Minerals

Question 1

DRV for iodine?

Answer 1

-RNI: 140ug Per day
-LRNI-70ug Per day

Question 2

Function of iodine in body

Answer 2

-needed for production of thyroid hormones (thyroxine and triiodothyronine
(thyroid gland traps and concentrates iodine from blood stream)

Question 3

What can happen if there is iodine deficiency?

Answer 3

-goitre- An enlargement of the thyroid gland
-Severe Iodine deficiency = thyroid hormone deficiency
-Mild deficiency associated with infertility In both men and women

Question 4

symptoms of goitre?

Answer 4

tiredness, weight gain, poor
concertation

Question 5

Effect of iodine deficiency in children?

Answer 5

-Severe-cretinism
-mild deficiency in pregnancy- cause reduced IQ in pregnancy

Question 6

Symptoms of cretinism in children?

Answer 6

-impaired mental & physical development in the womb or early life
-Stunted growth
-Impaired function of many organs
-Severe mental retardation

Question 7

Describe the global variation in iodine content/ consumption?

Answer 7

-areas close to the sea/ocean have iodine rich soil So plants grown in these areas have higher iodine content.
-Land locked areas (mountainous /away from the sea) have a lower iodine content.

-many countries have salt iodization programs increasing consumption

Question 8

Which group of people is iodine consumption particularly important for?

Answer 8

-Pregnant women

Question 9

Sources of iodine

Answer 9

-milk and sea fish

Question 9

Effect of plant milks on iodine consumption

Answer 9

-Increase on non dairy milk consumption in UK however although they are fortified with some nutrients no plant milks are fortified with iodine
-Therefore vegans have high risk of iodine deficiency

Question 10

Why are vegetarians encouraged to include seaweed in their diet?

Answer 10

-Contains iodine
-however some contain an excessive amount which can be harmful to health
-seaweed consumption is not recommended during pregnancy due to possibility of toxins

Question 11

Who should be taking iodine supplements?

Answer 11

-People who avoid milk, dairy foods and sea fish in their diet
-mean and women prior to conception
-Essential to women during pregnancy and lactation

Question 12

Name the major minerals

Answer 12

Sodium, potassium, magnesium, calcium, phosphorus, sulfur, chloride

Question 13

Difference between trace minerals and major minerals?

Answer 13

-Body needs less of trace minerals
-major minerals are Present in body tissues at concentrations >50 mg/kg and trace are Present in body tissues at concentrations <50 mg/kg

Question 14

Name the trace minerals/ elements

Answer 14

Chromium, manganese, iron, cobalt, molybdenum, copper, zinc, fluoride, iodine, selenium, silicon, tin, arsenic, nickel…

Question 15

Sodium functions

Answer 15

-helps uptake of nutrients and water in cells
-helps muscles contract
-helps nerves carry messages between brain and body
-balances bodies fluids and regulates blood pressure

Question 16

Why is calcium and iron absorption regulated differently to other minerals?

Answer 16

-regulated according to the needs of the body.
-Calcium absorption is related to the amount of specific binding protein within the enterocyte.
-The concentration of the calcium binding protein (Calbindin), which regulates calcium uptake from the gut, is secondary to vitamin D levels.

Question 17

Describe the presence of calcium in the body

Answer 17

-most abundant mineral in animal tissues
-found in blood and other tissues

Question 18

Calcium functions

Answer 18

Bone structure
Nerve function
Blood clotting
Muscle contraction
Cellular metabolism

Question 19

Sources of calcium

Answer 19

Milk and dairy products
(High bioavailability (fortified with vitamin D))
Green leafy vegetables
Poor absorption
Fish with bones
Fortified juice/cereal

Question 20

What 3 hormones are involved in regulation of calcium?

Answer 20

Vitamin D3 (from kidney)
Parathyroid hormone (PTH)
(from parathyroid gland)
Calcitonin
(from thyroid gland)

Question 21

Describe the regulation of calcium homeostasis?

Answer 21

1-thyroid gland secretes calcitonin
-this leads to decreased calcium absorption in SI, decreased bone breakdown, increased calcium excretion in urine
2-blod levels of calcium return to normal
3-parathyroid glands release parathyroid hormone (PTH)
4-PTH stimulates conversion to calcitriol in the kidneys
4-Together Calcitriol and PTH stimulate increased calcium absorption in SI, increased bone breakdown and decreased calcium excretion
5-blood levels of calcium return to normal

Question 22

Effect of calcium deficiency?

Answer 22

-rickets
-osteomalacia (osteoporosis)

Question 23

What is osteoporosis?

Answer 23

-at around age 40 bone breakdown exceeds formation causing large decrease in bone mass

Question 24

How can osteoporosis be prevented?

