Dietary Folate Equivalents DFE by alicejenny

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									The Water-Soluble Vitamins: B
   Vitamins and Vitamin C
 Chapter 10
The Vitamins – An Overview
• Vital to health, organic, and available in foods
• Vitamins differ from macronutrients
  – Structure
  – Function
  – Food contents
• Both deficiency and excess of vitamins can affect
  health
The Vitamins – An Overview
• Bioavailability
  ▫ Quantity provided by food
  ▫ Amount absorbed and used by body
  ▫ Factors influencing bioavailability
The Vitamins – An Overview
• Precursors
 ▫ AKA Provitamins
• Organic nature
 ▫ Can be destroyed during storage and in cooking
The Vitamins – An Overview
• Solubility
  – Affects absorption, transport, and excretion
  – Water-soluble (B vit & vit C) VS Fat-soluble
  – Consumption frequency of vitamins
The Vitamins – An Overview
• Toxicity
 ▫ More is not necessarily better
 ▫ Excessive intakes
The B Vitamins – As Individuals
• Very active in the body, but do not provide the
  body with fuel for energy.
 – Several B vits form part of the coenzymes
 – Others participate in metabolism and cell
   multiplication.
• Recommendations for B vits come from RDA,
  AI, and Tolerable Upper Intake Levels.
 – deficiencies, toxicities, and food sources are
   unique for each
The B Vitamins – As Individuals
The B Vitamins – Thiamin
• Part of coenzyme thiamin pyrophosphate (TPP)
 – Energy metabolism
 – Nerve activity and muscle activity
• Recommendations:
 – RDA Men: 1.2 mg/day.
 – RDA Women: 1.1 mg/day.
The B Vitamins – Thiamin
• Deficiency
  – Malnourished and alcoholics

• Deficiency symptoms:
  –   Enlarged heart and possible cardiac failure.
  –   Muscular weakness.
  –   Apathy, poor short-term memory, confusion, and irritability.
  –   Anorexia and weight loss.

• Wernicke-Korsakoff syndrome is a severe deficiency that
  develops in those who abuse alcohol.

• Deficiency results in the disease beriberi (dry & wet)

• Toxicity
  – None reported
The B Vitamins – Thiamin
• Food sources:
 – Whole-grain, fortified or enriched grain products
 – Moderate amounts in all foods
 – Pork
• Other Information:
 – easily destroyed by heat)
 – Leaches into water
 – Steaming and microwaving
The B Vitamins – Thiamin
The B Vitamins – Riboflavin
• Riboflavin (Vitamin B2):
• Involved in energy metabolism.
• Coenzyme forms:
  – Flavin mononucleotide (FMN) & flavin adenine dinucleotide
    (FAD)
• Recommendations
  – RDA Men: 1.3 mg/day; Women: 1.1 mg/day

• Deficiency
  – Inflammation of membranes
  – Deficiency symptoms
  – Deficiency disease is ariboflavinosis.

• Toxicity
  – No reported toxicities
The B Vitamins – Riboflavin
• Food sources
 – Milk and milk products, including yogurt and
   cheese
 – Whole-grain, fortified, and enriched grain
   products
 – Liver
• Destruction of riboflavin
 – Destroyed
 – Not destroyed by cooking
The B Vitamins – Riboflavin
The B Vitamins – Niacin(Vitamin B3)
• Two chemical structures
 ▫ Nicotinic acid
 ▫ Nicotinamide
• Two coenzyme forms – metabolic reactions
 ▫ Nicotinamide adenine dinucleotide (NAD)
 ▫ NADP (the phosphate form)
The B Vitamins – Niacin
• Recommendations
  – Body manufacturers from tryptophan

