Micronutrients: Vitamins and Minerals (ANT1005) - PDF

Nutrition and Health (ANT1005) © 123RF.com TOPIC 5: MICRONUTRIENTS  LEARNING OBJECTIVES 1. Distinguish between the two categories of vitamins: fat-soluble water-soluble 2. Distinguish between the two categories of minerals: ma...

Nutrition and Health (ANT1005) © 123RF.com TOPIC 5: MICRONUTRIENTS  LEARNING OBJECTIVES 1. Distinguish between the two categories of vitamins: fat-soluble water-soluble 2. Distinguish between the two categories of minerals: major/macro minerals minor/micro minerals 3. Identify the food sources of vitamins and minerals. 4. Explain factors affecting the bioavailability of minerals. 5. Explain the functions of vitamins and minerals to health. 6. State the dietary recommendations for vitamins and minerals to health. 7. Describe the effects of deficiency and toxicity of vitamins and minerals.  Key concepts to focus on 1. Types of vitamin: Fat-soluble vs Water-soluble 2. Classification of mineral: Major minerals vs Trace minerals 3. Each vitamin and mineral: Function Food sources Bioavailability Deficiency Toxicity No need to remember the amount of RDA  Definition Vitamins are: Organic compounds Essential nutrients, meaning the body cannot produce enough of them on its own. Inadequate intake from the diet can lead to deficiency symptoms. Not energy-yielding (do not provide calories) Required in small amounts (micronutrients) to support specific functions that promote growth, reproduction, and the maintenance of health and life  GENERAL FACTS & OVERVIEW Categorizing Nutrients: based on their molecular structures ORGANIC INORGANIC (contain C-C or C-H bonds) (does not contain C-C or C-H bonds) Carbohydrates Minerals Proteins Water Lipids Vitamins  Comparison Vitamins are different from CHO, proteins & lipids in the following ways: Structure - vitamins are individual units, not made up of subunits linked together Function - vitamins are not energy yielding but they assist enzymes that release energy from CHO, fats & protein Content in food - the amounts of vitamins people ingest daily from foods & the amount they require are very small, measured in mg or μg  TO QUALIFY AS A VITAMIN Body must be unable to synthesize the compound Absence from the diet for a defined period of time will produce deficiency symptoms  VITAMINS IN FOODS Vitamins are found naturally in fresh foods & can be added to processed foods Some of the vitamins in foods are present in inactive forms known as precursors or provitamins Once inside the body, precursors are changed to the chemically active form of the vitamin (e.g. from beta- carotene to vitamin A) Beta-carotene Vitamin A (inactive) (active) ADDITION OF VITAMINS IN FOODS ENRICHMENT FORTIFICATION Addition of vitamins to Addition of vitamins that replace the loss during were not originally present processing so that a food or present in insignificant will meet a specified amounts in a food standard Fortification can be used to correct/prevent a widespread nutrient deficiency or to balance the total nutrient profile of a food  ADDITION OF VITAMINS IN FOODS ENRICHMENT FORTIFICATION Wheat flour, bread, unenriched, Wheat flour, white, all purpose, 100 g contains 0.08 mg Vit B1, 0.06 100 g contains 15 mg calcium mg Vit B2, 1.0 mg Vit B3 Wheat flour, bread, enriched, Wheat flour, white, all purpose, 100 g contains 0.81 mg Vit B1, calcium-fortified 0.51 mg Vit B2, 7.5mg Vit B3 100 g contains 252 mg calcium  BIOAVAILABILITY Definition: Rate & extend to which a nutrient is absorbed & used by the body Factors affecting bioavailability: Efficiency of digestion & time of transit through the GI tract (affects absorption) Previous nutrient intake & nutrition status Other foods consumed at the same time can inhibit or enhance absorption Method of food preparation (raw, cooked, processed) Source of the nutrient (synthetic, fortified or naturally occurring)  TOXICITY Some vitamins taken in huge amounts can cause toxicity Fat-soluble vitamins A & D are not readily excreted, they easily accumulate in the body & cause toxic effects The Committee on Dietary Reference Intakes has established Tolerable Upper Intake Levels = the highest amount of a nutrient that is likely not to cause harm for most healthy people when consumed daily Adult, Male, 18 Singapore RDA US DRI Tolerable Upper years old Intake Level Vitamin C 105 mg 75 mg 2000 mg  More is better? Better Better (1) (2) More More Better (3) More  How much Ascorbic Acid? 1000 mg  CLASSIFICATION Vitamins were named alphabetically as they were discovered: A, B, C, D, E & K Can be classified into two groups based on solubility Fat-soluble: Vitamins A, D, E & K Water-soluble: B vitamins (B1 thiamin, B2 riboflavin, B3 niacin, biotin, pantothenic acid, vitamin B6, folate, vitamin B12) & vitamin C  COMPARISON Fat Soluble Water Soluble occur together in the found in the watery In food fats & oils of food compartment of food enter the lymph, then move directly into the Absorption the blood blood require protein In the blood travel freely carriers Upon freely circulate in water- held in fatty tissues & reaching filled compartments of liver until needed tissues/ cells the body  COMPARISON Fat Soluble Water Soluble Remain in fat storage Kidneys detect & Excretion sites, not excreted remove small excesses Less likely (but possible) More likely to reach to reach toxic levels Excess intake toxic levels when when consumed in consumed in excess excess Stored in the body. Retained for varying Eaten in large periods. Must be eaten Retention amounts once in a more regularly to meet while still meet body’s body’s needs needs FAT SOLUBLE VITAMINS VITAMIN A FOOD SOURCES ANIMAL-BASED Foods derived from animals provide: Preformed vitamin A / Retinoids The main form of retinoid from food is retinyl esters, which is absorbed as retinol in the small intestine These 3 are the active forms of vitamin A, collectively known as retinoids The body converts Retinol Retinal Retinoic acid (reversible) (irreversible) Good sources are beef liver, dairy products, fish liver oils, butter, eggs, fish like tuna, sardines. Also vitamin A-fortified milk & margarine  VITAMIN A FOOD SOURCES PLANT-BASED Foods derived from plants provide: Provitamin A carotenoids There are more than 600 carotenoids, fewer than 10% exhibit vitamin A activity (i.e. can be converted to retinol) Three important provitamin A carotenoids are β–carotene, α- carotene & β–cryptoxanthin, which are absorbed as free carotenoids in the small intestine Other common dietary carotenoids are lycopene, lutein & zeaxanthin. They form the yellow, red & orange pigments in fruits & vegetables Good sources are sweet potato, carrots, spinach, apricots, broccoli, cantaloupe, papaya, mango, pumpkin  VITAMIN A FORMS & FUNCTIONS FROM Retinyl esters β-Carotene FOOD from animal sources from plant sources Retinoic IN THE Retinol Retinal acid BODY Important role Important role in Important role in reproduction promoting vision in regulating