2 Chapter 11 - FSV Characteristics of fat-soluble vitamins Do not dissolve in water, but dissolve in fat or organic solvents.Dietary fat soluble vitamins need bile for absorption.The fat-soluble vitamins include vitamins A, D,E and KFound in the fats and oils of foods.Stored in the liver and fat tissue until needednot readily excreted from the body.Risk of toxicity.
3 Storage of vitamins in the body Vitamins A, D and E:These three fat-soluble vitamins can accumulate in the liver and fat tissue of the body and are not readily excreted. Long-term intakes more than the RDA can be toxic, particularly vitamins A and D.Vitamin K:The other fat-soluble vitamin, vitamin K, is readily excreted from the body.
4 Absorption & transport The fat-soluble vitamins, like lipids are absorbed with dietary fat.Bile aids in the absorption of fat-soluble vitamins.The GI must function adequately for efficient uptake of fat-soluble vitamins.Under normal conditions, healthy individuals will absorb 40-90% of fat-soluble vitamins.
5 Absorption & Transport Fat malabsorption interfere with the absorption of FSV.Unabsorbed fat is excreted as feces.The following conditions adversely affect the uptake of fat-soluble vitamins:Cystic fibrosisCrohn’s diseaseCeliac diseaseCertain medications
6 Vitamin A Family of compounds called Retinoids: Retinol – supports reproductive functionsFound in animal foods and nutrient supplements.Can converted to retinoic acid and retinal in the body.Retinal – Aid in visionRetinoic acid – regulates growth~90% of retinoids are absorbedThese are preformed Vitamin A – form that the body readily uses. Found only in animal sources
7 Provitamin A = carotenoids Found in plant sourcesNot biologically available until they are changed into one of the retinoids in the bodyThere are over 600 different carotenoids only 3 can be converted to vitamin ABeta carotene (most common form)Alpha caroteneBeta- cryptoxanthinAccounts for 25 – 35 percent of dietary vitamin A consumed in the US
8 Essential for healthy eyes Promotes cell differentiation Functions of Vit AEssential for healthy eyesPromotes cell differentiationDetermines what cell becomes in your bodySupports reproductive system, development of limbs, heart eyes and earsPromotes bone and teeth growthPlay a role in immunity and preventing infections by creating white blood cellsCarotenoids, which act as antioxidants, decrease the damaging effects of free radicals.
9 Sources of Vitamin A Sources Preformed Vit A Organ meats (liver), milk, cereals, cheese and eggs are the most popular sources ofProvitamin A (carotenoids)Fruits: peaches, apricots, cantaloupes, mangoes, papayaVegetables: tomatoes, carrots, winter squash, sweet potatoes, broccoli, romaine lettuce, collard greens and spinach.Adding as little as 1 tablespoon of vegetable oil to your diet can increase absorption of carotenoids by as much as 25%
10 Vitamin ARDA – can be measured in micrograms of retinoic activity equivalents (RAE) or in international units (IU). 1 RAE = 3.3 IU900 microgram for men700 microgram for womenUpper limit 3,000 microgram/dayDeficiencyNight blindness – difficulty seeing at dusk, can’t adjust from day light to darkVitamin A deficiency is the main cause of non-accidental blindness (Xerophthalmia)Many die after blindness as a result of infection.The eye becomes prone to infections when the conjunctiva is damaged.Infections can spread systemically throughout the body.
11 Figure 11.5: Vitamin A–Deficiency Symptom—Night Blindness. These photographs illustrate the eyes’ slow recovery in response to a flash of bright light at night. In animal research studies, the response rate is measured with electrodes.
