Vitamins Module 5 - Part 2 PDF

Vitamins Vitamins C (Chapter 8) Vitamins A, D, E, K (Chapter 9) 1 Vitamin C – Ascorbic Acid Or Ascorbate CHSC 2P91 Chapter 8 2  Vitamin C - History Scurvy – oldest vitamin deficiency described as early as...

Vitamins Vitamins C (Chapter 8) Vitamins A, D, E, K (Chapter 9) 1 Vitamin C – Ascorbic Acid Or Ascorbate CHSC 2P91 Chapter 8 2  Vitamin C - History Scurvy – oldest vitamin deficiency described as early as 1500 BC 1535 – Jacques Cartier – As many as 2/3 of men on long voyages became afflicted with the symptoms of a fatal disease, many died (swollen limbs, hemorrhaging gums and skin, loss of teeth, severe weakness) 3  Vitamin C – History (one of the 1st scientific experiments) 1747 – James Lind (British physician) – Thought that diet may be a cause of scurvy (because only men on long voyages got scurvy) Tested his theory by giving 12 sailors with scurvy 6 different diets - 2 men – oranges and lemons - 2 men seawater - 2 men – cider - 2 men vinegar - 2 men – sulfuric acid - 2 men laxatives (today used in car batteries, fertilizers) (spices added) - ** only the men who received oranges and lemons improved and recovered from scurvy - *concluded that something in the citrus fruits prevented scurvy - ***sadly, it was 50 years later before the British navy made “lime juice” required to be provided for every sailor - ** this gave the British sailors the nickname “Limeys” 4 4  Vitamin C - History 1970 – Linus Pauling The idea that vitamin C might prevent or cure the common cold was introduced in 1970 by Linus Pauling (He won a nobel prize for this!!!) – First developed his theory from rat studies – Book “Vitamin C and the Common Cold” – At the age of 64, he started taking 18 g vitamin C/day (DRI (RDA) – 75 – 90 mg) – When he felt a cold starting, he took 46 g/day!!!! – He died at the age of 98 years old - He believed that anyone can STOP a cold - Need to start early enough and in the right dose - Stated that people will know their own limit when they go to the bowel- tolerance limit, or the appearance of loose stools – once this occurs, then cutback 1 or 2 grams, and then that’s the right dose - Therefore, he states that high doses required to stop a cold will vary according to the individual 5 5  Vitamin C - History 1972 – 1975 - more research – Skiers (control (placebo group) and Vitamin C – Vitamin C group had less severity of symptoms but the same number of colds Sasazuki et al (2006) - 5 year randomized control trial - participants received 50mg or 500mg of Vitamin C - Results showed no effect on the duration or severity of a cold Rondanelli et al (2018) (Review Article) - 1 – 2 grams/day may reduce the duration and severity of a cold - An important point to consider is that overdosing Vitamin C might be negative for immune defense as it inhibits oxidative processes that are needed for first line defense against bacteria or viruses (works as a pro-oxidant) Hemila et al (2023) (Meta-analysis) - looked at studies examining at least 1 gram/day - duration of severe symptoms decreased, no effect on mild symptoms 6-  Vitamin C: Properties Water soluble, most unstable of all vitamins in solution Oxidizes readily in light, air, heat, and in the presence of iron and copper Canadian regulations, it is mandatory that Vitamin C be added to: Fruit-flavoured drinks, Infant formula, Meal replacement products, Instant breakfasts Evaporated milk It can also be added voluntarily to apple juice and dehydrated potatoes 7 7  Vitamin C: Properties Cooking implications: - Don’t leave cut foods exposed to air for long periods of time (apples turn brown, etc) - Put vegetables into water that is already boiling for less cooking time - Cook vegetables until tender, don’t overcook - Little cutting and chopping before cooking - Light and air – storage implications, in fridge (use opaque containers) - Iron and copper – don’t use these pots for cooking 8  Functions of Vitamin C 1.Collagen formation 2. Antioxidant 3. Aids in iron absorption 9  Vitamin C: Function/Deficiency Symptoms of scurvy: Main Function -bleeding, swollen gums, lesions Collagen formation around the teeth, teeth fall out wounds fail to heal Deficiency dry, scaly skin Poor wound healing muscle cramps