• RDA is stated in niacin equivalents
  – RDA Men: 16 NE/day.
  – RDA Women: 14 NE/day.
  – Upper level of 35 mg/day for adults.
The B Vitamins – Niacin
• Deficiency
 – Pellagra
 – Symptoms Deficiency symptoms:
• Toxicity
 – Supplements or drugs
   • Niacin flush
 – Toxicity symptoms
 – Potential health benefits of large doses of nicotinic
   acid:
The B Vitamins – Niacin
• Food sources
 – Milk, eggs, meat, poultry, and fish
 – Whole-grain and enriched breads and cereals
 – Nuts and all protein-containing foods
• Other Information
 – Also called nicotinic acid, nicotinamide, and
   niacinamide.
 – The amino acid tryptophan is the precursor.
 – The vitamin can be lost from foods when it leaches
   into water.
The B Vitamins – Niacin
The B Vitamins – Biotin
• As part of a coenzyme used in energy
  metabolism
• Coenzyme that carries activated carbon dioxide
 ▫ Critical in TCA cycle
 ▫ Participates in gluconeogenesis and fatty acid
   synthesis
 ▫ Participates in breakdown of fatty acids and amino
   acids
The B Vitamins – Biotin
• Recommendations – AI Adults: 30 g/day.
• Deficiency and Toxicity
 ▫ Deficiencies are rare.
 ▫ Deficiency symptoms:

 ▫ No reported toxicities.
The B Vitamins – Biotin
• Biotin can be bound with an egg-white protein
  called avidin.
• Food Sources:
 ▫   Widespread in foods.
 ▫   Organ meats, egg yolks, and fish.
 ▫   Soybeans.
 ▫   Whole grains.
• Biotin can also be synthesized by intestinal
  bacteria.
The B Vitamins – Pantothenic Acid
• Part of chemical structure of coenzyme A, used
  in E metabolism

• Recommendations
 ▫ AI: Adults 5mg/day

• Deficiency
 ▫ Rare
 ▫ Symptoms:
The B Vitamins – Pantothenic Acid
• Toxicity
 ▫ None reported

• Food sources (Widespread in foods):
 ▫ Chicken, beef, liver, and egg yolks.
 ▫ Potatoes, tomatoes, and broccoli.
 ▫ Whole grains and oats.

• Can be destroyed by freezing, canning, and
  refining.
The B Vitamins – B6
• Three forms: Pyridoxal, pyridoxine, and
  pyridoxamine

• Recent research claiming influence on cognitive
  performance, immune funx, steroid hormone
  activity.

• Stored exclusively in muscle tissue
The B Vitamins – B6
• Recommendations
 ▫ Adults (19-50yrs): 1.3mg/day

• Deficiency
 ▫ Symptoms:

 ▫ Alcohol destroys the vitamin.

 ▫ Isoniazid (INH) drug used for tuberculosis acts as an
   antagonist.
The B Vitamins – B6
• Toxicity

• Upper level for adults: 100 mg/day.

• Food sources
    Meats, fish, poultry, and liver
    Legumes and soy products
    Non-citrus fruits
    Fortified cereals, potatoes and other starchy vegetables.
The B Vitamins – B6
The B Vitamins – Folate
• Known as folacin or folic acid

• Primary coenzyme form – THF
  (tetrahydrofolate)

 ▫ Transfers single-carbon compounds during
   metabolism
The B Vitamins – Folate
• Recommendations
 ▫ RDA Adults: 400 g/day.
    Dietary Folate Equivalents (DFE)

 ▫ Higher recommendations for pregnant women.
     Folate and Neural Tube Defects



 ▫ Pregnant women should take folate supplements.
The B Vitamins – Folate
• Folate and Heart Disease
 ▫ High levels of homocysteine and low levels of
   folate increase risk of heart disease.
 ▫ Folate breaks down homocysteine.

• Folate may help to prevent cancer, but may also
  promote cancer growth once cancer has
  developed.
The B Vitamins – Folate
• Deficiency
 ▫ Elevated homocysteine levels.

• Most vulnerable of all the vitamins to
  interactions with medications.

• Toxicity
 ▫ Masks vitamin B12 deficiency symptoms.
The B Vitamins – Folate
• Toxicity:
  ▫ Upper level for adults: 1000 g/day.

