Minerals

Question 1

What are minerals in the context of the human diet?

Answer 1

Mineral are elements which are essential to the human diet as the body cannot produce them itself.

Question 2

What is the difference between major and trace (minor) minerals?

Answer 2

Major minerals if we require >100mg per day

Trace minerals if we require <100mg per day

Question 3

Why does the concentration of minerals vary so much in plant and animal foods?

Answer 3

The mineral content in food is greatly determined by the mineral content in the soil in which plants are grown, which are then either directly eaten by humans or fed to livestock which become animal food products

Question 4

What are the factors which inhibit good absorption of minerals from the diet?

Answer 4

• Excessive fibre (>38g per day) can cause lower mineral status. This is because phytic acid found in fibre binds to minerals and leads to excretion
• Oxalic acid in dark leafy greens also binds to minerals and causes them to be excreted
• Polyphenols and tannins interfere with mineral uptake (particularly iron)
• Consumption of several minerals of the same valence can decrease absorption of each of them (zinc 2+ and iron 2+)
• Antacids can reduce bioavailability as they reduce stomach acidity

Question 5

What are factors which increase the bioavailability and absorption of minerals?

Answer 5

• Vitamin C increases absorption of non-heme iron
• Good Vitamin D levels enable calcium absorption
• Absorption is increased when the needs are greater