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Chapter 10

NUTR 201 Chapter Notes - Chapter 10: Community Of Portuguese Language Countries, Synthes, Angular Cheilitis

Foods And Nutrition
Course Code
NUTR 201

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Chapter 10 Water-Soluble Vitamins
The Water-Soluble Vitamins: A Primer
There are nine essential water-soluble vitamins: eight B vitamins and vitamin C.
Water-Soluble Vitamins Tend to Have Similar Properties
o They dissolve in water
o The body generally digests, absorbs, and transports the water-soluble vitamins in similar
Absorbed mostly in the small intestine and the stomach
o Many water-soluble vitamins found in foods are bound to proteins that enzymes must
remove before the vitamins can be absorbed
o Their bioavailability can be influenced by many factors, including nutritional status, other
nutrients and substances in foods, medications, age, and illness
o All water-soluble compounds (except choline) are circulated directly to the liver in the
o Generally do not have toxic effects when consumed in large amounts
Water-Soluble Vitamins Function in Diverse Ways
o The functions of water-soluble vitamins or compounds are diverse and often unique
o Most of the water-soluble vitamins or compounds made from them serve as coenzymes in
energy metabolism pathways
Some Vitamins have Several Names
o B-complex vitamins a term used to describe all the B vitamins
o Vitamin C = ascorbic acid
Common Name
Pantothenic Acid
Some Foods are “Enriched” or “Fortified” with Micronutrients
o Some foods contain nutrients that are naturally occurring, others contain nutrients added
during processing
o Fortified food a food to which nutrients have been added
o Enrichment the fortification of a select group of foods with FDA-specified levels of
thiamin, niacin, riboflavin, folate, and iron
Only select foods can be labled as enriched: rice, flour, bread, or rolls, farina
(cream of wheat), pasta, cornmeal, and corn grits
o Enriched food is more nutrient-dense than its unprocessed counterpart
Water-Soluble Vitamins can be Destroyed by Cooking and Improper Storage
o A diet that provides the right balance and variety of foods and beverages can provide all
the nutrients needed to maintain health
o Some nutrients can be destroyed by exposure to water, air, heat, or light, whereas others
are affected by acidity (pH)
Vitamin B content can be preserved by some foods by not overcooking them and
covering them to decrease their exposure to light
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Thiamin (Vitamin ) Needed for Production of Acetyl Coenzyme A
Thiamin (Vitamin ) an essential water-soluble vitamin involved in energy metabolism;
synthesis of DNA, RNA, and NADPH + ; and nerve function
o Contains thiol (sulfur) and amine (nitrogen) groups
o Must first be altered to serve its physiological process
o Thiamin Pyrophosphate (TPP) the coenzyme form of thiamin that has two phosphate
o Thiamin Triphosphate (TTP) a form of thiamin with three phosphate groups
Whole Grains, Pork, and Fish are Rich in Thiamin
o Thiamin is available from a wide variety of foods:
Fish (tuna)
Legumes (black beans)
Enriched cereal products
Soy milk
o Thiamin is sensitive to heat and easily destroyed during cooking
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“Antithiamin Factors” Decrease Thiamin Bioavailability
o Thiamin absorption increases when thiamin intake is chronically low
o When thiamin intake is chronically high, its absorption proceeds more slowly by simple
o Compounds found in raw fish, coffee, tea, berries, Brussels sprouts, and cabbage can
destroy thiamin or interfere with its absorption
These “antithiamin factors” work in several ways:
Inactivating thiamin via oxidation
Vitamin C-rich foods can help prevent thiamin oxidation because vitamin
C acts as an antioxidant
Alcohol consumption can decrease the absorption of thiamin by
interfering with its active transport across the basolateral membrane of
o Thiamin circulates in the blood to the liver, where the vitamin is metabolized, used, or
recirculated in the blood to other cells in the body
o Excess thiamin is not stored, it is further metabolized and excreted in the urine
Thiamin is Critical for ATP Production
o Thiamin has many functions within cells, including both enzymes and non-coenzyme
o TTP is required to make ATP
o Thiamin-containing TPP (made in the liver) is need for the activation of an enzyme that
converts pyruvate to acetyl coenzyme A (acetyl-CoA)
o Acetyl-CoA is an important compound situated at the crossroads of ATP production
o TPP is a mandatory component of an enzyme required in the citric acid cycle and another
enzyme that allows some amino acids to enter the citric acid cycle
o Thiamin functions as an integral component of the body’s ATP-producing energy
metabolism pathways
o TPP also plays a role in the synthesis of DNA and RNA
Without TPP acting as a coenzyme that make DNA and RNA cannot function
properly and protein synthesis is halted
o TPP is also required for the synthesis of NADPH + , which is needed for triglyceride
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