growth VITAMIN A BIOAVAILABILITY The efficiency of absorption: 70-90% for preformed vitamin A, as long as the meal contains some fat 20-50% for provitamin A carotenoids Affected by food processing e.g. < 5% absorbed from raw vegetables or non-heat processed vegetable juices Absorption also  with  fiber intake. VITAMIN A FUNCTIONS 1. Proper development of cells (especially to maintain health of epithelial tissues & skin) 2. Promoting vision (retinal) 3. Supports reproduction & growth 4. Antioxidant properties (carotenoids) VITAMIN A FUNCTIONS Proper Development of Cells Vitamin A maintains the normal structure & functions of epithelial cells Epithelial cells cover external & internal body surfaces External body surface = skin Internal body surface = mucous membranes, lining the mouth, stomach, intestine, lungs, urinary system, reproductive system With vitamin A deficiency, mucous secreting cells are replaced by other cells ➔ epithelial cells lose their protection from invading microorganisms & harmful substances like stomach acid  VITAMIN A FUNCTIONS Promoting Vision 1. Vitamin A helps maintain a crystal-clear cornea by maintaining the normal structure & functions of corneal epithelial cells, prevents corneal drying, softening of the cornea, corneal degeneration & blindness Carotenoids protect against oxidative damage from sunlight  VITAMIN A FUNCTIONS Promoting Vision 2. Vitamin A (retinal) forms part of the pigment in the retina (rhodopsin) which participates in the conversion of light energy into nerve impulses that caries visual information to the brain This allows detection of light (light-dark vision / prevents night blindness) as well as colour vision VITAMIN A FUNCTIONS Reproduction In men, retinol participates in sperm development In women, retinol supports normal fetal development during pregnancy Growth Necessary for growth, especially growth of the epithelial cells Essential for bone growth VITAMIN A FUNCTIONS Antioxidant Properties Free radicals are molecules with one or more unpaired electrons. Become unstable free radical itself, starting a chain reactions and attack cells & cause widespread damage Antioxidants neutralize free radicals by donating one of their own electrons This ends the chain reaction Although they lose an electron, they do not become free radicals themselves because they are stable in either form VITAMIN A FUNCTIONS Antioxidant Properties Carotenoids can function as antioxidants β-carotene & other carotenoids like lycopene, α-carotene, β- cryptoxanthin & zeaxanthin have antioxidant properties Adequate intake of antioxidants may be protective against diseases such as cardiovascular disease, cancer & age-related macular degeneration (a common cause of blindness) VITAMIN A RECOMMENDED DIETARY ALLOWANCES (RDA) Retinol Equivalents (µg RE/day) Adult Men 750 Adult Women 750 VITAMIN A DEFICIENCY Vitamin A is stored in the liver If a person were to stop eating vitamin A containing foods, deficiency symptoms would not appear until the stores are depleted: 1-2 years in a healthy adult, much sooner in growing children The consequences are profound & severe One of the developing world’s major nutrition problem More than 100 million children worldwide have some degree of vitamin A deficiency, & so are vulnerable to infectious diseases & blindness. VITAMIN A DEFICIENCY WHO ARE AT RISK Premature infants Infants and young children in developing countries Pregnant and lactating women in developing countries Alcoholics & people with liver disease Individuals with AIDS Individuals with severe intestinal disease and fat malabsorption VITAMIN A DEFICIENCY SYMPTOMS 1. Night Blindness One of the first detectable signs of vitamin A deficiency The retina does not receive enough retinal to regenerate the visual pigments (rhodopsin) The person loses the ability to recover promptly from the temporary blinding that follows a flash of bright light OR to see after the lights go out VITAMIN A DEFICIENCY SYMPTOMS 2. Blindness (XEROPHTHALMIA) Total blindness is due to lack of vitamin A at the cornea. The normal structure & functions of corneal epithelial cells are not maintained. Develops in stages: cornea becomes dry & hard (xerosis) softening of the cornea (keratomalacia) degeneration & irreversible blindness (xerophthalmia) VITAMIN A DEFICIENCY SYMPTOMS Blindness (XEROPHTHALMIA) http://s160131.gridserver.com/wp-content/uploads/2013/04/5492473278_c771ae3f53_o.jpg VITAMIN A DEFICIENCY SYMPTOMS 3. Keratinization With vitamin A deficiency, mucous secreting cells of the epithelium are replaced by keratin secreting cells (keratin = hard inflexible protein found in nails & hair) Mucus production : the skin becomes dry, rough & scaly vision is affected (see xerophthalmia) VITAMIN A DEFICIENCY SYMPTOMS 4. Susceptibility to Infections Changes in the epithelial cells: weakens mucosal barriers/defenses, digestion & absorption from the GI tract is affected other epithelial tissues weaken ➔more susceptible to infections Immunity is compromised Vitamin A influence other aspects of the immune system function – e.g. phagocytic activity, antibody response In many developing countries, measles & other infectious diseases kill many children Vitamin A supplementation protects against the complications & reduce the risk of dying from these infections VITAMIN A TOXICITY Toxicity is possible when: a person takes large amounts of preformed vitamin A /retinoids from animal sources, fortified foods or supplements Hypervitaminosis A Acute: changes in vision, changes in consciousness, headache, nausea, vomiting Chronic: bone pain, liver damage/ liver abnormalities, vision problems, fatigue, malaise Children are most vulnerable because they need less & are more sensitive to overdoses VITAMIN A TOXICITY Serious effects: Bone defects as excessive intake over the years weaken the bones & contributes to fractures & osteoporosis Birth defects if taken excessively in early pregnancy, due to teratogen effect US Upper Levels (Adults): 3000 μg per day VITAMIN A TOXICITY Toxicity is not possible through: Overconsumption of natural β-carotene Not converted efficiently enough to cause toxicity Stored in the fat under the skin & may turn the skin yellow but this is harmless However, overconsumption of β-carotene from supplements may be harmful. At high levels of intake, this antioxidant becomes a prooxidant ➔adverse effects  12,500 μg per softgel US Upper Levels (Adults): 3000 μg per day VITAMIN D FOOD SOURCES ANIMAL-BASED Dietary vitamin D is obtained primarily from animal sources in the form of vitamin D3 (cholecalciferol) Good sources: liver, beef, veal, eggs, dairy products (milk, cheese), butter, some fish like salmon, tuna, sardines. Also vit D-fortified milk & margarine  VITAMIN D FOOD SOURCES PLANT-BASED From plant sources in the form of vitamin D2 (ergocalciferol) Sources: mushrooms, cereals & especially vitamin D- fortified cereals Vitamin D requirements and nutritional analysis are sometimes listed in international units (IU). For conversion purposes, 1μg is equal to 40 IU of vitamin D VITAMIN D BIOAVAILABILITY From food, about 80% of vitamin D is absorbed The presence of adequate dietary fat is essential for absorption Dietary sources not necessary if exposed to sunlight Vitamin D can be considered a non- essential nutrient!  