Unit 9 Vitamins PDF

Vitamins UNIT 9 NUTR 1100- Introduction to Nutrition Learning Objectives Differentiate between water-soluble and fat-soluble vitamins Role of vitamins in health and disease How to plan a diet to meet vitamins recommendations Vitamins Micronutrient: essential in small amou...

Vitamins UNIT 9 NUTR 1100- Introduction to Nutrition Learning Objectives Differentiate between water-soluble and fat-soluble vitamins Role of vitamins in health and disease How to plan a diet to meet vitamins recommendations Vitamins Micronutrient: essential in small amounts Essential nutrients: required in the diet since not synthesized by the body Organic compound that contains carbon Types of Vitamins Water soluble- act in extracellular fluids such as blood Fat soluble- protect cell membranes from oxidative damage Some are non-essential vs others need to obtained from diet Types of Vitamins Water-Soluble Vitamins (B&C) Absorption: small intestine > hepatic artery > liver Not stored in the body supplies can get depleted Must be consumed regularly (i.e daily) BUT it does take more than a few days to get a deficiency It can take years because there is a working amount in each cell Excess intake Removed from body via urine Some don’t have UL but some can still have toxic symptoms. B vitamins Vitamin B1 = Thiamine Vitamin B2 = Riboflavin Vitamin B3 = Niacin Vitamin B5 = Pantothenic Acid Vitamin B6 = Pyridoxine Vitamin B7 = Biotin Vitamin B9 = Folic Acid (Folate) Vitamin B12 = Cobalamin Fat soluble vitamins (A,D,E &K) Found in fats in foods Absorption: along with dietary fat> small intestine> chylomicrons> Lymphatic system>liver Stored in the body (liver and fatty tissues) Excess intake Cannot be removed via urine Intakes can vary without a risk of deficiency if average intake over weeks/months meets needs High prevalence of toxicity (UL high) Vitamin Bioavailability Bioavailability: the extend to which the body can absorb & use a nutrient. About 40-90% of vitamins in food are absorbed. Absorption occurs mainly in small intestine. Influenced by: composition of diet / food naturally in foods vs. supplement conditions in digestive tract Vitamin Bioavailability Factors influencing bioavailability: Absorption Fat-soluble vitamins: need dietary fat Transport in blood Water-soluble vitamins: blood proteins Fat-soluble vitamins: chylomicrons Conversion of inactive provitamins or vitamin precursors into active vitamins Vitamin Functions promote and regulate body processes necessary for growth, reproduction & maintenance of health promote & regulate body’s activities act as coenzymes act as antioxidants protecting the body against free radicals does not provide energy  Vitamin Functions Oxidative damage – Antioxidants- A, C, E, K © Can Stock Inc./chris74 Blood Vitamins- Immunity- A, B6, C, Folate, vitamin B6, and D, folate © Can Stock Inc./leungchopan vitamin B12, and vitamin K © Can Stock Inc./Romanenko/Alexey  Vitamin Functions growth & development- A and D produce ATP- B complex © Can Stock Inc./BenSilva protein & amino acid bone health- A, C, metabolism- Folate, B6 & D&K B12 © iStockphoto.com/Jana Lumley Vitamins in Foods What foods contain vitamins? Factors: whole vs. refined foods (nutrient density); location & processing. Some food groups lack specific vitamins important to eat a balanced, varied diet from all food groups. Vitamins added to foods Vitamin fortification Vitamin enrichment Adds nutrients to foods. Add nutrients back to food Government regulated that were lost during (mandatory and voluntary) processing e.g., heat, refining. Aims to prevent deficiencies leading to diseases toxicity false sense of security (healthfulness of food. Example: Flour in Canada Bran: (outer layer) fibre, iron, B vitamins Germ: Fat, B Vitamins, Iron, Protein Endosperm: starch & gluten (protein) Flours in Canada: Enriched White Free of bran coat & germ Enriched thiamin, riboflavin, niacin, iron & folic acid Whole Wheat Flour No less than 95% of kernel 85% endosperm 10% bran Whole Grain Flour Includes, bran, endosperm & germ Which choice is highest in vitamins? Fresh vegetables or frozen vegetables? Frozen/canned - minimal nutrient losses. Less expensive Longer shelf life Fresh- lower in nutrients as the they lose when travelling in a truck, storage unit, on the store shelf and then in your refrigerator Cooking methods/storage Dietary Reference Intakes (DRIs) Canadian & American nutrient requirements recommendations: Estimated Average Requirements (EARs) Recommended Daily Allowances (RDAs) Adequate Intakes (AIs) Tolerable Upper Intake Limits (ULs) Review - DRIs: EAR, RDA, & UL B Vitamins Water soluble Discussed as a group because share many similarities Energy metabolism. Help cells divide Often at risk for alcoholics. poor intake alcohol interferes with some of them. vitamins used in alcohol metabolism (break down) Rely on each other for activation Overdosing on one can mask a deficiency of another Come from similar foods except Vitamin B12 Folate (Folic Acid) Functions: promotes formation of RBC’s and protein tissue formation Intake: Poorly absorbed from food 100% absorbed from supplements Deficiency: Megaloblastic anemia (low no. of RBC and hence lack of O2) Neural tube develops about 20 days post conception ↓ folate ↑ risk neural tube defect (spina bifida). 