Nutrition Ch. 7 FINAL

absorption of B12

Intrinsic factor → protein released in stomach needed for b12 to be absorbed • binds to b12 in upper small intestine→ b12 intrinsic factor complex • Absorption of this newly form complex → occurs in lower small intestine, binds with receptors on mucosal cells • NOTE: only a small amount of b12 not bound to an intrinsic factor can be absorbed.

neural tube defects**

malformation of brain, spinal cord or both during embryonic development o Neural tube - embryonic tissue that will later develop into the brain and spinal cord. • It closes 28 days after conception. The bony central chamber closes fully encasing the cord, its membranes, and spinal fluid. • The concern: this is before most women know they are pregnant o Spina bifida is the most common NTD. o Three membranes that surround spinal cord often protrude from the spine as a sac o Portion of the spinal cord is sometimes in the sac o Mild cases may not be noticeable. Often accompanies by some degree of paralysis o Anencephaly is the absence of all or a major portion of the brain. All infants will die before or shortly after birth if they have anencephaly

Pellagra***

niacin-deficiency disease. o Early symptoms: fatigue, decreased appetite and indigestion. o ***As it progresses, the symptoms become the four "D's": diarrhea, dermatitis, dementia, death • Those at risk of developing pellagra→poorly nourished and alcohol addictions • Toxicity of niacin (supplementation & fortification) can bring about "niacin flush": o "niacin flush" → tingling, burning, and itching sensation of the skin caused by dilation of capillaries under the skin.

Choline

not a vitamin; considered an essential nutrient • Included in vitamin B complex supplements • Functions: 1. Needed for the synthesis of a neurotransmitter (acetylCHOLINE) 2. Needed for the making of cell membranes 3. Involved in the transportation of lipids 4. It is also needed in the metabolism of homocysteine

water soluble vitamins

o B vitamins: thiamin (B1), riboflavin (B2), niacin (B3), biotin, pantothenic acid, vitamin B6, folate/folic acid, and vitamin B12 (cyanocobalamin) o Vitamin C (ascorbic acid)

Vitamin C

• Another name for vitamin C → ascorbic acid • Vitamin C has many FUNCTIONS in the body: 1. It assists enzymes in the synthesis and maintenance of collagen 2. How? o Helps with formation of bonds between adjacent collagen strands, which makes the protein STRONG. o Reminder: Collagen is most abundant protein in the body. It is the main protein found in most connective tissue (Ex. scars, ligaments, tendons, bones, teeth, & skin). It provides structure for blood vessels as well. 3. It is an antioxidant: Protect substances from oxidation by free radicals; sacrifices itself by donating electrons. As an antioxidant (for example): • Helps to protect circulating vitamin E. (another antioxidant) & aids in keeping it active. • Helps to protect iron from oxidation (small intestine) & promotes its absorption. 4. Vitamin C aids in the absorption of iron, calcium, & folate 5. It is also involved in reactions that make neurotransmitters, hormone, bile acids, (and carnitine). 6. It helps to protect us against infections. How? Protects cells of immune system from oxidation 7. Prevention of the common cold? • It doesn't prevent, it may just decrease the severity of some of the symptoms and duration of the cold • Doesn't necessarily prevent it.

Pantothenic Acid

• As a component of a coenzyme A ("CoA"): o It is involved in the breakdown of → CHO, fatty acids, and amino acids o **It assists with the making of acetylcoA which is needed in the Citric Acid cycle and ultimately, ATP formation. o It is involved in the modification of proteins o It is also needed in the synthesis of →lipids, neurotransmitters, steroid hormones, and hemoglobin • Pantothenic acid is needed to make a molecule that is vital for the synthesis of cholesterol & fatty acids.

vitamin functions

• Coenzymes: organic non-protein substance (vitamins fit this criteria) that binds to an enzyme to promote the activity of the enzyme with which it is bound. o Enzymes that require coenzymes → are considered incomplete. Binding of coenzyme→ ACTIVE enzyme o NOTE: ALL OF THE B VITAMINS ACT AS COENZYMES

vitamin D deficiencies**

• Deficiency of vitamin D → only about 10% to 15% of calcium in the diet is absorbed. • ***Rickets is the vit. D deficiency in children → unable to mineralize newly formed bone; legs become bowed bc of not being able to support bone weight • ***OsteoMalacia is the vit. D deficiency in adults → loss of bone Minerals. Bones soften and become brittle increased risk for fractures (hip and spine) • **Osteoporosis is a loss of total bone mass not just minerals.

