HUN 4221 Folate 2011 1-pg

HUN 4221 Folate 2011 1-pg - HUN 4221 FOLATE Sp 2011 Folate...

Info iconThis preview shows pages 1–18. Sign up to view the full content.

View Full Document Right Arrow Icon
HUN 4221 FOLATE Sp 2011
Background image of page 1

Info iconThis preview has intentionally blurred sections. Sign up to view the full version.

View Full DocumentRight Arrow Icon
Folate as Folic Acid or Natural Food Folate
Background image of page 2
Folic Acid Folic acid: - supplements - fortified foods (enriched products)
Background image of page 3

Info iconThis preview has intentionally blurred sections. Sign up to view the full version.

View Full DocumentRight Arrow Icon
Folic Acid and Dietary Folate Equivalents: Fortified Foods Foods Average Serving Folic Acid (μg/avg serving ) Folate ( g DFE/serving) Macaroni 1 cup 92 167 Enriched White Rice 1 cup 87 153 Bagel 3” diameter 66 129 White Bread 2 slices 52 103 Flour Tortilla 8” diameter 42 77 Pretzels 1 oz 40 81 Hamburger/Hotdog Bun 1 whole 36 73 Saltine Crackers 10 crackers 32 64 Biscuit 1 medium 32 58 Pancakes 3 pancakes, 4” diameter 28 64
Background image of page 4
Fig 9.27
Background image of page 5

Info iconThis preview has intentionally blurred sections. Sign up to view the full version.

View Full DocumentRight Arrow Icon
Sources and Amounts of Folic Acid Fortified “Ready-to Eat” Breakfast Cereals Folic Acid- Containing Supplements 100 - 400 μg /serving 400 μg /supplement “Enriched” Cereal Grain Products ~150 μ g/day
Background image of page 6
Food Folate Occurs naturally Concentrated in selected foods
Background image of page 7

Info iconThis preview has intentionally blurred sections. Sign up to view the full version.

View Full DocumentRight Arrow Icon
Natural Food Sources of Folate Food Average Serving Folate (μg DFE/avg serving) Beef Liver 3 oz 215 Pinto Beans ½ cup 147 Asparagus ½ cup 134 Spinach (boiled) ½ cup 131 Black Beans ½ cup 128 Orange Juice (from concentrate) 1 cup 110 Romaine Lettuce 1 cup 64 Broccoli (raw) 1 cup 50 Orange 3” diameter 48 Peanuts 1 oz 41 Strawberries (whole) 1 cup 35
Background image of page 8
Glutamate Glutamate Glutamate Glutamate Glutamate Glutamate Glutamate Enzyme Monoglutamate = Folic Acid
Background image of page 9

Info iconThis preview has intentionally blurred sections. Sign up to view the full version.

View Full DocumentRight Arrow Icon
Food folate Folic acid Functions the same! Less readily absorbed than folic acid
Background image of page 10
Folate Absorption • Food folate predominately polyglutamate form • Intestinal absorption of food polyglutamate is a two-step process – Hydrolysis of polyglutamates to monoglutamate – Transport of monoglutamate through the intestinal membranes into enterocyte
Background image of page 11

Info iconThis preview has intentionally blurred sections. Sign up to view the full version.

View Full DocumentRight Arrow Icon
Folate Absorption • Food polyglutamates cleaved in the jejunal brush border by membrane deconjugase enzyme – Glutamate carboxypeptidase II (GCPII) – Acts as an exopeptidase cleaving terminal glutamates • pH optimum is 6.5 – drugs or disease that significantly affect jejunal pH can impair folate absorption
Background image of page 12
• Following deconjugation to monoglutamate form • Uptake through saturable or non- saturable process Folate Absorption
Background image of page 13

Info iconThis preview has intentionally blurred sections. Sign up to view the full version.

View Full DocumentRight Arrow Icon
Folate Absorption Carrier-mediated process-saturable in dietary range of concentration Specific carriers are transmembrane folate-binding proteins – Reduced folate carrier (RFC) • bi-directional • higher affinity for reduced folates • greatly reduced affinity for folic acid
Background image of page 14
Folate Absorption Proton-coupled folate transporter (PCFT) – transmembrane uni-directional transport protein – proton coupling allows concentrative transport of folates at acidic pH – Unlike RFC this carrier has similar affinity for reduced folates and folic acid – Appears to play primary role in folate absorption high and similar affinity for folic acid and reduced folates
Background image of page 15

Info iconThis preview has intentionally blurred sections. Sign up to view the full version.

View Full DocumentRight Arrow Icon
Folate Absorption • Non-saturable process of folate in supraphysiological/pharmacological range – Without a transporter
Background image of page 16
Glutamate Carboxypeptidase Proton Coupled Folate Transporter Reduced Folate Carrier
Background image of page 17

Info iconThis preview has intentionally blurred sections. Sign up to view the full version.

View Full DocumentRight Arrow Icon
Image of page 18
This is the end of the preview. Sign up to access the rest of the document.

This note was uploaded on 12/09/2011 for the course HUN 4445 taught by Professor Sitren during the Spring '08 term at University of Florida.

Page1 / 197

HUN 4221 Folate 2011 1-pg - HUN 4221 FOLATE Sp 2011 Folate...

This preview shows document pages 1 - 18. Sign up to view the full document.

View Full Document Right Arrow Icon
Ask a homework question - tutors are online