Essential Trace Elements

Trace elements are minerals your body needs in very small amounts to stay healthy. Even though you only need a little, they play big roles in keeping your bones strong, your immune system working, and your cells healthy.

Assorted healthy foods including a bowl of greens, meat, eggs, nuts, and seeds on a kitchen counter, , representing whole food sources of trace elements.

Copper

Copper is a trace mineral essential for forming red blood cells, maintaining healthy bones and connective tissue, and supporting immune function. It also acts as a cofactor for enzymes involved in energy production and iron metabolism.

Risks of Not Having Enough (Deficiency)

  • Anemia (low red blood cell count)
  • Weakened bones and connective tissue
  • Impaired immune response
  • Neurological problems (numbness, weakness)
  • Higher risk of cardiovascular issues

Risks of Having Too Much (Toxicity)

  • Nausea, vomiting, and diarrhea
  • Liver damage
  • Kidney problems
  • Neurological symptoms in severe cases

Food Sources

Food Serving Size Copper (mg)
Beef liver 3 oz (85 g) 12.4
Oysters 3 oz (85 g) 4.8
Dark chocolate (70-85%) 1 oz (28 g) 0.5
Cashews 1 oz (28 g) 0.6
Sunflower seeds 1 oz (28 g) 0.5
Lentils (cooked) 1 cup (198 g) 0.5
Shiitake mushrooms (cooked) 1 cup (145 g) 1.3

*USRDA for adults: 900 mcg (0.9 mg) per day

Summary of Genetic Impact

Genetic variations can affect copper absorption, transport (via ceruloplasmin), and utilization. Some individuals may have higher or lower copper needs based on variants in genes like ATP7A and ATP7B, which regulate copper metabolism.

Iodine

Iodine is essential for the production of thyroid hormones, which regulate metabolism, growth, and development. It is particularly important during pregnancy and early childhood for brain development.

Risks of Not Having Enough (Deficiency)

  • Goiter (enlarged thyroid gland)
  • Hypothyroidism (fatigue, weight gain, cold intolerance)
  • Impaired brain development in infants and children
  • Pregnancy complications
  • Cognitive impairment

Risks of Having Too Much (Toxicity)

  • Thyroid dysfunction (both hyper- and hypothyroidism)
  • Thyroiditis (inflammation of the thyroid)
  • Nausea, fever, and diarrhea in acute cases

Food Sources

Food Serving Size Iodine (mcg)
Seaweed (nori) 1 sheet (2.5 g) 16-43
Cod 3 oz (85 g) 158
Iodized salt 1/4 tsp (1.5 g) 71
Yogurt (plain) 1 cup (245 g) 75
Milk 1 cup (244 g) 56
Shrimp 3 oz (85 g) 35
Eggs 1 large (50 g) 24

*USRDA for adults: 150 mcg per day

Summary of Genetic Impact

Genetic variants in thyroid-related genes (such as TPO, TSHR, and DIO1/DIO2) can influence how efficiently your body uses iodine to produce thyroid hormones, potentially affecting your iodine requirements.

Manganese

Manganese is a trace mineral that serves as a cofactor for many enzymes involved in bone formation, blood clotting, metabolism of amino acids, carbohydrates, and cholesterol, and antioxidant defense.

Risks of Not Having Enough (Deficiency)

  • Poor bone health and skeletal abnormalities
  • Impaired glucose tolerance
  • Altered carbohydrate and fat metabolism
  • Skin rash
  • Impaired growth in children

Risks of Having Too Much (Toxicity)

  • Neurological symptoms resembling Parkinson's disease (manganism)
  • Tremors, difficulty walking
  • Cognitive and behavioral changes
  • Respiratory issues (from inhaled manganese dust)

Food Sources

Food Serving Size Manganese (mg)
Mussels 3 oz (85 g) 5.8
Hazelnuts 1 oz (28 g) 1.7
Pecans 1 oz (28 g) 1.3
Brown rice (cooked) 1 cup (202 g) 1.8
Oatmeal (cooked) 1 cup (234 g) 1.4
Pineapple 1 cup (165 g) 1.5
Spinach (cooked) 1 cup (180 g) 1.7

*Adequate Intake (AI) for adults: 2.3 mg/day (men), 1.8 mg/day (women)

Summary of Genetic Impact

Variants in SLC30A10 and SLC39A14 genes can affect manganese transport and metabolism, influencing both the risk of deficiency and the susceptibility to manganese toxicity.

Selenium

Selenium is a powerful antioxidant trace mineral that plays critical roles in thyroid function, DNA synthesis, and protecting the body from oxidative damage and infection. It is incorporated into selenoproteins that have wide-ranging functions.

Risks of Not Having Enough (Deficiency)

  • Weakened immune system
  • Increased susceptibility to infections
  • Keshan disease (a type of heart disease)
  • Kashin-Beck disease (a type of joint disease)
  • Thyroid dysfunction
  • Increased cancer risk (some studies suggest)

Risks of Having Too Much (Toxicity)

  • Selenosis: hair loss, nail brittleness
  • Garlic-like breath odor
  • Nausea, diarrhea
  • Skin rashes
  • Nervous system abnormalities
  • Fatigue and irritability

Food Sources

Food Serving Size Selenium (mcg)
Brazil nuts 1 nut (5 g) 96
Yellowfin tuna 3 oz (85 g) 92
Halibut 3 oz (85 g) 47
Sardines 3 oz (85 g) 45
Turkey 3 oz (85 g) 31
Chicken breast 3 oz (85 g) 22
Eggs 1 large (50 g) 15

*USRDA for adults: 55 mcg per day

Summary of Genetic Impact

Variants in selenoprotein genes (such as GPX1, SELENOP, and TXNRD1) can affect how efficiently your body utilizes selenium. Some people may need more selenium to achieve optimal selenoprotein activity based on their genetic profile.

