vitamins1 Flashcards
what are the vitamins? and what we call them?
organic compounds occurring in small quantities in natural foods (micronutrients))
why the vitamins are important?
they are necessary for the growth and maintenance of good health. they are essential for metabolism. they participate in the metabolism of lipids, proteins, carbohydrates
*which vitamins act as hormons?
both vitamin A and vitamin D act as hormones
which vitamins act as coenzymes?
many water-soluble vitamins act as coenzymes in metabolic reactions.
*what is the only one fat-soluble vitamin that has a coenzyme function?
vitamin K
how do we get the vitamins?
vitamins cannot be synthesized in adequate quantities by us, intestinal bacteria can synthesize, some vitamins must be supplied by the diet.
*can the body store water soluble vitamins?
with the exception of vitamin B12, the body has no storage capacity for water-soluble vitamins.
what are the vitamins deficiency reasons?
inadequate intake, poor absorption from gastrointestinal tract= (GIS), inefficient utilization, increased loss, increased demand.
what may deficiencies lead to and how do they develop?
deficiencies lead to specific clinical syndromes, may develop as a component of general malnutrition, may themselves be a cause of illness, may develop during Increased demand periods such as pregnancy or adolescent growth spurt, in old age deficiencies may be associated with less efficient intestinal absorption, may occur as a complication of GIS surgery, multiple micronutrient deficiencies are much more common than single ones.
*when do some vitamins become toxic?
some vitamins (fat-soluble) are toxic in excess
*what happens quickly in water-soluble vitamins?
water-soluble vitamins are excreted readily in urine (toxicity is rare), deficiency may occur quickly.
how do vitamins differ from other organic food
vitamins do not enter into tissue structures unlike proteins, vitamins do not undergo degradation for providing energy, unlike carbohydrates and lipids.
list the categories of vitamins and their members
vitamins:
water-soluble:
1-non-B complex- (ascorbic acid (vitamin C)).
2-B complex
1-energy releasing(Thiamine (Vitamin B1), Riboflavin (Vitamin B2), Niacin (vitamin B3), Biotin (vitamin B7), Pantothenic acid).
3-hematopoietic- folic acid (vitamin B9), Cobalamin (Vitamin B12).
4-Pyridoxine (Vitamin B6) is important for protein metabolisim, pyridoxal, pyridoxamine.
fat-soluble:
vitamin: A, D, K, E.
*list the water-soluble vitamins
Thiamine(Vitamin B1), Riboflavin(Vitamin B2), Niacin(Vitamin B3), Pyridoxine(Vitamin B6), Biotin(Vitamin B7), Pantothenic Acid(vitamin B5), Folic Acid, Cobalamine(Vitamin B12), Ascorbic Acid (Vitamin C).
why B-complex vitamins are important?
because they are essential for normal metabolism, serve as coenzymes in many reactions in lipid, carbohydrate, and protein metabolism.
*when does the requirement of B-complex vitamins increase?
the greater the caloric intake the larger the requirement of B vitamins. increased energy supply in particular form simple carbohydrates requires increased amounts of B vitamins. high carbohydrates intake requires a greater intake of Thiamine and other B vitamins. therefore Beriberi might develop on a high carbohydrate diet.
which disease may develop on a high-carbohydrate diet?
Beriberi might develop on a high-carbohydrate diet.
why is Thiamine (vitamin B1) important?
because it plays a key role in the energy metabolism of most cells.
particularly important in tissues of CNS (Central Nervous System).
*what is the biologically active coenzyme form of Thiamine (vitamin B1)?
Thiamine Pyro Phosphate (TPP)
what are the coenzyme functions of Thiamine Pyro Phosphate (TPP)?
Transketolase (Pentose Phosphate Pathway ).
Pyruvate Dehydrogenase ( Oxidative
Decarboxylation ).
Alpha Keto Glutarate Dehydrogenase ( Oxidative
Decarboxylation ).
Branched Chain Alpha Keto Acid Dehydrogenase of
Muscle Cells.
list the Thiamin deficiency causes
decreases in pyruvate dehydrogenase and alpha keto glutarate dehydrogenase enzyme's activates:
a decline in ATP production
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impaired cellular functionswhat causes Beriberi? and what does it do?
due to thiamine deficiency in diet (so beriberi is a thiamine deficiency): Inflammation of multiple nerves (Polyneuritis ). Heart disease ( Cardiopathy ). Edema ( Swelling ).
what is Beriberi?
Severe Thiamine deficiency syndrome is found in areas where Polished rice is the major component of the diet.
Peripheral Neurological deficit or.
Edema due to Cardiac dysfunction.
*what is dry Beriberi? and what doe it cause?
dry Beriberi: without fluid retention.
Peripheral Neuropathy especially in the legs. (foot drop) and (wrist drop).
*what is wet Beriberi?
wet (cardiovascular) Berberi: associated with cardiac failure with edema.
*what is Wernicke Korsakoff Syndrome? and what is the reason behind it?