Biotin

• It plays an important role in energy metabolism: • Biotin is needed in the synthesis of glucose from non-carbohydrate sources such as amino acids and glycerol. • It is needed in the synthesis of fatty acids and the breakdown of certain fatty acids and amino acids. • *It can be made in the body by bacteria in the GI tract. • Significance of avidin (protein found in raw egg whites) → binds with biotin; cooking denatures avidin and biotin is released

vitamin D

• Obtain it from → both food and ultraviolet of the sun • Making of vitamin D: o Ultraviolet light (sun) shines on a cholesterol compound in the skin, creating a vitamin D precursor The precursor is absorbed. o 1 ½ days later -liver & kidneys donate hydroxyl groups & it becomes active vitamin Even vitamin D in food has to be "activated" to be functional. • Diseases of the liver & kidney → impair the conversion of vitamin D to its active form. • Other factors that could affect the synthesis of vitamin D: a. Color of the skin → darker skin pigment requires more exposure b. Age → elderly have limited exposure; not as efficient at activating vitamin D c. Where someone lives → geography and climate; how often they get outside d. Time of the year → decreased exposure in the winter; angle of the sun e. Air pollution → ultraviolet rays cant penetrate f. Protective clothing →worn as protection or worn to be concealing g. Use of sunscreen → SPF 15 decreases synthesis by 99% Note: 5 to 10 minutes of midday exposure to the sun 3X/week in the spring, summer, & fall can provide a light-skinned individual with adequate vitamin D.

More info on vitamin A

• Some foods are fortified with vitamin A. • Absorbability of the retinoids & carotenoids: o **Retinoids are absorbed more readily than the carotenoids. o Because of this, recommendations are expressed as retinol activity equivalents with 12µg of beta-carotene = 1µg of retinol in the body. • Vitamin A (active & inactive) is bound to protein which can be released by protein digestive enzymes → pepsin and pancreatic proteases. • For vitamin A, as well as other fat-soluble vitamins to be absorbed, they are incorporated into micelles, a particle that is formed in the small intestine when the products of fat digestion (fatty acids, glycerol, monoglycerides, & cholesterol) are surrounded by bile. Deficiency in fat → deficiency in VITAMIN A

meeting vitamin needs

• The RDAs and the AIs are set at amounts to prevent deficiencies and promote health. o Vitamin needs can be met by → meeting calorie needs o Consuming nutrient dense foods o Eating a diet pattern suggested by myplate and dietary guidelines for Americans o Some vitamins have ULs (Tolerable Upper Intake Levels) →help avoid risk for toxicity • Food labels on packaged foods can be used to evaluate the vitamin content of a product. Required to list amounts of vitamin A and Vitamin C as a % of daily value. ***% Daily Value is 20% or more → excellent source % Daily Value is between 10% and 19% → good source % Daily Value that is 5% or less → poor source

scurvy***

(the vitamin C deficiency disease) (inability to form healthy collagen): o Symptoms: inflamed, swollen, and bleeding gums; loose teeth o Capillaries weaken and rupture → bleeding under the skin and into the joints. Joint weakness and pain follows. Bruising can occur easily. o Wounds that don't heal and frequent infections o Bone fractures and feeling fatigued and depressed.

catabolism

- breaking apart (destructive) component of metabolism that releases energy..... Think "canabal" they eat ppl and catabolism they are destructing things and releasing energy

symptoms of riboflavin deficiency

1. Cheilosis - cracking and redness of lips and corners of mouth 2. Flaking of skin- around nose, eyebrows and earlobes 3. Glossitis - inflammation of the tounge (red and swollen) 4. The eyes are affected →increased sensitivity to light, burning, tearing, and itching of the eyes

Folate

1. Folate and B12 are needed for the making of all new cells. Why? → necessary for making of DNA and RNA 2. Folate and B12 are needed for the replication of DNA which is especially important in rapidly-dividing tissues (bone marrow, GI tract, skin, developing fetus, etc.). 3. Folate, B12, & B6 - refer to vitamin B6 functions. 5. **Needed for reducing the risk of having of having a baby born with a neural tube effect.

