Trace Minerals in Food: A Cross-Reference Table for Iodine, Zinc, Selenium, Copper, Manganese and Chromium
One cross-reference table of iodine, zinc, selenium, copper, manganese and chromium in common foods, with official intake levels from the US and UK and why food values vary.
Content last updated . This page has not been medically reviewed.
Seafood, meat, eggs, dairy, nuts and whole grains supply most of these six trace minerals, but no single food covers all six. Oysters stand out for zinc and copper, Brazil nuts for selenium, seaweed and dairy for iodine, and whole grains and shellfish for manganese. [1][2][3][4][5] This page puts the numbers side by side. The single-mineral pages go deeper: iodine foods, zinc foods and copper and manganese foods.
How to read the tables
All amounts below come from the food tables in the US National Institutes of Health Office of Dietary Supplements (ODS) fact sheets. Each fact sheet uses its own serving size and its own choice of foods, so a cell shows the serving that sheet used. An empty cell ("not listed") means that mineral's table did not include that food. It does not mean the food has none. Iodine, selenium, copper and chromium are in micrograms (mcg), zinc and manganese in milligrams (mg). These are amounts of the element, not of a compound.
Cross-reference table: the same foods across minerals
| Food | Iodine | Zinc | Selenium | Copper | Manganese | Chromium |
|---|---|---|---|---|---|---|
| Oysters, cooked | 93 mcg (3 oz) [4] | 28.2 mg (Pacific, 3 oz) [1] | not listed | 4,850 mcg (eastern wild, 3 oz) [2] | 1.0 mg (Pacific, 3 oz) [5] | not listed |
| Egg, hard boiled | 31 mcg (1 large) [4] | 0.6 mg (1 large) [1] | 15 mcg (1 large) [3] | not listed | 0.0 mg (1 large) [5] | 0.2 mcg (1 medium) [6] |
| Shrimp, cooked | 13 mcg (3 oz) [4] | 1.4 mg (3 oz) [1] | 42 mcg (3 oz) [3] | not listed | 0.0 mg (3 oz) [5] | not listed |
| Beef, cooked | 3 mcg (chuck, 3 oz) [4] | 3.8 mg (bottom sirloin, 3 oz) [1] | 37 mcg (bottom round, 3 oz) [3] | not listed | not listed | 2.0 mcg (3 oz) [6] |
| Milk | 84 mcg (nonfat, 1 cup) [4] | 1.0 mg (1%, 1 cup) [1] | 6 mcg (1%, 1 cup) [3] | 27 mcg (nonfat, 1 cup) [2] | 0.0 mg (1%, 1 cup) [5] | under 0.1 mcg (fat free, 1 cup) [6] |
| Brown rice, cooked | 0 mcg (3/4 cup) [4] | 0.7 mg (long grain, 1/2 cup) [1] | 12 mcg (long grain, 1 cup) [3] | not listed | 1.1 mg (medium grain, 1/2 cup) [5] | not listed |
| Whole-wheat bread | 1 mcg without or 273 mcg with an iodate dough conditioner (2 slices) [4] | 0.6 mg (1 slice) [1] | 8 mcg (1 slice) [3] | not listed | 0.7 mg (1 slice) [5] | 1.0 mcg (1 slice) [6] |
The bread row shows how much one ingredient choice can change a number. The same table lists 2 slices of whole-wheat bread at 1 mcg iodine without the dough conditioner and 273 mcg with it. [4]
The standout foods for each mineral
- Iodine: dried nori, 116 mcg in 2 tablespoons (5 g). [4] Seaweed varies enormously: commercial seaweeds range from 16 to 2,984 mcg per gram. [4] Most fruits and vegetables are poor sources. [4]
- Zinc: farmed eastern oysters, raw, 32 mg in 3 oz. [1]
- Selenium: Brazil nuts, 544 mcg in 1 oz (6 to 8 nuts). [3]
- Copper: beef liver, pan fried, 12,400 mcg in 3 oz. [2]
- Manganese: blue mussels, cooked, 5.8 mg in 3 oz. [5] Whole grains are also rich sources. [5]
- Chromium: grape juice, 7.5 mcg per cup, the highest on that sheet's list. [6] The NHS lists meat, nuts and cereal grains as good sources. [7]
Why a number in a table is only a guide
- Soil and region. Selenium in plant foods varies widely by geography. [3] ODS gives Brazil nuts as 544 mcg per ounce but notes values from other analyses vary widely. [3] The NHS says the iodine in cereals and grains depends on the soil. [8]
- Farming of the animal or the dairy. Iodine in dairy depends on whether cows received iodine feed supplements. [4]
- Processing and pans. Chromium in oatmeal samples can vary 50-fold. [6] Some chromium can transfer to food from stainless steel equipment and from pots and pans. [6]
- Added iodine. In the US, noniodized salt is almost always used in processed foods. [4]
Official intake levels (adults, 19 years and older)
These are published levels for a stated group in one country, not advice for any person. The US figures are from NIH ODS. The UK figures are from the NHS page last reviewed in August 2020. A clinician or pharmacist decides what is right for an individual.
