MICRO-NUTRIENTS The VITAMINS AND MINERALS

January 20th 2015

Salome A. Rebello

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VITAMINS

¨  Organic substance (contain the elements hydrogen and carbon)

¨  Needed by the body in small amounts ¨  Inadequate intake results in deficiencies ¨  Excessive intake can lead to toxicity in some cases ¨  Two major types

¤ Fat Soluble: A, D, E and K ¤ Water Soluble : B, C and choline

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FAT and WATER SOLUBLE VITAMINS

FAT SOLUBLE VITAMINS WATER SOLUBLE VITAMINS

Characteristics Soluble in lipids Soluble in water

Found in Fatty or oily foods Foods having a high water content

Absorption Requires bile. Absorbed in the small intestine along with fats (chylomicrons)

Absorbed in the small intestine

Storage Adipose tissue or liver Generally not stored * * Exceptions: B6 (muscle) and B12 (liver)

Excreted Low excretion, some level of excretion via bile * * Exception: vitamin K (urine + bile)

Generally via urine

Toxicities Sometimes observed with excessive dietary intakes, possible with high supplement use

Rare, may be possible with mega-doses via supplements

Cooking losses Generally low. Cooking increases the availability of some of these vitamins

Susceptible to losses while cooking

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VITAMIN A Retinoids and Pro-vitamin A Carotenoids

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VITAMIN A

¨  Pro-vitamin A: Some carotenoids

§  Of 600 carotenoids, three can be converted to Vitamin A (retinoids) §  Alpha carotene §  Beta carotene §  Beta cryptoxanthin

§  Others carotenoids do not have vitamin A activity in humans §  Lycopene §  Leutin

�  Preformed : Retinoids §  Retinol, (alcohol form) §  Retinal, (aldehyde form) §  Retinoic acid, (acid form)

RETINOL RETINAL

Reversible

RETINOIC ACID

Irreversible

BETA-CAROTENE

Retinoids can exist as cis or trans forms

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β-ionone ring polyunsaturated tail

polar endgroup

= vitamin A aldehyde group

acid group

alcohol group

Slide courtesy of Dr. Silke Vogel 6

Provitamin A carotenoids

β-ionone ring

Slide courtesy of Dr. Silke Vogel 7

Food Sources and Absorption ¨  RETINOIDS ¨  70-90% absorbed ¨  Mal absorption

¤  Protein deficiency ¤  Fat malabsorption ¤  Diahorrea or

intestinal infections

¨  CAROTENOIDS

¨  15-50% absorbed

MILK EGGS

FISH

•  LIVER •  FISH OILS •  DAIRY PRODUCTS • FORTIFIED FOODS • SUPPLEMENTS

MANGO CARROTS

GREEN LEAFY VEGETABLES

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VITAMIN A UNITS

RETINOL ACTIVITY EQUIVALENTS (RAE) ¨  1 µg RAE = 1 µg retinol ¨  1 µg RAE = 2 µg all-trans-β-­‐carotene from

supplements ¨  1 µg RAE = 12 µg of all-trans-β-­‐carotene from

food ¨  1 µg RAE = 24 µg α-­‐carotene or β-­‐cryptoxanthin

from food ¨  1  µg retinol = 3.3 international units

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Functions of Vitamin A- VISION

Human Nutrition, 2nd Ed, Mary Barasi, 2003

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Night Blindness

©2003 Wadsworth, a division of Thomson Learning, Inc. Thomson Learning™ is a trademark used herein under license.

Aulus Cornelius Celsus

“ Sufferers should anoint their eyeballs with the stuff dripping from a liver whilst roasting, preferably of a he-goat, or failing that of a she-goat; and as well they should eat some of the liver itself.” Aulus Cornelius Celsus, 30 AD

Image courtesy of Dr. Silke Vogel

DARK ADAPTATION TEST: Speed at which we get accustomed to seeing in the dark – measure of vitamin A status

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FUNCTIONS OF VITAMIN-A: VISION

¨  Mediated primarily by retinoic acid ¨  Helps in cellular differentiation (determines ability to secrete mucus) ¨  Maintain the integrity of the cell ¨  Deficiency – Dry eyes (xerophthalmia)

  Bitot’s spots Dry, "foamy," silver-gray deposits appear on the delicate membranes covering the whites of the eyes. 