• Food Sources
  ▫   Fortified grains
  ▫   Leafy green vegetables
  ▫   Legumes and seeds
  ▫   Liver

• Easily destroyed by heat and oxygen.
The B Vitamins – Folate
The B Vitamins – Vitamin B12
• Cobalamin –
 ▫ Methylcobalamine and
   deoxyadenosylcobalamin are the coenzyme
   forms.

• Recommendations
 ▫ RDA Adults: 2.4 g/day.
The B Vitamins – Vitamin B12
• Deficiency symptoms
 ▫ Anemia
 ▫ Fatigue and degeneration of peripheral nerves
   progressing to paralysis.
 ▫ Sore tongue, loss of appetite, and constipation.

• Deficiency disease is called pernicious
  anemia.
The B Vitamins – Vitamin B12
• No known toxicities
• Food Sources.
 ▫ Meat, fish, poultry, and shellfish.
 ▫ Milk, cheese, and eggs.
 ▫ Fortified cereals.

• Other Information
 ▫ Binds with intrinsic factor
 ▫ Easily destroyed by microwave cooking.
The B Vitamins – In Concert
• Each B vitamin coenzyme is involved in energy
  metabolism
 ▫ Directly
 ▫ Indirectly

• Deficiencies
 ▫ Single B-vitamin deficiencies seldom show up in
   isolation
The B Vitamins – In Concert
• The B Vitamins are interdependent

• Presence of one may affect the absorption,
  metabolism, and excretion of another.

• A deficiency of one may affect the functioning or
  deficiency of another.

• A variety of foods from each food group will
  provide an adequate supply of all the B vitamins.
The B Vitamins – In Concert
• B Vitamin Roles
  ▫ Coenzymes involved directly or indirectly with energy
    metabolism.
  ▫ Facilitate energy-releasing reactions.
  ▫ Build new cells to deliver oxygen and nutrients for energy
    reactions.

• B Vitamin Deficiencies
  ▫ Deficiencies rarely occur singly except for beriberi and pellagra.
  ▫ Can be primary or secondary causes.
  ▫ Glossitis and cheilosis are two symptoms common to B
    vitamin deficiencies.
  ▫ Symptoms that individuals experience are not necessarily related
    to a vitamin deficiency.
The B Vitamins – In Concert
• B vitamin toxicities can occur with supplements.

• B Vitamin Food Sources
 ▫ Grains group provides thiamin, riboflavin, niacin
   and folate.
 ▫ Fruits and vegetables provide folate.
 ▫ Meat group provides thiamin, niacin, vitamin B6,
   and vitamin B12.
 ▫ Milk group provides riboflavin and vitamin B12.
The B Vitamins – In Concert
Vitamin C – Roles
• Antiscorbutic factor is the original name
• Roles
 ▫ Serves as a cofactor to facilitate the action of an
   enzyme
 ▫ Antioxidant
 ▫ As a Cofactor in Collagen Formation
Vitamin C
 ▫ As a Cofactor in Other Reactions
    Hydroxylation of carnitine
    Converts tryptophan to neurotransmitters
    Makes hormones
• Needs increase during body stress,
    i.e. infections, burns, extremely high or low
     temperatures, heavy metal intakes, certain
     medications, and smoking
Vitamin C
 ▫ In the Prevention and Treatment of the Common
   Cold
 ▫ Role in disease prevention is still being researched
• Vitamin C Recommendations
 ▫ RDA Men: 90 mg/day; Women: 75 mg/day
 ▫ Smokers: +35 mg/day
• Deficiency
 ▫ Disease is called scurvy
 ▫ Deficiency symptoms
Vitamin C – Deficiency
Vitamin C
• Toxicity
 ▫ Upper level for adults: 2000 mg/day
• Food Sources
 ▫ Citrus fruits, cantaloupe, strawberries, papayas,
   and mangoes
 ▫ Cabbage-type vegetables, dark green vegetables
   like red peppers and broccoli, lettuce, tomatoes,
   and potatoes
• Other information
 ▫ Also called ascorbic acid
 ▫ Easily destroyed by heat and oxygen
Vitamin C – Food Sources

								
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