Fat Soluble Vitamins PDF

FOOD & HEALTH F24 / FDE428 Fat Soluble Vitamins Dr. Ipek Bayram  WATER SOLUBLE FAT SOLUBLE B group vitamins Vitamin C Vitamin A Vitamin D B1 Vitamin E B2 Vitamin K B3 B5...

FOOD & HEALTH F24 / FDE428 Fat Soluble Vitamins Dr. Ipek Bayram  WATER SOLUBLE FAT SOLUBLE B group vitamins Vitamin C Vitamin A Vitamin D B1 Vitamin E B2 Vitamin K B3 B5 B6 B7 B9 B12 Fat Soluble Vitamins Fat-soluble vitamins differ from water-soluble vitamins in that: 1. They require bile for digestion and absorption. 2. They travel through the lymphatic system. 3. Excesses are stored in the liver and adipose tissues. 4. They are not readily excreted. increases risk of toxicity. Fat soluble Vitamins – Digestion ❑ Digestion and absorption follow a similar pathway to dietary fats ▪ Insoluble in water – packaged into chylomicrons ▪ Taken up by liver – can be stored ▪ Transported to other tissues – via proteins ❑ Condition which alters/hinders function of intestine or fat absorption will limit the absorption. Fat soluble Vitamins – the functions Vitamin A Vitamin D Vitamin E Vitamin K Vitamin A and Beta-Carotene Vitamin A ○ First fat-soluble vitamin recognized in 1913 ○ Precursor: beta-carotene Three different forms of vitamin A are active in the body: ○ Retinol, retinal, and retinoic acid Vitamin A and Beta-Carotene Foods derived from plants provide carotenoids, some of which can be converted to vitamin A in our body. Carotenoids are pigments that give yellow, orange, and red color to fruits and vegetables. The most studied of the carotenoids with vitamin A activity is beta-carotene, which can be split to form retinol in the intestine and liver. Vitamin A Forms 1 RAE = 1 μg Retinol = 12 μg β-carotene  Vitamin A There are two different sources of vitamin A: Pre-formed (Retinyl ester) Pro-vitamin (β-carotene) Retinol Plasma RBP Retinol-binding Protein Retinal Retinoic Acid Vitamin A Sources *Essential Nutrient* Vitamin A FUNCTION: Versatile Best known function is in vision Retinal is bound to a protein called opsin to form visual pigments like rhodopsin in rods (low-light vision) or cone pigments (color vision). Helps to maintain healthy epithelial tissue. Reproduction & Development Immunity Growth Vitamin A and Beta-Carotene REMEMBER: Because the body uses both the preformed vitamin A and the beta-carotene in foods to make retinol, the amount of vitamin A in foods is expressed in retinol activity equivalents (RAE)—a measure of the amount of retinol the body will derive from the food. 1 RAE = 1 μg Retinol = 12 μg β-carotene Vitamin A: Conversion Vitamin A & Vision Maintains clear cornea Converts light energy to nerve impulses in the retina Visual activity leads to repeated small losses of retinal, necessitating its constant replenishment either directly from foods or indirectly from retinol stores. Vitamin A & Vision Vitamin A: Protein Synthesis and Cell Differentiation 1. Epithelial cells on the outside of the body form skin. 2. Vitamin A and beta-carotene help protect against skin damage from sunlight 3. They also line the inside of the body, forming mucus membranes ▪ Within the body, the mucus membranes line an area larger than a tennis court, and vitamin A helps to maintain their integrity 4. Goblet cells synthesize and secrete mucus ▪ Vitamin A promotes differentiation of epithelial cells and goblet cells. Mucus coats and protects the epithelial cells from invasive microorganisms and other potentially damaging substances, such as gastric juices. Vitamin A & Mucus Membranes Vitamin A: Reproduction and Growth ▪ Sperm development ▪ Normal fetal development ▪ Growth of children o Bone remodeling ▪ Antioxidant function o Beta-carotene Vitamin A Deficiency Large problem in developing countries If a person were to stop eating vitamin A–containing foods, deficiency symptoms would not begin to appear until after stores were depleted—1 to 2 years for a healthy adult but much sooner for a growing child. Vitamin A status is related to: ○ Adequacy of stores Liver storage can store 40% to 90% of total vitamin A in the body. Vitamin A Deficiency Retinol-binding protein (RBP) status is also important, it serves as the vitamin’s transport carrier inside the body. Consequences of deficiency ○ Risk of infectious diseases (measles) ○ Night blindness and blindness Night blindness is caused by a lack of vitamin A at the back of the eye, the retina Total blindness is caused by a lack of vitamin A at the front of the eye, the cornea ○ Death Vitamin A Deficiency: Measles Vitamin A: Keratinization 1. Epithelial cells of the skin change shape in the absence of vitamin A and secrete excess keratin. As a result, skin becomes dry and scaly. 