Keratomalacia Cornea becomes soft, leading to infection, rupture, perforation, resulting in blindness. 

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Vitamin A: Other functions

¨  Preventions infection ¤  Maintains cellular integrity of the gastrointestinal tract and lungs ¤  Prevents bacteria from translocating ¤  Also may be involved in improving immunity

¨  Maintains healthy skin – Dry skin (follicular hyperkeratosis) ¨  Promotes normal growth in children

Follicular hyperkeratosis

Recommended Dietary Allowances (RDAs) 700 mcg for females 900 mcg for males

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¨  An estimated 250 000 to 500 000 vitamin A-deficient children become blind every year, half of them dying within 12 months of losing their sight.

IMPLICATIONS OF VITAMIN A DEFICIENCY Clinical vitamin-A deficiency in pre-school children (1995-2005)

Source: http://www.who.int/nutrition/topics/vad/en/ http://whqlibdoc.who.int/publications/2009/9789241598019_eng.pdf

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Vitamin A toxicity

¨  Acute ¤  1 or a few large doses (100 times recommended amount) ¤  GI upset, headache, blurred vision

¨  Chronic ¤  Repeated intake of 10 times the recommended amount ¤  Skin disorders, liver damage, double vision, coma

¨  Teratogenic : causing birth defects ¤  Extremely important for pregnant women ¤  Avoid large intake of liver, vitamin-A supplements, topical application of

vitamin-A creams ¨  Only results from excessive intake of retinoids ¨  Carotenoids from foods do not cause toxicity

¤  Can result in yellowing of the skin

Hypercarotenemia Upper limit: 3000 mcg of retinoids

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VITAMIN D 16

Sources of vitamin D

¨  Produced by the body

Sunshine (UV-B)

7-dehydrocholesterol (skin)

Vitamin D3

¨  Food sources Vitamin D2

MILK EGGS

OILY FISH

•  LIVER •  FISH OILS •  DAIRY PRODUCTS • FORTIFIED FOODS • SUPPLEMENTS

MUSHROOMS

Absorption: About 50%

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Metabolism and function of vitamin D

Vitamin D3 Sunshine supplements Animal food sources

Vitamin D2 (ergocalciferol) Plant food sources/supplements

Gastrointestinal tract

Increases calcium absorption from

food

Kidneys Increases calcium re-absoprtion from urine

Bone Releases calcium and

phosphorus from bones

Low plasma calcium levels

Maintain normal plasma Ca levels

Increase in Parathyroid (PTH) levels

RDA: 600 international units 18

DEFICIENCY

Rickets (children): bow legs, curved spines, bone pain, beaded thorax

Osteomalacia (Adults) §  Inadequate mineralization of the

bone tissue –soft bones §  Bone/muscle pain, bowing of the

spine

Source: van Schoor, Worldwide Vitamin D status (25) 2011, 671-680, Best Practice & Research Clinical Endocrinology & Metabolism

Measuring risk §  Based on serum 25 (OH) D concentrations

§  Sufficient: More than 50 nanomolar (nM) §  Clinical deficiency: Less than 25 nM §  Rickets/osteomalacia: Less than 15 nM

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Other potential health consequences of Vitamin D deficiency

Source: Holick, M. F. (2011) Health benefits of vitamin D and sunlight: a D‑bate Nat. Rev. Endocrinol. doi:10.1038/nrendo.2010.234 20

Prevalence of deficiency is high in Asia and Middle East

…..Toxicity: Deposition of Ca in soft tissue Upper Limit: 4000 IU

Source: van Schoor, Worldwide Vitamin D status (25) 2011, 671-680, Best Practice & Research Clinical Endocrinology & Metabolism

NORMAL LEVELS 50 nM

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At risk groups

¨  Obese ¨  Breast-fed infants beyond 6 months

¤  Breast fed infants are often given vitamin D supplements ¨  Dark-skinned individuals ¨  Reduced exposure to sunlight

¤  Pollution ¤  Elderly ¤  High degree of covering ¤  Increase sunscreen use ¤  Less outdoor activity

