Vitamins
organic compounds
needed in small amounts to regulate body processes
all vitamins have one or more important functions
many food are now fortified with vitamins to prevent symptoms of deficiency and increase marketability of products
bioavailability
the rate and extent to which a nutrient is absorbed or used
approx 40-90% of vitamins in food absorbed
determinants of bioavailability
-efficiency of digestion and time of transit through the DT
-previous nutrient intake and nutrition status
-other food consumed at the same time
-method of preparation
-sources of nutrient
-from foods vs. supplements
what destructs vitamins?
heat
UV light
oxidation
how do you prevent destruction of vitamins?
refrigeration
storing cut veggies etc. in airtight containers
wash fruits and veggies
steam veggies in small amounts of water
what are water-soluble vitamins?
B vitamins
Thiamin
Riboflavin
Niacin
Biotin
Panthothenic acid
Vitamin B6
Folate
Vitamin B12
Vitamin C
what are fat soluble vitamins?
A, D, E, K
water-soluble B vitamins and choline
function primarily as coenzymes (bind to enzymes to promote their activity and carry electrons, atoms and chemical groups)
few act as antioxidants
Thiamin (B1)
-functions: part of conenzyme TPP needed to convert pyruvate into acetyl CoA, synthesis of neurotransmitters
-symptoms of deficiency: alcoholics, Beriberi (characterized by weakness, fatigue, enlarged heart, poor short term memory, muscle paralysis)
-symp
Riboflavin (B2)
-functions: forms coenzyme involved in citric acid cycle (FAD), beta-oxidation (FMN), extracting dietary fuels
-symptoms of deficiency: alcoholics, poor wound healing, cracking lips, increased light sensitivity, burning, tearing, itchy eyes
-symptoms of t
Niacin (B3)
-functions: part of coenzyme NAD (vital for electron transport in glucose metabolism and synthesis of FAs and cholesterol), may lower LDL and raise HDL in high doses
-symptoms of deficiency: children in orphanages or where corn is staple, pellagra (charac
Panthothenic acid (B5)
-functions: part of coenzyme A involved in extraction of energy from dietary fuels, needed everywhere including synthesis of neurotransmitters, steroid hormones and Hb
-symptoms of deficiency: rare due to its wide distribution
-symptoms of toxicity: relat
Vitamin B6
-functions: part of coenzyme pyridoxal phosphate (PLP), transanimation and deamination, synthesis of Hb, WBC and myelin, conversion of tryptophan to niacin, glycogenolysis, important for amino acid and protein metabolism, synthesis for RBCs and WBC, myeli
Biotin
-functions: part of coenzyme that replenishes oxaloacetate
-symptoms of deficiency: uncommon, nausea, thinning hair, lethargy, hallucinations, those consuming large amounts of egg whites
-toxicity: none
-sources: liver, cooked eggs
Folate
-functions: important for embryonic development, synthesis of DNA, amino acid metabolism,
-symptoms of deficiency: pregnant women, alcoholics at risk, neural tube defects (spina bifida), poor growth, nerve dysfunction, diarhhea, tongue inflammation, megal
Cobolamine (B12)
-functions: production of ATP from some FAs, keep homocysteine levels low (converts homocysteine to methionine), maintain myelin sheath, activation of folate, intrinsic factor is required for B12 absorption
-symptoms of deficiency: vegans, older adults wi
Vitamin C
-functions: synthesis of collagen, synthesis of neurotransmitters, hormones, bile acids, antioxidant (maintain immune system)
-symptoms of deficiency: smokers, scurvy characterized by bleeding gums, tooth loss, joint pain, bleeding skin, fatigue
-symptoms
antioxidant
protect agains oxidative damage by free radicals
FRs steal electrons, damage structure, and function
oxidative damage associated with cancer, diabetes, heart disease and possible Alzheimers
prevent oxidation (loss of electrons)
vitamins: A, C, E
choline
-functions: synthesis of acetylcholine (neurotransitter), synthesis of cell membranes
-symptoms of deficiency: rare, liver dysfunction
-symptoms of toxicity: fishy body odour, sweating, reduced growth rate, low bp, liver damage
-sources: egg yolks, brocco
Vitamin A
-retinoids (found in animal products) and carotenoids (retinal, retinol, and retinoic acid
-functions: vision (retinal part of rhodopsin), cell differentiation (gene expression), reproduction and growth (important for normal fetal growth), antioxidant (ca
carotenoids
pigments in plants which can be converted into retinoids in the body
-beta-carotene: most common provitamin that can be converted into vit A in the boy
-those not converted into retinoids can function as antioxidants
Vitamin D
-function: maintaining calcium and phosphorous levels, promotes calcium absorption in the SI, reduces calcium excretion at the kidneys, mobilizes calcium from bone, reduced risk of caner growth, diabetes I, MS, high bp
-symptoms of deficiency: people livi
Vitamin D and calcium regulation
-calcium is an essential nutrient (nerve conduction, heart/muscle conraction)
-when levels drop, parathyroid hormone is released (activates vit D at kidney)
-activated vit D, through its role in gene expression (promotes ca absorption, reduced ca excretio
Vitamin E
-functions: antioxidant, helps prevent heart disease, cancer, macular degeneration, alzheimers and other chronic diseases, anti-inflammatory role, protects lipids
-symptoms of deficiency: people with poor fat absorption and premature infants are at risk,
Vitamin K
-functions: synthesis of blood clotting proteins, synthesis of bone remodelling proteins
-symptoms of deficiency: newborns and people on long term antibiotics are at risk, bruise easily, bleeding anemia, brain damage, decreased bone density
-symptoms of t
groups whom dietary supplements are recommended
-dieters
-vegas/those that eliminate dairy
-infants and children (flouride, vit D, iron)
-young women/pregnant women (400 folate)
-older adults (B12, vit D)
-indvs with restricted diets (depends)
-people taking certain meds
-smokers (vit C, maybe E)
-alco
population crisis
-pop hit 7 billion
-in order to sustain rate of growth, food production would need to increase by 70% (or food consumption, waste would have to decrease and birth rate would need to decrease)
-environmental pressure: meat consumption has sky-rocketed, wat
vitamin digestion and absorption
-starts in mouth with chewing
-in stomach, digestion of food releases vitamins, some niacin absorbed
-the gallbladder releases bile, which emulsifies fat and helps absorb fat soluble
-the pancreas secretes digestive enzymes
-SI-fat soluble vitamins are in
fat vs water soluble vitamins
absorption: water directly into blood, fat with lipids into lymph
transport: water-none, fat-require protein carriers
storage: water-free in aqueous compartments, fat- in cells associated with fats
excretion: water-readily available via kidneys, fat-not r
coenzymes
-organic nonprotein substances that bind to coenzymes to promote their activity
-carry electrons, atoms, chemical groups
-all B vitamins
why is milk packages in opaque containers?
to avoid being destroyed by UV light
megoblastic anemia
a reduction in the blood's capacity to carry oxygen that is characterized by abnormally large immature and mature RBC's
deficiency of folate and vitamin B12
vitamin B12 and folate
needed to prevent homocysteine levels from rising
convert homocysteine to methionine
atrophic gastritis
an inflammation of the stomach lining that results in reduced secretion of stomach acid, microbial overgrowth and in severe cases a reduction in the production of intrinsic factor
-without sufficient stomach acid, the enzymes that release vitB12 bound to