Major Minerals- Calcium

Question 1

State the major minerals

Answer 1

-Calcium
-Magnesium
-Phosphorus
-Potassium
-Sodium

Question 2

What are sources of Calcium?

Answer 2

-milk and milk products, eg cheese and yoghurts- calcium is well absorbed
-flour (white), products made from it, eg bread- white bread is fortified with calcium carbonate
-small fish, eg sardines
-fruit and veg- small amounts- green leafy veg, eg spinach and brocolli

Question 3

What are the functions of Calcium?

Answer 3

-Needed for the FORMATION and DEVELOPMENT of bones and teeth. Bone is made of CARTILAGE (PROTEIN- COLLAGEN)- forms a framework which CALCIUM PHOSPHATE is deposited
-Blood Clotting
-Normal functioning of nerves and muscles

Calcium, Vitamin D and Phosphorus have a RECIPROCAL RELATIONSHIP- functioning depend on one another

Question 4

Calcium Requirements during pregnancy?

Answer 4

-NO increases recommended during pregnancy- body can make better use of the calcium available

Question 5

What is a deficiency in Calcium?

Answer 5

-Children- RICKETS- long bones bend under body weight- cause knock knees and bow legs
-Adults- Osteomalacia- soft, weak and painful bones- may develop after repeated pregnancies, or if diet is poor

Question 6

What has Osteoporosis got to do with Calcium

Answer 6

-not a deficiency- can’t be caused by not eating enough Calcium
-High levels of Calcium and Vitamin D- up to 30-35 years (peak bone mass), thought to offer some protection against osteoporosis

Question 7

An Excess of Calcium?

Answer 7

-susceptible people- KIDNEY STONES

Question 8

Explain factors which ASSIST Calcium Absorption?

Answer 8

-only 1/3 of the calcium is absorbed and used by the body
The remaining 2/3 passes through the alimentary canal- out in faeces
-Absorption increases when diet is low
-LACTOSE- milk ENHANCES calcium absorption- keeps it in soluble form
-SOURCE- Calcium from milk/ milk products are made of better use in the body as MORE IS ABSORBED
-Calcium from PLANT sources is LESS efficiently absorbed

Question 9

Explain factors which REDUCE Calcium absorption

Answer 9

-SOURCE- Calcium from PLANT sources is not very well absorbed
-The BRAN of cereals contains PHYTIC ACID- forms an INSOLUBLE COMPLEX with calcium called CALCIUM PHYTATE- reduces absorption
-OXALIC ACID- found in spinach and rhubard- form an INSOLUBLE COMPLEX- CALCIUM OXALATE- reduces absorption
-Dietary Fibre content- calcium can BIND with dietary fibre- can be lost from body in faeces- diet must contain a lot of dietary fibre for this to happen

Question 10

Effects of Cooking on Calcium

Answer 10

-Little effect

Question 11

Explain groups with different Calcium Requirements

Answer 11

-Children
-Pregnant
-Lactating
-Elderly- may be due to the lack of vitamin D, poor appetite and diet
-Vegans- hard to meet RNI if dairy foods are excluded