¨  Malabsorption syndromes: Celiac disease ¨  Liver or Kidney disease

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VITAMIN E 23

Food Sources

¨  2 forms of vitamin – E §  Tocopherols – alpha, beta, gamma, delta isomers §  Tocotrienols - alpha, beta, gamma, delta isomers alpha tocopherol is most biologically active

PLANT SOURCES

Vegetable Oils

Peanuts

Almonds Avocado

ANIMAL SOURCES

Not as rich as plant sources § Poultry § Fish § Eggs

Absorption: About 20-50 %

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Functions of vitamin E

¨  Very important anti-oxidant

Normal metabolism, pollution, exercise, smoking Damage cell membranes,

and cell components including DNA

Free radicals: Molecules that have an unpaired electron, very reactive

§  Oxidized LDL- atherosclerosis- heart disease §  Damaged DNA - Cancer

Vitamin E

Oxidized Vitamin E

Vitamin C

§ Vitamin E donates an electron to the free radical § Vitamin E gets oxidized in this process § Vitamin C and Selenium help to regenerate Vitamin E RDA: 15 mg

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Deficiency and Toxicities

¨  Deficiency is rare in humans ¤  Red cell hemolysis (breakdown) ¤ Neurological symptoms

¨  At-risk of deficiency ¤  Fat malabsorption ¤  Smokers ¤  Preterm infants (low stores)

¨  Toxicity ¤ Uncommon (can be excreted via bile) ¤  Prevent vitamin K clotting action ¤ Upper Limit: 1000 mg

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Vitamin E and chronic disease

¨  Data from clinical studies do not support a protective effect of Vitamin E intake on ¤ Cancer ¤ Heart disease

¨  Along with other antioxidants, zinc, and copper vitamin E may slow the progression of an eye disease (Age-related macular degeneration) in people with early-stage disease.

Source: http://ods.od.nih.gov/factsheets/VitaminE-HealthProfessional/

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VITAMIN K 28

Food sources

¨  Phylloquinones (plant sources)

Green leafy vegetables

Green peas

¨  Menaquinones (animal sources)

Milk

Liver

Vegetable Oils Gut Bacteria (10%)

Absorption is about 40-80%

Menadione: synthetic form (water soluble)

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Functions

¨  Important for the function of “gla” proteins

¤  Blood clotting n Synthesis of blood clotting factors

¤  Bone mineralization n Osteocalcin which is needed for calcium deposition in the

bone

Adequate Intake (day): 90 microgram for women, 120 microgram for men

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Deficiency

¨  Deficiency can occur in newborns : increased risk of bleeding ¤  Low levels in human milk ¤  Low gastrointestinal production of menaquinones ¤  Given vitamin K at birth

¨  Rare in older children and adults ¤  Can occur with fat malabsorption ¤  Can occur with prolonged antibiotic use

¨  Megadoses of vitamin A and vitamin E can interfere with vitamin K action

TOXICITY •  Natural forms : Unlikely (low storage, excreted in the urine and bile) •  Menadione injections: Can cause jaundice in newborns and death has been reported. In the US vitamin K injections as phylloquinone have been administered. •  Upper Limit : None set

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B-complex and vitamin C

WATER SOLUBLE VITAMINS 32

B-Complex Vitamins

¨  Group of 8 vitamins

ENERGY METABOLISM

Thiamin (B1) Riboflavin (B2)

Niacin (B3) Panthothenic Acid

Biotin

AMINO ACID METABOLISM/ RED

BLOOD CELL SYNTHESIS

Folate Pyridoxine (B6)

Cobalamine (B12)

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B complex vitamins in Energy Metabolism

Slide courtesy : Prof Silke Vogel

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Whole grains are an important source of B vitamins

Grain milling results in loss of B vitamins and other nutrients which are present in the germ and bran layer

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Thiamin

¨  Food sources: varied including whole and enriched grains , beans, peanuts, mushrooms. ¤  Some foods (fish/shell fish) contain thiamin antagonist – destroyed

by cooking ¨  Major Function

¤  As thiamin pyrophosphate (TPP) needed for the metabolism of carbohydrate and amino acids

Glucose

Pyruvate

Acetyl Co A

Decarboxylation

Thiamin pyrophosphate (TPP)

Panthothenic Acid (CoA) Niacin (NAD)

Riboflavin (FAD)