2 conditions that often happen together;
Wernicke encephalopathy and Korsakoff syndrome.
reason: Dietary insufficiency or Impaired intestinal absorption of Thiamine.
Seen primarily in association with chronic alcoholism.
*what are the Wernicke Korsakoff Syndrome
symptoms?
Mental confusion.
Gait ataxia.
Nystagmus ( Involuntary rhythmic shaking ‘’Dancing ‘’ of Eyes ).
Ophthalmoplegia (Weakness of eye muscles ).
what are the symptoms of Wernicke Encephalopathy? how is it treatable? *and what are the tests used to assess Thiamine’s status?
Wernicke encephalopathy has hallucinations and memory problems and Korsakoff dementia.
treatable with thiamine supplementation but memory recovery is typically incomplete.
tests used to assess thiamine’s status: red blood cell transketolase activity.
what are the tests used to assess Thiamine’s status?
red blood cells transketolase activities.
case study
A 20-year-old female was brought to the emergency department with respiratory distress
• A known Alcoholic
• On examination she was pale, malnourished, agitated, and acutely ill
• She was in acute respiratory distress
• Her pulse was 110/minute, there was marked tachycardia and a systolic murmur was heard along the left sternal edge
• Bilateral crepitations were felt in the lungs, neck veins were engorged and liver was also enlarged, although non-tender
• Bilateral foot drop
what is the probable diagnosis?
• Patient is most probably suffering from Cardiac beriberi (wet form)
*• The criteria for diagnosing cardiac beriberi is:
• (1) Signs of heart failure,
• (2) Signs of neuropathies,
• (3) History of alcoholism or poor nutritional history,
• (4) Exclusion of other signs of heart failure,
*• (5) Low Red Blood Cell Transketolase activity,
• (6) Response by Thiamine administration
%what is the probable diagnosis?
- Patient is a known alcoholic.
- Malnourished.
- Heart failure.
- Bilateral foot drop.
- The probable diagnosis is Thiamine deficiency, which can be confirmed by RBC Transketolase activity.
- Thiamine deficiency (causing Beriberi) is most common among people subsisting on white rice or highly refined carbohydrates in developing countries and among alcoholics.
- Thiamine is given to help diagnose and treat the deficiency.
- Thiamine deficiency often occurs with other B vitamin deficiencies, multiple water-soluble vitamins are usually given for several weeks.
what are the criteria for diagnosing cardiac beriberi?
1-signs of heart failure.
2-signs of neuropathy.
3-history of alcoholism or poor nutritional history.
4-exclusion of other signs of heart failure.
5-low red blood cell transketolase activity.
6-response by thiamine administration.
thiamine deficiency can be confirmed by…..
RBC transketolase.
among which people Thiamine deficiency (causing Beriberi) is most common?
Thiamine deficiency (causing Beriberi) is most common among people subsisting on white rice or highly refined carbohydrates in developing countries and among alcoholics. Thiamine is given to help diagnose and treat the deficiency. Thiamine deficiency often occurs with other B vitamin deficiencies, multiple water-soluble vitamins are usually given for several weeks.
Riboflavin (vitamin B2) is required for…. and …. synthesis
FMN and FAD
what are the characteristics of FMN and FAD?
- Reversibly accepts 2 Hydrogen atoms
- Bound tightly, sometimes covalently to Flavoenzymes
- Function in Mitochondrial electron transfer
what is Riboflavin deficiency?
• Not associated with a major human
disease
• Frequently accompanies other vitamin deficiencies.
*what are the symptoms of riboflavin deficiency?
- SYMPTOMS;
- Dermatitis (inflammation of the skin)
- Angular stomatitis (Inflammation of the corners of the mouth)
- Cheilosis ( Fissuring at the corners of the mouth )
- Glossitis ( Tongue appearing smooth and dark )
- Corneal vascularization
what is Niacin (vitamin B3)=Nicotinic acid?
Nicotin amide occurs in the diet
Nicotin amide is readily deaminated in the body so; forms Niacin.
Niacin is required for the synthesis of what?
NAD,NADH,NADPH.
*…. and …. function as coenzymeS in redox reactions
NAD and NADP
requirement of niacin is related to what?
requirement for Niacin is related to energy expenditure.
Niacin is synthesized from what?
Tryptophan
what is Pellagra?
Tryptophan and/ or Niacin Deficiency.
pelle= skin agra= rough
what are the symptoms of pellagra?
3D symptoms:
• Photosensitive Dermatitis (Sunburn-like skin lesions in areas of the body exposed to sunlight and to pressure.
• Dementia and Diarrhea.
what happens if the Pellagra is untreated?
multi-organ failure and death.
4D= Dermatitis, Diarrhea, Dementia, Death
*what is Casal necklace?
a Pellagra symptom,
Dermatitis is precipitated by exposure to sunlight,
*Increased pigmentation around the neck is known as Casal necklace.
what is Zein and what are its characteristics?
Zein is a corn protein, it is low in both Tryotphan and Niacin.
corn based diets can cause what?
