The Water-Soluble Vitamins B Vitamins and Vitamin C Copyright 2005 Wadsworth Group, a division of...

The Water-Soluble Vitamins

B Vitamins and

Vitamin C

Copyright 2005 Wadsworth Group, a division of Thomson LearningCopyright 2005 Wadsworth Group, a division of Thomson Learning

The Vitamins• Vitamins vs carbohydrates, fats,

and proteins– Structure

•Individual units– Function

•Coenzymes and other– Food contents

• mcg or mg


The Vitamins• Bioavailability

• Precursors

• Organic nature


The Vitamins• Solubility

• Toxicity


The Vitamins


The Vitamins


The B Vitamins• Coenzymes


Thiamin


• Other names: Vitamin B1

• 1998 RDA – men: 1.2 mg/day– women: 1.1 mg/day

• Chief functions in the body– Part of coenzyme TPP (thiamin

pyrophosphate) used in energy metabolism

Thiamin


• Significant sources– Whole grain, fortified, or enriched

grain products– Moderate amounts in all nutritious

food– Pork

• Easily destroyed by heat

Thiamin


• Deficiency disease– Beriberi

• Wet, with edema• Dry, with muscle wasting

• Deficiency symptoms– Enlarged heart, cardiac failure– Muscular weakness– Apathy, poor short-term memory,

confusion, irritability– Anorexia, weight loss

• Toxicity symptoms: none reported

ThiaminSources



Riboflavin


Riboflavin


• Other names: Vitamin B2

• 1998 RDA– Men: 1.3 mg/day– Women: 1.1 mg/day

• Chief functions in the body– Part of coenzymes FMN (flavin

mononucleotide) and FAD (flavin adenine dinucleotide) used in energy metabolism.

Riboflavin


• Significant sources– Milk products (yogurt, cheese)– Enriched or whole grains– Liver

• Easily destroyed by ultraviolet light and irradiation

Riboflavin


• Deficiency disease: ariboflavinosis• Deficiency symptoms

– Inflamed eyelids and sensitivity to light, reddening of cornea

– Sore throat– Cracks and redness at corners of

mouth– Painful, smooth, purplish red tongue– Inflammation characterized by skin

lesions covered with greasy scales


RiboflavinSources



Niacin


• Other names– Nicotinic acid– Nicotinamide– Niacinamide

– Vitamin B3

• Precursor: dietary tryptophan• 1998 RDA

– Men: 16 mg NE/day– Women: 14 mg NE/day

• Upper level for adults: 35 mg/day

Niacin


• Chief functions in the body– Part of coenzymes NAD (nicotinamide

adenine dinucleotide) and NADP (its phosphate form) used in energy metabolism

• Significant sources– Milk, eggs, meat, poultry, fish– Whole-grain and enriched breads and

cereals– Nuts– All protein-containing foods

Niacin


• Deficiency disease: pellagra• Deficiency symptoms

– Diarrhea, abdominal pain, vomiting– Inflamed, swollen, smooth, bright red

tongue– Depression, apathy, fatigue, loss of

memory, headache– Bilateral symmetrical rash on areas

exposed to sunlight

Niacin


• Toxicity symptoms– Painful flush, hives, and rash (“niacin

flush”)– Excessive sweating– Blurred vision– Liver damage, impaired glucose

tolerance

NiacinSources



Biotin


• 1998 adequate intake (AI)– Adults: 30 g/day

• Chief functions in the body– Part of a coenzyme used in energy

metabolism, fat synthesis, amino acid metabolism, and glycogen synthesis

• Significant sources– Widespread in foods– Organ meats, egg yolks, soybeans,

fish, whole grains– Also produced by GI bacteria

Biotin


• Deficiency symptoms– Depression, lethargy, hallucinations,

numb or tingling sensation in the arms and legs

– Red, scaly rash around the eyes, nose, and mouth

– Hair loss


Pantothenic Acid


• 1998 adequate intake (AI)– Adults: 5 mg/day

• Chief functions in the body– Part of coenzyme A, used in energy

metabolism

• Significant sources– Widespread in foods– Organ meats, mushrooms, avocados,

broccoli, whole grains

• Easily destroyed by food processing

Pantothenic Acid


• Deficiency symptoms– Vomiting, nausea, stomach cramps– Insomnia, fatigue, depression,

irritability, restlessness, apathy– Hypoglycemia, increased sensitivity to

insulin


Vitamin B6


• Other names– Pyridoxine– Pyridoxal– Pyridoxamine

• 1998 RDA– Adults (19-50 years): 1.3 mg/day


Vitamin B6


• Chief functions in the body– Part of coenzymes PLP (pyridoxal

phosphate) and PMP (pyridoxamine phosphate) used in amino acid and fatty acid metabolism

– Helps to convert tryptophan to niacin and to serotonin

– Helps to make red blood cells

Vitamin B6


• Significant sources– Meats, fish, poultry– Potatoes, legumes, noncitrus fruits– Fortified cereals– Liver– Soy products