2. In the GI tract, goblet cells diminish. This limits the secretion of mucus. ▪ impedes digestion and absorption, often worsening malnutrition.  Vitamin A: Keratinization The Rough Skin of Keratinization Vitamin A Toxicity Develops when binding proteins are loaded ○ Vitamin A is free to damage cells Concentrated amounts of preformed vitamin A ○ From animal sources, fortified foods, supplements ○ Children most vulnerable Bone and birth defects Vitamin A Deficiency: Rare due to large storage in liver Night Blindness Embryo Defects Keratinization Toxicity: 3-4x RDA Embryo Defects Liver Disease; Double vision; Dry skin RDA: 700 μg 900μg (19-30 yrs) Vitamin A and Beta-Carotene Recommendations ○ Expressed as retinol activity equivalents (RAE) Food sources ○ Animal sources ○ Plant sources Through biotechnology, scientists have been able to genetically modify rice to be a significant source of beta- carotene. Vitamin A in Food Groups Vitamin A in Foods Vitamin A in Food Groups Vitamin A Review  WATER SOLUBLE FAT SOLUBLE B group vitamins Vitamin C Vitamin A Vitamin D B1 Vitamin E B2 Vitamin K B3 B5 B6 B7 B9 B12 Vitamin D ❑ Vitamin D is not an essential nutrient. ○ The body can synthesize vitamin D via exposure to sunlight from a precursor the body makes from cholesterol. ○ Therefore, vitamin D is not an essential nutrient; given enough time in the sun, people need no vitamin D from foods. ❑ Vitamin D requires two hydroxylation reactions to occur for it to become activated. ❑ These reactions occur first in the liver, then in the kidneys.  Vitamin D Diseases affecting either the liver or the kidneys can interfere with the activation of vitamin D and produce symptoms of deficiency. Vitamin D Roles in Body ❑ Vitamin D is significant for making and maintaining bones. ❑ Vitamin D assists in the absorption of calcium and phosphorous. The bones grow denser and stronger as they absorb and deposit these minerals. ❑ Calcium levels influence parathyroid hormone (PTH) levels, and, in turn, PTH levels affect the turnover rate of vitamin D. ❑ Vitamin D raises blood concentrations of bone minerals in two ways: 1. Vitamin D increases calcium synthesis in the skin. 2. Vitamin D decreases calcium excretion in the urine. Vitamin D Roles ❑ In brain and nerve cells, vitamin D may protect against cognitive decline. ❑ Vitamin D may also regulate adipose cells to influence obesity development. Vitamin D Roles Research shows vitamin D may be protective against heart disease, inflammation, brain disorders, type 2 diabetes, and more. Vitamin D – summary FUNCTION: Bone making and maintenance Assists in the absorption of dietary calcium. Helps to make calcium and phosphorus available in the blood. – increasing absorption from GI tract The body can synthesize it with the help of sunlight.  Vitamin D – EXPOSURE ❑ The pigments of dark skin provide some protection from the sun’s damage, but they also reduce vitamin D synthesis. o Dark-skinned people require more sunlight exposure than light-skinned people—perhaps as much as 4 to 6 times longer. ❑ The body’s vitamin D supplies from summer synthesis alone are insufficient to meet winter needs. Vitamin D – EXPOSURE ❑ Most people in the world meet at least some of their vitamin D needs through exposure to sunlight. ❑ Type B UV (UVB) radiation with a wavelength of approximately 290–320 nanometers penetrates uncovered skin and converts 7-dehydrocholesterol to previtamin D3, which in turn becomes vitamin D3. ❑ UVB radiation does not penetrate glass, so exposure to sunshine indoors through a window does not produce vitamin D. Vitamin D – EXPOSURE ❑ Latitude, season, and time of day also have dramatic Season, time of the day, length of the day, cloud cover, skin melanin content, and sunscreen are among the factors that affect UV radiation exposure and vitamin D synthesis. ❑ People who stay in the shade and wear long-sleeved clothing are twice as likely to develop vitamin D deficiency. ❑ Appx. 5–30 minutes of sun exposure, particularly between 10 a.m. and 4 p.m., either daily or at least twice a week to the