BIOCHEMISTRY- Nutrition Flashcards
Which vitamins are fat soluble?
A, D, E, K
Which organs carry the absoption of fat soluble vitamins?
Gut and pancreas
Which vitamins have more toxicity?
Fat vitamins
Why do vitamin A, D, E and K are more toxic?
Because they accumulate in fat
This diseases can cause fat soluble vitamin deficiencies because if a malabsoption syndrome
Cystic fibrosis and sprue
This are examples of watter soluble vitamins
B1, B2, B3, B5, B6, B7, B9, B12 and C
All watter soluble vitamins are easily wash out from the body except for…
Vitamin B12 and folate (B9)
Where do cobalamin and folate are stored?
In the liver
Which are the three characteristics of the B- complex deficiencies?
Dermatitis, glositis and diarrhea
Antoxidant, constituent of of visual pigments
Vitamin A
What other names does Vitamin A receives?
Retinol
What effect does Retinol has on epithelial cells?
Essential dor normal differentiation of ephitelial cells into specialized tissue
What kind of cancer does Vitamin A prevents?
prevents squamos metaplasia
What diseases are treated with vitamin A?
measles and AML, subtype M3
Vitamin A as Retin-A, topically which kind of use does it has?
For wrinkles and acne
Where can we find Vitamin A?
In liver and leafy vegetables
This are the consequences for Vitamin A deficiency
Night blindness (nyctalopia), dry, scaly skin (xerosis cutis); alopecia, cerebral edema, pseudotumor cerebri, corneal degeneration (keratomalacia); immune suppression
Arthralgia, skin changes (scalines), alopecia, cerebral edema, pseudotomor cerebri, osteoporosis hepatic abnormalities… are signs of which vitamin excess?
Vitamin A or Retinol
Before indicating Isotretinoin for treatment in severe acne, for what do we need to have special precautions?
Negative pregnancy test and reliable contraception because is very Teratogenic
What kind of Teratogenic abnormalities can be present with the excess of vitamin A?
Cleft palate, cardiac abnormalities
Which vitamin is the thiamine?
Vitamine B1
In vitamin B1, Which is the cofactor for several dehydrogenase enzyme reaction?
Thiamine pyrophosphate
Which are the enzyme reactions caused by Thiamine pyrophosphate?
Pyruvate deshydrogenase (links glycolysis to TCA cycle)
α ketoglutarate dehydrogenase (TCA cycle)
Transketolase (HMP shunt)
Branched-chain ketoacid dehydrogenase
If there is a vitamin B1 deficiency what happens to the glucose?
Impaired glucose breakdown
What happens to the ATP in Vitamin B1 deficiency? and what will happen if we give a glucose infusion?
ATP depletion worsened by glucose infusion
Which tissue are first affected by thiamine depletion?
Highly aerobic tissues (Brain and Heart)
Weinicke-Korsakoff syndrome and Beriberi are diseases for which vitamin deficiency?
Vitamin B1
Name two kind of patients that can present Thiamine deficiency
Seen in malnutrition and alcoholism
Which laboratory test helps in the diagnosis of Vitamin B1 deficiency?
Increase RBC transketolase activity following vitamin B1 administration
Which is the classic triad in Wernicke Korsakoff syndrome?
Confussion
Ophtalmoplegia
Ataxia
This are other symptoms that can be seen in Wernicke Korsakoff syndrome
confabulation personality change, memory loss (permanent)
Anatomically, where is the site of damage in the brain in Wernicke Korsakoff syndrome
Damage to medial dorsal nucleus of thalamus, mamilary bodies
Dry or Wet beriberi… polyneuritis, symmetrical muscle wasting
Dry beriberi
Dry or Wet beriberi… high output cardiac failure (dilated cardiomyopathy), edema
Wet beriberi
This vitamin is a component of flavins FAD and FMN
Vitamin B2 Riboflavin
What is the use of FAD and FMN?
Cofactors in redox reactions
This is an example of the FMN and FAD used as cofactors
The succinate dehydrogenase reaction in the TCA cycle
Which are the two manifestation If there is a Vitamin B2 deficiency?