• Deficiency symptoms– Scaly dermatitis– Anemia (small-cell type)– Depression, confusion, abnormal

brain wave pattern, convulsions

Vitamin B6


• Toxicity symptoms– Depression, fatigue, irritability,

headaches– Nerve damage causing numbness and

muscle weakness leading to an inability to walk and convulsions

– Skin lesions

VitaminB6

Sources



Folate


Folate


Folate• Absorption

• Activation

– Vitamin B12


Folate• Recommendations

– Dietary folate equivalents (DFE)•Natural = 1X•Synthetic = 1.7 X natural because

it is more bioavailable


Folate• Neural tube defects

– Spina bifida


Jan 1998

Folate• Heart disease

• Cancer


Folate: In Summary


• Other names– Folic acid– Folacin– Pteroylglutamic acid (PGA)

• 1998 RDA– Adults: 400 g/day

• Upper level for adults: 1000 g/day

Folate: In Summary


• Chief functions in the body– Part of coenzymes THF

(tetrahydrofolate) and DHF (dihydrofolate) used in DNA synthesis and therefore important in new cell formation

• Significant sources– Fortified grains– Leafy green vegetables, legumes,

seeds– Liver

Folate: In Summary


• Deficiency symptoms– Anemia (large-cell type)– Smooth, red tongue– Mental confusion, weakness, fatigue,

irritability, headache

• Toxicity symptoms– Masks vitamin B12-deficiency

symptoms

FolateSources


Vitamin B12

• Activation– Folate


Vitamin B12

• Absorption– HCl– Pepsin– Intrinsic factor


Vitamin B12• Deficiency of folate or B12 produces

pernicious anemia


Vitamin B12: In Summary


• Other names: cobalamin (and related forms)

• 1998 RDA– Adults: 2.4 g/day

• Chief functions in the body– Part of coenzymes methylcobalamin

and deoxyadenosylcobalamin used in new cell synthesis

– Helps to maintain nerve cells– Reforms folate coenzyme– Helps to break down some fatty acids

and amino acids



• Significant sources– Animal products (meat, fish, poultry,

shellfish, milk, cheese, eggs)– Fortified cereals

• Easily destroyed by microwave cooking

• Deficiency disease: pernicious anemia



• Deficiency symptoms– Anemia (large-cell type)– Fatigue, degeneration of peripheral

nerves progressing to paralysis


Non-B Vitamins• Choline


Non-B Vitamins• Inositol

• Carnitine

• Vitamin imposters



Metabolic Pathways Involving B Vitamins

The B Vitamins• B vitamin deficiencies

– Glossitis– Cheilosis

• B vitamin toxicities

• B vitamin food sources


Vitamin C


Vitamin C


• Other name: ascorbic acid• 2000 RDA

– Men: 90 mg/day– Women: 75 mg/day– Smokers: + 35 mg/day


Vitamin C


• Chief functions in the body– Collagen synthesis

• Strengthens blood vessel walls, forms scar tissue, provides matrix for bone growth

– Antioxidant– Thyroxin synthesis– Amino acid metabolism– Strengthens resistance to infection– Helps in absorption of iron

Vitamin C


• Significant sources– Citrus fruits– Cabbage-type vegetables, dark green

vegetables (such as bell peppers and broccoli)

– Cantaloupe, strawberries– Lettuce, tomatoes, potatoes– Papayas, mangoes

• Easily destroyed by heat and oxygen

Vitamin C


• Deficiency disease: scurvy• Deficiency symptoms

– Anemia (small-cell type)– Atherosclerotic plaques– Pinpoint hemorrhages, bone fragility,

joint pain– Poor wound healing, frequent

infections, bleeding gums, loosened teeth

– Muscle degeneration and pain, hysteria, depression, rough skin, blotchy bruises

Vitamin C• Deficiency disease: scurvy• Deficiency symptoms

– the four Hs– Hemorrhage

• Bleeding

– Hyperkeratosis• Flaky skin; poor wound healing

– Hematologic• Anemia (fatigue)

– Hypochondriasis• Depression, anxiety, hysteria

Vitamin C


• Toxicity symptoms– Nausea, abdominal cramps, diarrhea– Headache, fatigue, insomnia– Hot flashes, rashes– Interference with medical tests,

aggravation of gout symptoms, urinary tract problems, kidney stones

Vitamin C

Sources


5 servings of fruits and vegetables provides about 210 mg


Vitamin And Mineral Supplements

• Arguments for supplements– Correct overt deficiencies– Improve nutrition status– Reduce disease risks– Support increased nutrient needs– Improve the body’s defenses



• Who needs supplements?



• Arguments against supplements– Toxicity– Life-threatening misinformation– Unknown needs– False sense of security– Other invalid reasons



• Bioavailability

• Antagonistic actions



• Selection of supplements– Form– Contents– Misleading claims– Cost



• Regulation of supplements


An Example of a Supplement Label


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The Water-Soluble Vitamins B Vitamins and Vitamin C Copyright 2005 Wadsworth Group, a division of...

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