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DEMS Unit 2 Part 2 > Micronutrients > Flashcards

Flashcards in Micronutrients Deck (10):
1

Define trace minerals

Mineral for which daily intake is

2

What are the trace minerals?

- iron
- Iodine
- Zinc
- Copper
- Selenium
- Molybdenum
- Chromium
- Fluoride
- Manganese

3

Are trace minerals more or less bioavailable than macronutrients?

Less; they are susceptible to interference w/absorption

4

Iron - what does it do and how much of it is there?

- Total body iron = 5g
- 50% as hemoglobn iron
- storage Fe: 300-1500 mg

Function:
- O2 transport in blood and muscle
- Electron transport
- Enzymes for activation of O2
- Enzymes, dopamine synthesis, CNS myelination

5

Where do we get iron from?

Food:
Heme: meats/flesh, liver (all milks = poor source)
Non-heme: plant sources and Fe-fortified foods

6

Factors affecting absorption/bioavailability

Heme Fe >> non-heme
Insoluble complexes in plats inhibit absorption : phytate, oxalate, polyphenols, phosphate, fiber

7

Phytic acid

Binds cations in gut luman
Storage form of phosphorous in plants
Humans don't have phytases
Serves fxn as anti-oxidant

High in grains & legumes
Maize/wheat > legumes > rice

Likely the major cause of dietary deficiencies

8

more on absorption of iron

Oxidation state:
Fe3+ --> Fe2+ better absorbed;
- ascorbic acid reduces Fe, forms complex

Host factors
- deficiency --> inc absorption
- inflammation --> dec. absorption

Key factors: form of Fe & host status for absorption

9

Iron Homeostasis

1. Absorption = main point of regulation
- deficiency --> dec. hepcidin --> inc. uptake
- inflammation --> inc. hepcididn --> dec. uptake

2. Loss: bleeding, cell sloughing

3. Stores: ferritin - liver, bone marrow, spleen

4. Transferrin: transports Fe in body; no "free Fe"

10

At risk populations for iron

- BF infant (at birth use Fe in RBCs, but in 4-6 months, have to make their own RBCs so they need Fe from diet)
- Premies
- Young children
- Adolescent girls
- Pregnant women
- Blood loss
- Obese & s/p bariatric surgery