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Nutrition - Vitamins and Minerals, Essential Nutrients

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What are vitamins?
organic compounds needed in small quantities in the body, but not synthesized in adequate amounts by humans or not at all.
How much of vitamins is required?
micrograms to mg
What are the biological roles of vitamins?
essential cofactors for enzymatic reactions, components for energy carriers, precursors, biological regulatory molecules, antioxidant
What are the water-soluble vitamins?
B and C
What are the fat-soluble vitamins?
A, D, E, K
Name the characteristics of fat-soluble vitamins
1.Insoluble 2. Bound to carrier protein/part of lipoprotein particles 3.40-90% absorbed 4. Can be stores in body fat depots except Vitamin K
How are vitamins classified by?
solubility in water
Which of the fat soluble vitamins cannot be stored in body fat depot?
Vitamin K
Name the characteristics of water-soluble vitamins?
1. Soluble 2. Free form in circulation 3. not effectively stored in the body 4. Regular intake is important
Which vitamins deficiencies manifest late?
Deficiencies of fat soluble vitamins
Which vitamins deficiencies manifest early?
Deficiencies of water soluble vitamins
What is Vitamin A?
Trans- Retinol
What is Vitamin D?
Cholecalciferol
What is Vitamin E?
tocopherol
What is Vitamin K?
Vitamin K
What is Vitamin C?
Ascorbate
What are the different types of Vitamin B?
B1, 2, 3, 5,6, 7, 9, 12
What is Vitamin B1?
Thiamine
What is Vitamin B2?
Riboflavin
What is Vitamin B3?
Niacin
What is Vitamin B5?
Pantothenic Acid
What is Vitamin B6?
Pyridoxine
What is Vitamin B7?
Biotin
What is Vitamin B9?
Folic acid
Which vitamins are enzymatic cofactors?
Vitamins B1, 6, 7, 9, 12 and Vitamin K
Which vitamins are components of energy carriers?
Vitamins B2, B3, and B5
Which vitamins are antioxidant?
Vitamins C and E
Which vitamin is an antioxidant and essential co factor?
Vitamin C
Where does Vitamin C play a role a essential cofactor?
Hydroxylation of Proline and Lysine residues of collagen -> helps with crosslinking of collagen fibers
What is the result of Vitamin C deficiency?
Scurvy which is the reduction of tensile strength
What does RDA stand for?
Recommendation of Dietary Allowance in the US.
What is RDA ?
Estimated requirement of a vitamin/mineral to prevent deficiencies in population of healthy individuals, then increase by an amount sufficient to meet needs of nearly all (98%) members of that group
What is the population targeted by RDA?
healthy individuals, men and women, different age groups, pregnant and lactating women included
Is RDA referred in food labels?
Not
Why isn't RDA referred in food labels?
gender and age-specific
What is Reference Daily Intake?
highest RDA level across groups and usually referred as % Daily value
When and why were RDA first established?
WWII. To provide nutritional recommendations for armed forces and civilians during times of food rationing
What does DRI stand for?
Dietary Reference Index
What is the Dietary Reference Index? When has it been established?
In 1994, new set of dietary standards in the US
How is DRI different from RDA?
Include 1. Adequate Intake (AI) 2. Tolerable Upper Intake Level (UL) 3. Estimated Energy Requirements (EER).
What is Adequate Intake?
AI is established based on the levels of a given nutrient that are consumed by healthy people.
When are Adequate Intake values used instead of DRIs?
Insufficient experimental evidence and in infants
What is Tolerable Upper Intake Level?
Highest level of nutrient likely to pose no risks to adverse health effects
What are Estimated Energy Requirements?
Dietary energy intake needed to maintain energy balance in a healthy adult of a given age, gender, height, and level of physical activity
What is DRIs based on?
optimization of health for healthy individuals
For which individuals DRIs is not valid?
individuals that are ill, under stress from surgery, alcoholics or on medications
What is hypervitaminosis?
Toxicity due to excessive intake of vitamin supplementation
Which vitamins are usually involved in hypervitaminosis?
fat soluble vitamins, especially A and D
What is the role of Vitamin E?
1.Free radical scavenger in cell membrane and lipid stores 2. frequently advertised as supplement to prevent related to aging
What do recent clinical trials tell about Vitamin E ?
No significance in health benefit. High doses (>200UI/day)might even increase risk of stroke, prostate cancer, and other causes of death
What is the role of Vitamin K?
1.Metabolic Cofactor for gamma carboxylase.2. Essential for blood coagulation cascade 3. Regulation of bone formation and other cellular processes
What are rich sources of Vitamin E?
vegetable oils, nuts, green vegetables, eggs
Which group of population is affected by dietary deficiency of Vitamin E?