fortification

1. Government mandated o Examples: B vitamins & iron added to grains; milk fortified with vitamin B o Why fortify foods? → to prevent nutrient deficiencies and promote health 2. "Voluntary" fortification (NOT mandated): risk for exceeding tolerable upper intake levels (UL's) and nutrient toxicities • How a food is processed, prepared, and stored affects the amount of vitamins available in a food.

deficiency of B12

A deficiency of B12 due to the lack of intrinsic factor is called ***Pernicious Anemia which is characterized by the following: • large and immature red blood cells that can cause nerve damage • hard to tell difference between folate and b12 deficiencies Importance of early detection: • early detection important to prevent irreversible nerve damage creeping paralysis- begins at the extremities and works its way inward. • Two population groups at risk of a B12 deficiency: vegetarians and the elderly o Vegans → Strict vegetarians; eat only foods from plant sources; no B12 in plant foods; risk of deficiency; obtain B12 from supplements and/or foods fortified with B12. o Older adults are at risk because of atrophic gastritis, an inflammation of the stomach lining. ("atrophic" means waste away) Repercussions of the inflammation: • Reduce the secretion of stomach acids → leads to microbial overgrowth. Competition for the B12 • With severe inflammation → reduce the synthesis of the intrinsic factor. Supplementation may be needed and foods high in B12 are avacados, peanuts, shellfish, liver, fish, crab, tofu, cereals, beef, skim milk, cheese, and eggs

what helps to release vitamins from food?

Mechanical digestion in food • Chemical digestion: (some) in the stomach (niacin) and in small intestines ex. Pancreatic enzymes ****• Vitamin absorption occurs → occurs mainly in small intestines • Small amount of niacin in stomach

Thiamin

Part of a coenzyme o Aids in the breakdown of glucose to provide ENERGY. o Needed to convert pyruvate to acetylcoA [cellular respiration → ATP (energy)] 2. *Being a part of a coenzyme is especially important for nerve function. 3. Thiamin is needed for the synthesis of neurotransmitters, chemical substances produced by nerve cells that can stimulate or inhibit another cell. 4. Thiamin is needed in the metabolism of other sugars and amino acids. 5. Required for the synthesis of ribose and deoxyribose (sugars found in RNA & DNA).

main fxns of vitamin D

Regulation of calcium and phosphorus in the bones & teeth. o Controls the amount of calcium absorbed across the GI tract. o Controls the amount that goes in/out of bones. o Works with the kidneys in regulating the amount of calcium secreted in urine. Parathyroid hormone (PTH) & its role with increasing calcium levels in the blood: o o Blood levels of calcium get LOW → stimulates the release of PTH→ stimulates activation of vitamin D o Active vitamin D increases the absorption of calcium in the small intestine o Active vitamin D and PTH → increases breakdown of bone to release Ca and P and reduce Ca secreted by kidneys • Vitamin D functions as a "hormone" → it can be made by an organ (skin); it travels in the blood & has an effect on other organs (small intestine & the kidneys)

Riboflavin

Riboflavin is a part of two coenzymes )]. Act as electron carriers functioning in reactions needed to produce ATP from CHO. Fat and protein 2. Directly or indirectly involved in converting some vitamins into their active form such a folate, niacin, B6, and vitamin K. 3. Supports vision and skin health • A deficiency of riboflavin rarely occurs. But when it does occur → it can affect all new cell growth

fat soluble vitamins

Vitamins A, D, E, and K NOTE: Solubility of the vitamins determines→ how they're absorbed into the blood stream and transported and whether they are stored, and how easily they can be lost from the body