VITAMIN D ACTIVATION For your information only  VITAMIN D FUNCTIONS Vitamin D is actually a hormone! Three important functions of vitamin D: 1.Promoting normal cell differentiation, proliferation & growth e.g. bone cells, blood cells, intestinal epithelial cells 2.Modulating neuromuscular & immune functions, reduce inflammation 3.Calcium homeostasis  VITAMIN D FUNCTIONS Vitamin D & Strong Bones Increases absorption of calcium into the small intestine to maintains adequate serum calcium & phosphorous levels This prevents the release of calcium from the bones into the serum Allowing for normal bone mineralization through the deposition of calcium salt crystals VITAMIN D RECOMMENDED DIETARY ALLOWANCES (RDA) Vitamin D (µg /day) ≥ 18 years old 2.5 μg (100 IU) Interesting fact: RDA for 19 to 70 years old in US is 15μg of Vitamin D IU refers to International Unit VITAMIN D From the sun… Did you know? Melanin pigment in dark skin provides natural protection against the absorption of UV rays, which is why people with darker skins need greater sun exposure to make the same amount of Vitamin D VITAMIN D DEFICIENCY WHO ARE AT RISK People with limited sun exposure Individuals with darker skin Breastfed infants Older adults People with obesity Individuals with certain medical conditions such as chronic kidney or liver diseases, fat malabsorption disorders VITAMIN D DEFICIENCY Children & Adolescents A bone disease called rickets failure of bones to properly mineralize bones weaken (soft bones) & bow under pressure causing growth retardation & skeletal abnormalities VITAMIN D DEFICIENCY Adult Dark-skinned adults living in northern regions are particularly vulnerable Osteomalacia: softening of the bones Progressive bone With vitamin D Triggers demineralization as deficiency, serum PTH serum calcium levels calcium  release cannot be maintained Osteoporosis: “porous bone” VITAMIN D DEFICIENCY Elderly The skin, liver & kidney functions lose their capacity to make and activate Vitamin D with advancing age They typically consume little or no milk & other dairy products They spend much of their time indoors, when they venture out, they typically wear protective clothing VITAMIN D TOXICITY Of all vitamins, vitamin D is the most likely to cause toxic effects when consumed in excess → Hypervitaminosis D Nonspecific symptoms: nausea, vomiting, poor appetite, constipation, weakness & weight loss Serious effects: raised blood levels of calcium ➔calcification of soft tissues (blood vessels, kidneys, heart) mental status changes (confusion) heart rhythm abnormalities Mainly from the use of supplements VITAMIN D TOXICITY Not possible from excessive sun exposure because body regulates the amount synthesized & activated prolonged sun exposure destroys vitamin D precursor Tolerable Upper Intake Levels (ULs) for Vitamin D Source: National Institutes of Health, Office of Dietary Supplement VITAMIN E FORMS First identified as a component of vegetable oil necessary for reproduction in rats Called tocopherol = to bring forth offspring Tocopherols - α, β, γ, δ Tocotrienols - α, β, γ, δ All differ in chemical & physical properties -tocopherol is the only one with vitamin E activity in the human body VITAMIN E FOOD SOURCES Vitamin E is widespread in plant & animal foods The richest sources are oils from plants (vegetable oils) : canola, olive, sunflower, safflower & products made from them (salad dressings, mayonnaise, margarine) Also in nuts & seeds (products like peanut butter), whole grain cereals (esp the bran & germ parts, thus products like wheat germ & wheat bran), legumes, some fruits & green leafy vegetables From animal sources: liver, egg yolk, fatty meats VITAMIN E BIOAVAILABILITY The extent of absorption of vitamin E is unclear, ranging from 20 – 80% Depends on the simultaneous digestion & absorption of dietary fats Absorption hindered by dietary fiber (> 3% pectin or >20% wheat bran) Vitamin E is easily destroyed by oxidation & heat- processing (i.e. deep frying). Go for fresh or lightly processed foods  VITAMIN E FUNCTIONS As an antioxidant 1. Maintains membrane integrity Prevents oxidation of unsaturated fats in the phospholipid bilayer especially important for red blood cells 2. Complementary roles with other antioxidants like vitamin C, carotenoids & selenium May protect against diseases like cardiovascular disease, cancer & age-related macular degeneration  For your information only EXTRACELLULAR FLUID DAMAGED PHOSPHOLIPIDS PHOSPHOLIPIDS VITAMIN E FATTY ACID TAILS GLYCEROL HEADS NEUTRALIZED FREE RADICALS FREE RADICALS Cell membranes are made up of two layers of phospholipids, arranged in orderly INTRACELLULAR FLUID manner to form a bilayer VITAMIN E RECOMMENDED DIETARY ALLOWANCES (RDA) United State (US) Adult Men & Women 15 mg (22.5 IU) Based only on α-tocopherol UL (adults) = 1000 mg (1500 IU) ** No RDA of Vitamin E for Singapore population. VITAMIN E DEFICIENCY Rare in healthy adults WHO ARE AT RISK??? Premature infants People with fat malabsorption Symptoms Neuromuscular dysfunction involving spinal cord & retina of the eye – loss of muscle coordination & reflexes, impaired speech, impaired vision VITAMIN E DEFICIENCY Serious Consequence: Erythrocyte hemolysis Red blood cells break open & spill their contents due to oxidation of PUFA in their membranes Seen in premature infants (before transfer of vitamin E from mother to baby which occurs in the last weeks of pregnancy) VITAMIN E TOXICITY Vitamin E seems to be one of the least toxic of the vitamins Reports of vitamin E toxicity are rare Excessive amounts can inhibit the role of vitamin K in the blood clotting mechanism causing increased tendency for bleeding/hemorrhage VITAMIN K FORMS Vitamin K (K for koagulation, Danish for coagulation or blood clotting) Naturally occuring in two forms: Vitamin K1 (phylloquinone) from plants Vitamin K2 (menaquinones) from bacterial synthesis VITAMIN K FOOD SOURCES The richest & main plant sources are spinach, some salad greens, broccoli, watercress, kale Oils & margarine especially soybean, olive & products made from these Smaller amounts in cereals, fruits, dairy products, meat Exposure to light & heat destroys vitamin K Absorption enhanced by the presence of dietary lipids VITAMIN K FROM BACTERIAL SYNTHESIS Vitamin K2 (menaquinones) from bacterial synthesis especially in the colon not sufficient to meet the needs of children/ adults  VITAMIN K FUNCTIONS 1. Blood Clotting Vitamin K activates the proteins that form clots and stops bleeding Clotting Factors For your information only Several precursors earlier in the series depend on Vitamin K An inactive protein An active