face, arms, hands, and legs without sunscreen usually leads to sufficient vitamin D synthesis. Vitamin D Misconception More than 50% of the world's population is at risk for vitamin D deficiency. This deficiency is in part due to the inadequate fortification of foods with vitamin D and the misconception that a healthy diet contains an adequate amount of vitamin D. Vitamin D from the Sun Most of the world’s population relies on natural exposure to sunlight to maintain adequate vitamin D nutrition. The sun imposes no risk of vitamin D toxicity; prolonged exposure to sunlight degrades the vitamin D precursor in the skin, preventing its conversion to the active vitamin. Prolonged exposure to wrinkle the skin and cause skin cancer. Sunscreens help reduce these risks, but sunscreens with a sun protection factor (SPF) of 8 and higher can also reduce vitamin D synthesis. Still, even with an SPF 15 to 30 sunscreen, sufficient vitamin D synthesis can be obtained in 10 to 20 minutes of sun exposure. Alternatively, a person could apply sunscreen after enough time has elapsed to provide sufficient vitamin D synthesis. For most people, exposing hands, face, and arms on a clear summer day for 5 to 10 minutes two or three times a week should be sufficient to maintain vitamin D nutrition. Avoiding sun exposure completely may be harmful to health.  miss as much as 6 months of vitamin D production every year. Above 40° north latitude (and below 40° south latitude in the southern hemisphere), vitamin D synthesis essentially ceases for the 4 months of winter. Vitamin D Deficiency ❑ Four factors that contribute to vitamin D deficiency. ▪ dark skin, ▪ breastfeeding without supplementation, ▪ lack of sunlight, ▪ not consuming fortified milk ❑ In vitamin D deficiency, production of calbindin, a protein that binds calcium in the intestinal cells, slows. ❑ Thus, even when calcium in the diet is adequate, it passes through the GI tract unabsorbed, leaving the bones undersupplied. ❑ Consequently, a vitamin D deficiency creates a calcium deficiency and increases the risks of several chronic diseases and osteoporosis. Vitamin D–deficient adolescents do not reach their peak bone mass. Vitamin D Deficiency: Rickets In rickets, the bones fail to calcify normally, causing growth impairments and skeletal abnormalities. The bones become so weak that they bend when they have to support the body’s weight. A child with rickets who is old enough to walk characteristically develops bowed legs, often the most obvious sign of the disease. Vitamin D Deficiency Risk groups: Babies: only have 6 months of storage Vegetarians: can not get it from plants Dark skinned people: have melanin Older people: older skin, liver, kidney and less activity outdoors Vitamin D Deficiency Osteomalacia: Osteoporosis: In adults, the poor Any failure to synthesize mineralization of bone adequate vitamin D or results in this painful bone obtain enough from foods disease. sets the stage for a loss of The bones become calcium from the bones, increasingly soft, flexible, which can result in brittle, and deformed. fractures. Vitamin D Toxicity Most likely of the vitamins to have toxic effects ○ Supplements Raises blood calcium concentrations ○ Forms stones in soft tissues Kidneys ○ May harden blood vessels Can cause death Vitamin D Deficiency: Children = Ricket’s Disease – bow legs Adults = Osteomalacia – soft bones Calcium absorption; Blood Calcium = bone deficiency – skeletal system Toxicity: 10x RDA Calcium absorption; Blood Calcium = Calcium deposits on soft tissue e.g. kidney stones RDA: 15 μg/dl 20 μg/dl (19-30 yrs) Vitamin D Recommendations There are few food sources of vitamin D: Oily fish, egg yolks, fortified milk Vitamin D can be found in multivitamin-mineral supplements as well as a high-dose single supplement. As a single supplement, vitamin D3 is less expensive, more commonly available, and more effective than vitamin D2. Toxicity cannot occur from sun exposure. Meeting recommendations are difficult without sunlight, supplementation, or fortification. Vitamin D Vitamin D Review  WATER SOLUBLE FAT SOLUBLE B group vitamins Vitamin C Vitamin A Vitamin D B1 Vitamin E B2 Vitamin K B3 B5 B6 B7 B9 B12 Vitamin E Two subgroups: tocopherols and tocotrienols ○ Each contains four members: alpha, beta, gamma, and delta Position of methyl group ○ Only alpha-tocopherol maintained