L35: Micronutrients: The Vitamins (aishah) Flashcards
How many water soluble vitamins are required by humans?
13
Which type of vitamin is essential?
Water soluble vitamins; it gets excreted quickly fa we need to ingest it dietarily daily
What are characteristics of water soluble vitamins?
- they’re removed and excreted by the kidneys
- they aren’t stored in the body (vit b12 is an exception)
- they’re generally non-toxic (b6 is an exception)
- must be part of daily diet
- fragile and heat sensitive
If you were to choose between boiling and steaming which would you choose?
Steaming; you would lose less water
What are the sources of thiamin (b1)?
- Enriched grains consumed ad breakfast cereals and baked goods
- Found in meat and fish > dairy products
- Nuts, legumes
Thiamin may be destroyed by?
What is the recommended daily intake of thiamin for adults?
1.1-1.2 mg/day
What is the key co enzyme for energy producing reactions?
Thiamin phyrophosohate (TPP) is an active phosphorylated form of thiamin, it’s a co factor
- Pyruvate DEH
- Alpha Ketoglutarate
- Branched chain oxo-acid DEH
- Transketolase
Deficiency if thiamin leads to…
Suppression of aerobic metabolism ➡️ lactic acidemia
Requirements of thiamin is increased with…
Thiamin and the nervous system:
What is beri beri ?
- Beri beri is a disease of the 19th caused by thiamin deficiency (since we know that thiamin plays an important role in the nervous system)
- high risk population groups still exist
What are the symptoms of beri beri?
- Depression and weakness ☹️
2. Poor coordination, paralysis, and tingling in the arms and legs 🦵💪🏼
Thiamin deficiency causes what diseases?
- Beriberi
- Wernicke-korsakoff syndrome
- Common in malnourished alcoholics
Describe wernicke-korsakoffs syndrome
How does thiamin deficiency occur in malnourished alcoholics?
What are the sources of riboflavin (b2)?
- Milk **
- Red meat, poultry, fish
- Whole grains, enriched bread and cereals
- Asparagus, broccoli, mushrooms, and green leafy veggies
Features of riboflavin?
- Heat stable
2. Light sensitive (that’s why glass containers of milk were replaced with thick plastic containers)
What is the daily recommended intake of riboflavin?
1.1-1.3 mg/day
What is the function of riboflavin?
Transfer of H (electron transport chain)
What are examples of flavoenzymes?
How does riboflavin deficiency occur?
Occurs in conjunction with deficiencies of other B vitamins
Symptoms of riboflavin deficiency are known as?
What are the dietary sources of niacin?
De novo synthesis of niacin
It’s a non significant source under normal conditions; it doesnt really raise niacin levels in the body since the majority of niacin comes from the diet
What’s the recommended daily intake of niacin?
35 mg/day
Akthar mn b1 w b2
Which vitamins are heat stable?
Riboflavin and niacin
Niacin is a precursor for?
Active co enzymes of Niacin are:
Which disease does niacin deficiency cause?
And what are the symptoms?
Biotin is widely distributed in?
What are poor sources of biotin?
Widely distributed in nuts and eggs
Poor sources: Fruits and meats
True or false
Biotin cannot be synthesized by the body
False: it’s synthesized by intestinal microflora
Biotin is free or protein bound, how is it freed?
It is freed by biotidinase; has to be cleaved by this enzyme in order to be absorbed
Daily recommendation of biotin intake?
Describe biotin dependant carboxylation
How is biotin deficiency caused?
Biotin deficiency is not common
- Either ur born with a rare genetic disorder where you have biotidinase deficiency ( which is important to free biotin from protein-bound form and enhances its absorption)
Or
- Biotin-avidin interaction over long periods of time
How does biotin deficiency occur thru biotin-avidin interactions?
What are symptoms of biotin deficiency?
What does severe deficiency of biotin lead to? And how’s it treated?
Which is the most unstable vitamin?
Vitamin C; it’s very susceptible to degradation by heat, light, as well as oxidation
What are rich sources of vitamin c?
Loss of vitamin c is accelerated by?
Copper and iron utensils
RDA of vitamin C?
What are vitamin C functions?
Vitamin C deficiency results in?
Vitamin A exists in 2 forms:
Shnu il features + where are they found?
Absorbed vit A….
What are 2 inter convertible forms of vit A?
What is the function of retinoic acid?
- gene expression
- cell differentiation and growth
Function of carotenoids?
Antioxidant
What is the recommended intake of vit A for adults?
Function of vit a and the skin
Anti-Aging wrinkles and fine lines
Acne and blemish treatment 
Mechanism of how vit a acts on the skin
What is the most common cause of non-accidental blindness worldwide?
Vit A deficiency; very common in children in developing countries
Sh problem of vitamin a deficiency
Non accidental blindness is caused by a reduced intake of
Vit A toxicity:
Sources of Vit E, tocopherol
Vit E us sensitive to destruction by:
Oxygen, metals, light and heat
Recommended intake of Vit E for adults:
Vit E requirement increases as what increases?
Functions of Vit E
Deficiency of vitamin e leads to?
Toxicity of Vit E
List the lipid soluble vitamins
A D E K
Deficiency in which vitamin causes rbcs hemolysis and nerve damage?
Vit E
Deficiency in which vit causes blindness?
Vit a & riboflavin
Deficiency in which vitamin causes scurvy?
Vit C (ascorbic acid)
Deficiency in which vit causes Pellagra?
Niacin (vit b3)
Deficiency in which vit causes brittle nails, hair loss, muscke weakness and rashes?
Biotin (b7)
Deficiency in which vit causes wernicke and korsakoff syndrome?
Thiamin
Deficiency in which vit causes skin lesions, confusion, and nuclear cataracts and blindness?
Riboflavin (vit b2)