50%+ pregnancies unplanned. Canadian Recommendations: Women of child bearing age: 400 mcg (0.4 mg) supplement daily. Folate (folic acid deficiency: neural tube defects Neural tube defects: Abnormalities in the brain or spinal cord resulting from errors occurring during prenatal development. If a lower portion of the neural tube does not close normally, the result is spina bifida. Custom Medical Stock Photo, Inc. National Medical Slide Bank/  Folate (folic acid) deficiency: megaloblastic (macrocytic) anemia Deficiency: the abnormally large immature red blood cells, megaloblasts, maturing into abnormally large red blood cells called macrocytes that carry less oxygen and lead to anemia. Food sources Vitamin B12 Functions: DNA & RNA production Myelin sheath on nerve fibres Bone metabolism Energy metabolism… especially fatty acids Food Sources: Animal sources Nutritional yeast Fortified foods Digestion: B12 comes bound to proteins Requires HCl, pepsin, & R- factor (saliva) intrinsic factor (IF) 30% of adults 50+ have impaired absorption  need supplement Stored in liver Vitamin B12 Deficiency: Takes a long time to develop Most common in: Low intake i.e. vegans – supplements may be necessary Inadequate absorption (elderly) - monthly injection Symptoms Pernicious anemia Neural damage, numbness and tingling in extremities, inflammation of tongue & oral mucosa Canadian recommendations: Those at risk make significant effort to take fortified foods. Food sources of Vitamin B12 Vitamin D Made in skin exposed to ultraviolet (UV) light Inactive until modified in liver & kidneys Essential in the diet only when exposure to sunlight is limited or the body’s ability to synthesize it is reduced Dietary sources: Fish, Eggs Milk and other dairy (fortified in Canada) Functions of Vitamin D Vitamin D: Reduced Synthesis  UV exposure affected  Excessive use of sunscreen  Dark skin pigmentation by season & latitude.  Concealing clothing  Insufficient time spent outdoors Vitamin D: Functions Maintains normal levels of the minerals calcium and phosphorus in the blood bone health and nerves, muscles, glands, and other tissues Changes gene expression Intestines: turns on genes for calcium absorption Bone: turns on genes bone breakdown Prevention of cancer and inflammatory diseases – inconclusive Vitamin D: Deficiency Main causes of rickets: inadequate calcium absorption due to little sun exposure, fat malabsorption and vegan diet combined with too little sunlight. Antioxidants Common word in marketing of foods & cosmetics, but what does it mean? Structure of Atoms Atom: the smallest unit of matter Atoms are composed of particles Nucleus—positively charged center portion of the atom Electrons—negatively charged particles surrounding the nucleus Formation of Free Radicals Figure 8.4  Antioxidants Cells are made of molecules which, when assaulted loose an electron that makes them unstable which can cause damage to the cell…to the organ… to the body. Damaged cells are called free radicals. Antioxidants are molecules that can provide an electron to a free radical and still remain stable. What Causes Free Radicals? What can a Free Radical do? Depends where the damage is, in the body: Heart disease Hypertension, emphysema, atherosclerotic disease Inflammatory diseases Rheumatoid arthritis. Kidney disease, lupus Neurologic disease Alzheimer's, Parkinson's, Muscular Dystrophy Carcinogenesis (cancer) Aging… skin and systems Due to damage to DNA, proteins & lipids How do Antioxidants work? Antioxidants provide 3 lines of defense: Preventative action Scavenger action Repair action Each antioxidant has a specific range of action For e.g., Vitamin E is fat soluble  defends body again LDL oxidation protecting against plaques that block blood vessels Vitamin C is water soluble  protects saliva surfaces (i.e. mouth, larynx, esophagus) against cancer in smoking Can we eat ourselves healthy? Antioxidants are not a silver bullet They are associated with reduced risk of disease Each disease is multifactorial in origin Lack of antioxidants  disease Too many antioxidant supplements  disease Eat a balanced, varied diet from all food groups  Vitamin Supplements Supplements should be taken with caution. Potential problems: Too much of one can mask deficiencies of another If intake is unbalanced – can cause deficiency of another nutrient. Some nutrients interact in the GI tract – no benefit! Too much – body can’t absorb it. $$$$$$$$$ Billions spent  better used on food? Beneficial when there’s a specific need/deficiency.