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The Water-
Soluble
Vitamins: B1-6
Chapter 10
2018
The B Vitamins – Thiamin
Part of coenzyme thiamin pyrophosphate
(TPP)
Energy metabolism
Conversion of pyruvate to acetyl CoA
TCA cycle
Nerve activity and muscle activity
Recommendations
The B Vitamins – Thiamin
Deficiency
Malnourished and alcoholics
Beriberi
Dry – nervous system
Wet – cardiovascular system
Toxicity
No adverse effects
No UL
The B Vitamins – Thiamin
The B Vitamins – Thiamin
Food sources
Prolonged cooking destroys thiamin
Leaches into water when boiling or
blanching foods
Cooking methods that conserve thiamin
The B Vitamins – Thiamin
The B Vitamins – Riboflavin
Serves as coenzyme in energy metabolism
Flavin mononucleotide (FMN)
Flavin adenine dinucleotide (FAD)
Recommendations
Deficiency
Inflammation of membranes
Toxicity
No UL
The B Vitamins – Riboflavin
The B Vitamins – Riboflavin
Food sources
Milk and milk products
Other sources
Destruction of riboflavin
Ultraviolet light
Irradiation
Not destroyed by cooking
The B Vitamins – Riboflavin
The B Vitamins – Niacin
Recommendations
Adequate intake (AI)
Deficiencies
Rare
Symptoms
Toxicity
No UL
Food sources
The B Vitamins – Niacin
Toxicity
Naturally occurring
No harm
Supplements or drugs
“Niacin flush”
Potential health benefits of large doses of nicotinic acid
Food sources
Less vulnerable to food preparation losses
The B Vitamins – Niacin
Two chemical structures
Nicotinic acid
Nicotinamide
Major form of niacin in blood
Two coenzyme forms – metabolic reactions
Nicotinamide adenine dinucleotide (NAD)
Carries hydrogens and their electrons
NADP (the phosphate form)
The B Vitamins – Niacin
Recommendations
Body manufacturers from tryptophan
Only occurs after protein synthesis needs
have been met
RDA is stated in niacin equivalents
Deficiency
Pellagra
Symptoms
The B Vitamins – Niacin
The B Vitamins – Niacin
The B Vitamins – Biotin
Coenzyme that carries activated carbon
dioxide
Critical in TCA cycle
Delivers carbon to pyruvate to form
oxaloacetate
Participates in gluconeogenesis and fatty
acid synthesis
Participates in breakdown of fatty acids
and amino acids
The B Vitamins – Pantothenic
Acid
Part of chemical structure of coenzyme A
Roles in body
Recommendations
AI
Deficiency
Rare
Toxicity
Food sources
The B Vitamins – B6
Three forms
Pyridoxal, pyridoxine, and pyridoxamine
Conversion to coenzyme PLP
Amino acid metabolism
Urea metabolism
Conversion of tryptophan to niacin or
serotonin
Synthesis of heme, nucleic acids, & lecithin
Stored exclusively in muscle tissue
The B Vitamins – B6
Recommendations
Large doses
Deficiency
Symptoms
Alcohol & isoniazid
Toxicity
Irreversible nerve degeneration
Food sources
The B Vitamins – B6