| Mineral | US level (NIH ODS, read 2026) | Upper limit, US | UK (NHS, 2020) |
|---|---|---|---|
| Iodine | RDA 150 mcg; pregnancy 220 mcg; breastfeeding 290 mcg [4] | 1,100 mcg [4] | 140 mcg a day for adults [8] |
| Zinc | RDA 11 mg men, 8 mg women [1] | 40 mg [1] | 9.5 mg men aged 19 to 64 [7] |
| Selenium | RDA 55 mcg (19 to 50 years); pregnancy 60 mcg; breastfeeding 70 mcg [3] | 400 mcg [3] | 75 mcg men aged 19 to 64 [7] |
| Copper | RDA 900 mcg; pregnancy 1,000 mcg; breastfeeding 1,300 mcg [2] | 10,000 mcg [2] | 1.2 mg, adults 19 to 64 [7] |
| Manganese | Adequate Intake 2.3 mg men, 1.8 mg women (19 to 50 years) [5] | 11 mg [5] | no need figure on the NHS page; supplements of 4 mg or less a day unlikely to cause harm for most people [7] |
| Chromium | Adequate Intake 35 mcg men, 25 mcg women (19 to 50 years) [6] | none set; the Food and Nutrition Board found no adverse effects linked to high intakes but advised caution [6] | around 25 mcg a day for adults [7] |
The two countries differ, so never treat one country's figure as universal.
Frequently asked questions
Which single food gives the most of several trace minerals?
Oysters rank high for zinc and copper on ODS tables, and shellfish and organ meats are among the richest copper sources. No one food tops all six minerals. [1][2]
Do Brazil nuts provide a reliable amount of selenium?
ODS lists 544 mcg per ounce (6 to 8 nuts), but says values from other analyses vary widely. That figure is far above the US adult upper limit of 400 mcg. [3]
Does sea salt provide iodine?
The ODS iodine table lists noniodized sea salt at 0 mcg per quarter teaspoon, and says specialty salts are not usually iodized. Check the label. [4]
Is there an upper limit for chromium?
The US Food and Nutrition Board did not set one, but noted data are limited and caution may be warranted. The NHS says 10 mg or less a day from food and supplements is unlikely to cause harm. [6][7]
Can I tell from symptoms that I am low in one of these minerals?
No. Symptoms overlap with many conditions. Chromium deficiency has not been reported in healthy populations. Ask a clinician about testing rather than treating a suspected shortage alone. [6]
More details: evidence, limits and cautions
The details behind this page: cautions, limits of the evidence and where sources disagree. Open any note to read it.
Safety, children and pregnancy
- Too much is possible from supplements. Many iodine-only supplements contain high doses, sometimes above the upper limit. [4] Long-term high iodine can change thyroid function. [8] Too much selenium causes selenosis. [7] High zinc reduces copper absorption. [7]
- Older adults. The NHS says older people may be more sensitive to manganese and gives a lower supplement figure of 0.5 mg a day or less. [7]
- Kidney and liver conditions. The Food and Nutrition Board noted that people with kidney and liver disease might be susceptible to adverse effects from high chromium intakes. [6]
- Medical iodine use. The US upper limits do not apply to people receiving iodine for medical treatment. [4]
- Pregnancy, breastfeeding and children. Needs differ in these groups, as the table shows for iodine, selenium and copper. See minerals in pregnancy and ask a clinician before using supplements.
- Medicines and product quality. Check medication interactions with a pharmacist and read about quality testing.
For the single-mineral overviews see selenium, chromium and understanding minerals.
References
- NIH Office of Dietary Supplements, Zinc Fact Sheet for Health Professionals. Read 2026-10-22 as an Internet Archive copy dated 2026-01-01 because the live ODS page blocked automated download.
- NIH Office of Dietary Supplements, Copper Fact Sheet for Health Professionals. Read 2026-10-22 as an Internet Archive copy dated 2026-01-07 because the live ODS page blocked automated download.
- NIH Office of Dietary Supplements, Selenium Fact Sheet for Health Professionals. Read 2026-10-22 as an Internet Archive copy dated 2025-12-30 because the live ODS page blocked automated download.
- NIH Office of Dietary Supplements, Iodine Fact Sheet for Health Professionals. Read 2026-10-22 as an Internet Archive copy dated 2026-01-02 because the live ODS page blocked automated download.
- NIH Office of Dietary Supplements, Manganese Fact Sheet for Health Professionals. Read 2026-10-22 as an Internet Archive copy dated 2025-12-30 because the live ODS page blocked automated download.
- NIH Office of Dietary Supplements, Chromium Fact Sheet for Health Professionals. Read 2026-10-22 as an Internet Archive copy dated 2025-12-20 because the live ODS page blocked automated download.
- NHS, Others: vitamins and minerals (chromium, copper, manganese, selenium, zinc and others). Page last reviewed 3 August 2020. Read 2026-10-22.
- NHS, Vitamins and minerals: iodine. Page last reviewed 3 August 2020. Read 2026-10-22.