swollen joints “aching bones” Scurvy Children: failure to grow, skeletal changes “frogs leg” position bleeding under the skin (pinpoint hemorrhages) 10 10  Vitamin C: Functions Anti-oxidant: Protects tissues from oxidative stress (Vitamin C gets destroyed before tissues) 11 11  Vitamin C: Functions Curing a Cold????? Histamine – Nasal congestion is due to elevated blood levels of histamine – people take anti-histamines to prevent runny, ‘stuffed up’ noses – Vitamin C deactivates histamine, therefore working like a drug (cold and allergy medication) – Does NOT cure a cold or prevent a cold, it may help relieve the symptoms of a cold 12  Vitamin C - Toxicity Although Vitamin C is water soluble, toxicity symptoms can result from 2 g/day or more 2000mg/day is the DRI - Upper Level Symptoms – Diarrhea – Nausea, Abdominal cramps, – Kidney stones (in people who are susceptible to them) – Acidic urine – Rashes – False positive for high glucose (urine) (possibly due to similar structure) – Headache – Fatigue – Rebound scurvy 13 13  Vitamin C Intake (mg/day) 3000 Adverse consequences may appear at such a high dose (mega dosing) 2000 Upper level for adults , toxicity may result in 2 g or more per day Limited absorption and little increase in blood concentrations at higher doses, 200 no added benefits, excess excreted in the urine 125 Recommendation for men smokers – 125mg ( 90mg plus 35mg) 110 Recommendation for women smokers – 110 mg (75mg plus 35 mg) 100 Saturates tissues 90 RDA for men 90 mg 75 RDA for women 75 mg 30 Supports metabolism 10 14 14 Prevents scurvy (however doesn’t saturate tissues, minimal daily amount) 0 Vitamin C: Dietary Sources (DRI: F - 75mg/day, M - 90 mg/day) 1 Tomato: 16 mg 1 white potato: 26 mg 1 cup sweet potato: 40mg 1 cup Broccoli: 78 mg Best Dietary Source: Vegetables and Fruits (citrus fruits best) 1 Orange: 70 mg 1 cup OJ: 124 mg 1 Kiwi: 74 mg 1 cup strawberries: 84 mg 15 15 Vitamin C in Foods: Best dietary sources: vegetables and fruit 16 Summary of the Water-Soluble Vitamins 17 Fat Soluble Vitamins Chapter 9 18  Fat-Soluble Vitamins A, D, E, K Fat-soluble vitamins require bile and dietary fat for absorption. Once absorbed, they are transported with fats through the lymphatic system in chylomicrons before entering the blood. Fat-soluble vitamins can be stored in body fat, meaning that intakes can vary without a risk of deficiency (as long as there are average intakes over time). Because they can be stored in body fat, they are not easily excreted. This increases the risk of toxicity with high intakes. 19  Vitamin A 1st vitamin to be discovered Fat soluble Can get destroyed by exposure to light and oxygen Liver is the main storage site Fat tissue another storage site Retinol Binding Protein (RBP) is a transport protein that picks up Vitamin A from the liver and carries it in the blood 20  Vitamin A (Properties and Functions) Vitamin A occurs in 2 forms: 1) Retinoids (active form) - foods derived from animals i) retinol (supports reproduction) ii) retinal (participates in vision) iii) retinoic acid (regulates growth, normal development of bones and teeth, maintains tissues and skin) 2) Carotenoids (precursor form) - foods derived from plants - most common form is beta-carotene - carotene gets converted to Vitamin A Functions as an anti-oxidant 21  Vitamin A–Deficiency Symptom—Night Blindness In dim light, you can make out the A flash of bright light momentarily blinds details in this room. You are using you as the pigment in the rods is bleached. your rods for vision. You quickly recover and can see With inadequate vitamin A, you do not the details again in a few seconds. recover but remain blinded for many 22 seconds.  