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12.2 Vitamins. chapter 19. Vitamins are nutritionally important organic compounds. Often coenzymes or cofactors for enzyme function. Vitamins form biochemically through the life processes of the plants and animals we eat. Plants and animals synthesize vitamins. MICRONUTRIENTS 2.
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12.2 Vitamins chapter 19
Vitamins are nutritionally important organic compounds. Often coenzymes or cofactors for enzyme function. Vitamins form biochemically through the life processes of the plants and animals we eat. Plants and animals synthesize vitamins. MICRONUTRIENTS 2
Originally it was thought these necessary compounds were all amines. Since they were vital to our health they became known as “vital amines”, ie. vitamines. When it was discovered that some were not amines, ie. not ' --ines', the name was changed to vitamins.
The fat - soluble vitamins are much more soluble in fats, hydrocarbons and similar solvents than in water Vitamins A, D, K, E Water- soluble vitamins are much more soluble in water than in 'organic' solvents. C, B complex (B1,2,3,6,12), Pantothenic acid(B5), Biotin(B7), Folate(B9)
Vitamin Requirements Name(Letter) RDI Water-Soluble Thiamin (B1) Riboflavin (B2) Niacin (B3) Pantothenic acid (B5) Pyridoxine (B6) Biotin (B7) Folic acid (B9) Cobalamin (B12) Ascorbic acid (C) 1.5 mg 1.7 mg 2 mg 10 mg 2 mg 0.3 mg 0.4 mg 6 g 60 mg
Vitamin Requirements Name(Letter) RDI Oil-soluble Retinol (A) Calciferol (D) *Tocopherol (E) Phylloquinone (K) 5000 IU 400 IU 30 IU 70 g WHAT is An IU??
Vitamin levels in foods or supplements are sometimes stated in Retinol Equivalents (RE's) or in International Units (IU's). (2 sets of Units!!) Several esters of retinol are equally effective and thus are retinol equivalents (RE’s). By definition , 1 RE of retinol = 1 microgram Also by definition, one International unit (IU) of Vitamin A =.3 micrograms retinol Thus 1 RE=3.33 IU’s of Vitamin A
IU’s • Can apply to all vitamins and always = 0.3 micrograms or 0.3 x10-6 grams • RE’s only apply to Vitamin A (retinol)
Metabolism of beta carotene • Oxidative cleavage of C=C and reduction to alcohol • Carrots etc. lots of beta carotene and eventually an excellent source of Vitamin A
Free Radicals - the Metabolic Oxidizers Free radical = unpaired electron very reactive . OH OH . OH OH Oxygen radicals: Hydroxy (HO•) / Peroxy (HOO•)
Do you smoke?? • Each puff contains ~ 1015 OH radicals • Also cyanides (bind to hemoglobin) • PNAH’s • Try the blow test: exhale through a kleenex and see the tar!
An antioxidant is a chemical so easily oxidized itself that it protects others from oxidation. and / or Double Bond eg. Vitamin A Phenol Part of Vitamin E molecule
Vitamins - Some Generalities • Fat-soluble vitamins can be accumulated in body tissue/organs, eg. liver. Often there can be serious metabolic consequences when ingesting 'mega- doses', ie.10 - 100X the RDI. • The water-soluble vitamins are often destroyed by heat/water in the cooking process; also by prolonged storage. Since they are excreted there is usually no danger from 'overdosing' (vit B6!). • Diet-related deficiencies do occur in vegans, the elderly and alcoholics • Chirality! ie. natural (D or L) vs. synthetic (D/L)
Water-Soluble Vitamins ( B1 & B5) Thiamine (B1) Pantothenic Acid (B5)
Water-Soluble Vitamins (B3,B7,C &?) Biotin(B7) Niacin(B3) HOCH2CH2N+(CH3)3 Choline Ascorbic Acid(C)
Water-Soluble Vitamin(B12) Cobalamin
A - Retinol Uses: vision pigment, good anti-oxidant (heart disease? cancer?) Deficiency: night blindness, (infant mortality) Excess: blurred vision, teratogenic for pregnant women, serious liver disease,skin yellowing Sources: highly coloured vegetables, liver, egg yolks, fish liver oils
D - Calciferol Uses: regulates absorption of calcium & phosphorus Deficiency: rickets (bone deformation) Excess: damage to kidneys/tissue due to Calcium 'deposits' Sources: eggs, liver, fish oils, fortified milk, sunshine
E - Tocopherol Uses: excellent anti-oxidant (protects cell membranes); skin care Deficiency: rare; (anemia, edema in infants) Excess: 2005 study*** Heart attacks if overused Source: vegetable oils, green vegetables, nuts/seeds, wheat germ, meat Vitamin E is not recommended over and above what is in a multivitamin as of 2005
E: the vitamin looking for a disease! • Still no well documented evidence for any diseases directly due to its deficiency. • Don’t take supplements!
