Water soluble vitamins Flashcards
What are things that could potentially cause damage to vitamins?
Light
Oxidation
Cooking
Storage
How is absorption of water and fat soluble vitamins different?
Water soluble vitamins are absorbed into bloodstream and are excreted in urine.
Fat soluble vitamins are absorbed into lymph then blood. In blood they are carried by protein carriers and stored in cells that typically store fat.
What is a big risk factor for fat-soluble vitamin toxicity?
Fat-soluble vitamins are likely to reach toxic levels with
supplement use
What is the Estimated Average Requirement and how is this taken into account when deciding an RDI?
Different people have different requirements for certain nutrients. EAR takes into account 50% of the population.
RDI is set at a value well above the EAR and as a result covers 98% of the population.
What is bioavailability?
Bioavailability is the rate and extent that a nutrient
is absorbed and used
What other forms can vitamins be consumed in?
Precursors (provitamins) are
consumed in an inactive form and become active
vitamins in the body
What is the function of thiamin (Vitamin B1)?
Thiamin is involved in energy metabolism as part of
the coenzyme thiamin pyrophosphate (TPP)?
What is the RDI of thiamin?
Men: 1.2mg/day
Women:1.1mg/day
What are the symptoms of thiamin deficiency?
Enlarged heart and possible cardiac failure
Muscular weakness
Apathy, poor short-term memory, confusion, and
irritability
Anorexia and weight loss
What deficiency causes Wernicke-Korsakoff syndrome?
Thiamin deficiency (caused by alcohol abuse)
What are the effects of alcohol consumption on thiamin?
Alcohol decreases absorption and increases excretion of vitamin B1.
Which vitamin deficiency causes the disease beriberi?
Thiamin
What is the difference between dry and wet beriberi?
Wet beriberi reflects damage to the cardiovascular
systems and presents with oedema (accumulation of vasodilators)
Dry beriberi reflects damage to the nervous system and
presents with muscle wasting
How common is the incidence of thiamin toxicity?
There are no reported toxicities
What are some food sources of vitamin B1?
Wholegrain, fortified or enriched grain products
Moderate amounts in all foods ( I remember this using its function; thiamine is involved in TPP function which is a step shared by all living creatures. We eat other living things so we get some vitamin B1 from other things.)
Yeast spreads (Vegemite)
Pork, my favourite yum
How does thiamin respond to cooking?
Vitamin is destroyed by heat so it needs to be steamed or microwaved.
What is the function of riboflavin?
Riboflavin is involved in energy metabolism
Flavin mononucleotide (FMN) and flavin adenine dinucleotide (FAD) are the reducing equivalent coenzyme forms
What is the RDI of riboflavin?
Men: 1.3mg/day
Women: 1.1mg/day
What are the symptoms of riboflavin deficiency? What is the name of the condition?
‘A’riboflavinosis:
Inflammation of the membranes of the mouth, skin, eye
and GI tract.
Sore throat and cracks and redness at corner of mouth.
Skin lesions covered with greasy scales.
Painful, smooth, and purplish red tongue
How common is the incidence of riboflavin toxicity?
No reported toxicities
What are some sources of vitamin B2?
Milk products; including yoghurt and cheese.
Enriched and whole grains.
Liver
Is vitamin B2 destroyed by cooking?
No
What destroys vitamin B2?
ultraviolet light.
What is the function of niacin (vitamin B3)?
Glucose, lipid, fat, and alcohol metabolism (NAD+ coenzyme)
What is the RDI of niacin?
Since body can obtain niacin from dietary tryptophan the RDI is in niacin equivalents (NE);
60mg trp = 1mg niacin
In men: 16NE/day
In women: 14NE/day
What is the upper intake level of niacin?
35mg/day
How can niacin be destroyed or lost?
It can be lost into water
What other functions does Niacin have?
It can transport electrons to pyruvate during anaerobic respiration (lactate production)
What are the deficiencies associated with niacin?
diarrhoea, abdominal pain, and vomiting
inflamed, swollen, smooth and bright red tongue
depression, apathy, fatigue, loss of memory, and
headache
Rash when exposed to sunlight
the four Ds: Diarrhea Dermatitis Dementia Death
Deficiency in what vitamin results in pellagra?