vitamin E

antioxidant o Protects the body against oxidative damage. o Donates electrons to highly reactive free radicals. o Reminder: free radicals are atoms or molecules that have one or more UNPAIRED electrons. This makes them highly reactive and potentially destructive. o Examples of molecules & cells that vitamin E help to protect: • Protects lipids in cell membranes, DNA, proteins, red blood cells, white blood cells, nerve cells, & cells of the lungs. • Helps protect cells from heavy metals (lead & mercury), toxins, & an assortment of drugs. • A deficiency of vitamin E is rare. It is found in many foods & the body recycles it. • Though rare, population groups at risk of a deficiency: 1. Premature infants are at risk of ***hemolytic anemia (insufficient number of red blood cells because many BURST bc hemolysis is the bursting of red blood cells). • Insufficient amounts of vitamin E cause the cell membranes of many red blood cells to rupture, which decreases the number of red blood cells. • Note: The infant was born before most of the vitamin E was delivered via the placenta during later stages of development. • Premature infant would be given supplemental vitamin E to prevent red blood cells from rupturing. 4. Those who consume large amounts of heavily processed foods. Vitamin E can be destroyed by high temperatures. • Absorption of vitamin E → it is with fat in the small intestine via micelles • Storage of vitamin E → fatty tissue, liver and muscles • Concerns about individuals taking anticoagulant medications, which prevent blood from coagulating (forming a clot, Vitamin E can intensify the effects, i.e. could result in uncontrollable bleeding. • Role in disease prevention such as with heart disease and cancer: o As an antioxidant → reduce risk of developing heart disease and cancer. o Anti-inflammatory functions & immune response → reduce risk of developing heart disease.

oxidative damage

caused by highly reactive oxygen molecules that steal electrons from other compounds, causing changes in structure and function. o A free radical is type of highly reactive molecule. o Antioxidants donate electrons. Significance of this →stabilizes free radical ***Which vitamins are antioxidants? →vitamin C, vitamin E, and provitamin A

anabolism

constructive part of metabolism where new material is MADE • NOTE: The B vitamins do NOT provide us with energy.

B vitamins and C (water soluble)

easily absorbed o They are not stored in the body to any large extent → excess is excreted in urine Hence, they have to be consumed regularly. • B Vitamins (introduction) o Thiamin, riboflavin, niacin, folate, B6, B12, biotin, and pantothenic acid → o ****^ " Tender Romance Never Fails w/ 6 or 12 Beautiful Pearls" ^ o Every B vitamin is part of what? → coenzymes o B vitamins, directly or indirectly, are involved in energy metabolism (catabolism and anabolism).

Vitamin

essential nutrients • Needed in small amounts • Organic compounds-contain carbon

bioavailability

extent to which the body can absorb and use a nutrient. 1. Vitamin bioavailability is influenced by the following: composition of the diet, conditions of GI tract, and the rest of the body (in general) Impaired absorption (examples): o Diet very low in fat → impaired fat-solible vitamin absorption o Low concentrations of blood proteins → vitamin transporters would impair the absorption of water soluble vitamins 2. Some vitamins are absorbed in an inactive form. Provitamin/vitamin precursor- compound in its inactive form that is converted to the active form once in the body.

what can cause nutrient losses?

heat, light, oxygen, passage of time, food processing, cooking, and storage o Fresh vs. canned vs. frozen (Figure 7.2): frozen fruits and veggies may supply more vitamins than fresh ones o High temps used in canning reduce nutrient content. But bc canned foods keep for a long time, do not require refrigeration and are often less expensive than fresh or frozen foods, they provide an available affordable source of nutrients that may be the best choice in some situations o Sometimes fresh produce is lower in nutrients than you would expect bc it has spent a week in a truck, traveling to ur store, several days on a shelf, and maybe another week in ur fridge

absorption of fat soluble vitamins

is different (micelles and chylomicrons). 1. Micelles :small droplets that form in the small intestine when the products of fat digestion are surrounded by bile. a. Composition: fatty acids, glycerol, monogycerides, cholesterol, and fat soluble vitamin surrounded by bile b. Purpose: facilitates the absorption of fat and fat soluble vitamins via simple diffusion 2. Chylomicron :a lipoprotein comprised of newly reassembled TGs, cholesterol, fat-soluble vitamins that are packaged with phospholipids and protein. a. Purpose: transport fats and fat soluble vitamins out of the mucousal cells b. How do they leave the mucosal cells? Why this route? c. Leave via the lymph bc they're too big for capillary system--> bloodstream delivers TG's to cells in the body • Large intestine → bacteria can make a small smount of some vitamins, some of which are absorbed.

toxicity of vitamin A

o Culprit: toxicity→ can be avoided o Exceeding the UL can be avoided by → o Early symptoms of toxicity: loss of appetite, nausea, vomiting, headaches, dizziness, blurred vision, headache, itching of the skin, and lack of muscle coordination. o Chronic toxicity - weight loss, hair loss, skin rashes, visual defects, birth defects, muscle and joint pain, loss or coordination, bone abnormalities and fractures, and damage to the liver. o Excessive vitamin A is of particular concern for pregnant women → may contribute to birth defects. • Toxicity of beta-carotene would only lead to the yellowing of the skin (hypercarotenemia).