Cheilosis and Corneal vascularization
Which is the alternative name of vitamin B3
Niacin
What importance does the Niacin has in redox reactions?
Constituent of NAD+, NADP+
This vitamin is derived from tryptophan
Vitamin B3 (Niacin)
Which vitamins does Niacin requires for its synthesis
Vitamin B2 and Vitamin B6
Which disease is treated with vitamin B3?
Dyslipidemia
How does Niacin helps in the treatment of Dyslipidemia?
Lowers levels of VLDL and raises levels of HDL
Severe deficiency of Niacin, What disease does it causes?
Pellagra
Which is the disease that has a decrease in tryptophan absorption? and which disease can be the consequence?
Hartnup disease, which can cause Pellagra due to decrease in tryptophan absorption
What kind of disease has an increase trypthophan metabolism that leads to Pellagra?
Malignant carcinoid
This first-line medication in prevention and treatment of tuberculosis decreases vitamin B6 which can lead to vitamin B3 deficiency
Isoniazid
This are 3 main causes of Pellagra
Hartnup disease
Malignant carcinoid syndrome
Use of Isoniazid
Which is one of the main findings in Vitamin B3 deficiency?
Glossitis
Which are the three symptoms found in pellagra?
Diarrhea, Dementia and Dermatitis
How does the Dermatitis is manifested in Pellagra?
Casal necklace or hyperpigmentation of sun exposed limbs
Facial flushing induced by prostanglandin, hyperglicemia, hyperuricemia… this are findings of which vitamin excess?
Niacin
This vitamin is essential component of coenzyme A and fatty acid synthase
Vitamin B5
Which is the importance of CoA?
Is a cofactor for acyl transfers
Which is the other name for vitamin B5?
pantothenate
This are the findings in vitamin B5 deficiency
Dermatitis, enteritis, alopecia, adrenal insufficiency
Better known as pyridoxine
Vitamin B6
Vitamin B6 is converted to which cofactor, in order to be used in transamination, decarboxylation reactions and glycogen phosphorylase?
pyridoxal phosphate
In which synthesis process is necessary the pyridoxine?
Cystathionine, heme, niacin, histaminem and neurotransmitters including serotonin, epinephrine, norepinephrine, dopamine, and GABA
Convulsions, hyperirritability, peripheral neuropathy and anemia… this findings correspond to which vitamin deficiency?
Vitamin B6
What kind of anemia is caused by pyridoxine deficiency? What is the explanation for this anemia?
Sideroblastic anemias due to impaired hemoglobin synthesis and iron excess
This vitamin is a cofactor for carboxylation enzymes (which add a 1 carbon group)
Vitamin B7
This is the alternative name for Vitamin B7
Biotin
This are the sites where the Vitamin B7 works as a cofactor and adds 1 Carbon group
Pyruvate carboxylase: pyruvate to oxaloacetate
Acetyl-CoA carboxylase: acetyk CoA to malonyl-CoA
Propionyl-CoA carboxylase: propionyk-CoA to methylmalonyl-CoA
Which is the cause of biotin deficiency?
Caused by antibiotic use or excessive ingestion of raw egg whites
It´s relatively rare to see a Vitamin B7 deficiency, but when this happens which kind of findings are common?
Dermatitis, alopecia, enteritis
Which vitamin is Folic Acid?
Vitamin B9
Folic Acid is converted to…
Tetrahydrofolate (THF)
What is it for THF?
A coenzyme for 1’carbon transfer/methylation reactions
What importance does the THF and folic acid have in DNA and RNA?
Important for the synthesis of nitrogenous bases in DNA and RNA
Where do we find Vitamin B9
Found in leafy green vegetables
Where does the folic acid is absorbed?
In jejunum
Where is the small reserved of folic acid?
Primarily in the liver
If there is a deficiency in folic acid, how are the blood cell affected?
Macrocytic, megaloblastic anemia
hypersegmented PMN
What is the difference between vitamin B9 and B12 symptoms?
There is no neurologic symptoms in folic acid deficiency
Which labs alterations do we see in acid folic deficiency?