in the body. The others are not converted to alpha-tocopherol in the body, nor are they recognized by its transport protein. ○ RDA is based only on alpha tocopherol. Antioxidant ○ Stops chain reaction of free radicals Protects cells and their membranes Prevents oxidation of poly unsaturated fatty acids (PUFAs) Heart disease and protection of LDLs Vitamin E – tocopherol – related to child birth α-tocopherol only one to have activity in human body Performs a key role as an antioxidant in the body. – it gets oxidized Absorption requires dietary fats Stored in adipose tissue, muscles, and cell membrane of tissues Vitamin E Vitamin E Deficiency: Rare Premature infants - reproductive failure in rats Those who cannot absorb fats - adults on a low fat diet Toxicity: Rare blood clotting mechanisms – affects Vit K RDA: 15 mg 15 mg (19-30 yrs) Vitamin E Deficiency Primary deficiency is rare Secondary deficiency (associated with diseases) ○ Fat malabsorption, ○ e.g., cystic fibrosis Vitamin E Deficiency Effects of deficiency ○ Red blood cells split as PUFAs become oxidized Erythrocyte hemolysis ○ Prolonged deficiency: Neuromuscular dysfunction ○ Vitamin E treatment helps to correct neurological symptoms Vitamin E Toxicity Liver regulates vitamin E concentrations ○ Toxicity is rare UL is 65 times greater than RDA for adults Extremely high doses of vitamin E ○ interfere with blood-clotting of vitamin K activity Hemorrhage (acute blood loss from a damaged vessel) Vitamin E Recommendations The RDA is based on the alpha tocopherol form only. Vitamin E is widespread in foods. ○ Much of dietary vitamin E comes from vegetable oils or foods containing them. Vitamin E is destroyed by oxidation and heat, therefore fresh foods are preferable sources. Vitamin E Review  WATER SOLUBLE FAT SOLUBLE B group vitamins Vitamin C Vitamin A Vitamin D B1 Vitamin E B2 Vitamin K B3 B5 B6 B7 B9 B12 Vitamin K Vitamin K Vitamin K is a fat-soluble vitamin that comes in two forms: The main type is called phylloquinone, found in green leafy vegetables like kale and spinach. The other type, menaquinones, are found in some animal foods and fermented foods. Menaquinones can also be produced by bacteria in the human body. ✓ Vitamin K appropriately gets its name from the Danish word koagulation (“coagulation” or “clotting”). ✓ Its primary action is blood clotting, in which its presence can make the difference between life and death. ✓ Blood has a remarkable ability to remain liquid, but it can clot within seconds when the integrity of that system is disturbed. Vitamin K More than a dozen different proteins and the mineral calcium are involved in making a blood clot. Vitamin K is essential for the activation of several of these proteins, among them prothrombin, made by the liver as a precursor of the protein thrombin. When any of the blood-clotting factors is lacking, hemorrhagic disease results. If an artery or vein is cut or broken, bleeding goes unchecked. Of course, this is not to say that hemorrhaging is always caused by vitamin K deficiency. Another cause is the genetic disorder hemophilia, which is neither caused nor cured by vitamin K. Vitamin K Deficiency: Rare Maybe if you take antibiotics Fractures because it works with Vit D Babies – no bacteria in GI tract; within 6 hours of birth get injection to prevent hemorrhaging Toxicity: Rare Affect anti-coagulation drug RDA: 90 μg 120 μg (19-30 yrs) Vitamin K: Blood-Clotting Process Vitamin K also participates in the metabolism of bone proteins, most notably osteocalcin. Without vitamin K, osteocalcin cannot bind to the minerals that normally form bones, resulting in low bone density. An adequate intake of vitamin K helps decrease bone turnover and protect against fractures. Vitamin K is historically known for its role in blood clotting, and more recently for its participation in bone building, but additional roles continue to be discovered. Recent research suggests that vitamin K may be associated with a reduced risk of heart disease, some cancers, and all- cause mortality. Vitamin K – family of quinones (phyllo – and menaquinones) FUNCTION: Blood clotting Synthesis of 7 proteins involved in clotting Koagulation = Danish word = coagulation Bone health Works with vitamin D to regulate calcium Synthesized by intestinal flora- bacteria in GI tract Stored in liver Vitamin K Deficiency A primary deficiency