Chapter 8 Flashcards
Vitamins
Organic compounds needed in the diet in small amounts to promote and regulate the chemical reactions and processes needed for growth, reproduction, and the maintenance of health.
- organic
- micronutrient
- essential
- not energy yielding
- classified as water or fat soluble
- cofactors in cell functions
Water soluble vitamins
Vitamins that dissolve in water
- B, C
- are easily absorbed
- not stores in tissues excessively
- seldom reach toxic levels
- Thiamin B1
- Riboflavin B2
- Niacin B3
- Pantothenic acid
- Pyridoxine B6
- Biotin
- Folate
- Cobalamin B12
-Vitamin C
Fat soluble vitamins
Vitamins that dissolve in fat
- require bile and dietary fat for absorption
- transported in lymphatic system in chylomicrons before blood
- stored in body fat meaning that intakes can vary without a risk of deficiency
- may be toxic in excess : not easily excreted
- A, D, E, K
Vitamin examples in
- whole grains
- veggies and fruit
- protein foods
- Healthy fat
- B Vitamins
- B, C, A, E, K vitamins
- protein: B, Milk: B, A, D, K
- Vitamin E
Fortification
A term used generally to describe the process of adding nutrients to foods that are not normally there; such as the addition of vitamin D to milk
-some mandatory fortification by government
Ex:Table salt with Iodine, Vitamin D in milk, grains with B vitamins, iron
-prevents deficiencies leading to diseases but may also cause toxicity
Enrichment
Refers to a food that has had nutrients added to restore those lost in processing to a level equal to or higher than originally present
Bioavailability
A get real term that refers to how well a nutrient can be absorbed and used by the body
- 40-90% of vitamins absorbed
- fat soluble vitamins require fat in diet to be absorbed
- water soluble vitamins may require transport molecules
- some vitamins are absorbed in inactive provitamin people vitamin precursor forms that must be converted into active forms by the body.
Digestion of vitamins steps
- Chewing releases vitamins in food
- stomach digestion release vitamins and some niacin is absorbed here
- gallbladder releases bile which emulsifies fat and helps absorb fat-soluble vitamins
- Pancreas secreted digestive enzymes that aid in release of vitamins from food
- in small intestine, fat-soluble vitamins are incorporated into micelles, and then absorbed by simple diffusion. Once inside mucosal cells, fat-soluble vitamins are packaged into chylomicrons to enter lymph before passing into blood.
- water-soluble vitamins are absorbed from small intestine directly into blood
- in large intestine, bacteria synthesize small amounts of vitamins and some are absorbed
Provitamin or vitamin precursor
A compound that can be converted into an active form of a vitamin in the body
Ex: provitamin A is a name for beta-carotene, which has only about 1/6 the biological activity of retinol (vitamin A); the body uses an enzyme to convert beta-carotene to retinol
Does it take longer to develop a deficiency for water soluble or fat soluble vitamins
Water soluble-not stored and can easily be excreted in urine.
Fat-soluble are stored in liver and fatty tissues and cannot be excreted in urine
Coenzymes
Small non-protein organic molecules that act as carriers of electrons or atoms in metabolic reactions and are necessary for the proper functioning of many enzymes
-ex: B vitamins like thiamin, riboflavin, niacin, panthothenic acid and biotin serve as coenzymes for reactions that release energy from carbs, fat and protein
Beriberi
The disease resulting from a deficiency of thiamin (vitamin B1). Causes lethargy, fatigue, neurological symptoms like depression, and cardiovascular issues (heart issues)
-need bran or you get beriberi
Thiamin pyrophosphate
The active coenzyme form of thiamin. It is the predominant form found inside cells, where it aids reactions in which a carbon-containing group is lost as CO2.
-essential for production of ATP
Who is most at risk of beriberi
Alcoholics!
-alcohol disrupts absorption of thiamin
Wernicke-korsakoff syndrome
A form of thiamin deficiency associated with alcohol abuse that is characterized by mental confusion, disorientation, loss of memory, and a staggering gut
Best source of riboflavin in Canadian diet?
What protects riboflavin?
Milk, red meat, fish, asparagus, mushrooms, leafy greens
Light exposure
Flavin adenine dinucleotide (FAD)
Flavin mononucleotide (FMN)
The active coenzyme forms of riboflavin. The structure of these molecules allows them to pick up and donate hydrogens and electrons in chemical reactions
Can riboflavin be tired in body?