protein An active protein that forms a solid clot A cut, blood exposed to air Formation of Platelet Plug Development of Clot VITAMIN K FUNCTIONS 2. Bone Mineralization Vitamin K participates in the synthesis of bone proteins → Osteocalcin Without vitamin K, osteocalcin cannot bind to the minerals to form strong bones Resulting in low bone density Vit K Calcium Inactive Active Osteocalcin Osteocalcin Calcium incorporated into bone VITAMIN K RECOMMENDED INTAKE US (µg/day) Adult (19 - > 70 years) Men 120 Women 90 ** No RDA for Vitamin K for Singapore VITAMIN K DEFICIENCY Not common in adults When deficiency occurs, it can be fatal ➔hemorrhage May occur with: Fat malabsorption Some drugs disrupt vitamin K’s synthesis & action Antibiotics — destroy vitamin K producing bacteria in the intestine Anticoagulant drugs — interferes with vitamin K metabolism & activity VITAMIN K DEFICIENCY More likely in newborn infants Sterile GI tract Vitamin K-producing bacteria take weeks to establish themselves Plasma prothrombin concentration low Usually given vitamin K injection to prevent hemorrhagic disease in the newborn VITAMIN K TOXICITY Toxicity is not common UL not established There are risk of concern in certain High doses can reduce effectiveness of anticoagulant drugs used to prevent blood clotting People taking Warfarin should reduce intake of vitamin K rich foods and keep their intakes consistent from day to day Water Soluble Vitamins Nutrition and Health (ANT1005) Water Soluble Vitamins The B Vitamins Thiamin (B1) Riboflavin (B2) Niacin (B3) Pantothenic Acid (B5) B-COMPLEX Pyridoxine (B6) Biotin (B7) Folate (B9) Cobalamin (B12) Vitamin C  B Vitamins Play essential roles in energy production, brain function, and maintaining healthy cells. B vitamins function as key components of coenzymes, which assist enzymes in performing biochemical reactions. Energy Metabolism: Coenzymes derived from B vitamins (e.g., NAD+ from B3 and FAD from B2) help break down carbohydrates, fats, and proteins into energy. DNA and Cell Function: B9 (folate) and B12 (cobalamin) are vital for DNA synthesis, cell division, and red blood cell production. Without B vitamins, key enzymatic reactions in the body would slow down or stop, affecting energy levels, cell repair, and overall health. NAD+ refers to Nicotinamide Adenine Dinucleotide; FAD refers to Flavin Adenine Dinucleotide  THIAMIN (Vitamins B1) FUNCTIONS 1. Part of coenzyme TPP (thiamin pyrophosphate) which assists in energy metabolism of all cells 2. Thiamin occupies a special site on the membranes of nerve cells – neuromuscular processes depend on thiamin  THIAMIN (Vitamins B1) DIETARY SOURCES Richest source: Pork Wholegrains, meat and fish Other good sources: Fortified/ enriched cereals and bread Milk For your information only Bread has 20%–30% less Vit B1 Soymilk than its raw ingredients as heating it reduce Vit B1 content Sunflower seeds  THIAMIN (Vitamins B1) BIOAVAILABILITY Absorption from foods primarily in the jejunum absorption increases when intakes are low Anti-thiamin factors may destroy thiamin: thiaminase in raw fish (which can be inactivated by cooking) polyphenols like tannic & caffeic acids in coffee, tea Easily destroyed by heat e.g. during prolonged cooking Sensitive  THIAMIN (Vitamins B1) RECOMMENDED DIETARY ALLOWANCE (RDA) Singapore RDA mg/day 18-30 yrs 1.18 Men 30-60 yrs 1.16 18-30 yrs 0.84 Women 30-60 yrs 0.86  THIAMIN (Vitamins B1) DEFICIENCY Can happen to people who fail to eat enough nutritious food to meet energy needs Alcoholics are at risk Prolonged deficiency results in the disease beriberi Dry beriberi – damage to the nervous system, leading to muscle weakness in the arms and legs Wet beriberi – damage to the cardiovascular system, leading to dilated blood vessels which cause the heart to work harder and kidney to retain salt and water, resulting in edema  THIAMIN (Vitamins B1) TOXICITY No adverse effects have been reported with excesses of thiamin No UL has been determined RIBOFLAVIN (Vitamins B2) Flavus means “yellow” in Latin It becomes fluorescent when it comes into contact with UV light  RIBOFLAVIN (Vitamins B2) FUNCTIONS FAD FADH2 FMN FMNH2 Part of two important coenzymes: 1. Flavin mononucleotide (FMN) 2. Flavin adenine dinucleotide (FAD) that participate in many energy-yielding metabolic pathways, acting as electron/hydrogen donors & acceptors in many oxidation-reduction reactions  RIBOFLAVIN (Vitamins B2) DIETARY SOURCES Richest source: Milk & milk products (cheese & yoghurt) Other good sources: Beef liver, steak Clams, oysters Whole/enriched grains Fortified cereals Eggs  RIBOFLAVIN (Vitamins B2) BIOAVAILABILITY About 95% of riboflavin from foods is absorbed Easily destroyed by ultraviolet light and radiation Stable to heat Sensitive Sensitive  RIBOFLAVIN (Vitamins B2) RECOMMENDED DIETARY ALLOWANCE (RDA) Singapore RDA mg/day 18-30 yrs 1.77 Men 30-60 yrs 1.74 18-30 yrs 1.26 Women 30-60 yrs 1.29  RIBOFLAVIN (Vitamins B2) DEFICIENCY Most often occurs along with other nutrient deficiencies Prolonged deficiency results in the disease ariboflavinosis Symptoms: Inflammation of the membranes of the mouth, skin, eyes, GI tract, sore throat, cracks & redness on the outside of lips & at corners of mouth, painful, smooth, purplish red tongue, inflammation  RIBOFLAVIN (Vitamins B2) TOXICITY No adverse effects have been reported with excesses of riboflavin No UL has been determined  NIACIN (Vitamins B3) The name niacin describes two chemical structures: nicotinic acid & nicotinamide/niacinamide FUNCTIONS NAD+ NADH NADP NADPH Part of two coenzymes, Nicotinamide adenine dinucleotide (NAD) and Nicotinamide adenine dinucleotide phosphate (NADP) that participate in energy-transfer reactions especially in the metabolism of glucose, fat & alcohol (mainly in oxidation- reduction reactions)  NIACIN (Vitamins B3) DIETARY SOURCES Protein containing foods in general are excellent sources of niacin Meat, poultry, fish, legumes, whole/enriched grains Other good sources: Nuts, legumes, eggs and fortified cereals Niacin can also be made from tryptophan Body can make niacin from the amino acid tryptophan For your information only 1 mg niacin requires 60 mg of tryptophan  NIACIN (Vitamins B3) BIOAVAILABILITY Niacin is less vulnerable to losses during food preparation & storage than other water-soluble vitamins Very stable to heat, little is lost with reasonable cooking time Niacin in some foods (corn, wheat & some cereal products) may be bound to complex CHO or small peptides Chemical treatment with alkaline such as lime water Ca(OH)2 can improve availability  NIACIN (Vitamins B3) RECOMMENDED DIETARY ALLOWANCE (RDA) Singapore RDA mg NE/day 18-30 yrs 19.5 Men 30-60 yrs 19.1 18-30 yrs 13.9 Women 30-60 yrs 14.2 NE = niacin equivalent 1NE = 1mg niacin or 60mg tryptophan  NIACIN (Vitamins B3) DEFICIENCY In populations whose diets lack sufficient protein & niacin Prolonged deficiency results in the disease pellagra (pelle = skin; agra = rough) US