12 ToxicityHypervitaminosis A - is a condition that results from excessive intake of vitamin A from supplementsCause defective physical development during early development of the fetus resulting in birth defectsEven 3X RDA vitamin A is considered risky during pregnancy.Accutane is associated with congenital malformations result involving the head and brain.FDA has recommended that women of childbearing years limit their vitamin A intake to 100% RDA
13 ToxicityHigh consumption of vitamin A has been linked to osteoporosis and increased risk of fracturesProvitamin A carotenoids in foods are not toxicExtra carotenoids are stored in the liver and in the fat under the skin, causing carotenodermia
14 Figure 11.7: Symptom of Beta-Carotene Excess—Discoloration of the Skin. Fig. 11-7, p. 375
15 Vitamin D/calceferolAlso called the “sunshine vitamin” because it is made with the help of ultraviolet (UV) rays from sunlightVitamin D enters your body in an inactive formThe kidneys convert dietary vitamin D into the active formPrecursor = body’s cholesterol
16 Vitamin D/ calceferol Functions of Vit D Sources of vit D Helps bone health by regulating calcium and phosphorus concentration in the bloodWhen blood concentration of calcium is low, vitamin D and parathyroid hormone signals the kidney to decrease excretion of calcium and phosphorousSources of vit DFortified milk, cereals, yogurt, fatty fish
17 Vitamin D Adequate Intake: 5 micrograms/day for 19-50 yr Upper level: 50 micrograms/day
18 Vitamin D Deficiency Rickets in children (soft bones) poor bone mineralizationBowed legsUnable to hold up their own weight when standing upRecently researchers have found a rise in rickets among children,linked to increase consumption of soft drinksLimited outdoor activitiesFear of skin cancerAir pollution reduces ultraviolet rays of the sun by as much as 60%
20 Vitamin D Osteomalacia - adult form of rickets Occurs in women with decreased calcium and phosphorus intakeCauses bone weakness and painCan lead to osteoporosis
21 Vitamin D ToxicityHypervitaminosis D – associated with over-consumption of supplementsIncreased calcium withdrawal in bones and intestinesIncreased calcium and phosphorousconcentrations in the blood (hypercalcemia)Increase calcium deposits in kidneys, lungs, blood vessels and heart
22 Vitamin E Vitamin E is an effective antioxidant Prevent oxidation of lipids, vit A and LDL to prevent build-up in the arteriesNeutralize free radicals before they damage cell membranesPrevents blood clotting in the blood by acting as anticoagulantThere are 8 different forms, only one is active in the body (alpha- tocopherol)The synthetic is only half as active as the natural
23 Vitamin E Sources Polyunsaturated plant oils (vegetable oils) Nuts and seedsLeafy green vegetablesFortified cerealsRDA:Adults need 15 milligrams/dayUpper limit is 1,000 milligrams
24 Vitamin EDeficiencyErythrocyte hemolysis in premature infants (red blood cell destruction causing anemia)Toxicity from synthetic form or fortified foodsincrease risk of hemorrhageA deficiency of vitamin K can increase the anticoagulant effect
25 Vitamin K There are two forms of vitamin K: Menaquinone – synthesized by the intestinal tractPhylloquinone – found in green plantsFunctionsEssential for blood clottingVitamin K plays a role synthesizing clotting factorsWithout vit k a simple cut on the finger would cause uncontrollable bleedingSynthesis of bone protein (osteocalcin) that regulates blood calcium.
26 Vitamin KInadequate amount of vitamin K may contribute to osteoporosis, associated with increased risk of hip fracturesSourcesIntestinal bacteria can make vitamin K but not enough to meet all of the body’s needsLeafy green vegetablesCabbage family vegetablesVegetable oils and margarine
27 Vitamin K Deficiency Toxicity Newborn infants receive a single dose of vitamin K at birth because of a sterile intestinal tract to prevent hemorrhagic diseaseRare in healthy individualsToxicityNo known adverse effect from consuming too much vitamin K from food or supplementInterferes with anticlotting medication (coumadin)
28 Recommendation for Vitamin K Adequate Intake (based on amount that is consumed on average)Infants: 2 – 2.5 microgramChildren: 30 – 55 microgramMen: 60 – 120 microgramWomen: 60 – 90 microgram
29 Homework/extra credit 5 points Complete the vitamin/mineral evaluation form posted on the course website