Vitamin A - Deficiency Xerophthalmia An eye disorder associated with Vitamin A deficiency Begins as night blindness Extreme dryness Progresses to wrinkling, cloudiness and softening of the cornea (keratomalacia) If left untreated, it can result in rupture of the cornea, infection, degenerative tissue changes, and permanent blindness 23  Vitamin A deficiency: Keratinization When Vitamin A is deficient, mature cells can’t differentiate normally Instead of mucous secreting cells, they become cells that produce keratin (a hard protein that makes up hair and nails). As the mucous secreting cells die and are replaced by keratin producing cells, the epithelial surface becomes hard and dry 24 Vitamin A–Deficiency Symptom—The Rough Skin of Keratinization 25  Vitamin A: toxicity Toxicity is called hypervitaminosis A – Nausea, vomiting, headache, dizziness, blurred vision, lack of muscle coordination – Bone defects, weak bones (prevents calcium absorption) – Birth defects if taken in excess during pregnancy – Increases tumor size in lung cancer patients – Medications made from Vitamin A (e.g. Retin A, Accutane) (dry, itchy skin, chapped lips, others) 26  Vitamin A Toxicity Beta-carotene toxicity – Not an actual toxicity, because not enough gets converted to Vitamin A to cause hypervitaminosis – Instead, excess gets stored in fat tissue – Skin turns yellow 27 Symptom of Beta-Carotene Excess – Discolouration of the Skin The hand on the right shows the skin discolouration that occurs when blood levels of B- carotene rise in response to a diet high in carrots, pumpkin, sweet potato, etc Left - normal 28  Vitamin A: toxicity Increase risk for bone fractures - a high intake of Vitamin A may inhibit the ability of Vitamin D to help the body absorb calcium - Too much Vitamin A may increase the risk of hip fractures in older women - Found that women with the highest total intake, from both food and vitamin supplements, had double the risk of hip fractures, compared with women with the lowest intake Conclusion: should not take vitamin A supplements 29  Vitamin A as a Drug Retin A (topical cream) and Accutane (taken orally) are derivatives of retinoic acid (Vitamin A) - Acts by increasing the turnover of cells - In patients with acne, new cells replace the cells of existing pimples, and the rapid turnover of cells prevents new pimples from forming - The medications can have serious side effects, including: - dry, itchy skin and chapped lips, - Irritated eyes, joint and muscle pain, decreased night vision, depression, increases in blood lipids - Pregnant women: deliver babies with severe birth defects (brain damage, physical malformations) - It is important to remember that these are drugs and should only be taken under the care of a physician 30  Vitamin A: RDA/dietary sources RDA: Male: 900 g/day UL: 3000 g/day Female: 700 g/day 12 µg of beta-carotene are equivalent to 1 µg of vitamin A. Therefore, RDA is stated in ug of RAE Best Dietary Sources: Vitamin A: Fortified Milk and milk products, liver, eggs, butter 1 cup milk: 145 4 oz liver: 8751 !!! 1 egg: 70 Beta-carotene: yellow/orange vegetables (1 cup carrots: 900ug) : dark green leafy vegetables 31  Vitamin A – dietary sources RDA – Male 900ug , Female 700ug 1 red 1 cup pepper spinach 116 ug 140 ug ½ cup squash 535 ug 1 carrot 1 sweet potato: 433ug 1096 ug 1 mango: 79 ug ½ cantelope: 466 ug 32 Vitamin A in Foods 33  Vitamin D Vitamin D can be obtained from food and the sun Animal version: Vitamin D3 (cholecalciferol) Plant version: Vitamin D2 (ergocalciferol, sunlight converts ergosterol (the provitamin form) to ergocalciferol Precursor form (cholesterol): 7 – dehydrocholesterol Active form (calcitriol):1,25 hydroxy Vit D3 Referred to as Vitamin D or calciferol Main Function: mineralization of bones (required for the absorption of calcium) 34  Vitamin D Synthesis and Activation In the skin: In the liver, Vit D (7- 7-dehydrocholesterol (a precursor made in the dehydrocholesterol) liver from cholesterol) can be made from Ultraviolet cholesterol (precursor) light from the sun Previtamin D3 Foods In it’s final Vitamin D3 (an inactive form) active form, cholecalciferol Vit D In the liver: Hydroxylation influences the 25-hydroxy vitamin D3 metabolism of: Ca and P In the Hydroxylation kidneys: The final (bone product , active 1,25-hydroxy vitamin D3 development) (calcitriol) form of Vitamin 35 (active form) D The precursor of Vitamin D is made in the liver from cholesterol. Cholesterol Vitamin D3 36  Vit D: Deficiencies 1) Children: rickets :‘beaded ribs’ called rachitic rosary : delayed closing of the fontanel 2) Adults: osteomalacia (adult form of rickets) 3) resistant rickets : inability to absorb Vit D Symptoms: weak, brittle bones; malformation of bones 37 Rickets of the