in the 1900s, many people subsisted on low protein diets centered on corn ➔ inadequate niacin & tryptophan 70% of niacin in corn is bound to complex CHO & small peptides, making it unavailable for absorption Corn is also high in leucine which interferes with tryptophan-to- niacin conversion ➔ pellagra Symptoms: 4 ‘Ds’ : Diarrhea, Dermatitis, Dementia, Death  NIACIN (Vitamins B3) TOXICITY Naturally occurring niacin from food causes no harm UL for male & female, >19yrs old: 35mg Large doses (3-4x RDA) of nicotinic acid – dilate the capillaries and causes a tingling sensation that can be painful → “niacin flush” Excessive nicotinamide does not cause skin flushing and has fewer adverse effects than nicotinic acid, and these effects typically begin with much higher doses: nausea, vomiting, and signs of liver toxicity  PANTOTHENIC ACID (Vitamin B5) FUNCTIONS Part of coenzyme A, which forms acetyl CoA, an important compound in energy metabolism pathways of CHO, lipids & protein. DIETARY SOURCES Present in all foods Good sources: beef, poultry, wholegrains, potatoes, tomatoes, brocolli  PANTOTHENIC ACID (Vitamin B5) BIOAVAILABILITY Easily destroyed by the freezing, canning and refining processes Primarily in the jejunum RECOMMENDED INTAKE RDA not established Adequate intake (AI) is 5 mg/day for adults  PANTOTHENIC ACID (Vitamin B5) DEFICIENCY Deficiency is rare (except for persons suffering form severe malnutrition) Symptoms: numbness and burning of the hands and feet, headache, fatigue, irritability, restlessness, disturbed sleep TOXICITY None reported No UL has been determined  PYRIDOXINE (VITAMIN B6) Occurs in 3 forms: Pyridoxal, Pyridoxine and Pyridoxamine All 3 forms can be converted to the coenzyme PLP (pyridoxal phosphate) FUNCTIONS Coenzyme PLP is active in amino acid metabolism: the synthesis of non-essential amino acids from essential amino acids the synthesis of niacin from tryptophan the synthesis of neurotransmitter serotonin from tryptophan the synthesis of heme (part of hemoglobin), urea, nucleic acids (DNA & RNA)  PYRIDOXINE (VITAMIN B6) DIETARY SOURCES Animal foods (meat, fish, poultry) and organ meat are best sources Other good sources: Potatoes, legumes, whole grains, fortified cereals, soy products, prune juice, tomato juice  PYRIDOXINE (VITAMIN B6) BIOAVAILABILITY Easily destroyed by heat More readily absorbed from animal foods than plant foods Primarily in the jejunum RECOMMENDED DIETARY ALLOWANCE (RDA) US RDA mg/day Singapore RDA mg/day Adults (19-50 yrs) 1.3 Not established  PYRIDOXINE (VITAMIN B6) DEFICIENCY Synthesis of key neurotransmitters diminish, abnormal compounds from tryptophan metabolism accumulate in the brain early symptoms: depression & confusion late symptoms: abnormal brain wave patterns & convulsions Alcohol contributes to the destruction & loss of Vitamin B6 alcohol metabolism creates a byproduct, acetyldehyde which dislodges PLP coenzyme from its enzyme Medication such INH* drug. It acts as a vitamin B6 antagonist. This drug binds and inactivates vitamin B6. It can induce a deficiency. *Isonicotinylhydrazine (INH) also known as Isoniazid (Laniazid, Nydrazid). A medication that inhibits the growth of the tuberculosis bacterium (TB).  PYRIDOXINE (VITAMIN B6) TOXICITY Very rare through diet Intake of 1–6 g oral pyridoxine per day for 12–40 months can cause severe and progressive sensory neuropathy characterized by ataxia (loss of control of bodily movements) Other effects of excessive vitamin B6 intakes include painful, disfiguring dermatological lesions; photosensitivity; and gastrointestinal symptoms, such as nausea and heartburn Upper limit (adults) = 100mg/day  BIOTIN (Vitamin B7) In food, biotin is bound to protein or to the amino acid lysine FUNCTIONS Part of a coenzyme in energy metabolism, mainly carrying activated CO2 for carboxylation reactions in Fatty acid synthesis Gluconeogenesis Metabolism of certain fatty acids & amino acids  BIOTIN (Vitamin B7) DIETARY SOURCES Widespread in foods Good sources: Liver, kidney, yeast, egg yolks, soy beans, fish, whole grains Also synthesized by intestinal bacteria but the amount may not contribute much to the biotin absorbed  BIOTIN (Vitamin B7) BIOAVAILABILITY Dietary biotin is thought to be nearly completely absorbed Certain processing techniques (e.g. canning) can reduce the biotin content of foods Avidin, a glycoprotein in raw eggs white, binds biotin and prevents absorption. Cooking denatures avidin & improves bioavailability Absorption primarily in jejunum Biotin synthesized by colonic bacteria is absorbed in the colon  BIOTIN (Vitamin B7) RECOMMENDED INTAKE Biotin is needed in very small amounts RDA not established. Adequate intake is 30 μg/day for adults DEFICIENCY Deficiency is rare Induced by feeding raw egg whites (> 2 dozens daily for several months) Symptoms: thinning hair with progression to loss of all hair on the body; scaly, red rash around body openings (eyes, nose, mouth) TOXICITY None reported. No UL has been determined FOLATE (Vitamin B9) Folate Folic acid  FOLATE (Vitamin B9) FUNCTIONS 1. Part of coenzyme THF (tetrahydrofolate), which transfers one-carbon compounds during metabolism: Converts vitamin B12 to one of its coenzyme forms Required in amino acid metabolism Helps synthesize DNA required for all rapidly growing cells  FOLATE (Vitamin B9) FUNCTIONS 2. Relationships with diseases Defending against heart disease Folate breaks down homocysteine High levels of homocysteine seem to enhance blood clot formation & arterial wall deterioration Preventing neural tube defects (NTD) Adequate folate taken in the early weeks of pregnancy ensures normal brain & spinal cord development from the neural tube  FOLATE (Vitamin B9) DIETARY SOURCES Dark green leafy vegetables, legumes (lima & kidney beans), mushrooms, avocado, citrus fruits (strawberries, oranges & their juices), organ meats, yeast Spinach, liver, asparagus, and brussel sprouts are among the foods with the highest folate levels  FOLATE (Vitamin B9) BIOAVAILABILITY The bioavailability of folate  50% from foods (estimated 50 - 95% of folate originally present is lost in preparation & processing) The bioavailability is 100% from supplements taken on empty stomach Alcohol consumption adversely affects folate absorption, due to GI cell damage Folate travels in the same enterohepatic circulation as bile: secreted back into GI tract with bile and reabsorbed repeatedly Sensitive to heat and oxidation during cooking and storage  FOLATE (Vitamin B9) RECOMMENDED DIETARY ALLOWANCE (RDA) Singapore RDA μg/day 400 Adults (19-50 yrs) (600 for pregnancy) (500 for lactation) DFE = dietary folate equivalents 1 μg DFE = 1 μg food folate  FOLATE (Vitamin B9) DEFICIENCY Impaired cell division & protein synthesis critical in growing tissues, rapidly dividing cells (RBCs & GI tract cells) → 2 first symptoms: anemia & GI tract damage Megaloblastic/macrocytic anemia: large immature RBCs produced due to ↓ DNA synthesis → failure of cells