RDA: 1.1 mg for women, and 1.2 for men

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Thiamin Deficiency

Beri Beri Some signs can develop only 14 days on a thiamin-free diet §  Dry : Primarily neurological symptoms

§  Peripheral neuropathy, edema, weight loss, poor memory, confusion §  Wet: Also includes cardiovascular symptoms

§  Heart enlargement

Wernicke-Korsakoff (Cerebral Beri Beri) Vision problems (double vision), impaired mental function §  Seen in alcoholics

§  Alcohol decreases thiamin absorption §  Alcohol increases thiamin urinary excretion §  Alcoholics typically have a poor diet

Toxicity : Not observed, no Upper Limit

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38 http://eresources.nlb.gov.sg/newspapers/Digitised/Article/straitstimes19050414.2.67.aspx

Riboflavin (yellow vitamin)

Milk Eggs

Meats

Green leafy vegetables

RDA: 1.1 mg for women, 1.3 for men Toxicity : Not observed, no Upper Limit

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Riboflavin

¨  As part of the 2 important co-factors participates in a large number of oxidation-reduction reactions ¤  Flavin mononucleotide (FMN) ¤  Flavin adenine dinucleotide (FAD)

¨  Some pathways include ¤  Macronutrient metabolism: Krebs cycle, fatty acid beta-oxidation ¤  Folate metabolism ¤  Antioxidant function

Deficiency : Mouth, skin and red blood cells

Glossitis: Painful inflamed tongue, smooth texture

Angular stomatitis : Inflammation at the corners of the mouth

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Niacin

¨  SOURCES ¨  Obtained from the diet

¤  Poultry, fish, meat, enriched cereal products, coffee ¨  Made from the amino acid trypytophan

¤  60 mg of tryptophan -> 1 mg niacin

¨  FUNCTION ¨  Part of NAD and NADP participates in a wide variety of

oxidation-reduction reaction ¨  carbohydrate, protein and fat metabolism ¨  Fatty acid synthesis ¨  Alcohol metabolism

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Niacin Deficiency

PELLAGRA (pelle , skin; agra, rough)

4 D’s §  Dermatitis §  Diahorrea §  Dementia § Death

Casal’s necklace : Rough red rash that appears on areas exposed to sunlight

- RDA: 14 mg for women, 16 mg for men - Upper limit : 35 mg/d (supplements /fortified foods) flushing observed at very high doses

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Emergence of Pellagra as a public health problem

Used by South Americans - Treat it with lime (alkaline solution of calcium hydroxide) -  Culinary advantages Can be ground into a flour and made into a dough -  Nutritional advantages Releases niacin for absorption

Explorers took it back to Europe (1700’s) - Corn was not treated with lime -  Major component of the diet - Seen in poor peasants

Casal (1771) : “ the color of the skin becomes red,… the skin becomes dry,..the affected skin falls in white scales just like bran, ..becomes repulsively disfigured,..the disease rages recurrently till at length the skin, becomes wrinkled, thickened and full of fissures. Then for the first time the patients begin to have trouble in the head, fear, sadness wakefulness, and vertigo, mental stupor,..fluxes from the bowels and sometimes to suffer from mania, then the strength of the body begins to fail, …they begin to lose motion,..to emaciate in the highest degree, to be seized with a colliquative diahorrea most resistant to all remedies and consumed with a ghastly wasting they approach the last extremity”

Possible treatment was only identified in the mid 1900s

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Vitamin B6 (Pyridoxine)

¨  Plant Foods ¤ Whole grains ¤ Carrots, spinach,

potatoes and bananas

¨  Animal Food ¤ Stored in muscle tissue of

animals ¤ May be better absorbed ¤ Meat, fish and poultry

PYRIDOXINE PYRIDOXAL AND PYRIDOXAMINE

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Vitamin B6 : Functions

Functions: Involved in multiple reactions including §  Synthesis of porphyrin (haem) §  Synthesis of neurotransmitters (dopamine, serotonin) §  Synthesis of non-essential amino acids §  Metabolism of fatty acids §  Utilization of glycogen in the liver

RDA: 1.3 mg (males), 1.2 mg (females)