knees - Bowing of the femur - increase in distance between end of shaft and epiphyseal center 38  Vitamin D deficiency in infants – delayed closing of fontanel This results in rapid enlargement of the head 39  Vitamin D deficiency in children ‘beaded ribs’ called rachitic rosary (results from poorly formed attachments of the bones to the cartilage) 40  Vitamin D: Toxicity Called hypervitaminosis D Not caused by diet or sunlight Vitamin D Supplementation Raises the [ ] of blood calcium Excess blood calcium accumulates in soft tissue, leading to calcification of soft tissues Kidney stones – because calcium is concentrated in the kidneys in the effort to excrete it Calcification may also harden the blood vessels 41  Vitamin D: Dietary Sources DRI: RDA – 15 (F), 20 (M) g/day UL – 100g/day Dietary Sources (animal sources) Best source: Fortified milk (cows milk not a good source unless fortified) Also: egg yolks, liver, fatty fish (salmon, sardines) 42 42 Vitamin D in Foods 43  Vitamin D: Non-Dietary Source Non-dietary source: sunlight exposing hands, face, arms for 10 to 15 minutes a few times per week is sufficient to maintain vitamin D nutrition Vitamin D stores from summer exposure is not sufficient to meet winter needs of Vitamin D sunscreen (SPF 8 or >) prevents Vitamin D synthesis Note: darker skin people make less Vit D on exposure to sunlight; 3 hours exposure = 30 min in fair skin people Depending on the radiation used (UVB rays between 290 and 310), tanning beds may provide vitamin D 44 44  Effects of Latitude on Sun Exposure During the winter, at latitudes greater than about 40 degrees north or south, there is not enough UV radiation to synthesize adequate amount of Vitamin D 45  Vitamin E Also called -tocopherol – Early in its discovery, researchers discovered a compound in vegetable oils necessary for reproduction in rats and named this “antis-terility factor” tocopherol, which means “to bring forth offspring” Vitamin E is sensitive to destruction by: – Oxygen – Metals, – Light – Heat – Some is lost during food processing, cooking, storage 46  Vitamin E Main Function: anti-oxidant i) Stabilizes cell membranes in the body (prevents cell destruction) Supplements are sold as “anti-aging” products (do they work?) ii) Protects PUFA’s and vitamin A from destruction in the body – In the body, the main carriers of -tocopherol are LDL and HDL 47  Vit E: Main Function Antioxidant -tocopherol reacts with compounds that have an upaired electron these compounds are called free radicals Vitamin E can protect cell membranes against the damaging effects of free radicals which may contribute to diseases such as cancer and CVD 48  Vit E: Functions By preventing oxidative damage, Vit E increases the stability of cellular and inter-cellular structures, particularly cell membranes Research suggests that oxidative damage to LDL promotes several steps in atherosclerosis, thus vitamin E may inhibit the oxidation of LDL or other free radical reactions 49  Free-Radical Formation and Antioxidant Protection Free-radical formation and damage 1 2 3 O2 (oxygen) 1 Occasionally, oxygen gains an extra electron from the 2 To regain its stability, electron transport chain, the free radical attacks 3 Left with an unpaired electron, this molecule thereby generating a free a nearby molecule (such becomes a free radical itself and attacks radical. as a lipid or protein) and another nearby molecule. The chain reaction steals an electron. continues, causing widespread damage. Antioxidant protection Active vitamin E 2 1 3 1 Antioxidants, such as 2 The destructive chain 3 Like vitamin E, vitamin C acts as vitamin E and C, neutralize free reaction is stopped, but an antioxidant; it also restores radicals by donating one vitamin E is no longer vitamin E to its active form. An of their own electrons. active. abundance of dietary antioxidants minimizes free-radical damage. 