Overview
This lecture introduces trace minerals, reviews general mineral concepts, and highlights their dietary sources, bioavailability, and essential functions.
Recap of Minerals
- Minerals are essential nutrients; we must get them from our diet since our bodies can't make enough.
- They are inorganic substances that provide zero calories.
- Minerals are classified as major if RDA > 100 mg/day, and trace if RDA < 100 mg/day (typically under 20 mg).
- Minerals are stable and resistant to heat, light, and oxidation.
- Bioavailability (how well a mineral is absorbed and used) is influenced by nutrition status, other foods, and mineral form.
- Deficiency in a mineral increases absorption.
- Plant foods often contain oxalates, phytates, and polyphenols, which reduce mineral absorption.
- Supplement forms and the mineral's chemical form affect absorption, particularly with trace minerals like iron.
- Functions of minerals include fluid balance, acting as co-enzymes, supporting bone/muscle health, and aiding muscle action.
- Minerals can be more toxic than vitamins, especially from supplements.
Introduction to Trace Minerals
- There are nine essential trace minerals; focus will be on seven major ones.
- Trace minerals' content in food varies by soil composition and region.
- Food processing, especially refining grains, reduces mineral content by removing layers rich in minerals.
- Trace minerals often function as co-enzymes and are involved in producing hormones, notably thyroid hormone.
- Some trace minerals serve as antioxidants (e.g., zinc).
- Several are important for bone and tooth structure.
Key Terms & Definitions
- Mineral — an inorganic nutrient essential for body function, must be obtained through the diet.
- Trace Mineral — a mineral required in amounts less than 100 mg/day.
- Bioavailability — the proportion of a nutrient that is absorbed and utilized by the body.
- Oxalates, Phytates, Polyphenols — plant compounds that can reduce mineral absorption.
Action Items / Next Steps
- Review main trace minerals (especially iron) in upcoming materials.
- Remember effects of soil content and food processing on mineral content.
- Avoid unnecessary mineral supplementation unless advised.