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Vitamin B6: Deficiency

¨  Anemia ¨  Neuromuscular problems

¤  Infants : convulsions ¤  Irritability, fatigue, muscle weakness, headache

¨  Often co-exists with deficiencies of other vitamins ¤ Riboflavin deficiency : angular stomatitis ¤ Niacin deficiency : dermatitis

RISK GROUPS § Poor nutrition intake § Increased demand (pregnancy, women on oral contraceptives)

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Vitamin B6 Excess

¨  Upper Limit ¤ 100 mg/day

¨  Long term intake of > 200 mg per day ¤ Neurological effects such as walking difficulties and

hand/foot numbness

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Folate

¨  Natural folates (generally polyglutamate form) ¤ Green leafy vegetables ¤  Liver

n  Monoglutamate form better absorbed ¤  Needs zinc, inhibited by alcohol ¤ About 50 % absorbed

¨  Synthetic folate (folic acid) ¤  Supplements ¤  Fortification ¤ About 85 % absorbed

Name is derived from folium which means leaf in Latin

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Functions of folate

¨  Participates in one-carbon transfer ¤ Synthesis of purines and pyrimidines

n Needed for DNA synthesis

¤  Conversion of amino acids ¤ Conversion of homocysteine to methionine RDA: 400 mcg/day

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Folate and B12, interrelationship

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Folate deficiency, vulnerable groups

Blood Cells

§ Gastrointestinal cells Diahorrea and constipation

§  White blood cells: lower immunity

§  Red blood cells: Macrocytic anemia

Vulnerable Groups § Pregnant women Increased needs § Premature infants § Elderly § Alcoholics Reduced folate absorption

Folate Toxicity: Can potentially mask vitamin B12 deficiency Upper limit: 1000 mcg per day

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Folate and neural tube defects (NTDs)

§  Neural tube is the precursor to the brain and spinal cord in the developing fetus

§  Defects in events that occur in the 21-28th day of pregnancy lead to neural tube defects

§  About 1 in every 1000 pregnancies

§  Folic acid deficiency in the mother increases the risk of NTDs in her child (studies in the 1990’s)

§  Fortification of flour in the US, estimated provision of 200 mcg/day (1998)

§  Reduced incidence of NTDS in the US by 23-27% (2003-2005)

§  In addition women of child bearing age are advised to take a 400 mcg from supplements or fortified foods

Anencephaly: Baby usually dies in utero or shortly after birth

http://www.cdc.gov/ncbddd/birthdefects/anencephaly.html#ref, http://www.cdc.gov/ncbddd/spinabifida/data.html

Spina Bifida : Physical and neuriological defects

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Vitamin B12

¨  Group of compounds ¤ Has cobalt in the center

¨  Dietary Sources ¤ Only animal foods

¤  Liver, fish, meat, eggs and milk ¨  Absorption of dietary B12 requires intrinsic factor (IF) produced

by cells in the stomach ¤  Absorption occurs in the small intestine

¨  Up to 80% can be absorbed

RDA: 2.4 mcg per day Toxicity: No known adverse effects No upper limit

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Vitamin B12 : Function and deficiency

Secondary folate deficiency and its consequences (Megalobastic Anemia) In the event that there is B12 deficiency due to lack of intrinsic factor production , the anemia is termed as “Pernicious Anemia”

Neurological effects: Damage of the myelin sheaths

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Causes for B12 deficiency

•  malabsorption in pernicious anemia: autoimmune disease where parietal cells are destroyed-- IF production diminshed

•  atrophic gastritis: loss or inflammation of gastric cells- IF decreased

•  gastrectomy: Intrinsic factor affected

•  achlorhydria (decreased HCL release): B12 cannot be efficiently released from food matrix

•  decreased absorptive surface of the ileum - ileal resection, celiac sprue, ileitis

vegans and strict vegetarians infants of vegan mothers

Inadequate intake

Inadequate absorption

Slide : courtsey Dr. Silke Vogel 55

Vitamin C : Food Sources and Functions

§  Sources §  Fruits: Guava, Indian gooseberry (amla), mango, citrus fruits ,

papaya, strawberries §  Vegetables: cauliflowers, broccoli, green peppers, potatoes

§  Very sensitive to cooking losses §  Air, light, heat or alkali (soda bicarbonate)

