Trace Minerals Flashcards
What is the difference between heam and nonheam iron?
Heam iron is combined with the organic molecule heam (component of heamoglobin and myoglobin) where as non heam iron exists as inorganic salts eg iron hydroxide, iron chloride
Heam iron is better absorbed because it is readily absorbed by the intestinal cells, non heam needs to be in the Fe2+ state to be absorbed because Fe2+ is not soluble.
What are the roles of iron in the body and what are the RDIs for men and woman?
Serves as a cofactors in redox reactions due to its ability to convert from Fe2+ to Fe3+
Participates in electron transport chain as an electron carrier
Forms major part of heamoglobin and myoglobin which transport oxygen throughout the body.
RDI: men 8mg, woman 18mg (vegetarians x 1.8)
Which factors enhance the absorption of iron and which factors limit the absorption if iron?
Enhanced by Vitamin C organic salts and MFP factor peptide
Inhibited by phytates in legumes and whole grains, some poly phenols and calcium
How is iron absorbed, transported and stored in the body?
Iron is absorbed from food in the intestinal cells and stored there by ferritin.
Transferritin receives iron from ferretin when it is needed by the body.
Bloodtransferritin transports iron around the body.
Heamoiderin stores iron (primarily in times of iron overload)
Excess is deposited in the intestinal cells which are regularly shed and expelled in faeces.
What is the difference between iron deficiency and iron deficiency anaemia?
Iron deficiency is a state of being without iron in the tissues.
Iron deficiency anaemia is a condition of small pale red blood cells resulting from iron deficiency. Causes fatigue, apathy, weakness and headaches.
What is iron overload?
Usually caused by a genetic disorder that results in low expression of regulatory protein (hepcidin) which normally controls influx of iron from small intestine. Symptoms include fatigue, joint pain, organ damage and GI stress.
Can be treated with chelation therapy.
What are the roles of zinc in the body?
Forms part of metalloenzymes that carry it a variety of bodily functions. Stabilises cell membranes Immune function Growth and development Production of insulin and sperm
How is zinc stored and absorbed?
Absorbed through intestine where it can be utilised straight away or it is bound by metallothionein. Transport through the blood and found in the liver.
What are the symptoms of zinc deficiency and toxicity?
Deficiency: growth retardation, delayed sexual maturation
Toxicity: loss of appetite, impaired immunity, copper and iron deficiency
Supplements: used often in developing countries not widely needed in developed countries.
14mg men, 8mg woman
How do the absorption and storage of iron differ?
For both the absorption is dependant on persons status and for both the absorption is inhibited by phytates and fibre.
Body can only get iron from food but it can get zinc from pancreatic excretions.
Different storage methods: Fe= ferritin, Zn= metallothionein
Excess of one can effect the storage and absorption of another
Iodine
Part of thyroid hormones that regulate body temperature, metabolic functions, growth etc.
Deficiencies result in simple goitre- enlarged thyroid gland, and retardation on children
Selenium
Part of enzymes that act as antioxidants, help regulate thyroid hormones.
Some links with cancer but not conclusive
Found in seafood, vegetables depending on soil
Copper
Part of many enzymes, catalyst in heamoglobin formation and collagen synthesis, wound healing
Seafood, nuts seeds and whole grains
Manganese
Cofactors for many enzymes involved in bone formation
Nuts, whole grains, leafy greens, tea
Chromium
Part of glucose tolerance factor, enhances insulin action–diabetes
Advertised as weight loss- no proven links
Liver, grains and brewers yeast