to divide properly → enlarged, oval shaped GI: diarrhea, loss of appetite & weight loss, sore tongue Also headaches, heart palpitations, irritability, forgetfulness & behavioral disorders  FOLATE (Vitamin B9) DEFICIENCY For your information only Source: Whitney, EN and Rolfes, SR (2015). Understanding nutrition, Australia ; Wadsworth, Cengage Learning,  FOLATE DEFICIENCY Maternal deficiency of folate linked to birth defects called neural tube defects Malformation of the brain, spinal cord or both during embryonic development Two main types: Spina bifida (‘split spine’) & anencephaly (‘no brain’) → degrees of paralysis & mental retardation Adequate folate status prior to conception & continued throughout the first trimester recommended  FOLATE (Vitamin B9) TOXICITY Naturally occurring folate from foods alone appears to cause no harm High intake of folate from supplements may mask vitamin B12 deficiency symptoms & delay diagnosis of neurological damage UL (adult): 1000 μg per day  COBALAMIN (VITAMIN B12) Contain the mineral → cobalt Vitamin B12 can be produced by gut microorganisms FUNCTIONS 1. B12 together with folate, participates in the Conversion of the amino acid methionine to homocysteine Synthesis of DNA & RNA 2. B12 activates the folate coenzyme 3. B12 maintains myelin sheaths that protect nerve fibres & maintain their normal growth 4. B12 supports bone cell activity & metabolism  COBALAMIN (VITAMIN B12) DIETARY SOURCES Found exclusively in foods derived from animal, greatest availability from milk and fish Plant sources: fortified cereals, fortified soymilk, fermented products e.g. miso  COBALAMIN (VITAMIN B12) BIOAVAILABILITY Ingested cobalamin must be released from the polypeptides to which they are linked → require HCl & pepsin Cobalamin then travels to the small intestine where it binds with a molecule called intrinsic factor → this complex form is needed for absorption Enterohepatic circulation Cobalamin is secreted into the bile → it binds with intrinsic factor → reabsorbed Malabsorption syndromes will reduce cobalamin absorption & the enterohepatic circulation Unlike other water-soluble vitamins B12 can be stored & retained in the body for long periods of time, even years Vitamin B12 absorption For your information only  COBALAMIN (VITAMIN B12) RECOMMENDED DIETARY ALLOWANCE (RDA) Singapore RDA μg/day 2.4 Adults (19-50 yrs) (2.6 for pregnancy) (2.8 for lactation)  COBALAMIN (VITAMIN B12) DEFICIENCY Caused by inadequate absorption of B12 rather than inadequate dietary intake, except for vegans Inadequate absorption Lack of HCl &/or lack of intrinsic factor Absence of part or all of the stomach or ileum Bacterial overgrowth in the small intestine For your Atrophic gastritis, a condition affecting 10%–30% of older information only adults, decreases secretion of hydrochloric acid in the stomach  COBALAMIN (VITAMIN B12) DEFICIENCY Since B12 is required to convert folate to its coenzyme, megaloblastic/macrocytic anemia of folate deficiency will develop large immature RBCs produced due to  DNA synthesis → failure of cells to divide properly → enlarged, oval shaped The anemia can be treated with either folate or B12 but at the same time… Vitamin B12 is essential for producing and http://www.fairviewebenezer.org/fv/groups/public/documents/images/176946.jpg maintaining the myelin sheath, which insulates nerves and allows electrical signals to travel efficiently. Without B12, the myelin deteriorates, leading to nerve damage leading to paralysis. If the condition is wrongly diagnosed & only folate is given, the anemia is treated BUT permanent nerve damage & paralysis results. Correct treatment should be B12.  COBALAMIN (VITAMIN B12) DEFICIENCY Pernicious anemia → megaloblastic anemia that develops due to inability to absorb B12 from lack of intrinsic factor Other symptoms include muscle weakness & irreversible neurological damage Treated with B12 pills or injections http://www.fairviewebenezer.org/fv/groups/public/documents/images/176946.jpg TOXICITY None reported No UL Vitamin C  VITAMIN C Also known as ascorbic acid or ascorbate FUNCTIONS 1. Helps in collagen formation ✓ Collagen is the structural protein of connective tissues. It is also the matrix in bones & teeth ✓ Wounds heal as collagen glues the separated tissue together 2. Acts as an antioxidant ✓ Vit C loses electrons quickly to defend against free radicals. ✓ Protect tissues from oxidative stress & prevent diseases  VITAMIN C FUNCTIONS 3. Aids in iron absorption ✓ Increases absorption of non-heme iron (from plant sources) by reducing it to ferrous state (Fe2+) for uptake by cells ✓ Protect from formation of insoluble/unabsorbable complexes 4. In the prevention & treatment of the Common Cold ✓ Slight but consistent reduction in the duration of the common cold  VITAMIN C FUNCTIONS 5. Cofactor for synthesis of important compounds Hydroxylation of carnitine (carnitine helps to transport fatty acids) Conversion of amino acids to neurotransmitters, o Tryptophan Serotonin o Tyrosine Norepinephrine Assist in making hormones o e.g. thyroxine which helps to regulate metabolic rate  VITAMIN C DIETARY SOURCES Almost exclusively in fruits & vegetables Citrus fruits (orange, grapefruit), guava, kiwi, green leafy vegetables (broccoli, brussel sprouts), capsicum, tomato, mango, strawberries, papaya, cantaloupe BIOAVAILABILITY Sensitive Sensitive Absorbed in the small intestine Absorption becomes less efficient with high intake Ingestion of large amounts of iron together with vit C in the GI, may result in the oxidative destruction of vit C  VITAMIN C RECOMMENDED DIETARY ALLOWANCE (RDA) Singapore RDA mg/day Men 105 Women 85  VITAMIN C DEFICIENCY Acute Vit C deficiency leads to scurvy Symptoms: fatigue, malaise, inflammation of gums Gums bleed easily around the teeth, capillaries under the skin break → pinpoint hemorrhages If deficiency continues, Inadequate collagen synthesis → further hemorrhaging Muscles, including heart muscles degenerate Skin becomes rough, brown, scaly, dry Poor wound healing  VITAMIN C TOXICITY Symptoms: Nausea, abdominal cramps & diarrhea, headache, fatigue, insomnia, flushes, rashes Interference with medical tests as large amounts of vit C in the urine obscure results of tests Urinary tract problems, kidney stones UL (adults) = 2000 mg/day Nutrition and Health MICRONUTRIENTS (Part II): MINERALS  OVERVIEW Major/ Macro Mineral Minor / Micro / Trace Mineral Required in amounts > 100mg per day Required in amounts < 100 mg per day Examples: Examples: ❑ Sodium ❑ Iron ❑ Potassium ❑ Zinc ❑ Chloride ❑ Iodine ❑ Calcium ❑ Selenium ❑ Phosphorus ❑ Chromium ❑ Magnesium ❑ Copper ❑ Sulfur ❑ Fluoride ❑ Manganese ❑ Molybdenum New terms: Cation – An ion that has a positive charge Anion – An ion that has a negative charge  SODIUM (Na +) Functions 1. Maintains normal fluid balance (by regulating the amount of sodium in different compartments): Principal cation of the ECF and primary regulator of its volume. Sodium helps maintain fluid balance by pulling water into the right compartments in the body, such as cells and blood vessels.  