Minerals - introduction Flashcards
Organic
A chemical structure containing carbon
Inorganic
A chemical structure without carbon
Mineral – Inorganic elements and absorption
Minerals are inorganic elements that originate in the earth that cannot be made by living organisms
* For humans to absorb and use minerals they must first bound to organic compounds (containing carbon)
* Plants obtain minerals from the soil and most of the minerals in our diet come directly from plants (or indirectly from the animal sources)
* Inorganic minerals may also be present in the water we drink (not usable by the body)
* Mineral levels from plants also vary depending on the mineral content in soil
Minerals
- Minerals represents 4–5% of total body weight
- The body uses minerals to perform many different functions
- Minerals are found in all body tissues
- Calcium and phosphorus and make up the majority (approximately 75%)
Macro minerals
Macro = Needed in larger amounts
* Calcium (Ca)
* Phosphorus (P)
* Magnesium (Mg)
* Potassium (K)
* Sodium (Na)
* Chloride (Cl)
* Sulphur (S)
Trace minerals
Micro = Needed in trace amounts
* Iron (Fe)
* Zinc (Zn)
* Iodine (I)
* Selenium (Se)
* Manganese (Mn)
* Molybdenum (Mo)
* Copper (Cu)
* Chromium (Cr)
* Boron (B)
* Fluoride (F)
* Silicone (Si)
Macro Minerals – Ionic State
Macro minerals exist in the body (and in food) mainly in the ionic state (as cations or anions)
Cations
Cation = A positively charged ions
Cations:
* K+ (Potassium)
* Mg ²+ (Magnesium)
* Ca ²+ (Calcium)
* Na²+ (Sodium)
Anions
Anion = A negatively charged ion
Anions:
* Cl (Chlorine as Chloride)
* S (Sulphur as Sulphate)
* P (Phosphorus as phosphate)
Minerals as other components
Minerals also exist as components of organic compounds such as:
* Phosphoproteins (A protein attached to a phosphate group)
* Phospholipids (i.e. cell membranes)
* Metalloenzymeis (e.g. zinc is required for ‘alcohol dehydrogenase’, which breaks down alcohol)
* Metalloproteins (e.g. haemoglobin; a protein with iron)
Mineral absorption
- Minerals are absorbed in the GIT (mostly in the small intestine) in their ionic state (with the exception of iron) and must be unbound from the organic compound with the help of digestive secretions (e.g. stomach acid) before being utilised by the body.
- Any unabsorbed minerals are excreted in the faeces
Mineral functions
- Building tissues: E.g. skeletal system, teeth
- Nerve and muscle function
- Thyroid health (supporting metabolism)
- Supporting immune health
- Components of enzymes
Bioavailability: definition and factors affecting mineral bioavailability
Bioavailability = The proportion of a substance which enters and then has an active effect
Several factors can affect mineral bioavailability, including:
1. Mineral status in the body
2. Substances present in food
3. Other minerals present in food
Bioavailability: Mineral status in the body
Mineral status in the body:
* In mineral deficiency states, the body up regulates absorption of the mineral. In excess states, it down regulates absorption
Bioavailability: Substances present in food
Substances present in food:
* Can enhance absorption (E.g. ascorbic acid and Fe)
* Can inhibit absorption (E.g. phytates and Fe)
