Minerals Flashcards
Functions of calcium
- Contraction and relaxation of muscle, especially important for heart muscle
- Formation of strong bones and teeth - mineralisation
- Transmission of nerve impulses
Importance of maintaining a constant calcium level in the blood:
- Heart is not able to contract properly
- Calcium is taken from the bones to maintain high enough blood calcium levels for heart
food sources of calcium
Vegetarian sources: Milk and milk products (35% is absorbed)
Animal sources: Fish with small bones eg sardines
Plant sources:
Tofu (soy bean curd)
Almonds, sesame seeds
Dark green vegetables (eg. Broccoli and bok choy) and seaweed (nori)…….absorption varies from 5-60%
What is calcium absorption increased by
Salmon
Tuna
Margarine
Butter
Fortified milk
Fortified cereals
What is calcium absorption decreased by
Caffiene
Why do post menopausal women require more calcium
Post menopausal women require more calcium because estrogen decreases after memopaise. This can cause osteoclasts and lead to osteoporosis making bones weaker and more brittle.
Why do elderly men and women (70+ years) require more calcium
Aging is associated with a gradual loss of bone mass, and therefore they need to consume more calcium
Calcium is leeched from their bones
describe two reasons why people who eat a mainly plant based diet may be at higher risk of having lower bone density.
They have to get calcium from non dairy sources
Lower levels of calcium in plant based foods
More vitamin D in plant based foods
Suggest two strategies that people following a mainly plant based diet can use to improve bone density.
Don’t drink coffee
Take supplements
Get lots of vitamin D
functions of iron
Forms part of haemoglobin which carries oxygen around the body (red blood cells)
Forms part of mitochondria in muscles, which makes oxygen available for muscle contraction
dietary sources of haem iron
red meat, kangaroo, fish, pork, egg yolk, liver
Absorption rates of harm iron
Up to 25%
Generally unaffected by other dietary factors
Dietary sources of non-haem iron
dark green leafy veg, fortified Weetbix, all bran,
Absorbtion rate of non-haem iron
10-17%
Decreased by calcium, caffeine
Increased by haem iron, vitamin C
who needs more iron
people following a vegetarian diet
Women in reproductive years
Anorexia
Extreme diets
Developing countries