Download Lecture 11

What is a Vitamin?
Lecture 11:
Vitamins and Metabolism
• Organic compound (made mainly of
carbon, hydrogen, and oxygen)
Nutrition 150
• Essential nutrients (must be
consumed in the diet, not made by
body)
Shallin Busch, Ph.D.
Vitamins and Metabolism
Vitamins and minerals
– Are required for proper metabolism
– Do not directly provide energy
– Are necessary for obtaining energy from
the macronutrients
– Often function as coenzymes
Coenzymes
Coenzymes: Complex organic molecules
that work with enzymes to facilitate
the enzyme’s activity.
B Vitamins and Metabolism
B Vitamins
Thiamin (B1)
Act as coenzymes
Riboflavin (B2)
- In reactions that
Niacin (B3)
1) Release energy from food
2) Regulate metabolism
- In cell multiplication
Biotin
Pantothenic Acids
B6
1) Red blood cells
Folate
2) Cells of the GI lining
Vitamins and Metabolism
B12
Aerobic Catabolism of Glucose
Glucose
Uses energy
(ATP)
Coenzyme
Coenzyme
Yields energy
(ATP)
Coenzyme
Coenzyme
2 Pyruvate
Pantothenic Acid
Coenzyme
Coenzyme
2 CoA
Coenzyme
Coenzyme
2 Carbon
dioxide
CoA
CoA
2 Acetyl CoA
To TCA Cycle
B6
To Electron
Transport
Chain
Makes ATP
Niacin
To Electron
Transport
Chain
Makes ATP
Catabolism of Fatty Acid
Catabolism of Amino Acids
16-C fatty acid
Amino acids
Niacin
Pyruvate
CoA
CoA
Pantothenic Acid
Coenzyme
Pantothenic Acid
Uses energy
(ATP)
Coenzyme
Carbon
dioxide
CoA
Coenzyme
To Electron
Transport
Chain
Coenzyme
CoA
Pyruvate
Coenzyme
Acetyl CoA
(from carbon
dioxide)
CoA
Niacin
Riboflavin
(Biotin)
Coenzyme
Acetyl CoA
B6
Makes ATP
The TCA Cycle
CoA
All B Vitamins are involved in
the TCA cycle!
Thiamin (B1)
Coenzyme
Riboflavin (B2)
Coenzyme
Coenzyme
Coenzyme
Coenzyme
Coenzyme
Coenzyme
Coenzyme
Coenzyme
(as carbon
dioxide)
Coenzyme
To Electron
Transport
Chain (makes ATP)
Yields energy
(captured in high-energy
compound similar to ATP)
(as carbon
dioxide)
Niacin (B3)
Biotin
Pantothenic Acids
B6
Folate
To Electron
Transport
Chain (makes ATP)
Makes ATP
To TCA Cycle
Oxaloacetate
Coenzyme
To Electron
Transport
Chain
B12
B vitamins and the
Electron Transport Chain
Metabolic Pathways Involving B Vitamins
Glycogen
Glucose
Some amino acids
Pyruvate
Niacin
Ribolavin
Some amino acids
Some amino acids
Some amino acids
Acetyl--
TCA Cycle
Yields
energy
Other compounds
Yields
energy
Foods with B vitamins
• In general, B vitamins are found in a
wide range of foods
• B vitamins are more likely found in
foods of animal origins (B12), proteinrich foods, whole-grain foods,
fortified foods
• Many B vitamins are found in lots of
different food
Fat
Yields
energy
Keeping B Vitamins in Foods
• Easily destroyed by UV rays (sun),
heat, exposure to oxygen
– Implications for cooking and storage
• Water soluble
– They leach out of foods when washed
and cooked in water
In-text Figure
Page 322
Is more always better?
No! More is better up to a point and then is harmful.
To minimize vitamin losses, wrap cut fruits and
vegetables or store them in airtight containers.
B Vitamin Toxicity
Some B vitamins are toxic if too much
is consumed:
– Niacin: Flush, Liver damage, Impaired
glucose regulation
– B6: Nerve degeneration, skin lesions
– Folate: Masks B12 deficiency
B Vitamin Deficiency Diseases
With general B deficiencies, can see:
glossitis - smooth, glossy tongue
due to atrophy of the tissue
B Vitamin Deficiencies Diseases
Niacin: Pellagra - Diarrhea,
dermatitis, dementia, death
Thiamin: Beriberi - Muscle wasting and
nerve damage, sometime edema
Riboflavin: Ariboflavinosis - Sore throat,
swollen mucous membranes
Folate Deficiency
- Failure to replace tissues that turnover
frequently (GI tract, red blood cells)
- Anemia: not enough red blood cells present or
properly functioning
- GI tract deterioration
- Spinal bifida: Improper development of
spinal chord in fetus
Folate
- Involved in DNA synthesis, amino acid
metabolism
- Helps prevent heart disease and
cancer
- Critical for cell division of very early
embryos
- Critical for formation of neural tube
in developing fetus
Vitamin B12
• Part of coenzymes for blood formation
• Required for nerve functioning
• Required for homocysteine breakdown
• Deficiency results in anemia, low energy,
fatigue, shortness of breath, and can
lead to pernicious anemia
• Deficiencies seen in vegetarians, older
people with GI system complications
Manganese
• Mineral (not a vitamin)
• Coenzyme involved in energy metabolism
In-Class Activity
Work with a partner to design a meal
that is high in B vitamins
- Meal should include protein,
carbohydrates, and vegetables