Trace Minerals in Human Nutrition

Zinc (Zn)

Zinc is an essential trace mineral involved in numerous enzymatic and structural functions in the human body. It plays a critical role in growth, immune function, and gene expression.

• Main Bodily Functions:

  • Acts as an enzymatic cofactor for over 300 enzymes.

  • Provides structural stability to proteins.

  • Helps regulate gene expression, especially in fetal development.

  • May reduce the duration of the common cold.

• Food Sources:

  • Fish, meat, and whole grains (especially oysters).

  • Enriched cereals.

• Things That Limit Absorption:

  • Non-heme iron, fiber, phytates.

• Deficiency (Rare):

  • Delayed growth.

  • Delayed sexual maturation.

  • Reduced appetite.

  • Increased susceptibility to infection.

• Excess/Toxicity (Rare):

  • Nausea/diarrhea.

  • Headaches.

  • Impaired immune function.

  • Interferes with copper absorption.

Example: Oysters are an excellent source of zinc.

Selenium (Se)

Selenium is a trace mineral that functions as a cofactor for antioxidant enzymes and is important for thyroid hormone metabolism.

• Main Bodily Functions:

  • Cofactor for many enzymes, especially those involved in antioxidant defense.

  • Critical for thyroid hormone production.

  • May reduce risk of certain cancers.

• Food Sources:

  • Amount in food depends on soil selenium content.

  • Common sources: seafood, meats, grains, eggs.

• Deficiency (Rare):

  • Impaired thyroid function.

  • Keshan disease (heart disorder).

• Excess/Toxicity (Rare):

  • Hair loss and nail brittleness.

  • Skin rashes.

  • Liver damage.

Example: Selenium levels in foods vary depending on soil content; fertilized crops may be higher in selenium.

Manganese (Mn), Chromium (Cr), and Molybdenum (Mo)

These trace minerals serve as enzyme cofactors and are involved in metabolism and other essential body functions.

Example: Chromium enhances insulin function and is found in meats and whole grains.

Key Terms and Definitions

• Trace Mineral: A mineral required in small amounts (<100 mg/day) for normal physiological functions.

• Enzyme Cofactor: A non-protein chemical compound that is required for the biological activity of an enzyme.

• Gene Expression: The process by which information from a gene is used to synthesize a functional gene product, often a protein.

Formulas and Equations

• Recommended Dietary Allowance (RDA): (adults) (adults)

Short Comparison Table: Deficiency vs. Toxicity

Additional info: Soil content can significantly affect selenium levels in plant-based foods, which in turn impacts dietary intake.