MICRO and TRACE MINERALS

Iron

Overview

Iron is a vital mineral required for making hemoglobin, the protein in red blood cells that carries oxygen throughout the body. It also supports energy production and immune function.

Key Functions in the Body

• Produces hemoglobin and myoglobin
• Supports oxygen transport
• Aids energy metabolism
• Strengthens immune system

Daily Recommended Intake (NIH Guidelines)

Best Food Sources

• Beef liver – 6.5 mg per 3 oz (36% DV)
• Lean red meat – 2.7 mg per 3 oz (15% DV)
• Lentils – 3.3 mg per ½ cup cooked (18% DV)
• Spinach – 3.6 mg per cup cooked (20% DV)
• Fortified cereals – up to 18 mg per serving (100% DV)

Health Benefits (Evidence-Based)

• Prevents anemia – maintains healthy red blood cells
• Supports energy – oxygen delivery to muscles and brain
• Boosts immunity – essential for immune cell function

Deficiency Symptoms & Causes

Symptoms:

• Fatigue
• Pale skin
• Shortness of breath

Causes:

• Blood loss
• Poor dietary intake
• Pregnancy

Toxicity & Safe Upper Limits

UL: 45 mg/day (adults)
Excess iron can cause liver damage and increase heart disease risk

Scientific References

• NIH: Iron Fact Sheet

Zinc

Overview

Zinc is an essential trace mineral involved in over 300 enzymes that support immune function, wound healing, and DNA synthesis.

Key Functions in the Body

• Supports immune system health
• Aids wound healing
• Helps taste and smell perception
• Promotes growth and development

Daily Recommended Intake (NIH Guidelines)

Best Food Sources

• Oysters – 32 mg per 6 medium (290% DV)
• Beef – 5.3 mg per 3 oz (48% DV)
• Pumpkin seeds – 2.2 mg per 1 oz (20% DV)
• Chickpeas – 1.3 mg per ½ cup cooked (12% DV)
• Fortified cereals – up to 3 mg per serving (27% DV)

Health Benefits (Evidence-Based)

• Immune support – reduces risk of infections
• Skin health – promotes wound healing
• Reproductive health – supports sperm production

Deficiency Symptoms & Causes

Symptoms:

• Hair loss
• Delayed wound healing
• Loss of taste/smell

Causes:

• Poor diet
• Malabsorption disorders

Toxicity & Safe Upper Limits

UL: 40 mg/day (adults)
Excess zinc may cause nausea, vomiting, and copper deficiency

Scientific References

• NIH: Zinc Fact Sheet

Copper

Overview

Copper is a trace mineral that supports iron metabolism, nervous system health, and connective tissue formation.

Key Functions in the Body

• Helps form red blood cells
• Produces collagen for bones and tissues
• Supports nerve health
• Acts as an antioxidant

Daily Recommended Intake (NIH Guidelines)

Best Food Sources

• Oysters – 4.8 mg per 3 oz (533% DV)
• Cashews – 0.6 mg per 1 oz (67% DV)
• Sunflower seeds – 0.5 mg per 1 oz (56% DV)
• Dark chocolate – 0.5 mg per 1 oz (56% DV)
• Lentils – 0.5 mg per cup cooked (56% DV)

Health Benefits (Evidence-Based)

• Red blood cell production – works with iron to prevent anemia
• Bone health – supports collagen production
• Brain function – essential for neurotransmitter activity

Deficiency Symptoms & Causes

Symptoms:

• Anemia
• Weak immune system
• Osteoporosis

Causes:

• Malabsorption
• Excess zinc intake

Toxicity & Safe Upper Limits

UL: 10 mg/day (adults)
Excess copper can cause nausea, vomiting, and liver damage

Scientific References

• NIH: Copper Fact Sheet

Manganese

Overview

Manganese is a trace mineral important for bone formation, metabolism, and antioxidant defense.

Key Functions in the Body

• Supports bone development
• Aids metabolism of carbohydrates and proteins
• Protects cells from oxidative stress

Daily Recommended Intake (NIH Guidelines)

Best Food Sources

• Mussels – 5.8 mg per 3 oz (252% DV)
• Pineapple – 1.5 mg per cup (65% DV)
• Brown rice – 1.1 mg per cup cooked (48% DV)
• Spinach – 0.8 mg per cup cooked (35% DV)
• Nuts – ~0.5–1 mg per 1 oz (22–44% DV)

Health Benefits (Evidence-Based)

• Bone health – supports cartilage and bone formation
• Antioxidant defense – part of superoxide dismutase (SOD) enzyme
• Metabolic function – assists in nutrient processing

Deficiency Symptoms & Causes

Rare, but may cause:

• Weak bones
• Poor growth
• Fertility issues

Toxicity & Safe Upper Limits

UL: 11 mg/day (adults)
Excess can cause neurological issues

Scientific References

• NIH: Manganese Fact Sheet

Iodine

Overview

Iodine is an essential trace mineral required for the production of thyroid hormones, which regulate growth, development, and metabolism.

