nutr - micronutrients

• needed in the diet in small amounts
• not endogenously synthesized at suffient rates to meet requirements
• perform specific biological functions

results in deficiency

by adding nutrient back into the diet

calcium = 1150g in a 60kg person

• essential organic nutrients required in small amounts (mg or ug)
• many are susceptible to degradation in food

they function as coenzymes

different from of a vitamin can have different functions, conversion between forms and form precursors

Vitamins A, D, E, K

Vitamins Bs and C

• intermediary metabolism
• B1 (thiamin) = coenzyme for pyruvate decarboxylation
• B2 (riboflavin) = coenzyme for FAD, FMN
• B3 (niacin) = coenzyme for NAD, NADP
• B5 (pantothenic acid) = CoA in acetyl CoA
• B6 (pyridoxine) = coenzyme in transamination reactions

• 1. Enzyme is inactive without coenzyme
• chemical compound cannot bind to enzyme
• chemical reaction cannot take place

• 2. Enzyme is activated by addition of coenzyme
• compound binds to enzyme
• chemical reaction takes place

Vitamin A (as retinoid acid) = cell differentiation

Vitamin D (as calcitriol) = calcium availability

• Vitamins C and E
• e = lipid soluble antioxidant
• imp. in protein lipid membranes in FAs that are being oxidized

• 1. hypochromic microcytic anemia
• 2. megaloblastic or pernicious anemia

• iron deficiency
• most common form of anemia
• RBCs are pale, low in color and smaller than normal
• hemoglobin content = ↓

women and children

• folate of vitamin B12 deficiency
• really big RBCs that don't mature properly
• don't carry O2 well
• hangs on and won't go away
• B12 deficiency = most likely pernicious

elderly

• to transfer oxygen
• as part of a Heme group in a protein

transport of oxygen in a protein

• for muscle storage of oxygen
• muscle binds to iron
• short term reservoir of oxygen in muscle

• transport of electrons through respiratory chain (cytochromes)
• many enzymes such as peroxidase, myeloperoxidase, catalase

4 protein units + Fe center

ironically, heme is made of AA but its NOT a protein!!!

normocytic cells = biconcave disk to maximize surface area for O2

• tiredness
• ↓ work performance
• ↓ childhood development - psychomotor and intellectual
• ↑ lead poisoning susceptibility
• (Pb2+ causes brain damage)

• men = Hgb <140g/L
• women = Hgb < 120g/L

• Developing countries
• 50% of women and children, 25% of men

• Developed countries
• 7-12% of women and children
• 25% of low income infants in Montreal

4-5 billion people are deficient in iron

EAR for women = ↑er than for men

• Fe2+ (ferrous iron) = absorbed in the intestinal eithelial cells
• it binds to the protein ferritin
• when iron is bound to a transporter, it is oxidised

• iron intake = iron loss
• iron intake : dietary iron and its bioavailability
• amount of iron in storage
• rate of erythrocyte production (RBCs)
• iron loses

• 1. Depletion of iron stores
• ↓ plasma ferritin

• 2. Changes in iron transport
• ↑ absorption efficiency
• ↑ transferrin iron binding capacity
• ↓ transferrin saturation %
• ↑ transferrin receptors

• 3. Defective erythropoiesis
• ↓ plasma iron
• ↑ free erythrocyte protoporphyrin

• 4. Iron deficiency anemia
• microcytic hypochromatic erythrocytes
• associated behavioural signs

• 1. Decreased ↓ dietary iron
• less iron is absorbed
• vegetarian diets lack heme

• 2. Inhibition of absorption
• mineral interaction: calcium, zinc supplements can ↓ iron absorption

• 3. Increased ↑ red cell mass
• pregnancy
• growth

• 4. Increased ↑ losses
• hemolysis
• GI bleeding (occult)
• Heavy menstrual losses
• undiagnosed colon cancer

• change in diet
• taking iron supplement: ferrous sulphate (FeSO4)
• retst hemoglobin = to see if its a secondary deficiency due to heavy bleeding (menstruation), malabsorption

• fortify food supply: pasta and grains are already fortified with FeSO4 because of a law
• there are pro/cons