Vitamins Flashcards
what are they?
Specific roles and needed in diet - essential organic molecules
Not made in the body
13 identified
Water soluble (B, C) - difficult to reach toxic level
Fat soluble (A, D, E, K) - stored in adipose tissue
Imp role in energy met
Don’t contain any useful energy themselves
biological functions
Eyes: A
Teeth: A, D and C
Blood clotting: K
Hormone function: A, pantothenic acid (steroids) and B6 (noradrenaline and thyroxine)
Neuromuscular function: A, C, B^12, niacin, thiamine and pantothenic acid
Cell membrane: E
Energy release: Thiamine, riboflavin, niacin, biotin, B6 and pantothenic acid
Blood formation: B6, B12 and folate
Bones: A, D and C
Reproduction: A and riboflavin
Skin: A, C, B6, niacin, riboflavin and pantothenic acid
Blood cells: E
what are the antioxidant vitamins
A
C
E
vitamins as antioxidants
remove free radicals and prevents oxidative damage
Exercise
Free radical production (oxidative damage) - highly reactive
Maybe tissue damage - fatigue
Large dose of single antioxidant compounds not recommended
Get from diet
Protection against cancer and heart disease
water soluble vitamins
Dissolve in water
Consume daily - cant be stored
Destroyed by high heats and bright light
Excreted if excess - when levels high
role of water soluble B vitamins
12+ in total
Needed for energy release
B1, 2, 3, 5, 6, and 7
Hematopoietic - RBC production
B5, 6, 9 and 12
Cellular met, coenzymes and facilitation of ATP resynthesis
Conversion pyruvate —> acetyl Co A
B1
thiamine
Thiamin pyrophosphate (TPP)/Thiamin diphosphate (TDP) - refine food - may become deficient
B2
riboflavin
FAD, FMN
B3
niacin
NAD, NADP
B5
pantothenic acid
coenzyme A
B6
pyridoxine
Pyridoxal phosphate (PLP)
B7
biotin
coenzyme of decarboxylases
B9
folate
Coenzyme in formation of haem and nucleic acids
B12
cobalamin
Coenzyme in formation of nucleic acids
do athletes need more energy mat related B vitamins?
Ex could increase need:
Altered absorption
Increased turnover, metabolism, loss
Biochem adaptations
Increased mitochondria
Increased tissue repair
High intakes of macronutrients
Higher intake of food in general
Increased need for vitamins met by increased energy intake
do athletes need more haemopoietic B vitamins?
Ex could increase need:
Altered absorption
Increased turnover, met, loss
Biochem adaptations - amount RBCs
Increased tissue repair
Altering RBC fragility - altered 1/2 life RBCs
B1 deficiency
Beriberi
Muscle weakness
Fast and enlarged heart
B2 deficiency
Ariboflavinosis
Red, swollen tongue
Swelling of mucous membranes and phalangeal
B3 deficiency
Pellagra
Vomiting and diarrhoea - mental confusion
B9 and 12 deficiency
megaloblastic anemia
Impact of RBCs - enlarged and don’t work as effectively
other B deficiencies
B5 = numbness, tingling, vomiting (v. Rare)
B6 = dermatitis, glossitis, convulsions
B7 = anorexia, nausea, flaky skin, depression (v. Rare)
deficiencies and ex perf
Decreased thiamin, riboflavin and B6
Over 11 weeks
12% decreased VO2 max
7% decrease in OBLA
12% decrease in O2 consumption at OBLA
9% decrease in peak power
7% decrease in mean power
Impacts all of ex perf pathways due to role in energy reg and role in processing of RBCs
vitamin C (ascorbic acid)
Antioxidant
Synthesis (multiple) - carnitine, collagen and ntms, CCK, serotonin (mood), DNA
Catabolism (tyrosine)
Required for normal iron absorption - carries oxygen
Facs cytochrome P450 enzyme function
Immune function? Cold illness prevention?
