BIOL 103, Chapter 9

• Understanding Vitamins
• Fat Soluble Vitamins: A, D, E, K, and
Carotenoids
• The Water-Soluble Vitamins: Eight Bs and a C
• Bogus Vitamins

• Vitamins
– Needed in small amounts
– Not an energy source
– Individual units
– Organic compounds essential for normal functioning, growth, and maintenance of the body.

• Fat soluble vs. water-soluble
– Fat-soluble: vitamins A, D, E, K
• Absorbed with fat, with lymphatic system
• Stored in larger quantities
– Water-soluble: 8 B vitamins and vitamin C
• Absorbed into the bloodstream
• Stored in small amounts
– Which is more vulnerable to cooking losses?

• Food preparation affections vitamin content in the foods
– Factors that determine amounts:
1. Source
2. Sunlight
3. Moisture
4. Growing conditions
5. Plant’s maturity at harvest
6. Packaging and storage

• Vitamins in foods
– Enrichment and fortification
• Enriched
• Fortified
• Some is required by law
– Provitamins
• Inactive forms of vitamins

• Functions
– Vision, cell development and health, immunity
• Food sources
– Preformed vitamin A: liver, milk, egg yolks
– Beta-carotene: yellow/orange fruits and vegetable

• Three active forms of Vitamin A, collectively known as Retinoids:
1. Retinol
2. Retinal
3. Retinoic acid
• Carotenoids: precursors of vitamin A

1. Vision: night and day
– Night and color vision
– Becomes part of the retina
2. Cell production and differentiation
– Regulate production of enzymes, blood carrier proteins, and structural proteins
– Cell differentiation
3. Skin
– Required to replace epithelial cells, which make up epithelial tissues

4. Immune Function
– Produce immune cells to fight microorganisms
5. Reproduction
– Keeps reproduction tracts healthy
– Cell differentiation contributes to embryo development during pregnancy
6. Bones
– Trigger an increase in osteoclasts; this contributes to bone “remodeling”

• Dietary Recommendations
– Retinol activity equivalent (RAE) = 1 ug retinol
• Uses RAE to account for differences between retinoids and carotenoids
• Sources of vitamin A
– Animal: retinoids
– Plant: provitamin A carotenoids
– Fortified foods

1. Eyes
– Xerophtalmia
2. The skin and other epithelial cells
– Hyperkeratosis
3. Immune function
– Vulnerable to infection
4. Other effects:
– Growth retardation, bone deformities, defective teeth, kidney stones

• Symptoms:
– fatigue, vomiting, abdominal pain, bone and joint pain, loss of appetite, skin disorders, headache, blurred or double vision, and liver damage
1. Teratogen
– Causes birth defects
2. Discoloration of skin
3. Acne Treatment:
– Retin-A and Accutane

• Plant pigments (deep yellow, orange, red color)
• Can be converted to vitamin A
– Beta-carotene supplies the most vitamin A of the carotenoids.
• Functions:
1. Vision
2. Lower risk of certain cancer

• Food sources:
– Orange/yellow fruit and vegetables (tomatoes, apricots, carrots), dark green vegetables
– Absorb 20-40% of what we eat
– Dietary fat and cooking with heat (breaks down cell walls) increases absorption

• Forms and formations:
– Activated in liver and kidney
• In the skin, UV light converts a form of cholesterol to D3
 to liver  dietary and synthesized forms of vitamin
D are converted to an intermediate form  goes to kidneys  active form: 25-hydroxyvitamin D [25(OH)D]
or calcitrol
– Functions:
• Essential for bone health
• Regulate blood calcium levels

• Sources:
– Sun exposure helps activate an inactive form of vitamin D
– Fortified milk
– Fortified food
• Question: Why would manufacturers choose milk to be fortified with vitamin D?

• Name at least three reasons why people around the world will not have similar levels of vitamin D.

• Deficiency:
– In children:
• Rickets
– In adults:
• Osteomalacia or “soft bones”
• Osteoporosis
• Toxicity
– Hypercalcemia: a high concentration of calcium in blood  excess deposit of calcium in soft tissues
• Fun Topic: Melanin and Tanning

• Forms
– 8 similar compounds
• Essential: alpha-tocopherol
– Stored mainly in body fat
• Functions
– Antioxidant
• Protects cell membranes from free radicals

• Food sources
– Nuts, seeds, vegetable oil, whole grain, wheat germ oil, fruit, vegetables, and animal products
• Deficiency
– Occurs with fat malabsorption
– Rare genetic disorder
• Toxicity
– Nontoxic and adverse effects have not been found
– Can interfere with blood clotting

• Forms:
– K1
– K2
• Functions:
– Blood clotting (also requires calcium)
– Bone formations
• Food sources;
– Green vegetables (spinach, broccoli, brussel sprouts), plant oils, intestinal bacteria

• Deficiency
– Rare in healthy people
– Newborn baby at risk
• Toxicity
– Can interfere with anticoagulant medications
– Toxicity is rare

• Primarily coenzymes
• Antioxidants
• What to keep in mind about each vitamins:
– Function
– Food sources
– Toxicity vs. Deficiency

• Coenzyme: a small compound that helps enzymes in biochemical reactions. Most coenzymes are derived from vitamins or are made from vitamins.