Vitamin B3 (NIacin)
What are the symptoms of niacin toxicity?
Niacin flush (painful tingling sensation results from dilated capillaries)
painful flush, hives and rash
excessive sweating
blurred vision
liver damage
impaired glucose tolerance
What are some niacin sources?
Milk
Eggs, meat, poultry, fish
whole-grain and enriched breads and cereals
nuts and all protein-containing foods
How can niacin bioavailability in food be improved?
Treating food with alkaline
What is the function of pantothenic acid?
Pantothenic acid is involved in energy metabolism
as a part of coenzyme A
What is the RDI of pantothenic acid?
Men: 6mg/day
Women: 4mg/day
What are the symptoms of pantothenic acid deficiency?
vomiting, nausea, and stomach cramps
• insomnia and fatigue
• depression, irritability, restlessness, and apathy
• hypoglycaemia and increased sensitivity to insulin
What are the symptoms of pantothenic acid toxicity?
There are no reported toxicities
What are some pantothenic acid food sources?
widespread in foods
– organ meats
– mushrooms, avocados, and broccoli
– wholegrains
What factors cause loss of pantothenic acid from food?
Freezing
Canning
Refining
What are vitamin B6 food sources?
meats, fish, poultry and liver
– legumes and soy products
– non-citrus fruits
– fortified cereals
What are some symptoms of vitamin B6 toxicity?
depression, fatigue, irritability, and headaches
• nerve damage causing numbness and muscle
weakness leading to inability to walk
• convulsions
• skin lesions
What is the upper level intake for vitamin B6?
50mg/day
What are the symptoms of vitamin B6 deficiency?
Scaly dermatitis
• Anaemia – small cell type
• Depression, confusion, abnormal brain wave pattern, and
convulsions
– Diminished synthesis of key neurotransmitter
– Accumulation of product of tryptophan metabolism in brain
What is the coenzyme form of vitamin B6?
pyridoxal phosphate
What kind of reactions is vitamin B6 involved in?
Participates in reactions involving amino
group (NH2) transfer and decarboxylation:
Amino acid metabolism
– Conversion of tryptophan to niacin or serotonin (a
neurotransmitter)
Urea metabolism
Decarboxylation of histidine
– Production of red blood cells
What factors can destroy vitamin B6?
Heat
What is the function of biotin?
Part of a coenzyme used in energy metabolism,
biotin assists in glycogen synthesis, fat synthesis, and
amino acid metabolism.
Involves in 1-carbon transfer reactions
• Example, synthesis of oxaloacetate (4C) from pyruvate (3C) and CO2
What is the RDI for biotin?
Men: 30 micrograms/day
Women: 25 micrograms/day
What are some biotin deficiency symptoms?
depression, lethargy, and hallucinations
• numb or tingling sensation in the arms and legs
• red, scaly rash around the eyes, nose and mouth
• hair loss
Name some biotin food sources.
widespread in foods
– organ meats, egg yolks and fish
– soybeans
– wholegrains
Biotin can also be synthesised by intestinal bacteria (hence the name)
Good summary video for water soluble vitamins (including vitamin C)
https://www.youtube.com/watch?v=lXgXTx1-d1k
What is the function of folate?
Involved in synthesis of DNA and formation of new cells
What other vitamin does folate work with to carry out its function?
vitamin B12 is required for the activation of folate.
What is the naturally occuring form of folate?
polyglutamate
What is folate’s RDI?
400 micrograms/day
Why is folate calculated in DFE?
bioavailability is different in different foods.
What birth defects are associated with folate deficiency?
spina bifida
anencephaly
How does alcohol contribute to folate deficiency?
Alcohol damage GI tract epithelial cells reducing reabsorption of folic
acid
• Deficiency of folic acid leads to deterioration of GI tract further
increasing folate deficiency
How is folate related to heart disease?
Folate breaks down homocysteine. High levels of homocysteine and low levels of folate cause heart disease.