SODIUM (Na +) Functions 2. Assist in nerve impulse transmission 3. Role in muscle contraction 4. Regulate blood pressure 5. Helps to maintain acid-base balance  SODIUM (Na +) Food Source Naturally occurring Sodium added Processed while cooking food The main source of sodium in the diet is added salt in the form of sodium chloride  SODIUM (Na +) Sodium VS Salt A mineral & one of the (also known as sodium chloride) is chemical elements found in a crystal-like compound comprising salt. of about 40% sodium and 60% chloride. Recommended intake Limit Sodium to bone tissue deposited is higher than the amount of bone tissue that is broken to provide the calcium necessary for skeletal modelling and consolidation (helps achieve Peak Bone Mass) It is important to achieve your maximum peak bone mass (before age 30) to reduce the chance of osteoporosis in later life. During childhood and adolescence, bone tissue deposited is higher than the amount of bone tissue that is broken.  CALCIUM (Ca +) Bioavailability An adult absorbs  25% of the calcium they ingest Factors that enhance calcium absorption: 1. Physiological need – e.g. pregnant women, growing children (up to 50% absorption), times of inadequate intakes ➔ the body absorbs more to meet needs 2. Stomach’s acidity helps keep calcium soluble & in absorbable form 3. Vit D makes calcium binding protein for absorption in the GI (PTH & estrogen associated with  synthesis of vit D)  CALCIUM (Ca +) Bioavailability Factors that reduce calcium absorption: 1. Lack of stomach acid 2. Lack of vitamin D 3. Phytates found in seeds, nuts & grains bind with calcium 4. Oxalates found in beet greens, rhubarb & spinach bind with calcium 5. Dietary fibers increases transit time & reduces time available for calcium absorption 6. Zn2+, Mg2+ compete with calcium for absorption  CALCIUM (Ca +) Food Sources MILK & MILK products - the best sources of calcium Other good sources: oysters, fish eaten with bones, calcium fortified foods such as fortified tofu, broccoli, cauliflower, turnip greens, brussels sprouts, mustard greens, almonds Recommended Dietary Allowance (RDA) Singapore RDA mg/day Adults 19-50 yrs: 800 >51 yrs: 1000 Pregnant / Breast Feeding: 1000  CALCIUM (Ca +) Deficiency Causes: 1. Inadequate calcium intake 2. Poor calcium absorption/excessive calcium losses (due to kidney failure, parathyroid disorders, vit D deficiency) Symptoms: Chronic hypocalcemia ➔ stunted growth of children, failure to achieve maximal bone density & bone loss in adults (osteoporosis)  CALCIUM (Ca +) Calcium & Osteoporosis Osteoporosis (‘porous’ bones): a condition in adults where bones become porous & fragile due to loss of minerals People with osteoporosis are more prone to bone fractures Osteoporosis is particularly prevalent in postmenopausal women because they lose estrogen at the time of menopause, which accelerates bone loss  CALCIUM (Ca +) Toxicity Causes: ▪ High intakes from calcium supplements ▪ Over production of PTH by the parathyroid gland Symptoms: ▪ Hypercalcemia ➔ calcium deposited in soft tissues leading to organ malfunction ▪ Constipation, loss of appetite, decreased absorption of other minerals increased risk of kidney dysfunction & kidney stones  PHOSPHORUS (P -) The second most abundant mineral in the body 85% of the body’s phosphorus is present together with calcium in the bones & teeth The rest is present in soft tissues & extracellular fluid Functions 1. Mineralization of bones & teeth 2. Component of DNA & RNA 3. Component of phospholipids in cell membranes 4. pH regulation – in all body cells as part of major buffer system 5. Assists in energy metabolism  PHOSPHORUS (P -) Food Sources Foods rich in protein are the best sources of phosphorus : legumes, meat (liver) & milk products (milk, yogurt, cheese), processed foods (including soft drinks), sunflower seeds, almonds Recommended Dietary Allowances Singapore RDA mg/day Adults Men: 1200 Women 18-30 yrs: 1200 > 30 yrs: 800  PHOSPHORUS (P -) Bioavailability ✓ Phosphorus is well absorbed by the intestines & does not change with changing needs ✓ Vitamin D promotes absorption of phosphorus ✓ High levels of aluminium, magnesium & calcium reduce phosphorus absorption ✓ Phytates, the major form of phosphorus in grains & legumes: poor bioavailability.  PHOSPHORUS (P -) Toxicity Toxicity is rare Calcification of non-skeletal tissues, esp the kidneys Deficiency Deficiency is rare Causes muscular weakness, bone pain  MAGNESIUM (Mg 2+) Extracellular fluid 1% in extracellular 60% in bones fluid MAGNESIUM (silver white metallic mineral) 39% in soft tissue  MAGNESIUM (Mg 2+) Functions 1. Essential for mineralization of bones & teeth 2. Cofactor for over 200 enzymes 3. Involved in energy metabolism : needed in the synthesis of ATP, fat & protein, body’s use of glucose 4. Regulates muscle contraction, nerve impulse transmission, blood clotting, blood pressure & immune system  MAGNESIUM (Mg 2+) Food Sources Rich sources : legumes, nuts & seeds Green leafy vegetables as magnesium forms the chlorophyll molecule No RDA of magnesium for Singapore population. Recommended Intake US RDA (mg/day) Adults Men 19-30 yrs: 400 >30 yrs: 420 Women 19-30 yrs: 310 >30 yrs: 320 UL (adults): 350 non-food Mg2+  MAGNESIUM (Mg 2+) Toxicity Rare but can be fatal From non-food sources (supplements, medications e.g. laxatives, antacids) Symptoms of HYPERMAGNESEMIA: diarrhea, dehydration, nausea, double vision, slurred speech, muscular paralysis Deficiency Deficiency is rare in healthy non-alcoholic people. Causes irregular heartbeat with weakness, muscle pain, disorientation and seizures. Alcoholics, diuretic users, those with chronic protein deficiency develop magnesium deficiency  SULFUR Our body does not use sulfur by itself as a nutrient It occurs with vitamins - thiamin & biotin, and amino acids – methionine & cysteine Sulfur plays an important role in stabilizing the structure of proteins e.g. collagen structure Part of insulin molecule Part of glutathione, an antioxidant which protects cells from oxidative damage , important in liver’s detoxifying pathways  SULFUR Food sources Mainly found in protein foods (from the sulfur-containing amino acids) Toxicity May occur with excessive intake of sulfur-containing amino acids In animals this leads to stunted growth Deficiency None known Protein deficiency would occur first  IRON Iron exists in two oxidation states: Ferrous iron Ferric iron (Fe2+) (Fe3+) Functions 1. Part of hemoglobin (in blood) & myoglobin (in muscles); carry oxygen for use in energy metabolism Hemoglobin in the RBCs transports oxygen from the lungs to cells throughout the body Myoglobin in muscle cells carries oxygen from the blood into the muscle cells 2. Part of enzymes involved in many reactions, especially oxidation- reduction reactions, synthesis of amino acids, collagen, hormones 3. Part of