• Functions:
– Coenzyme in energy metabolism
– Part of the coenzyme: thiamin pyrophosphate
(TPP)
• Food sources:
– Pork, legumes, nuts and seeds, fish and seafood, enriched grain product
– Cooking reduces content

• Deficiency:
– Beriberi: overall profound muscle weakness and nerve destruction
• “I can’t, I can’t”
– Q: Why would Beriberi be more common in
Southeast Asia?
• Toxicity:
– None reported

• Functions:
1. Coenzyme in energy metabolism (extracts energy from glucose, fatty acids, and amino acids)
2. Supports antioxidants
• Food sources:
– Milk and dairy products
– Enriched grains, eggs
• Deficiency:
– Arbioflavinosis
• Toxicity: UL is not set

• Functions:
1. Coenzyme in energy metabolism
2. Supports fatty acid synthesis
• Food sources:
– Can be made from tryptophan
• Need B1, B6, and iron to convert to B3
– Whole and enriched grains
– Meat, poultry, fish, nuts, peanuts

• Deficiency:
– Pellegra: “rough skin”
• Four D’s: dermatitis, diarrhea, dementia, and death
– Can worsen if also deficient in B1, B6, and iron.
• Toxicity and medicinal uses
– High doses used to treat high blood cholesterol
– Side effects: skin flushing, liver damage

• Functions:
1. Coenzyme in protein and amino acid metabolism
2. Supports immune system
3. Helps to lower blood levels of homocysteine  reduce risk for heart disease
• Diagram:
• Food sources:
– Meat, fish, poultry, potatoes, bananas, sunflower seeds

• Deficiency
– Microcytic hypochromic anemia
• Can also be caused by deficiency in iron.
• Toxicity
– Can cause subtle neurological damage
– Other symptoms: upset stomach, headaches, sleepiness, tingling/prickling or burning sensation

• Functions:
1. Coenzyme in DNA synthesis and cell division
2. Needed for normal red blood cell synthesis
3. Works with B6 and B12 to help control homocysteine levels
• Food sources:
– Fortified cereals, enriched grains
– Green, leafy vegetables

• Deficiency:
1. Megaloblastic anemia
2. Birth defects in the Neural Tube: Spina Bifida
3. Heart disease from elevated homocysteine levels
• Toxicity:
– Can mask vitamin B12 deficiency when you take folate supplements

• “Cobalt-containing compounds” (cobalamin)
• Functions:
1. Needed for normal folate functions
• DNA and red blood cell synthesis
• Metabolize homocysteine
2. Maintains myelin sheath around nerves  nerves protection
• Food sources:
– Only animal foods: meats, liver, milk, eggs
– Some fortified foods

• Absorption:
– Requires adequate stomach acid and intrinsic factor
• Deficiency:
– Can be caused by Pernicious anemia: autoimmune disorder that damages stomach linings  reduced
B12 absorption
– Nerve damage
• Toxicity:
– No UL set

• Function:
1. Component of coenzyme A
 extract energy from nutrients and help build fatty acids
• Food sources:
– Widespread in foods
– Reduced by freezing, canning, refining
• Deficiency/Toxicity: Rare

• Functions:
– Acts as a coenzyme in:
1. Amino acid metabolism (amino acids  glucose)
2. Fatty acid synthesis
• Food sources:
– Cauliflower, liver, peanuts, cheese
– Protein avidin (raw egg whites) binds biotin and prevents absorption
• Deficiency and Toxicity are rare

• Functions:
– Antioxidant
– Needed for collagen synthesis
– Enhances the absorption of iron from plant foods
• Food sources:
– Fruits: citrus, strawberries, kiwi
– Vegetables: broccoli, tomatoes, leafy green, potatoes

• Deficiency:
– Scurvy
• Toxicity:
– May cause GI distress
– For some people: kidney stones, iron toxicity

• Function:
– Act as a catalyst to help metabolize homocysteine
• Food sources:
– Milk, liver, egg yolk, peanuts; overall is abundant in food
• Deficiency: Unlikely in healthy people
• Toxicity:
– Diarrhea, falling blood pressure, fishy body odor

• Bogus vitamins: Unnecessary substances found in some supplements
– Examples: hesperidin, para-aminobenzoic acid
(PABA), pangamic acid, rutin
– Think twice before you buy them!