beriberi****

o Marked by inflammatory or degenerative changes of the nerves, digestive system, and the heart. o Without thiamin, glucose can't be used normally. o Nerve impulses cannot be transmitted normally. o Symptoms of beriberi: loss of sensation in the hands and feet; edema; muscle weakness & poor coordination; advancing paralysis, poor short-term memory and confusion; and changes to the heart (enlargement and possibly heart failure) • Alcoholics are at risk of a thiamin deficiency. • Ethanol interferes with absorption of thiamin and hastens its secretion • With little thiamin that is available is being used to metabolism with ethanol.

absorption of water soluble vitamins

o Some need assistance → transport system (energy needed) or they bind to a specific molecule o What happens after they are absorbed? Theyre able to go directly into the bloodstream. Need transportation in the blood- most are bound to blood proteins

deficiencies for folate

o The Food and Drug Administration (FDA) (1998) → mandated the fortification of grain products with folic acid • ***Deficiency in folate could result in an anemia called megaloblastic or macrocytic anemia. • Lack of folate→ red blood cells unable to divide • Red blood cells become larger=megaloblastic anemia • Fewer mature red blood cell→ reduce oxygen carrying capacity of the blood • Other deficiency symptoms: poor growth, nerve development & function problems, & smooth, red tongue.

vitamin B12

o Vitamin B12 & folate required for the making of new cells (DNA & RNA synthesis). o Needed for the maintenance of the myelin sheath o It is also needed to convert folate to an active coenzyme form. Significance of this conversion →needed for conversion of homocysteine to cysteine • Water-soluble vitamins are not stored to any large extent. What about B12? Body stores and reuses B12 more efficiently than other water soluble vitamins. • What helps to release it? → Change of acidity in stomach • And pepsin in stomach

Niacin

part of two coenzymes o Metabolism of CHO, fat, and alcohol o Synthesis of fatty acids and cholesterol • Niacin can be made in the body from tryptophan(essential amino acid). o Niacin equivalents (NE) → a measure that accounts for the availability of tryptophan o Tryptophan is abundant → in most proteins. Diet sufficient in high quality proteins= lots of niacins

vitamin K

role in Clotting of blood o Prothrombin → thrombin o Fibrinogen → fibrin Fibrin → fibrinogen, forms solid clot • Another function of vitamin K: Needed for the synthesis of important bone proteins which enable minerals to bond for the formation of bone. o Without these proteins→ bone density would be low. o Hence, vitamin K may have role in prevention/treatment of osteoporosis.

Vitamin B6 (look at processes in notebook)

role in amino acid and protein metabolism • Additional Functions: 1. Role as a coenzyme 2. Making of nonessential amino acids via **transamination reactions. How? → aids in the joining of the amino group and the carbon compound forms a new AA Coenzyme: helps more than 100 enzymes in metabolism of CHO, protein, and fat 3. ***Needed for deamination reactions → aids in the removal of the NH2 (amino group) 4. group (NH2); remaining carbon compound used for energy or making of glucose 5. Involved in the synthesis of neurotransmitters → deamination aids in removal of the acid group (COOH) from the amino acid; remaining molecule is used to make the neurotransmitter 6. Needed for the synthesis of lipids that are a part of the myelin sheath (fatty substance that surrounds/protects nerves, spinal cord, & brain; required for the growth of nerves; & aids in nerve transmissions.) 7. B6, folate & B12, it is needed for the synthesis of hemoglobin & for the formation and maturation of red blood cells & white blood cells. 8. B6, folate, & B12: Needed in the conversion of homocysteine (intermediate compound produced during the metabolism of the essential amino acid methionine) to cysteine (nonessential amino acid). Significance → elevated levels of homocysteins in blood may enhance blood clot formation and causes a deterioration of the walls of arteries. It acts as an irritant→ injury to arterial wall→ accumulation of a fatty substance= blot clot 9. Needed to convert tryptophan into niacin 10. Needed for breaking down glycogen to release glucose into the blood.