§  Function

Ascorbate Dehydroascorbate

NADH, NADPH can act as hydrogen donors to regenerate ascorbate

The hydrogen released from ascorbate is used in a wide variety of reactions including reduction of vitamin E Can also act directly as an anti-oxidant

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Vitamin C: Function

Function ¨  Hydroxylation reactions

¤ Collagen synthesis ¤ Use of fatty acids for generating energy ¤  Synthesis of norepinephrine ¤  Synthesis of brain peptide

¨  Helps in iron absorption ¨  RDA: 75 mg for women; 90 mg for men Toxicity q  Cramps, diahorrea, increases risk of kidney stones

q Upper limit: 2 grams per day

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Vitamin C Deficiency : Scurvy

Gums: spongy, bleeding Skin: pinpoint hemorrages

Death due to pnuemonia and cardiac failure

§ Progressive weakness § Muscle /bone pain § Delayed wound healing § Subcutaneous bleeding

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Vitamin C Deficiency: Scurvy

Dr. James Lind

Source: http://fn.bmj.com/content/76/1/F64.full

“On the 20th of May 1747, I selected twelve patients in the scurvy, on board the Salisbury at sea. Their cases were as similar as I could have them. They all in general had putrid gums, the spots and lassitude, with weakness of the knees. They lay together in one place, being a proper apartment for the sick in the fore-hold; and had one diet common to all, viz. water gruel sweetened with sugar in the morning; fresh mutton-broth often times for dinner; at other times light puddings, boiled biscuit with sugar, etc., and for supper, barley and raisins, rice and currants, sago and wine or the like. Two were ordered each a quart of cyder a day. Two others took twenty-five drops of elixir vitriol three times a day … Two others took two spoonfuls of vinegar three times a day … Two of the worst patients were put on a course of sea-water … Two others had each two oranges and one lemon given them every day … The two remaining patients, took … an electary recommended by a hospital surgeon … The consequence was, that the most sudden and visible good effects were perceived from the use of oranges and lemons; one of those who had taken them, being at the end of six days fit for duty … The other was the best recovered of any in his condition; and … was appointed to attend the rest of the sick. Next to the oranges, I thought the cyder had the best effects 

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MINERALS 60

Minerals

¨  Present in the human body ¤  Structural: As a part of

biological components n Hemoglobin n Bone n Thyroid hormones

¤  Ionized forms involved in various cellular processes n Ca ions, K(potassium) ions n  Signaling, muscle

contractions

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Other features of minerals

¨  Absorption and availability ¤  Some minerals (Ca, Fe, Zn) may be present in foods

attached to other compounds (such as phytates) which limit their availability

¤  Large amounts of some minerals (e.g. Ca) may inhibit absorption of others (e.g. Fe)

¤ Generally resistant to cooking losses

¨  Excretion ¤ Urine or bile

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Other features of minerals MACROMINERALS §  Require more than 100 mg per day § Examples: Ca, P (phosphorus), S (sulphur), Na (sodium) , K (potassium), Mg (magnesium) , Cl (chloride)

TRACE MINERALS §  Require less than 100 mg per day § Examples: Fe (iron), Zn (Zinc), Cu (copper), Mn (Manganese), I (iodine), F( fluorine)

TOXIC MINERALS §  No known requirements : Lead, Mercury § Difficult to excrete, may accumulate in the body

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Calcium : Sources

§  Milk and its products §  Tofu, fortified soy milk §  Green leafy vegetables §  Small fish

Dietary Calcium Intake in Singaporean Adults

Source: Singapore National Nutrition Survey, 2010

RDA: 1000 mg/d

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Calcium : absorption and excretion

¨  Only about 30 % of Ca is absorbed ¨  Absorption Enhancers:

¤  Vitamin D à synthesis of Ca binding protein which increase intestinal absorption ¤  Lactose àmaintains solubility, facilitating absorption ¤  Acidity à maintain solubility, facilitating absorption

¨  Absorption Inhibitors ¤  Phytates which form insoluble complexes with Ca ¤  Oxalates (spinach, chocolate, tea, strawberries) form insoluble complexes

¨  Calcium Excretion ¤  Urine ( typically 97 % re-absorbed by the kidney tubule)

n  Increased by high Ca intake, high protein intake, high sodium intake n  Decreased by high potassium , phosphorus intake and by active vitamin D