K- Phylloquinone Uses: essential cofactor in blood clotting Deficiency: (bruising/bleeding in infants-increased coagulation time) Excess: dangerous if taking anti-coagulants such as ASA Sources: green leafy vegetables (spinach, kale) Cofactor: a small molecule or atom that is required for an enzyme to be active
B1- Thiamin Uses: necessary for carbohydrate metabolism Deficiency: nervous system deterioration (beriberi), esp. in Far East because of milled rice Excess: not known Sources: lean meat, legumes, whole grains, in 'fortified' flour since 1940s
B2 - Riboflavin Uses: cofactor in much metabolism Deficiency: poor wound healing, breakdown of tissue in mouth/nose Excess: not likely (yellow urine!) Sources: milk, organ meats, fortified cereals
B3 - Niacin Uses: required for all metabolic oxidations (needed by every cell daily!), lowers cholesterol (in excess) Deficiency: deterioration of nervous system & skin (pellagra) Excess: not normal (dizziness, liver damage) Sources: yeasts, meats, legumes, 'enriched' flour
B5 - Pantothenic Acid Uses: cofactor in fatty acid metabolism Deficiency: not observed Excess: not observed Sources: organ meats, egg yolks, yoghurt, legumes
B6 - Pyridoxine Uses: cofactor in >60 enzymes for a.a. metabolism (the master vitamin!) Deficiency: anemia, nervous disorders (est. in almost 50% of NA women, esp. those on oral contraceptives) Excess: disable nervous system (present in body- building diets) Sources: green leafy vegetables, meats, fruit
B7 - Biotin Uses: cofactor in synthesis of fatty acids Deficiency: not observed Excess: not observed Sources: liver, egg yolks, nuts, legumes, soy
B9 - Folic Acid Uses: cofactor for nucleic acid and heme synthesis Deficiency: some anemias, if during pregnancy the fetus has high probability of spina bifida or other birth defects Excess: possible danger for hormone related cancers Sources: green leafy vegetables, asparagus, organ meats
B12 - Cobalamin Uses: controlling factor for pernicious anemia Deficiency: normally rare, but with inability to absorb (>50 and vegans) Excess: not known Sources: animal protein, organ meats, milk, eggs
Vegans (ovo-lacto vegetarians) • Need Vitamin B supplements containing the cobalamin complex or take Brewers Yeast
C - Ascorbic Acid Uses: cofactor for collagen production, enhances iron absorption, excellent anti-oxidant Deficiency: scurvy Excess: probably should avoid >1g/day (Linus Pauling advocated up to 3g/day but no proven benefits!) Sources: citrus fruits, potatoes, cabbage, tomatoes
Vitamin C - will it cure my cold? > NO, but….30% decrease in upper respiratory tract infections > ~1/3 of all NA ingests Vit.C = tons! > Loses potency when exposed to air (50% less in your OJ after 3 weeks in fridge). > Helps maintain other antioxidants > Smokers need ~twice the RDI/USRDA By 1750 it was known that weekly rations of citrus fruit would prevent scurvy. This fact allowed Britain to 'rule the waves' and for these sailors to be called "limeys". Not isolated until 1928.
Phytochemicals - non-nutrient compounds, found in plant-derived foods, that have biological activity in the body. 2009 OJ: packaging “phytonutrients!” Antioxidants (anti-aging/cancer/heart disease?) - catechins (berries, green/black tea), lycopene (tomatoes,watermelon), bioflavanoids (citrus fruit, grapes), coenzyme Q (nuts,oils).
Plant Pigments = Potent Antioxidants Almost 2000 known plant pigments. >800 flavonoids, ~450 carotenoids and ~150 anthocyanins. Red(lycopene) – tomatoes, pink/red grapefruit, watermelon, guava, red peppers. Red/Blue/Purple(anthocyanins) – red/blue grapes, blue-/straw-/raspberries, beets, cherries, egg plant, plums, red cabbage. Orange(carotene) – squash, pumpkin, yams, carrots, mango, cantaloupe.
Plant Pigments = Phytochemicals Orange/Yellow(cryptoxanthin) – peach, orange, nectarine, papaya. Yellow/Green(lutein, zeaxanthin = especially good for health of eyes) – corn, cucumber skins, yellow/green peppers, green beans/peas, spinach, honeydew melon, kiwi, romaine lettuce,
Had your ORAC Foods Today ? high Oxygen Radical Absorbance Capacity foods – the top 15(for ~100g/3.5oz) prunes raisins blueberries stawberries raspberries plums oranges red grapes cherries 5770 2830 2400 1540 1220 949 750 739 670 kale spinach sprouts broccoli beets red pepper corn eggplant carrot 1770 1260 980 890 840 710 400 390 210
Too Much Broccoli ! Two women with diseases characterized by abnormal blood clotting did not improve when they were given Warfarin. When questioned about their diets, one woman reported that she ate at least a pound of broccoli every day, and the other ate broccoli soup and a broccoli salad every day. When broccoli was removed from their diets, warfarin became effective in preventing the abnormal clotting of their blood. Because broccoli is high in vitamin K, these patients had been getting enough dietary vitamin K to compete with the drug, thereby making the drug ineffective.