Premature infants. Adults with defective lipid absorption or transport
What is the action of gamma carboxylase?
γ-carboxylation of glutamic acid
Why is γ-carboxylation of glutamic acid?
post translational modification of precursors of clotting factors 2, 7, 9, 10
What drug inhibits action of Vitamin K?
Warfarin
What is the action of Warfarin?
Anticoagulant. Acts on the enzyme responsible for the regeneration of the active form of vitamin K
What produces Vitamin K?
Intestinal Bacteria
Where is gamma carboxylase found?
ER of liver cells
Why does newborn infant get an injection of Vitamin K at birth?
To prevent hemorrhagic disease
How much of vitamin K is contained in breast milk?
1/5 of daily requirement
What is associated with reduced Vitamin K level?
Bleeding disorders
What are food sources for Vitamin K?
green vegetables
What is the role of Vitamin A?
1. Regulatory Vitamin in vision, reproduction, embryonic development, immune function, differentiation and maintenance of epithelial tissues
Where are Vitamin K-dependent carboxylated proteins found?
blood coagulation cascade, osteoblasts (bone reformation), chondrocytes, and smooth muscle cells
Which vitamin has the most diverse roles?
Vitamin A
What are the food sources for Vitamin A?
orange vegetables, liver and milk products
What is the plasma carrier protein for Vitamin A?
Retinol-Binding Protein
What does the isomerization of trans- to cis- retinol trigger?
In rod cells of the eye, triggers the signaling pathway that allows us to detect light
What is the earliest signs of Vitamin A deficiency?
Night blindness
What is retinal?
Prosthetic group of rhodopsin
What is rhodopsin?
light harvesting pigment protein of the rod cells
Where is vitamin A synthesized and stored?
Liver mainly
What are retinoic acids?
Transcriptional regulators linked to cellular differentiation and cancer biology
What are the mode of action of retinoic acids (RA)?
Treatment of skin disorders (acne, psoriasis) and certain types of cancers
What disorders result in hypervitaminosis A?
Toxic syndrome, skin, liver and nervous system abnormalities, congenital malformations. Can increase tumor growth
What disorders result in retinoic acids deficiency?
squamous cell carcinomas
What is the adequate Intake in infants based on?
levels of nutrients in breast milk of healthy mothers
What are minerals?
Inorganic elements or compounds required as structural components of enzymes, electrolytes, signaling molecules etc..
Name the macrominerals
Ca, Mg, P, Na, Cl
Name the trace minerals
Fe, Zn, Cu, iodine, selenium, Mn, Fluoride, chromium, molydebnum
What are the quantities required for macrominerals?
100s of mg- g/ day
What are the quantities required for trace minerals?
mg-g/ day
What is the Recommended Dietary Accommodation for copper?
For adult men and women: 900 µg/d
What are the two oxidation states of Cu found in the body?
Cu1+ or Cu2+
What is the formula of cupric ion?
Cu2+
What is the formula of cuprous ion?
Cu1+
What is the function of Cu?
Enzyme cofactor, accept and donate electrons
Which enzymes are highly dependent on copper?
Ceruloplasmin, cytochrome C, superoxide dismutase, tyrosinase
What is the function of ceruloplasmin?
Converting Fe2+ to Fe3+
Where is ceruloplasmin synthesized?
Liver
Does lack of ceruloplasmin result in copper deficiency? yes/no? why?
No. b/c presence of other copper containing proteins that overt the symptoms
What are the consequences of ceruloplasmin deficiency?
Deficiency of iron metabolism. Accumulation of iron in the pancreas, retina and brain-> diabetes, blindness and neurological symptoms.
What form of iron can cross plasma membrane?
Fe3+
Where is the function of Cytochrome C?
Final component of ETC
What is the role of superoxide dismutase?
Key antioxidant enzyme vs. ROS
What is the role of tyrosinase?
key enzyme in synthesis of melanin
What are food sources for copper?
animal and plant orifin
What is the average copper intake in the US?
1.7mg/d
How common is copper deficiency?
Rare in the US
Name genetic disorders related to cupper metabolism
Wilson's disease and Menkel's syndrome
Describe Wilson's disease.
AR disease. Defect in Cu transporter required for biliary excretion (but not Cu uptake). Low serum ceruloplasmin, high urinary copper excretion and high hepatic copper content. Accumulation of Cu in liver, brain and kidney.
Describe Menkel's syndrome
Rare X linked disease. Defect in a distinct Cu transporter that transports Cu to the fetus or through the intestine after birth ->Cu deficiency.
Low Cu levels in serum and most tissues. Very High Cu levels in intestine and kidney.
What drug is responsible for treating Wilson's disease?
penicillamine
What is the action of penicillamine?
chelating agent. Solubilizes copper and promotes its urinary excretion and dietary zinc, which inhibits copper absorption.