¤  Fecal losses n  Un-absorbed from the diet n  Via sloughing off intestinal cells n  Digestive secretions

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Calcium metabolism and action

Skeletal Health : maintain integrity Bones act as a Ca depot

Low plasma

Ca levels

High plasma

Ca levels

Normal plasma Ca Levels

1, 25 (OH)2 D

Kidney Thyroid

Calcitonin

Blood clotting Nerve transmission Muscle contraction

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Calcium Deficiency

¨  Calcium deficiency ¤ Blood levels are very closely regulated ¤ Low blood levels (hypocalcemia) occurs under medial

conditions such as kidney failure or abuse of diuretics n Numbness and tingling in the fingers, muscle cramps,

convulsions, lethargy, poor appetite, and abnormal heart rhythms

¨  Required for bone mineralization ¤ Long term deficiency can result in low bone mass

(osteopenia) and osteoporosis

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Osteoporosis

Osteoporosis “porous bones”

Loss of bone mineral, fragile bones, prone to fractures

§ Micronutrients Calcium, Vitamin D, Vitamin K, Vitamin C §  Weight bearing exercise §  Low body weight resulting in lack of menstrual cycles in young adult females §  Alcohol and smoking: reduce bone accretion

Supplementation with calcium plus vitamin D has been shown to be effective in reducing fractures and falls in institutionalized older adults

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Calcium and Health

¨  May be associated with lower risk of colon cancer ¨  Supplemental Ca may be associated with higher risk of

prostate cancer -> mixed evidence ¨  Supplemental Ca (>1500-2000 mg/d) may increase

the risk of kidney stones ¨  Some evidence to suggest lower blood pressure with

high Ca intakes particularly in hypertensive persons ¨  Mixed evidence for supplemental Ca increasing risk of

cardiovascular disease ¨  Upper Limit: 2500 mg

Source: http://ods.od.nih.gov/factsheets/Calcium-HealthProfessional/

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Iron : Sources

¨  Non-haem iron (inorganic iron), Ferric form

¤  Present in Plant foods ¤  Less bio-available (generally less than 10%)

n  Converted to ferrous form (soluble) prior to absorption

n  Enhanced by vitamin-C , gastric acid n  Reduced by phytates, polyphenols (tea,

coffee), oxalic acid, Ca and Zn ¤  Legumes, Green vegetables, cereals

(fortified)

¨  Haem iron (organic iron), Ferrous form ¤  Present in Animal foods ¤  More bio-available (20-25 % absorbed) ¤  Liver, meat, fish

¨  Recycling of iron from hemoglobin in the body

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Iron absorption, excretion and losses

¨  Absorption is highly regulated by iron stores in the body ¤  Low body iron stores: 35-40% absorbed ¤  High body iron stores: 5 % absorbed

¨  Gastrointestinal muscosal cells act as block “ Mucosal Block” ¤  High iron stores: iron can be trapped inside the mucosal cell by ferritin ¤  Iron is lost when the cells are shed

¨  Very little free iron is available in the body ¤  Free iron can form free-radicals that can increase oxidative stress ¤  Stored as ferritin and hemosiderin (liver, bone marrow and spleen)

¨  Iron losses ¤  Small obligatory losses (loss of skin, mucosal cells) ¤  Premenopausal adult women, menstrual losses ¤  Pathological conditions

n  Ulcers n  Stomach cancers

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Iron : Function

¨  Hemoglobin: Oxygen carrier in the blood ¨  Myoglobin: Oxgen carrier in muscle ¨  Production of cytochromes

¤ Drug and alcohol metabolism

¨  Immune function ¤ Production of lymphocytes

RDA: 8 mg for males, and 18 mg for females

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Iron deficiency: Microcytic anemia

Microcytic , hypochromic anemia

Picture Source: http://www.dnwalcker.com/Laboratory2.html

Lower number of red blood cells (RBCs) RBCs contain less hemoglobin (hypochromic) Smaller RBCs (microcytic) Symptoms Fatigues, loss of appetite, brittle nails, may impair future learning ability(infants), depressed immunity

Iron deficiency anemia is a major public health problem: At risk : premature infants, young children, menstruating women, vegetarians, blood donors (> 2-4 times each year)