Increase homcystein, normal methylmalonic acid
Most common vitamin deficiency
Folic Acid deficiency
Which kind of patients present vitamin B9 deficiency
Alcoholism and pregnant patients
Which kind of drugs can cause acid folic deficiency?
Phenytoin, Sulfonamides, Methotrexate
The suplementation of this vitamin can decrease the risk of neural tube defects in the early pregnancy
Vitamin B9 or folic Acid
Cofactor for homocysteine methyltransferase and methylmalonyl CoA mutase
Vitamin B12
In which form does Cobalamin transfers CH3 groups
As Methylcobalamin
Which kind of food is high in vitamin B12?
Animal products
Who synthesized cobalamin?
Only by microorganisms
How much time can Vitamin B12 be reserved in the liver?
Several years
Which are the reasons for cobalamin deficiency?
Insuficient intake (Veganism)
Malabsoption (Sprue, enteritis)
Lack of intrinsic factor (pernicious anemia, gastric bypass surgery)
Absence of terminal ileum (Chron disease)
Which bacteria is the cause of malabsorption of Vitamin B12?
Diphyllobotrium lactum
What do we need to make the diagnosis of Pernicious anemia?
Anti-intrinsic factor antibodies
In blood studies this are the main findings in Cobalamin deficiency…
Macrocytic, megaloblastic anemia; hypersegmented PMN
Which kind of neurologic findings are seen in cobalamin deficiency?
paresthesias and subacute combined degeneration
Anatomically where are the degenerations of Vitamin B12 deficiency?
Degeneration of dorsal columns, lateral corticospinal tracts and spinocerebellar tracts
Why does subacute combined degeneration happens in patients with cobalamin deficiency?
Due to abnormal myelin
This laboratories are altered in patients with cobalamin deficiency
Increase serum homocysteine and methylmalonic acid levels
Neurologically, what happens if there is a prolonged deficiency of Vitamin B12 deficiency?
Irreversible nerve damage
This antioxidant is found in fruits and vegetables
Vitamin C
How does Vitamin C facilitates iron absorption?
By reducing it to Fe2+ state
Why does Ascorbic Acid is required for collagen synthesis?
Because is necessary for hydroxylation of proline and lysine in collagen synthesis
How does Vitamin C is related to dopamine?
Because it is necessary for dopamine β-hydroxylase, which converts dopamine to NE
This vitamin is tha ancillary treatment for methemoglobinemia by reducing Fe3+ to Fe2+
Vitamin C
This disease is caused by ascorbic acid deficiency
Scurvy
How does vitamin C deficiency causes Scurvy?
Due to a collagen synthesis defect
This are the characteristics of a patient with Scurvy
Swollen gums, bruising, hemarthrosis, anemia, poor wound healingm perifollicular, and subperiosteal hemorrhages, corkscrew hair
How is the immune response in the scury patients?
Weakened immune response
Nausea, vomiting, diarrhea, fatigue, nephrolithiasis are findings related to which vitamin excess?
Vitamin C
Which kind of kidney stones are form with ascorbic acid excess?
Calcium oxalate nephrolithiasis
Better known as ergocalciferol
Vitamin D2
This kind of vitamin D is ingested from plants
Ergocalciferol (Vitamin D2)
What is the other name for Vitamin D3?
Cholecalciferol
From where do we get Vitamin D3?
Consumed in milk, formed in sun exposed skin
In which stratum of the skin, does cholecalciferol is formed after the sun exposure?
Stratum basale
Which is the storage form of vitamin D3?
25-OH D3
This is the active form of Vitamin D3
1,25 (OH)2 D3 (calcitriol)
What kind of function does Vitamin D has?
Increases intestinal absoption of calcium and phosphate
Increases bone mineralization
Rickets in children is the manifestation of this vitamin deficiency
Vitamin D deficiency
In adults what is the name of the disease caused by Vitamin D deficiency?
Osteomalacia
Aside of rickets and osteomalacia, which other disease can happen with Vitamin D deficiency?
hypocalcemic tetany
In breastfed infants, which vitamin should receive orally?