No-water soluble- is excreted in urine
Ariboflavinosis
The condition resulting from a deficiency of riboflavin
-inflammation of eyes, lips, mouth and tongue, scaly greasy skin eruptions, confusion
Pellagra
The disease resulting from a deficiency of niacin
- progressive physical and mental deterioration and death
- extreme fatigue
- indigestion
- dermatitis, diarrhea, dementia, death
Good sources of niacin
Meat (chicken) fish, peanuts, grains, legumes, wheat bran, tryptophan
Nicotinamide adenine dinucleotide (NAD) and nicotinamide adenine dinucleotide phosphate (NADP)
The active coenzyme forms of niacin that are able to pick up and donate hydrogens and electrons. They are important in the transfer of electrons to oxygen in cellular respiration and in many synthetic reactions
Niacin equivalents (NE)
The measure used to express the amount of niacin present in food, including that which can be made from its precursor, tryptophan. One NE is equal to 1mg of niacin or 60mg of tryptophan
Sources of Biotin
Liver, egg yolks, yogurt and nuts
-avoid uncooked egg whites, protein avidin binds biotin making it unavailable
Panthothenic acid food sources
B vitamin
-meat, eggs, whole grains and legumes
Vitamin B6 sources
Found in both plant and animal foods
Pyridoxine
Pyridoxal phosphate
The chemical term for vitamin B6
The major coenzyme form of vitamin B6 that functions in more than 100 enzymatic reactions, many of which involve amino acid metabolism. Needed for formation of hemoglobin, and myelin on nerves
Single carbon metabolism
The transfer of single carbon groups, such as methyl groups between compounds.
-metabolizes homocysteine
Folate and Folacin
Folic acid
General term for the many forms of this vitamin
The monoglutamate form of folate, which is present in the diet in fortified foods and vitamin supplements
Sources of folate
Liver, yeast, asparagus, oranges, legumes, lentils
Foliage
Neural tube defects
Abnormalities in the brain or spinal cord that result from errors that occur during prenatal development. Defects in the brain are fatal, while those in the spinal cord often result in paralysis.
- folate deficiency can increase risk
- decreased by 50% since fortification in foods but increase in colon cancer
Epigenetics
The study of genetics unrelated to changes in the sequence of DNA, but related to its chemical modification due to reactions such as methylation
-folate has epigenetic role in NTD
Dietary folate equivalents (DFE)
The unit to express the amount of folate present in food. One DFE is equivalent to 1 microgram of folate naturally occurring in food, 0.6 micrograms of synthetic folic acid from fortified foods consumed with food, or 0.5 micrograms of synthetic folic acid consumed on empty stomach
Mega blasts
Large, immature red blood cells that are formed when developing red blood cells are unable to divide normally.
-folate deficiency causes anemia where cells in bone marrow that develop into RBC cannot duplicate their DNA, and so cannot divide. Instead they just grow bigger into mega blasts.
Macrocytes
Larger-than normal mature red blood cells that have a shortened life span
-derived from mega blasts
Issue from folate deficiency
Megablastic or macrocytic anemia
A condition in which there are abnormally large immature and mature red blood cells in the blood stream and a reduction in the total number of red blood cells and the oxygen-carrying capacity of the blood
Spina Bifida
A birth defect resulting from the incorrect development of the spinal cord that can leave the spinal cord exposed. This can result in paralysis. -NTD
Anencephaly
A birth defect due to failure of the neural tube to close that results in the absence of a major portion of the brain, skull and scalp. The is a fatal defect.-NTD
Pernicious anemia
An anemia resulting from vitamin B12 deficiency that occurs when dietary vitamin B12 cannot be absorbed due to a lack of intrinsic factor.
- become unresponsive to iron supplementation
- excess intake of folic acid can mask B12 deficiency
Vitamin B12 sources
Animal products
Intrinsic factor
A protein produced in the stomach (parietal cells) that is needed for the absorption of adequate amounts of vitamin B12
Parietal cells
Cells in the stomach lining that make HCL and intrinsic factor in response to nervous or hormonal stimulation
Cobalamin
The chemical term for vitamin B12
Atrophic gastritis
An inflammation of the stomach lining that results in reduced stomach acid secretion and bacterial overgrowth
-vitamin B12 deficiency because vitamin B12 can not be broken down by stomach acid
Pernicious anemia
Sun to immune disease where parietal cells that make intrinsic factor are destroyed so vitamin B12 can not be absorbed
Scurvy
The vitamin C deficiency disease
Ascorbic acid or ascorbate
Chemical germ for vitamin C
- water soluble vitamin
- antioxidant in blood and body fluids
- synthesis and maintainable of collagen, and the base of all connective tissue
- needed for synthesis of neurotransmitters, hormones, bile acids, and carnitine (fatty acid breakdown)
- enhances iron absorption
- regenerates active antioxidant form of vitamin E
Collagen
The major protein in connective tissue
- Need vitamin C for strength and healthy
- makes you squishy
Antioxidant
Oxidative damage
A substance that is able to neutralize reactive oxygen molecules and thereby reduce oxidative damage
-Vitamin C
-damage caused by highly reactive oxygen molecules that steal electrons from other compounds, causing changes in structure and function
Free radicals
One type of highly reactive molecule that causes oxidative damage
- Molecule with one or more unpaired electrons that are highly unstable!!!!
- to regain stability, the free radical quickly finds a stable compound from which to steal and electron
- then that compound becomes a free radical itself and steaks from another!!!!
- damage to DNA
- aging, heart disease, cancer, Alzheimer’s
Oxidative stress
A condition that occurs when there are more reactive oxygen molecules than can be neutralized by available antioxidant defences. It occurs either because excessive amounts of reactive oxygen molecules are generated or because antioxidant defences are deficient
Pro-oxidant
A substance that promotes oxidative damage
Dietary antioxidants
A substance in food that significantly decreased the adverse effects of reactive species on normal physiological functions in humans
What vitamin can limit colds
Vitamin C
Choline
- functions
- deficiency symptoms
- sources
Vitamin needed to synthesize a number of important molecules, including phospholipids found in cell membranes, neurotransmitter acetylcholine.