What are the symptoms in Wilson's disease?
Mental degeneration and liver damage
What are the symptoms in Menkel's syndrome?
Infancy: slow growth, mental degeneration (irreversible), kinky white hair. Most individuals die within the first few years of life
How to get adequate amount of vitamins and minerals in diet?
Vegetable and fruit
When do vitamin/mineral supplementation have significant health benefits?
If health conditions limit absorption, transport/metabolism of vitamins or minerals. Calcium for teens and young adults
What are essential amino acids?
Aa that cannot by synthesized by humans . Must be take by diet
What is Vitamin B12?
Cobalamin
What is the role of Vitamin B12?
Enzymatic Cofactor for methylation reactions
Name the 9 essential aa .
His, Iso, Leu, Lys, Met, Phe, Thr, Trp, Val
What is the aa intake requirement for male adults?
60g/d
What is the aa intake requirement for female adults?
50g/d
What are semiessential aa?
Aa synthesized from essential aa
Name two semiessential aa
cys and tyr
Which aa are considered essential in infants?
cysteine
Describe protein requirements in rapidly growing infants
high protein need, low endogeneous rate of cysteine synthesis. Cysteine is essential
Which aa are considered essential in pre-term infants?
tyrosine, glutamine, arginine, proline, and glycine
Which aa is essential during critical illness?
glutamine
Name the essential FA
linoleic and linolenic acid
What is linoleic acid?
omega-6 FA
How many carbon atoms are found linoleic acid? How many double bonds?
18; 2
Where are the double bonds found in linoleic acid?
9th and 12 th position according to Delta system
What is linolenic acid?
omega-3 FA
How many carbon atoms are found in linolenic acid? How many double bonds?
18; 3
Where are the double bonds found in linoleic acid?
9th, 12th, and 15th position
What is the role of essential FA?
1. maintaining function and integrity of membranes 2. precursors for the synthesis of eicosanoids 3.Critical signaling molecules in inflammatory responses, blood clotting, etc..
Name 3 eicosanoids
prostaglandin, thromboxanes, leukotrienes
When do symptoms associated with essential FA deficiency manifest? Why>
Months to manifest b/c large endogenous stores of essential FA
What is the difference between omega and delta system?
Delta system counts carbon from the carboxyl end. Omega system counts from the methyl end. For omega, only the position of the double bond most proximal the methyl end is given. Any additional double bonds always separated by 3 carbons like for linoleic acid
What is the nomenclature for FA?
1st number is the total number of C atoms. the second number is the number of double bonds.
Why FA essentials? Name their characteristics
1. Humans lack the enzyme req. to insert a double bond 3 or 6 carbons from the omega end. 2. very low quantity is needed but required 3. deficiencies are rare in general population 4. Essential diet component for enteral/parenteral nutrition
What is the amount of essential FA required?
1 tbs of plant oil/d
What role do non essential dietary components play in our health?
Dietary supplement can influence positively or negatively individuals health. Can be produced by humans in sufficient quantities
Name non essential dietary components
cholesterol, creatine
Name semi essential nutrients.
choline, taurine, carnitene
What is a dietary fiber?
Plant-derived carbs and lignins that are not digested in human stomach or small intestine
Why are dietary fibers beneficial for our health?
Decrease intestinal transit time and increase ease of elimination of feces, reducing risk for development of diverticulitis, hemorrhoids, and colon cancer
What role do high fiber food play in our diet?
Aid weight control by increasing appetite satiety w/o yielding much energy and slowing carbohydrate absorption
Name dietary fibers
cellulose, pectins, gums, mucilages
What are the glycosidic bonds found in cellulose?
beta glycosidic bonds
What are insoluble fiber?
ingestible dietary fibers. Do not dissolve in water and add bulk to feces
What are soluble fibers?
Dissolved/swell in water. Digested by bacteria in large intestine into short chain FA and gases.
What are food sources for insoluble fiber?
wheat bran, wheat products, brown rice
What are food sources for soluble fibers?
fruits, carrots, oats, kidney beans
What is the energy contained in short chain FA?
3kcal/g if absorbed
What is cholesterol?
membrane structure. precursor to steroids, bile acids
What is lycopene?
caretenoid found in tomatoes , red fruits and vegetables
What are the health benefits of lycopene?
Anti-oxidant for free radicals. Reduce risk for cancers, cvd, osteoporosis, diabetes, macular degeneration. Not FDA approved
What are semi-essential nutrients?
Nutrients that can be synthesized by humans, but under certain circumstances could be limiting
What is taurine?
component of bile acids
What is creatine?
energy store as creatine phosphate in muscle
What is carnitene?
Mt transport of FA