Pellagra.
what are the Pelleagra precipitating factors?
corn rich diet and alcoholism.
*what is Hartnup disease?
Intestinal and renal tubular reabsorption defect of Neutral
amino acids ( Gly, Ala, Val, Tre, Leu, Ile, Phe, Tyr, Trp, His )
• Defective reabsorption of Tryptophan
• Can result in Pellagra like symptoms
*how to diagnose Hartnup disease? and what is the therapy?
Diagnosis;
• In Urine; High levels of Neutral amino acids.
• In Plasma; Low levels of Neutral amino acids.
• Therapy; Nicotin amide daily, Sun protection.
what are the symptoms and signs of hartnup disease?
red scaly photosensitive rashes, diarrhea, renal aminoaciduria, seizures.
how does Niacin treat Hyperlipidemia?
decreases both levels in the blood of TG, triglyceride (in VLDL, very low-density lipoprotein), and cholesterol (in LDL, low-density lipoprotein)
what do the high doses of Niacin cause? and what is that reaction accompanied with? and what can reduce this side effect?
• Can cause acute, Prostaglandin- mediated flushing
• Transient vasodilation of the cutaneous vessels and
Histamine release, Reaction is accompanied by itching, burning, and tingling. aspirin can reduce this side effect.
what is Pantothenic acid (vitamin B5)?
Forms a part of Coenzyme A molecule. • Acetyl CoA • Succinyl CoA • Fatty acyl CoA its function is Acyl group transfer. it is widely distributed. rich sources; eggs, liver, and yeast. no evidence of deficiency in humans.
where is the Pyridoxine (vitamin B6), Pyridoxal, Pyridoxamine found?
Pyridoxine occurs primarily in plants.
Pyridoxal and Pyridoxamine are found in animal foods.
*what do Pyridoxine, Pyridoxal, Pyridoxamine do?
• Participates in Carbohydrate and Lipid metabolism
*• Particularly important for Amino acid metabolism
*what is the biologically active coenzyme form of Pyridoxine, Pyridoxal, Pyridoxamine?
Biologically active Coenzyme form: Pyridoxal phosphate is Coenzyme for enzymes, particularly in Amino acid
metabolism.
* Pyridoxal phosphate; Coenzyme of Transamination, Deamination, Decarboxylation, and Condensation reactions.
what are the reactions that Pyridoxine is involved in and how many are they?
• Involved in more than 100 reactions in
carbohydrate and lipid metabolism
• In the synthesis, catabolism, and interconversion
of amino acids
• In the metabolism of one-carbon units
Pyridoxin is required for the synthesis of what? and what does it influence?
- Neurotransmitters Serotonin and Noradrenaline
- Sphingosine, a component of sphingomyelin and sphingolipids and
- Heme
- Influences immune function
*Vitamin B6 requirements increase with what and why?
Because of its role in Amino acid metabolism, Vitamin B6
requirements increase with high protein intake.
Deficiency of vitamin B6 causes what?
Neurologic symptoms and Anemia
Mild form deficiency of vitamin B6 causes what?
causes irritability, nervousness, and depression.
*severe deficiency of vitamin B6 causes what? and it is associated with what?
*peripheral neuropathy, convulsions, and coma.
and it is also associated with *Sideroblastic anemia(Anemia characterized by the presence of nucleated red blood cells with iron
granules)
• Dermatitis, cheilosis, and glossitis
decreased levels of vitamin B6 are in what cases?
• Alcoholism • Obesity • Malabsorption states (Crohn’s disease, celiac disease, and ulcerative colitis) • End-stage renal disease • Autoimmune conditions
what is vitamin B7 called?
Biotin, vitamin H, because in German language Haar= hair, Haut= skin
*what does Biotin (vitamin B7) do?
*act as a coenzyme for carboxylation reactions.
serves as a carrier of activated carbon dioxide.
Biotin (vitamin B7) serves as a coenzyme in multienzyme complexes that is involved in what?
- Carboxylation reactions,
- Lipogenesis
- Gluconeogenesis
- Catabolism of Branched-chain amino acids
how does Biotin (vitamin B7) deficiency occur?
• Biotin is widely distributed in food
• Intestinal bacteria provide most part of our Biotin
requirements
• Deficiency does not occur naturally
*what are the Biotin (vitamin B7) deficiency symptoms
Dermatitis, *Hair loss, loss of appetite, Nausea, Hallucinations, Muscle pain.
what is Avidin?
Avidin act as a Biotin (vitamin B7) antagonist,
• A protein present in Egg White
• Raw Egg White has a great affinity to Biotin
• Avidin tightly binds Biotin and prevents its absorption from the intestine
• One molecule of Avidin can combine four molecules of Biotin
• With a normal diet; Eating 20 Raw eggs/ day is required to induce Biotin deficiency.
• Addition of raw egg White to diet as a source of protein
can induce Biotin deficiency’s symptoms
• Avidin is heat labile
• Boiling of egg neutralize Avidin’s inhibitory activity