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Iron excess

¨  Upper Limit for adults set at 45 mg /d ¨  Acute toxicity

¤ Consumption of multi-nutrient supplements ¤ Children are at risk of toxicity

n  Diahorrea, vomiting, nausea, can be fatal

¨  Large iron stores ¤ Hemochromatosis : 1 in 200-300 people (genetic defect) ¤  Over-supplementation or frequent blood transfusions

¤  Iron is deposited in liver, heart and other organs ¤  Liver damage, diabetes mellitus, cardiac failure, skin discoloration ¤  Upper limit : 45 mg

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Iodine : Sources and Absorption

Oceanic sources §  Fish, sea food, seaweed §  Dairy products

§ Cattle feed contain iodine § Sanitizing solutions contain iodine

§  Plants sources §  Higher to areas near the sea

§ Iodized salts 1/2 tsp of salt meets iodine requirement

Goitrogens §  Compounds found in raw vegetables such as cauliflower, broccoli, cabbage, soy, peanuts, and strawberries §  Reduce iodine absorption § Reduce iodine use by the thyroid gland

RDA: 150 micrograms

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Iodine utilization

Iodide

Source of images: Mayo foundation , The Guardian, World Journal of Endocrine Surgery, May-August 2010;2(2):103-104, http://www.endocrinesurgery.net.au/goitre

Thyroid contains about 70-80% of the body's iodine stores Iodine + tyrosine = Thyroid hormone

Low blood thyroid hormone levels

Brain

Thyroid stimulating hormone (TSH)

Increases iodine uptake by thyroid

Iodine deficiency: cells of the gland increase to capture more iodine; gland enlargement - GOITRE

Thyroid hormones are involved in a variety of metabolic processes -  Basal metabolic rate -  Bone growth -  Neural maturation

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Iodine deficiency

Cretinism: dwarfism severe neurological damage (deaf-mutism, spasticity, motor rigidity)

Image Source: http://prezi.com/t1pmzldh6w6y/cretenism/

¨ Signs/Symptoms ¨  Increased sensitivity to cold

temperature ¨  Fatigue ¨  Joint or muscle pain ¨  Paleness or dry skin ¨  Sadness or depression ¨  Weakness ¨  Weight gain ¨  Decreased taste and smell ¨  Hoarseness ¨  Puffy face, hands, and feet ¨  Slow speech ¨  Thickening of the skin ¨  Thinning of eyebrows

Iodine inadequacy during pregnancy can result in development abnormalities in the newborn

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Iodine excess

¨  Inhibits thyroid hormone synthesis and thereby increases TSH stimulation, which can also produce goiter 

¨  Thyroid inflammation and can increase the risk of thyroid cancer

¨  Upper limit: 1.1 mg

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Public Health Significance of Iodine Nutrition

266 million children and 2 billion people worldwide are at risk for iodine deficiency

Source : http://www.who.int/vmnis/iodine/status/en/

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Sodium: Sources

Preserved foods

Packaged and canned foods

Sauces §  Taste (sodium chloride, MSG) §  Preservation (sodium benzoate) §  Leavening agent (sodium bicarbonate) §  Curing agents (sodium nitrates)

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Sodium absorption and excretion

¨  Almost all is absorbed ¨  Excretion via urine (primary), perspiration ¨  Physiological requirement : 200 mg /day ¨  Adequate Intake(day) : 1500 mg ¨  Function

¤ Glucose absorption ¤ Muscle contraction and nerve transmission

n Sodium-potassium gradient

¤ Maintains water balance

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Sodium deficiency

¨  Rare ¤ Diarrhea /vomiting in children ¤ Athletes who over-consume water

¨  Symptoms ¤ Headache, nausea, muscle cramps ¤ Can be fatal

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Sodium excess

¨  Adequate Intake : 1500 mg /day(< 51 year) ¨  Upper Limit : 2300 mg /day (approximately 1 teaspoon of salt, 5 g)

- Increases risk of high blood pressure, heart disease and stroke -  Increases losses of Ca in the urine - May increase the risk of stomach cancer

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Sodium reduction initiatives in SE Asia

Batcagan-Abueg et al, Asia Pac J Clin Nutr 2013;22(4):490-504

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NEXT CLASS: - DIETARY RECOMMENDATION STANDARDS - ASSESS DIET

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