functions of vitamin A

role in gene expression Info coded in genes is used to synthesize proteins Vitamin A turns the genes on/off 2. Vitamin A has two very important roles in vision. a. Processing of light in the retina • Retinal (in the retina) combines with opsin (protein) to make rhodopsin a light-sensitive pigment in rod cells of the retina that enables us to see in dim light • ****A deficiency of vitamin A could result in night blindness, which is the slow recovery of vision after exposure to flashes of bright light. Possible reason for such: the rhodopsin has a hard time recovering b. Helps to keep the cornea healthy. • ***Deficiency could lead to clouding due to accumulation of keratin, which is a condition called keratinization. • It will get worse if untreated. • Will also cause **xerosis: the drying of the cornea. • **Xerophthalmia: advanced vitamin A deficiency; cornea thickens and becomes hard; can lead to blindness. 3. Vitamin A helps with the growth and replenishment of epithelial tissue. How? o Vitamin A has a role in cell differentiation, a process in which immature cells are stimulated to mature. As a result, cells have the ability to carry out their specific functions. o Failure to mature → cells die and accumulate; tissue is vulnerable to infection. 4. Aids in our ability to smell, hear, and taste. A deficiency in vitamin A would affect → taste buds→ sense of taste altered→ loss of appetite 5. Key role in the immune system → regulates genes that make proteins involved with immunity, such as antibodies. 6. Needed for normal reproduction growth - examples being sperm development in men and normal fetal development in pregnant women. 7. Assists in the growth of bone and teeth ("remodeling" of the ends of bones): o Remodeling: dismantling the old bone structure & replacing it with new bone. o NOTE: Failure of children to grow is one of the 1st signs of a deficiency of vitamin A.

antioxidant

substance that decreases the adverse effects of reactive molecules on normal physiological function. They protect against oxidative damage. "Anti" and "oxy" =

folic acid

synthetic form of folate use din supplements and fortification of grain products o It is more readily absorbed than "naturally" occurring folate. Bioavailability is almost twice that of folate. • Another way of looking at the bioavailability of folic acid → for every 1 ug folic acid, you would need about 2 ug folate • Studies have shown that adequate intakes of folic acid before & during early pregnancy can greatly reduce the risk of having a baby being born with a neural tube defect such as spina bifida and anencephaly.

deficiency**

• Those at risk for a deficiency: 1. Newborns → at birth- do not possess bacteria to make vitamin K 2. Intestines are sterile 3. They are given oral dose of vitamin K at birth 4. Long term antibiotic usage → can kill the "good" bacteria (lg. intestine) as well. 5. Taking of anticoagulant medications → vitamin K interferes with the blood thinner & vice versa. o ***It can cause jaundice → red blood cells in the liver rupture and release a pigment called bilirubin, which can cause the skin to turn yellow. o Concern → if bilirubin circulates to the brain of an infant, it could lead to brain damage. o Jaundice can also occur in individuals who are in a severe stage of hepatitis (inflammation of the liver).

vitamin A

• Two forms of vitamin A: 1. *Retinoids - preformed/active vitamin A 2.* Carotenoids - INACTIVE form of vitamin A • Some are precursors of vit. A → once in the body → can be converted to retinoids. • Carotenoids are natural pigments made by plants; give certain fruits & vegetables their yellow or orange color. • ****An example of a carotenoid is beta carotene: some remain in the inactive form and some are precursors of vitamin that are converted into active vitamin A. • Sources of beta-carotene: orange & yellow veggies as well as dark green vegetables (pigment concealed by chlorophyll) • Beta-carotene that is NOT converted into active vitamin A may FUNCTION as an antioxidant: o Neutralizes reactive oxygen molecules & protects body from oxidative damage o May have a protective role against cancer & heart disease. • Beta-carotene that is converted into retinols (active form of vitamin A): o **How? → once in body, its split in half which is RETINOL o Cannot be converted back to beta carotene o Storage → Retinol made from beta-carotene is stored in liver. • Retinol leaves liver via retinol binding proteins. • Zinc is needed to make these proteins.

vitamins in our foods

• Where are vitamins found? → all food groups • Which food groups lack B12? →fruits veggies and grains • Which food groups lack Vitamin C? → grains, dairy and protein • Another source of vitamins - fortification-adding of nutrients to food