Key Functions in the Body

• Supports thyroid hormone production
• Regulates metabolism and energy use
• Promotes normal growth and brain development

Daily Recommended Intake (NIH Guidelines)

Best Food Sources

• Seaweed – up to 2,984 µg per sheet (1,989% DV)
• Cod – 99 µg per 3 oz (66% DV)
• Yogurt – 75 µg per cup (50% DV)
• Iodized salt – 71 µg per ¼ tsp (47% DV)
• Milk – 56 µg per cup (37% DV)

Health Benefits (Evidence-Based)

• Prevents goiter – enlargement of the thyroid gland
• Supports pregnancy health – fetal brain development
• Regulates metabolism – energy and body weight balance

Deficiency Symptoms & Causes

Symptoms:

• Goiter
• Fatigue
• Weight gain

Causes:

• Low dietary intake
• Non-iodized salt use

Toxicity & Safe Upper Limits

UL: 1,100 µg/day (adults)
Excess iodine may cause thyroid dysfunction

Scientific References

• NIH: Iodine Fact Sheet

Selenium

Overview

Selenium is a powerful antioxidant that protects cells from oxidative stress and supports thyroid function.

Key Functions in the Body

• Protects against oxidative damage
• Supports immune system
• Helps produce thyroid hormones

Daily Recommended Intake (NIH Guidelines)

Best Food Sources

• Brazil nuts – 544 µg per oz (988% DV)
• Tuna – 92 µg per 3 oz (167% DV)
• Halibut – 47 µg per 3 oz (85% DV)
• Sardines – 45 µg per 3 oz (82% DV)
• Eggs – 15 µg per large (27% DV)

Health Benefits (Evidence-Based)

• Antioxidant defense – protects cells from damage
• Thyroid health – supports hormone metabolism
• Immune support – helps fight infections

Deficiency Symptoms & Causes

Symptoms:

• Fatigue
• Weakened immunity
• Hair loss

Causes:

• Selenium-poor soil in diet
• Malabsorption disorders

Toxicity & Safe Upper Limits

UL: 400 µg/day (adults)
Excess selenium may cause hair loss, nail brittleness, and neurological issues

Scientific References

• NIH: Selenium Fact Sheet

Fluoride

Overview

Fluoride is a mineral best known for its role in dental health and bone strength.

Key Functions in the Body

• Strengthens tooth enamel
• Prevents dental cavities
• Supports bone mineralization

Daily Recommended Intake (NIH Guidelines)

Best Food Sources

• Fluoridated water – 0.7 mg per liter
• Black tea – 0.3–0.5 mg per cup
• Canned sardines – 0.2–0.3 mg per 3 oz
• Grapes – 0.1 mg per cup

Health Benefits (Evidence-Based)

• Prevents cavities – remineralizes tooth enamel
• Bone health – strengthens skeletal structure

Deficiency Symptoms & Causes

Rare in areas with fluoridated water but may cause:

• Increased risk of tooth decay

Toxicity & Safe Upper Limits

UL: 10 mg/day (adults)
Excess may cause dental fluorosis and skeletal issues

Scientific References

• NIH: Fluoride Fact Sheet

Chromium

Overview

Chromium is a trace mineral that enhances insulin action and helps regulate blood sugar.

Key Functions in the Body

• Improves insulin sensitivity
• Helps regulate carbohydrate, fat, and protein metabolism

Daily Recommended Intake (NIH Guidelines)

Best Food Sources

• Broccoli – 22 µg per cup (63% DV)
• Grape juice – 7.5 µg per cup (21% DV)
• Whole wheat bread – 4 µg per slice (11% DV)
• Beef – 2 µg per 3 oz (6% DV)

Health Benefits (Evidence-Based)

• Blood sugar control – helps manage type 2 diabetes
• Metabolic health – supports nutrient utilization

Deficiency Symptoms & Causes

Rare but may cause:

• Impaired glucose tolerance
• Increased blood sugar

Toxicity & Safe Upper Limits

No established UL for trivalent chromium (dietary form).
Hexavalent chromium is toxic and industrial, not from food.

Scientific References

• NIH: Chromium Fact Sheet

Molybdenum

Overview

Molybdenum is a trace mineral that acts as a cofactor for enzymes involved in amino acid metabolism and detoxification.

Key Functions in the Body

• Supports breakdown of amino acids
• Aids metabolism of drugs and toxins
• Helps produce uric acid for waste removal

Daily Recommended Intake (NIH Guidelines)

Best Food Sources

• Legumes – 130 µg per cup cooked (289% DV)
• Grains – 76 µg per cup cooked (169% DV)
• Nuts – ~40–50 µg per oz (89–111% DV)
• Liver – 104 µg per 3 oz (231% DV)

Health Benefits (Evidence-Based)

• Enzyme activation – supports metabolic processes
• Detox support – aids sulfite breakdown

Deficiency Symptoms & Causes

Very rare but may cause:

• Neurological issues
• Sulfite sensitivity

Toxicity & Safe Upper Limits

UL: 2,000 µg/day (adults)
Excess may cause gout-like symptoms

Scientific References

• NIH: Molybdenum Fact Sheet