50 Antioxidant Mechanism of Vitamin E 51  Vitamin E: Deficiency/Toxicity Deficiency - red blood cell breakage - can result in anemia Toxicity Interferes with Vitamin K (blood clotting) Blood may not clot Research has also shown that Vitamin E supplementation increases the risk for heart disease (may act as a pro- oxidant rather than an anti-oxidant) (see next slide) 52 HOPE-TOO: Heart Outcome Prevention Evaluation –The Ongoing Outcome Trial Extension, 2005: JAMA 293;1338-1347 Heart Failure Hospitalization for Heart Failure Vit E Placeb o Vit E placeb o 7030 patients (55 yrs >) at high risk for CVD and/or diabetes, received 400 IU (267mg) Vitamin E or placebo Results: Vitamin E group had 19% higher risk for heart failure and a 40% higher risk of hospital admission due to heart failure 53 Vitamin E: DRI – RDA: 15 mg/day UL: 1000 mg/day Oils (1 tbsp) Wheat germ oil: 20 mg Safflower oil: 6 mg Sunflower oil: 6 mg Corn oil: 2 mg Olive oil: 2 mg Canola oil: 2 mg ¼ cup almonds 9 mg ¼ cup sunflower seeds: 9 mg ¼ cup peanuts: 2.6 mg Omega 3 egg (1): 7 mg Main Dietary Sources: vegetable oils, seeds, nuts, also green leafy vegetables 54 54 Vitamin E in Foods 55  Vitamin K: History 1930’s – Henrik Dam; discovered a hemorrhagic disease in newborn chickens By giving them pig’s liver, alfalfa, cabbage, and spinach, normal blood clotting time was restored It was suggested that the hemorrhaging was due to decreased levels of prothrombin (a compound required for normal blood clotting) He named the “blood clotting vitamin” Vitamin K (K for koagulation (Danish)) (coagulation – English) 1943 – shared a Nobel prize in medicine for his discovery (with Edward Doisy who isolated the chemical nature of Vitamin K) 56  Vitamin K Vitamin K: different forms 1) K1 (phylloquinone, phytonadione): natural form of Vitamin K; found in green plants 2) K2 (menaquinone): formed as the result of bacterial action in the intestinal tract 3) K3 (menadione – synthetic form) 2X as potent as K2 Our body can convert K3 to K2 4) naphthoquinone 57  Vitamin K: Main Function: Blood-Clotting Calcium and thromboplastin Fibrinogen Vitamin K (a phospholipid) (a soluble protein) from blood platelets Several precursors Prothrombin Thrombin earlier in the series (an inactive protein) (an active enzyme) depend on Vit K Fibrin Vitamin K is essential for synthesis of (a solid clot) prothrombin (and several other proteins) involved in blood clotting Vitamin K deficiency: Hemorrhaging (bleeding) 58 Vitamin K: Main Function: Blood- Clotting Simplified version of previous slide 59  Vitamin K: Deficiency Usually occur from: i) inadequate absorption from the intestinal tract ii) an inability to utilize it in the liver (eg. Liver disease) Newborn infants are susceptible to prothrombin deficiency (during the first few days of life) This is due to poor placental transfer of Vit K Newborn infants are given Vit K1 injections immediately after birth 60  Vitamin K: deficiencies Secondary deficiencies can result from: 1) antibiotics – because they reduce bacterial synthesis 2) anticoagulant drugs and aspirin – because they are antagonists to Vitamin K – Prescribed to patients with CVD to prevent blood from clotting) 3) anticonvulsant drugs – they increase the rate which Vitamin K is metabolized and eliminated 4) intestinal surgery – bacterial synthesis and absorption will decrease Toxicity: none 61  Vitamin K: Dietary Sources Males: 120 ug/day Females: 90 ug/day Best dietary source: Green leafy vegetables Broccoli – has a lot!!!! 160 ug/cup Also milk, eggs, kiwi, soybean oil Other sources: Bacterial synthesis in the digestive tract provides 40 to 70% of what the body requires 62 62 Vitamin K in Foods 63 A Summary of the Fat-Soluble Vitamins 64  Label Literacy About 40% of Canadian adults use vitamin and mineral supplements. You can purchase almost any nutrient as an individual supplement or you can choose from a number of combinations of nutrients, herbs and other components. Health Canada regulates minimum and maximum doses of vitamins and minerals that are permitted in a supplement. The maximum allowable dose is usually the UL. 65  Label Literacy The information included on supplement labels can be used to determine if a supplement includes the nutrients that you want and whether they are present in appropriate amounts. Supplements can be part of an effective strategy to promote good health for those individuals who require them, but they should never be considered a substitute for other good health habits (e.g. healthy diet) and should never be used instead of medical therapy. 66