10-1000mg day - only mammal the cant synthesise it - others do it from glucose
what happens if you have too much C?
(unlikley as water sol)
GI distress
Kidney oxalate stone formation
what happens if you have too little C?
Scurvy - limeys
Poor health
fat sol vitamins
Can get to toxic levels - stored in fat
A - retinol - vision, reproduction, bone, immune and skin
D - calciferol - absorb calcium, bone and immune
E - tocopherol - antioxidant,
immune and toxins
K - madanione - blood clotting factors and bone health
vitamin A
Stored as rainy esters - pre-form of vitamin A
Obtained from plant (beta carotene) and animal sources (retinol)
Also some roles in collagen production - teeth and connective tissue
Transported in chylomicrons with fat and stored in liver
3rd most common worldwide
easy to get into diet
A deficiency
Rare
Loss of vision/night blindness
Skin issues
A toxicity
Acute - nausea, blurry vision and vomiting
Chronic - impact on organs and increases fracture risk
vitamin D
Made from the sun and in skin from cholesterol
Activated in kidney and liver
Healthy bones/kidneys and intestine
Regulates calcium balance
Blood and bone calcium levels
Urinary excretion
Intestinal absorption
Can only make enough if have enough cholesterol and sunlight
D deficiency
At risk in winter months esp. in northern hem
Rickets - athletes may supplement it as well as children
Osteomalacia
Osteoporosis
D toxicity
Hypercalcaemia/hypercalcuria
Bone demineralisation - draws calcium out of bones
vitamin K
K for coagulation/clotting
Synthesised by gut bacteria
Antibiotics reduce it - at risk if not synthesising enough
Blood clotting (cofactor for prothrombin synthesis)
Formation of bone
K deficiency
malnourished/babies/anticoagulants
Blood vomit/bleeding into joint capsules/bruising/bleeding gums
K toxicity
Babies - intestines still sterile - no bacteria - more at risk
Jaundice/;anaemia/hyperbilirubinemia - formula fed
vitamin E food sources
Nuts (almonds), seeds, wheat germ, veg oils, margarine, salad dressing
E functions
Most potent vitamin antioxidant
Selenium met
vitamin E
No clear deficiency disease but general feelings of illness
High doses of vitamin E can interfere with absorption of V and K
LT effects and safety of supplementation unclear
vitamins excess and loss
Vitamin deficiencies detrimental to athletic perf and health
Excessive doses of fat soluble vitamins accumulate in body and are toxic - too much and little get similar symptoms
Excess water soluble excreted in urine
Losses of vitamins in sweat negligible
Biochem adaptation to ex may increase requirement for some vitamins (B2, 6, A, C, E)
vitamin intake in athletes
For most part athletes for riboflavin, pyridoxine and C have RDA
Supplements unnecessary for athletes consuming balanced diet that meets requirement for energy
Supplements don’t improve ex perf when intake adequate
Excessive intakes may be harmful
vitamins and ex
Deficiencies will impair perf
Low energy athletes
Weight category sports - make/maintain weight
Vegetarians - may cut out certain parts of diet that arent being replaced
Limited access to fresh fruit and veg
Taking additional = no impact on perf
how do we obtain vitamins?
plants manufacture vitamins during p/s
animals obtain vitamins from the plants they eat/meats other animals that previously consumed food
animals produce some vitamins from precursor substances known as provitamins
when is the period for max potency for the body of water-sol vitamins
8-14h following ingestion
how do DRIs differ from RDAs?
RDIs focus more on promoting health maintenance and risk reduction for nutrient-dependent diseases rather than traditional criterion of preventing deficiency diseases
what do DRI values include?
recommendations that apply to gender and life stages of growth and development based on age and pregnancy and lactation
what do vitamins do?
regulate met
fac energy release
serve imp functions in bone and tissue synthesis
which vitamins fac the conversion of homocysteine to AAs?
folate, B6 and 12
an increase in homocysteine levels promote cholesterol’s damaging effects on arterial lumen
