Vitamins Vital Keys to Health BIOL 103 Chapter

Vitamins: Vital Keys to Health BIOL 103, Chapter 9

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

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

Understanding Vitamins • 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?

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

Understanding Vitamins • Vitamins in foods – Enrichment and fortification • Enriched: replacing lost nutrients • Fortified: adding extra nutrients to foods • Some is required by law – Provitamins • ___________ forms of vitamins

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

4 Forms of Vitamin A • Three active forms of Vitamin A, collectively known as Retinoids: 1. Retinol 2. Retinal 3. Retinoic acid • Carotenoids are provitamins: _______ of vitamin A

Functions of Vitamin A 1. Vision: night and day – Night and color vision – Becomes part of the retina 2. Cell production and differentiation – Help make cells, enzymes, proteins – Cell differentiation: stem cells specific cells 3. Skin – Required to replace epithelial cells of your skin

Functions of Vitamin A (cont. ) 4. Immune Function – Produce immune cells to fight microorganisms 5. Reproduction – Keeps reproduction tracts healthy – Embryo development 6. Bones – Bone “remodeling” • Increase in osteoclasts

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

Vitamin A Deficiency 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

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

The Carotenoids • 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

The Carotenoids • Food sources: – __________ 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

Vitamin D • Forms and formations – Activated in liver and kidney • In the skin, UV light converts a form of cholesterol to D 3 to liver kidneys active form: 25 hydroxyvitamin D [25(OH)D] or calcitrol – Functions • Essential for bone health • Regulate blood calcium levels

Vitamin D • Sources: – Sun exposure helps activate an inactive form of vitamin D – Fortified milk/foods – Oily fish, egg yolk, butter, liver • Question: Why would manufacturers choose milk to be fortified with vitamin D?

Problem Set 9 Question #1 • Name at least three reasons why people around the world will not have similar levels of vitamin D.

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 (Stones, Bones, Groans, Thrones, Psychiatric overtones)

Melanin, Sunscreens and UV Light • Melanin, Chemical Sunscreen = Absorb UV • Physical Sunscreen = Reflect UV

Vitamin E • Forms – 8 similar compounds • Essential: alpha-tocopherol – Stored mainly in ___________. • Functions – Antioxidant • Protects cell membranes from free radicals

Vitamin E • 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 _______

Vitamin K • Forms: – K 1 – K 2 • Functions: – ___________ (also requires calcium) – Bone formations • Food sources; – Green vegetables (spinach, broccoli, brussel sprouts), plant oils, intestinal bacteria

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

Summary of Fat-Soluble Vitamins

The Water-Soluble Vitamins: Eight Bs and a C • Primarily coenzymes • Antioxidants • What to keep in mind about each vitamins: – Function – Food sources – Toxicity vs. Deficiency

Vocabs to Know: • Coenzyme: a small compound that helps enzymes in biochemical reactions. Most coenzymes are derived from vitamins or are made from vitamins. • Energy Metabolism: process of generating energy from nutrients (glucose, fatty acids, amino acids). • Glycogen Metabolism • Fat Metabolism • Protein Metabolism

Thiamin/B 1 • Functions: – Part of the coenzyme: thiamin pyrophosphate (TPP): 1. Power protein and fatty acid synthesis 2. Breaks down glucose energy • Food sources: – Pork, legumes, nuts and seeds, fish and seafood, enriched grain product – Cooking __________ content

Thiamin/B 1 • Deficiency/”Ariboflavinosis”: – Can be caused by chronic alcoholism and poor diet – Beriberi: overall profound muscle weakness and nerve destruction can’t stand up • Toxicity: – None reported

Riboflavin/B 2 • Functions: 1. Coenzyme in energy metabolism 2. Supports antioxidant activity • Food sources: – Milk and dairy products – Enriched grains, eggs • Toxicity: UL is not set

Milk Packaging • Light breaks down riboflavin easily, so foods high in riboflavin are stored in opaque containers. • That’s why it’s rare to see milk in bottles…

Niacin/B 3 • Functions: 1. Coenzyme in energy metabolism 2. Supports fatty acid synthesis • Food sources: – Can be made from tryptophan. • Need B 1, B 6, and iron to convert to B 3 – Whole and enriched grains – Meat, poultry, fish, nuts, peanuts

Niacin/B 3 • Deficiency: – Pellegra: “rough skin” • Four D’s: dermatitis, diarrhea, dementia, and death – Can worsen if also deficient in ____, and iron. • Toxicity – Side effects: skin flushing, liver damage

Pyridoxine/B 6 • Functions: 1. _______, coenzyme in protein and amino acid metabolism, gluconeogenesis (AA glucose) 2. Produce neurotransmitters 3. Helps to lower blood levels of homocysteine reduce risk for heart disease • Diagram: • Food sources: – Meat, fish, poultry, potatoes, bananas, sunflower seeds

Pyridoxine/B 6 • Deficiency – Microcytic hypochromic anemia • Can also be caused by deficiency in iron. – Damage nervous system depression, headaches, confusion, convulsions. • Toxicity – Can cause subtle neurological damage – Other symptoms: upset stomach, headaches, sleepiness, tingling/prickling or burning sensation

Folate/B 9 • Functions: 1. 2. 3. 4. Coenzyme in DNA synthesis and cell division Coenzyme in amino acid metabolism Needed for normal red blood cell maturation Works with B 6 and B 12 to help control homocysteine levels • Food sources: – Fortified cereals, enriched grains – Green, leafy vegetables

Folate/B 9 • Deficiency: 1. Megaloblastic anemia RBC cannot form ______ cannot ____ remain large, immature cells cannot carry oxygen properly anemia 1. Birth defects in the Neural Tube: ___________ 2. Heart disease from elevated homocysteine levels

Folate/B 9 • Toxicity: – Can mask vitamin B 12 deficiency when you take folate supplements until nerve damage is irreversible. – In rare cases, some may suffer hives or respiratory distress

Cobalamin/B 12 • “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 protection • Food sources: – Only animal foods: meats, liver, milk, eggs – Some fortified foods

Cobalamin/B 12 • Absorption: – Requires adequate stomach acid and intrinsic factor • Deficiency: – Can be caused by Pernicious anemia: autoimmune disorder that damages stomach linings reduced B 12 absorption – Nerve damage • Toxicity: – No UL set

Pantothenic Acid/B 5 • 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

Biotin/B 7 • 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

Vitamin C • 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

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

Summary of Water-soluble Vitamins

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