How is folate related to cancer?
Sufficient folate may protect against cancer but enhance progression after it has begun.
What are symptoms of folate deficiency?
impaired cell division + Protein synthesis.
Smooth, red tongue
Mental confusion, weakness, fatigue, irritability and headaches.
macrocytic anemia aka megaloblastic anemia.
What are the symptoms of folate toxicity?
No known toxicties. It masks vitamin B12 deficiency symptoms.
What are some folate sources?
fortified grains
Leafy green vegetables
Legumes and seeds
Liver
What is the function of vitamin B12?
Synthesis of new cells
maintaining nerve cells
reforming folate coenzymes
breaking down fatty acids and amino acids.
What are the coenzyme forms of vitamin B12?
methylcobalamin (active)
deoxyadenosylcobalamin
What is the RDI of vitamin B12?
2.4 μg/day
What are the vitamin B12 deficiency symptoms?
exacerbate folic deficiency related megalomaniac anaemia
fatigue and depression
degeneration of peripheral nerves progressing to paralysis
What are some causes of vitamin B12 deficiency?
atrophic gastritis can cause vitamin B12 deficiency because it inhibits it’s release from food proteins.
What are the toxicity symptoms of vitamin B12?
No known toxicities.
What are some vitamin B12 sources to remember?
Meat, fish, poultry, shelfish
Milk, cheese and egg
Fortified cereals
How is vitamin B12 absorbed at the intestine?
Vitamin B12 binds with intrinsic factor before it is absorbed.
What factors destroy vitamin B12?
Microwave cooking
How does mitomycin affect cells?
Mitomycin cross links to DNA strands preventing replication
How does doxorubicin affect cells?
Doxorubicin intercalates DNA
How does taxol affect cells?
Taxol targets microtubules which prevents cell replication.
How can folate be used in cancer therapy?
Folate receptor is overexpressed in cancer cells and so folate is attached to drugs to target anti-cancer chemicals directly to the cancer cells.
What are some methods for targetting medical therapies to cancer cells?
Antibodies are often used to target medicine to cancer.
Peptides
Folate
Why is folate linked to the drug by an acid labile linker?
Acid labile linkage is required for release of the drug the targeted cancer cells.
What are the symptoms associated with vitamin B deficiencies in general?
glossitis (inflamed tongue) and cheilosis (scaling of lips) are
two symptoms common to B vitamin deficiencies
What is the function of vitamin C?
an antioxidant
cofactor in collagen formation
As a cofactor in other reactions
• hydroxylation of carnitine
• converts tryptophan to neurotransmitters
• Synthesis of some hormones
Vitamin C needs to increase
• during body stress, i.e. infections, burns, extremely high or low
temperatures, heavy metal intakes, certain medications, and smoking
– As a cure for the common cold
• some relief of symptoms
• vitamin C deactivates histamine like an antihistamine
– Effectiveness in disease prevention is still being researched
What is the RDI for vitamin C?
adults: 45mg/day
smokers: 80mg/day
What condition results from scurvy and what are its symptoms?
Scruvy; symptoms:
rough skin and blotchy bruises
bleeding gums and loose teeth
pinpoint haemorrhages
poor wound healing and frequent infections
atherosclerotic plaques
bone fragility and joint pain
anemia (small cell)
Muscle degeneration and pain, hysteria, and depression
What are the symptoms of vitamin C toxicity?
Acidosis
– Toxicity symptoms
• nausea, abdominal cramps, diarrhoea, headache, fatigue
and insomnia
• hot flashes and rashes
• interference with medical tests, creating a false positive or
a false negative
• aggravation of gout symptoms, urinary tract infections,
and kidney stones
What is the upper level for vitamin C consumption?
Upper level for adults unable to be determined. Thought to be 1000 mg/day
What are some sources of vitamin C?
citrus fruits, cantaloupe, strawberries, papayas and
mangoes
– cabbage-type vegetables, dark green vegetables like
capsicum and broccoli, lettuce, tomatoes and potatoes.
What factors destroy vitamin C?
heat and oxygen