- deficiency cause liver abnormality, during pregnancy; issues in fetal brain
- found in egg yolks, organ meats, spinach, nuts and wheat germ
- water soluble
- essential nutrients
- not currently classified as a vitamin..
Almost all ___ contain some vitamin
Foods
Depends on how much is in it naturally or is added or taken in processing/storing/prepared
Approximately, ____ of Canadians use vitamins and mineral supplements
40%
Who benefits from a vitamin and mineral supplements
- calorie restricted diets
- vegans or non dairy
- infants and children
- young women and pregnant women
- older adults
- darker pigmentation skin or cover whole body outside
- restricted diets
- people taking medications (BCP)
- cigarette smokers and alcohol users
What affects bioavailability
- efficiency of digestion and find of transit through the GI tract
- previous nutrient intake and nutrients status
- other foods consumed at the same time
- method of food preparation
- source of the nutrient (synthetic, fortified, naturally occurring)
B vitamin purpose
Energy metabolism
Thiamin
B1
- coenzyme needed for glucose breakdown to provide energy
- needed for metabolism of other sugars, certain amino acids and synthesis of ribose (in RNA) and deoxyribose (DNA)
- important for nerve function because glucose is nerve cell energy source and needed for synthesis of neurotransmitters
-first b vitamin to be identified
Sources of thiamin
Bran layer of whole grain, enriched grains, pork, legumes, and seeds
Deficiency in thiamin
- Beri beri
- wernicke-korsakoff
Excess of thiamin
No reported effects, no UL
Riboflavin
B2
- forms two active co enzymes
- helps reactions needed to produce ATP from carbohydrate, fat and protein
- involved in conceding folate, niacin, B6, and vitamin K into active forms
- easily destroyed by heat and light
- important component in the citric acid cycle, and for assisting the body with the absorption of other vitamins
Deficiency and excess of riboflavin
- injuries don’t heal, cracking lips, sensitivity to light, eye burning, itchy, skin flakes on nose, eyebrows and earlobes
- no reported effects but turns urine bright fluorescent yellow
Niacin
B3
- added to enriched flours
- be synthesized in body by tryptophan if diet is adequate
- role in the production of energy and in general metabolism
- two forms of niacin are nicotinic acid and nicotinamide
- coenzyme in glucose metabolism and synthesis of fatty acids and cholesterol
- excellent and old treatment for unbalanced cholesterol ratios
Deficiency and excess of niacin
Pellagra
No reported effects from food but supplements can be toxic causing skin flushing and rash, tingling in hands and feet, nausea, vomiting, diarrhea, high blood sugar levels,, liver abnormality
Biotin in the body
Coenzyme involved in citric acid cycle / d glucose synthesis
Panthothenic acid in the body
Part of coenzyme A
Part of the acyl carrier protein for cholesterol and fatty acid synthesis
Vitamin B6 functions
- amino acid and protein metabolism
- synthesis of non essential amino acids, neurotransmitters and hemoglobin
- conversion of tryptophan into niacin
- glucose and amino acid breakdown
3 forms of vitamin B6
Pyridoxal, Pyridoxine, Pyriodoxamine
-converted into active co enzyme Pyridoxal phosphate needed for the activity of >100 enzymes in carbohydrate, fat, and protein metabolism
Deficiency and excess of vitamin B6
Poor growth, skin lesions, decreased immunity, anemia, neurological symptoms like anxiety and nightmares
No reported effects from food but supplements can be toxic causing severe nerve impairment
Folate functions
B9
- Folate coenzymes needed for DNA synthesis and some amino acid metabolism
- important in early pregnancy gut neural tube formation, which develops into brain and spinal cord
- prevent homocysteine levels from rising to prevent heart disease
Folic acid
Synthetic or lab made folate
Excess folate issues
Concerns that excess with prevent folate-deficiency symptoms and mask B12 deficiencies, breast cancer risk
Folate deficiency in blood cells
Red blood cell can’t decide properly and create megablasts and macrocyte
Vitamin B12
Important for
- ATP production from certain fatty acids
- conversion of homocysteine to methionine
- maintainable of myelin coating on nerves
- amino acid and protein metabolism
- necessary for iron absorption
- found in animals!!!!!!!!
- Any gut disorder may lead to B12 deficiency
Deficiency and excess of vitamin B 12
- no energy, pernicious anemia, increased homocysteine, decreased folate activation, numbness, memory loss, paralysis, death, disorientation
- no reported effects from intakes of up to 100 micrograms/day from food or supplements
Deficiency and excess of vitamin C
Scurvy, gum and tooth pain, joint pain, bleeding, poor wound healing, fatigue, depression, hysteria
Excess supplementation can cause diarrhea, nausea, abdominal cramps, possible increased kidney stone formation
Excess choline
Smell like fish, sweaty, reduced growth, low blood pressure, liver damage