Answer 24

-Maintain adequate calcium and vitamin D intake
-Perform weight-bearing exercise
-Hormone Replacement Therapy

Question 25

What chronic diseases can milk and calcium consumption reduce the risk of

Answer 25

Degenerative diseases
Heart disease
Lowers blood pressure
Cancer
Breast, prostate, colon
Obesity

Question 26

what are trace elements?

Answer 26

-Inorganic elements occur in nature and are found in water, soil and rock
-Taken up by plant roots and hence into animals and humans
-exist in the body as Biological components – in the skeleton, in haemoglobin, in thyroid hormones and in many enzymes

Question 27

where can iron be found in the body?

Answer 27

-haemoglobin of red blood cells (60%)
-myoglobin in muscles (8%)
-transferrin (2%)
-stores in liver (25%)
-enzymes (5%)

Question 28

how is iron lost from the body?

Answer 28

from cell losses from the skin and interior surfaces of the body such as the intestines, urinary tract and airways and through bleeding.

Question 29

why is there a high iron requirement in newborns and infants?

Answer 29

-As they have no iron stores and this a period of rapid growth
-iron deficiency can be reduced at this stage due to most infant cereals as they are fortified with iron

Question 30

why is there an increased iron requirement in adolescents?

Answer 30

-Period of rapid growth
-also during puberty there’s an increase in haemoglobin mass and concentration increasing requirements

Question 31

what does iron absorption depend on?

Answer 31

-The type of iron
(ahem or non-haem)
-2 separate types of receptor are used on the mucosal cells and are absorbed in different efficiencies

Question 32

Describe haem iron absorption?

Answer 32

-found in meat and meat products and is derived from haemoglobin and myoglobin in meat
-absorption is 10-30%
-generally not affected by diet
-more fast absorbed

Question 33

Describe Non haem iron absorption

Answer 33

-main form of dietary iron and is found in cereals, vegetables, pulses, beans, fruits etc.
-is in the form of iron salts, iron in other proteins & iron derived from processing or storage methods.
-only 2-10% consumed can be absorbed
-more slow absorbed
-is affected by other components in diet

Question 34

What factors can inhibit non-haem iron absorption?

Answer 34

-Phytates – found in plant cells. In western-type diets 90% of phytates originate from cereals.
-Polyphenols – are part of the plant’s defence mechanism against insects, animals and man. E.g. tannin.
-Calcium– in the form of dairy products such as milk and cheese. Also inhibits haem iron absorption.

Question 35

what factors can enhance non-haem iron absorption?

Answer 35

-Ascorbic acid/vitamin C – Most potent enhancer. It does this by converting the iron from ferric (Fe3+) to ferrous (Fe2+) forms.
-Meat, fish & seafood – In addition to providing haem iron themselves they also promote the absorption of non-haem iron.
-alcohol

Question 37

what is bioavailabitly?

Answer 37

the degree to which a substance is available to the body.

Question 38

what non-heme iron sources have a high bioavailability?

Answer 38

-lemons, oranges, tomatoes
-brocolli, cabbage
-white whine
-fish, meat, poultry

Question 39

Functions of iron?

Answer 39

-It is part of haemoglobin which carries oxygen to body tissues
-It helps store oxygen in muscle cells through myoglobin
-It is a component of various tissue enzymes involved in energy production and brain function.

Question 39

Symptoms of iron defiiciency?

Answer 39

Fatigue
Restlessness
Impaired work performance

Question 39

Cereals contain which form of iron?

Answer 39

Non-haem iron

Question 39

Main predictors of a low iron status?

Answer 39

-women carrying out menstruation
-no consumption of red meat

Question 39

what are the 3 stages that adequate iron status can progress to iron deficiency then anaemia?

Answer 39

1-Depletion of storage iron
2-Decrease in transported iron in transferrin proteins
3-Reduction in red blood cell formation (anaemia)

Question 39

Main predictors of a good iron status?

Answer 39

Regular consumption of raw vegetables (salads)
Regular consumption of red meat

Question 40

How can excessive iron absorption occur and what can this cause?

Answer 40

-consumption of iron supplements
-alcohlics- consuming large amounts of wine with high iron content
-can cause tissue damage

Question 40

How can vegetarians help ensure they have a sufficient iron absorption?

Answer 40

-fresh fruit/ juice with meals help with absorption
-salad veg contain vit C which helps absorption
-green leafy veg is good source of iron
-avoid drinking tea with meals as this reduces iron absorption

Question 41

how can iron toxicity be caused by genetic disorders?

Answer 41

-iron absorption isn’t regulated due to disease eg. idiopathic hereditary hemochromatosis
-sufferers must avoid iron fortified foods