of vitamin K is rare, but a secondary deficiency may occur in two circumstances. First, whenever fat absorption falters, as occurs when bile production fails, vitamin K absorption diminishes. Second, some drugs disrupt vitamin K’s synthesis and action in the body: antibiotics kill the vitamin K–producing bacteria in the intestine, and anticoagulant drugs interfere with vitamin K metabolism and activity. Excessive bleeding due to a vitamin K deficiency can be fatal. Vitamin K Deficiency Newborn infants present a unique case of vitamin K nutrition because they are born with a sterile intestinal tract, and the vitamin K–producing bacteria take weeks to establish themselves. Furthermore, vitamin K is minimally transported across the placenta and its concentration in breast milk is low. At the same time, plasma prothrombin concentrations are low, which reduces the likelihood of fatal blood clotting during the stress of birth. To prevent hemorrhagic disease in the newborn, a single dose of vitamin K is given at birth by intramuscular injection. Vitamin K Deficiency Soon after birth, newborn infants receive a dose of vitamin K to prevent hemorrhagic disease. Vitamin K: Recommendations and Food Sources  Vitamin K Review Vitamin K helps with blood clotting, and its deficiency causes hemorrhagic disease (uncontrolled bleeding). Bacteria in the GI tract can make the vitamin; people typically receive about half of their requirements from bacterial synthesis and half from foods such as green vegetables and vegetable oils. Because people depend on bacterial synthesis for Vitamin K, deficiency is most likely in newborn infants and people taking antibiotics. Vitamin K Toxicity Not common ○ No adverse effects with high intakes No UL High doses can reduce effectiveness of anticoagulant drugs ○ Consistent intake of vitamin K is best  WATER SOLUBLE FAT SOLUBLE B group vitamins Vitamin C Vitamin A Vitamin D B1 Vitamin E B2 Vitamin K B3 B5 B6 B7 B9 B12  Extra Topic: Vitamin and Mineral Supplements  Healthy children and adults should be able to get all the nutrients they need by eating a variety of food ENJOY A BALANCED DIET What if I am not getting a balanced diet?? X Can I get the nutrients from supplements? Vitamin Supplements According to the 2005 Dietary Guidelines for Americans, "Nutrient needs should be met primarily through consuming foods. Foods provide an array of nutrients and other compounds that may have beneficial effects on health. In certain cases, fortified foods and dietary supplements may be useful sources of one or more nutrients that otherwise might be consumed in less than recommended amounts. However, dietary supplements, while recommended in some cases, cannot replace a healthful diet." Vitamin Supplements We should get all our nutrients from our diet but; do we???? Do you eat a nutritious, whole grain breakfast every day? Do you eat a natural healthy snack every 2-3 hours? Do you eat at least 2 piece of fruit every day? Do you eat at least 5 serves of vegetables every day? Do you eat at least 3 serves of deep sea fresh fish every week? Do you drink at least 2 litres of purified water every day? Vitamin Supplements Who needs vitamin supplements People following very low-calorie diets People with reduced appetite, having conditions related to absorption or excretion of nutrients Strict vegetarians Women – excessive menstrual bleeding, pregnant, breastfeeding, planning pregnancy Lactose intolerant Recovery from surgery Heart disease or other chronic diseases Vitamin and Mineral Supplements: Who should NOT TAKE? Vitamin Supplements Be informed: Seek unbiased, scientific sources Inform your physician, especially if taking prescribed medications Dietary supplements cannot replace the benefits of a diet containing a wide variety of foods. Dietary supplement production is not supervised by the FDA. Do not exceed recommended doses or use for prolonged periods. Vitamin Supplements Supplements are presumed safe until the Food and Drug Administration (FDA) receives well-documented reports of adverse reactions. Supplements are not obliged to meet any standards of effectiveness or safety. Products cannot state on the label that they will “prevent,” “treat,” “diagnose,” ”mitigate,” or “cure” disease. Product must carry a disclaimer on the label - “This product has not been evaluated by the Food and Drug Administration.”