Vitamin D
This are other risk factors that exacerbates the disease
By low sun exposure, pigmented skin, prematurity
This are the after effects that can be seen in Vitamin D excess?
Hypercalcemia, hypercalciuria, loss of apetite, stupor
Which vitamin is altered in Sarcoidosis?
Increase activation of vitamin D by epithelioid macrophages
What is the function of Vitamin E?
Antioxidant (protects erythrocytes and membranes from free radicals damage)
What effect does Vitamin E can have in conjuction with Warfarin?
Can enhance anticoagulant effects of Warfarin
Which findings are common on tocopherol deficiency?
Hemolytic anemia, achanthocytosis, muscle weakness, posterior column and spniocerebellar tract demyelination
The neurological presentation of Vitamin E is similar from which other vitamin?
Vitamin B12
Tocopherol/tocotrienol are other names for this vitamin
Vitamin E
Cofactor for the γ- carboxylation of glutamic acid residues on various proteins required for blood clotting
Vitamin K
Who synthesizes Vitamin K?
Intestinal Flora
Which Clotting factors require vitamin K for their activitation?
II, VII, IX, X, and protein C and S
Which medicine is Vitamin K antagonist?
Warfarin
When do we suspect of neonatal deficiency vitamin K?
Neonatal hemorrhage with ↑ PT and ↑ aPTT but normal bleeding time
Can neonates synthesize vitamin K?
No, neonates have sterile intestines and are unable to synthesize vitamin K
When is another situation of Vitamin K deficiency?
After prolonged use of broad spectrum antibiotics
In order to prevent bleeding diathesis in neonates, what do we do?
Neonates are given vitamin K injection at birth
Is Vitamin K in breast milk?
No
This suplementation is essential for the activity if 100+ enzymes
Zinc
This is a transcription factor motif
Zinc fingers
Which findings are common in Zinc deficiency?
Delayed wound healing, hypogonadism, decrease adult hair, dysgeusia, anosmia, acrodermatitis enteropathica. May predispose to alcoholic cirrhosis
Which is the product of alcohol dehydrogenase in ethanol? where does it takes place?
Convertion to Acetaldehyde in cytosol
From Acetaldehyde to Acetate which enzyme it´s the responsable to act? and where does this takes place?
Acetaldehyde dehydrogenase working in the mitochondria
In the ethanol metabolism, who is the limiting reagent?
NAD+
How does Alcohol dehydrogenase operates?
via zero order kinetics
What does the ↑ NADH/ NAD+ ratio in ethanol metabolism in the liver causes?
Pyruvate → Lactate (Lactic Acidosis)
Oxaloacetate→ Malate (prevents gluconeogenesis → fasting hypoglicemia)
Glyceraldehyde 3 phosphate →glycerol 3 phosphate (combines with fatty acids to make triglycerides→hepatosteatosis)
How does the ↑ NADH/ NAD+ ratio is related to Acetyl CoA?
↑ NADH/ NAD+ ratio disfavors TCA production of NADH so it leads to ↑ utilization of acetyl CoA for Ketogenesis
If there is ↑ utilization of acetyl CoA for ketogenesis, which would be the repercussions?
Ketoacidosis and lipogenesis (leads to more hepatosteatosis)
This medicine is the antidote for methanol or ethylene glycol poisoning
Fomepizole
Where does Fomepizole works?
Inhibits alcohol dehydrogenase
This medicine inhibits acetaldehyde dehydrogenase
Disulfiram
Which metabolit accumulates and causes hangover symptoms?
Acetaldehyde
With Disulfiram use, this are common symptoms
Hangover symptoms becuase of Acetaldehyde accumulation
This disease is the result of protein malnutrition
Kwashiorkor
Which are the results of protein malnutrition?
Skin lesions, edema, liver malfunction
Why is liver malfunction present in Kwashiorkor child?
Fatty change due to ↓ apolipoprotein synthesis
Which is the clinical picture of Kwashiorkor child?
Small child with swollen belly
What is the difference between marasmus and kwashiorkor?
Marasmus has a total calorie malnutrition
Which are the results of Marasmus?
Resulting in tissue and muscle wasting, loss of subcutaneous fat and variable edeme