Zinc

Zinc is essential for immune function, wound healing, protein and DNA synthesis, cell division, and proper sense of taste and smell. It is involved in over 300 enzymatic reactions in the body.

Risks of Not Having Enough (Deficiency)

  • Weakened immune system and frequent infections
  • Delayed wound healing
  • Hair loss
  • Loss of appetite and taste
  • Growth retardation in children
  • Skin lesions
  • Impaired cognitive function

Risks of Having Too Much (Toxicity)

  • Nausea, vomiting, and diarrhea
  • Copper deficiency (zinc competes with copper absorption)
  • Lowered immune function (paradoxically, from chronic excess)
  • Reduced HDL ("good") cholesterol
  • Headaches and abdominal cramps

Food Sources

Food Serving Size Zinc (mg)
Oysters 3 oz (85 g) 74.0
Beef chuck roast 3 oz (85 g) 7.0
Crab (Alaska king) 3 oz (85 g) 6.5
Pork chop 3 oz (85 g) 2.9
Baked beans 1/2 cup (130 g) 2.9
Pumpkin seeds 1 oz (28 g) 2.2
Chickpeas (cooked) 1/2 cup (82 g) 1.3

*USRDA for adults: 11 mg/day (men), 8 mg/day (women)

Summary of Genetic Impact

Genetic variants in zinc transporters (SLC30A and SLC39A gene families) can influence zinc absorption, distribution, and excretion. These variations may affect individual zinc requirements and susceptibility to deficiency.

References

References

Numbers in the text match this list. Accessed February 9, 2026.

  1. MedlinePlus (NIH). Nutrition. https://medlineplus.gov/nutrition.html

  2. CDC (NCHS). Nutrition (Health, United States): macronutrients and chronic disease risk. https://www.cdc.gov/nchs/hus/topics/nutrition.htm

  3. MedlinePlus (NIH). Carbohydrates. https://medlineplus.gov/ency/article/002469.htm

  4. MedlinePlus (NIH). Dietary Fiber. https://medlineplus.gov/dietaryfiber.html

  5. World Health Organization (WHO). Guideline: Sugars intake for adults and children (2015). https://www.who.int/publications/i/item/9789241549028

  6. USDA Nutrition Evidence Systematic Review (NESR). Sugar-sweetened beverages and risk of type 2 diabetes: systematic review (Nov 2024). https://nesr.usda.gov/sites/default/files/2024-11/Sugar-sweetened-beverages_type-2-diabetes-2025DGACSystematicReview.pdf

  7. CDC. About Cavities (Tooth Decay). https://www.cdc.gov/oral-health/about/cavities-tooth-decay.html

  8. American Heart Association (AHA). Whole grains, refined grains, and dietary fiber. https://www.heart.org/en/healthy-living/healthy-eating/eat-smart/nutrition-basics/whole-grains-refined-grains-and-dietary-fiber

  9. BMJ. Whole grain foods and risk of type 2 diabetes: meta-analysis summary. https://www.bmj.com/content/370/bmj.m2206

  10. MedlinePlus (NIH). Dietary fats explained. https://medlineplus.gov/ency/patientinstructions/000104.htm

  11. American Heart Association (AHA). Fats in Foods. https://www.heart.org/en/healthy-living/healthy-eating/eat-smart/fats/fats-in-foods

  12. USDA Food and Nutrition Service (FNS). Dietary Guidelines for Americans (current edition). https://www.fns.usda.gov/cnpp/dietary-guidelines-americans

  13. MyPlate (USDA). More Key Topics: Oils, Added Sugars, Saturated Fats. https://www.myplate.gov/eat-healthy/more-key-topics

  14. NCCIH (NIH). Omega-3 supplements: what you need to know. https://www.nccih.nih.gov/health/omega3-supplements-what-you-need-to-know

  15. MedlinePlus (NIH). Protein in diet. https://medlineplus.gov/ency/article/002467.htm

  16. MyPlate (USDA). Protein Foods Group. https://www.myplate.gov/eat-healthy/protein-foods

  17. NIH Office of Dietary Supplements (ODS). Vitamin B12 fact sheet for consumers (PDF). https://ods.od.nih.gov/pdf/factsheets/VitaminB12-Consumer.pdf

  18. IARC (WHO). IARC Monographs evaluate consumption of red meat and processed meat (Press Release No. 240, 2015) (PDF). https://www.iarc.who.int/wp-content/uploads/2018/07/pr240_E.pdf

  19. National Kidney Foundation. CKD Diet: How much protein is the right amount?. https://www.kidney.org/kidney-topics/ckd-diet-how-much-protein-right-amount

USDA. FoodData Central (nutrition database). https://fdc.nal.usda.gov/