID:7230. https://doi.org/10.1016/0005-7967(76)90076-0
19. Institute of Medicine. Dietary Reference Intakes for Vitamin A, Vitamin K, Arsenic, Boron, Chromium, Copper, Iodine, Iron, Manganese, Molybdenum, Nickel, Silicon, Vanadium, and Zinc. National Academy Press: Washington DC, 2001. 2001.
20. Lininger SW, et al. A-Z guide to drug-herb-vitamin interactions. Prima Health, Rocklin, CA, 2000. 2000.
21. Nath R. Copper deficiency and heart disease: molecular basis, recent advances and current concepts. 0. PMID:7240. https://doi.org/10.1042/bj1550005
22. Roughead ZK, Lukaski HC. Inadequate copper intake reduces serum insulin-like growth factor-I and bone strength in growing rats fed graded amounts of copper and zinc. J Nutr 2003 Feb;133(2):442-8. 2003. https://doi.org/10.1093/jn/133.2.442
23. Schaefer M, Gitlin JD. Genetic disorders of membrane transport IV. Wilson's disease and Menkes disease. 0. PMID:7220. https://doi.org/10.1038/icb.1975.38
24. Strausak D, Mercer JF, Dieter HH, et al. Copper in disorders with neurological symptoms: Alzheimer's, Menkes, and Wilson diseases. Brain Res Bull 2001 May 15;55(2):175-85. 2001. PMID:15260. https://doi.org/10.1073/pnas.74.3.931
25. Waggoner DJ, Bartnikas TB, Gitlin JD. The role of copper in neurodegenerative disease. 0. PMID:7200. https://doi.org/10.1016/0003-9861(76)90339-8
26. Burkitt MJ. A critical overview of the chemistry of copper-dependent low density lipoprotein oxidation: roles of lipid hydroperoxides, alpha-tocopherol, thiols, and ceruloplasmin. Arch Biochem Biophys 2001 Oct 1;394(1):117-35 2001. PMID:15240.
27. Davis CD. Low dietary copper increases fecal free radical production, fecal water alkaline phosphatase activity and cytotoxicity in healthy men. J Nutr. 2003 Feb; 133(2):522-7 2003. https://doi.org/10.1093/jn/133.2.522
28. Groff JL, Gropper SS, Hunt SM. Advanced Nutrition and Human Metabolism. West Publishing Company, New York, 1995 1995.
29. Harris ED. Copper homeostasis: the role of cellular transporters. Nutr Rev 2001 Sep;59(9):281-5 2001. PMID:15230.
30. Harris ED, Qian Y, Tiffany-Castiglioni E, et al. Functional analysis of copper homeostasis in cell culture models: a new perspective on internal copper transport. PMID:7230. https://doi.org/10.1016/0005-7967(76)90076-0
31. Institute of Medicine. Dietary Reference Intakes for Vitamin A, Vitamin K, Arsenic, Boron, Chromium, Copper, Iodine, Iron, Manganese, Molybdenum, Nickel, Silicon, Vanadium, and Zinc. National Academy Press: Washington DC, 2001 2001.
32. Lininger SW, et al. A-Z guide to drug-herb-vitamin interactions. Prima Health, Rocklin, CA, 2000 2000.
33. Nath R. Copper deficiency and heart disease: molecular basis, recent advances and current concepts. PMID:7240. https://doi.org/10.1042/bj1550005
34. Roughead ZK, Lukaski HC. Inadequate copper intake reduces serum insulin-like growth factor-I and bone strength in growing rats fed graded amounts of copper and zinc. J Nutr 2003 Feb;133(2):442-8 2003. https://doi.org/10.1093/jn/133.2.442
35. Schaefer M, Gitlin JD. Genetic disorders of membrane transport IV. Wilson's disease and Menkes disease. PMID:7220. https://doi.org/10.1038/icb.1975.38
36. Strausak D, Mercer JF, Dieter HH, et al. Copper in disorders with neurological symptoms: Alzheimer's, Menkes, and Wilson diseases. Brain Res Bull 2001 May 15;55(2):175-85 2001. PMID:15260. https://doi.org/10.1073/pnas.74.3.931
37. Waggoner DJ, Bartnikas TB, Gitlin JD. The role of copper in neurodegenerative disease. PMID:7200. https://doi.org/10.1016/0003-9861(76)90339-8