electron carriers in energy metabolism 4. For optimal immune function  IRON Heme & Nonheme Iron HEME IRON NON-HEME IRON Part of Present in Hemoglobin & Not part of hemoglobin & myoglobin myoglobin (iron salts) Food Sources Only found in animal flesh FOUND IN BOTH ANIMAL & PLANT FOODS Intake & Accounts for 10% of daily intake Accounts for 90% of daily intake, Absorption but better absorbed by the body absorption depending on body stores & other dietary factors Absorption Independent of meal Strongly influenced by meal composition composition, increased absorption when consumed with Vitamin C Whitney E., Rolfes S R. (2016).Understanding Nutrition. The Lipids: Triglycerides, Phospholipids, and Sterols (pp. 138) ‘14e; USA: Wadsworth, Cengage Learning  IRON Absorption - Non-heme Iron Factors enhancing absorption 1. Acidic condition – adequate gastric HCl or presence of citric acid/lactic acid in foods 2. Vitamin C- keeps iron in reduced ferrous form (Fe2+) 3. MFP factor – Meat, Fish & Poultry contain a factor that promotes absorption of non-heme iron present in same foods or other foods eaten at the same time  IRON Absorption - Non-heme Iron Factors that inhibit absorption 1. Inadequate acidic condition – inadequate gastric HCl 2. Absence of MFP factor 3. Phytates & fiber (grains & vegetables) 4. Oxalates (spinach, beets, rhubarb) 5. Calcium & phosphorus (milk) 6. Tannic acid & other polyphenols (coffee & tea) 7. Zinc competes with iron for absorption  IRON Food Sources Meat, fish & poultry contribute the most iron (liver is an excellent source) Other good sources: Other protein-rich foods like legumes & eggs Whole grains, enriched & fortified products Milk & dairy products are very poor sources of iron  IRON Recommended Intake Singapore RDA mg/day Adults Men: 8 Women 18-60 yrs: 18 >60 yrs: 8 Pregnant: 27 Lactating 9 to 18 Iron from supplements is less well absorbed than that from foods? Absorption of iron taken as ferrous sulphate is better than that from other iron supplements. Absorption also improves when supplements are taken between meals, at bedtime on an empty stomach and with liquid (other than milk, tea, or coffee which inhibit absorption). There is no benefit to take iron supplement with orange juice as Vitamin C does not enhance absorption from For your information only supplement as it does from food.  IRON Toxicity Ingestion of iron-containing supplements is a leading cause of toxicity in small children In general, a diet that includes fortified foods poses no special risk for iron toxicity Iron overload (hemochromatosis) usually caused by genetic disorder that enhances iron absorption or repeated blood transfusions or supplements  IRON Deficiency An inadequate iron intake or heavy blood loss depletes iron stores & leads to deficiency Symptoms ▪ Fatigue & breathlessness with exertion ➔ decreased work performance ▪ Microcytic, hypochromic anemia (small, pale RBCs) ➔ pallor/paleness of skin & lining of the eye ▪ Behavioural changes- short attention span, irritability ▪ Impaired immune function, cognitive function & growth  IRON Whitney E., Rolfes S R. (2016).Understanding Nutrition. The Lipids: Triglycerides, Phospholipids, and Sterols (pp. 138) ‘14e; USA: Wadsworth, Cengage Learning  ZINC Functions Required as co-factor by many enzymes Support DNA synthesis Strengthens anti-oxidant processes against free- radicals Helps in immune function Assist in wound healing Involved in sperm production & fetal development  ZINC Bioavailability Rate of absorption varies ~ 15 – 40% Rate of As zinc zinc intake absorption increases decreases And vice versa!  ZINC Toxicity > 50mg/day causes vomiting, diarrhea, headaches & exhaustion Deficiency Severe growth retardation Immature sexual development Damages central nervous system & poor motor development Whitney E., Rolfes S R. (2016).Understanding Nutrition. The Lipids: Triglycerides, Phospholipids, and Sterols (pp. 138) ‘14e; USA: Wadsworth, Cengage Learning  ZINC Food Sources Highest in protein rich foods: shellfish esp oysters, meats, poultry, milk, cheese, liver Supplementation – Plays major role in developing countries to treat childhood infectious diseases (e.g. death due to diarrhea) Recommended Intake Singapore RDA mg/day Adults Men: 15 Women: 12  IODINE Forms integral part of the thyroid hormone that plays a role in: – regulating body temperature – metabolic rate – blood cell production – influences basal metabolism Food Sources Seafood Iodised salt Iodised bread, fish paste, dairy-products, plants grown in iodine-rich soils, animals fed on those plants  IODINE Deficiency Thyroid hormone (TRH) production declines ▪ Body secretes more Thyroid Stimulating hormone (TSH) to accelerate iodide uptake in the gland ▪ Thyroid gland enlarges to TRAP as much Deficiency iodide in neck (GOITRE) during pregnancy ▪ Severe - Cause mental & physical retardation, brain damage, cretinism (midget) Toxicity Interferes will thyroid function and enlarges the gland  OTHER MICRO MINERALS Micro- Main Functions Food Source Rec Intake Toxicity/ mineral Deficiency Antioxidant part Seafood, meat, RDA Toxicity of enzyme that whole grains, (adults): Loss & brittleness activates vegetables 55μg of hair, nails, thyroxine nervous system SELENIUM UL (adults): disorder, garlic breath odor 400μg Deficiency Predisposition to heart disease  OTHER MICRO MINERALS Micro- Main Functions Food Source Rec Intake Toxicity/ mineral Deficiency Maintains glucose Unprocessed AI Toxicity homeostasis by foods – meats, Men: 35μg None reported CHROMIUM enhancing activity liver, brewer’s Women: of insulin yeast, whole 25μg grains Deficiency Diabetes-like condition  OTHER MICRO MINERALS Micro- Main Functions Food Source Rec Intake Toxicity/ mineral Deficiency Needed for Seafood, nuts, RDA Toxicity absorption & use whole grains, (adults): Liver damage COPPER of iron in the seeds, legumes 900μg formation of hemoglobin, part Deficiency of several UL (adults): Anemia, bone enzymes 10,000μg abnormalities Wilson’s disease: Copper accumulation in liver & brain causing toxicity  OTHER MICRO MINERALS Micro- Main Functions Food Source Rec Intake Toxicity/ mineral Deficiency For mineralization Fluoridated AI Toxicity of bones & teeth, drinking water is Men: 4mg Fluorosis (pitting & FLUORIDE prevent tooth the best source, Women: 3mg discoloration of decay fish & most teas teeth at UL(adults): 10 mg developmental stage) Deficiency  risk of tooth decay  OTHER MICRO MINERALS Micro- Main Functions Food Source Rec Intake Toxicity/ mineral Deficiency Part of several Legumes, RDA (adult): Toxicity MOLYBDENUM enzymes cereals, organ 45μg None reported meats UL(adult): 2 Deficiency mg unknown  OTHER MICRO MINERALS Micro- Main Functions Food Source Rec Intake Toxicity/ mineral Deficiency Cofactor for Many plant AI Toxicity many enzymes foods esp Men: Nervous system MANGANESE in energy grains, nuts, 2.3mg disorders metabolism, leafy vege, tea Women: bone formation 1.8mg Deficiency Rare UL (adults): 11mg