Vitamins and Vitamin-Like Substances

Vitamins and Vitamin-Like Substances
By:Eric Niederhoffer & SIU-SOM

* Names and roles - vitamins
* Names and roles - vitamin-like
* Deficiencies and sources -vitamins
* Deficiencies and sources - vitamin-like
* Role in pathways
* Neurotransmitter overview
* Neurotransmitter pathway
* Tetrahydrofolate conversions
* Tetrahydrofolate examples
* B12 pathways

Names and Roles Vitamins
Names and Roles Vitamin-Like Substances
Deficiencies and Sources
Vitamins

A - night blindness
preformed: liver, egg yolk, butter, milk
b-carotene: dark green and yellow veggies
D - ricketts, osteomalacia
milk, fortified food, fish oils, egg yolks, liver
E - neurologic?, hemolytic anemia
veggie oils, nuts
K - bleeding disorders
green leafy veggies, fruits, dairy products, veggie oils, cereals, meats
B1 - beri-beri
seeds, nuts, wheatgerms, legumes, lean meat
B2 - pellagra
meats, nuts, legumes
B3 - pellagra
meats, nuts, legumes
B6 - neurologic disease
yeast, liver, wheatgerm, nuts, beans, bananas
B7 - widespread injury
corn, soy, egg yolk, liver, kidney, tomatoes
B12 - pernicious anemia
liver, kidney, egg, cheese
B9 - anemia
yeast, liver, leafy veggies
C - scurvy
citrus and soft fruits
B5 - none known
yeast, grains, egg yolk, liver


Deficiencies and Sources Vitamins-Like Substances
Choline - rare
whole eggs, liver, beef steak, and soy (lecithin)
Carnitine - unlikely
meat, dairy products, asparagus, wheat grem
Bioflavonoids - none known
fruits, vegetables, tea, coffee, cocoa, wine, beer
Lipoic acid - none known
liver
Coenzyme Q - rare
fruits, vegetables, meats
Inositol - none known
cereal grains
p-Aminobenzoic acid - see B9
liver, rice bran, whole wheat
Glycolysis
TCA
cycle
Glycogenolysis
Role in Pathways
Neurotransmitter Overview

Review Questions

* What are the different names for vitamins A, B1, B2, B3, B5, B6, C, and B12?
* Which pathway depends on vitamin A?
* Which pathways and enzymes depend on vitamin B1, B2, B3, B6 and B12?
* Which pathway and enzyme depends on choline?
* Which pathways and enzymes depend on folic acid?

Vitamins and Vitamin-Like Substances.ppt

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CALCIUM METABOLISM

CALCIUM METABOLISM

CALCIUM METABOLISM
* PHYSIOLOGY OF CALCIUM METABOLISM
* HYPERCALCEMIA
* HYPOCALCEMIA
* METABOLIC BONE DISEASES

CALCIUM PHYSIOLOGY: BLOOD CALCIUM

* BLOOD CALCIUM IS TIGHTLY REGULATED
o PRINCIPLE ORGAN SYSTEMS
o HORMONES
o INTEGRATED PHYSIOLOGY OF ORGAN SYSTEMS AND HORMONES MAINTAIN BLOOD CALCIUM

CALCIUM PHYSIOLOGY: BLOOD CALCIUM

* CALCIUM FLUX INTO AND OUT OF BLOOD
CALCIUM HOMEOSTASIS
DIETARY CALCIUM
INTESTINAL ABSORPTION
ORGAN PHYSIOLOGY
ENDOCRINE PHYSIOLOGY
DIETARY HABITS,
SUPPLEMENTS
BLOOD CALCIUM
BONE
KIDNEYS
URINE


VITAMIN D PHYSIOLOGY
VITAMIN D SYNTHESIS
TISSUE-SPECIFIC VITAMIN D RESPONSES
VITAMIN D MECHANISM OF ACTION: VITAMIN D RECEPTOR
VITAMIN D REPCEPTOR: TRANSCRIPTIONAL REGULATION
VITAMIN D MECHANISM OF ACTION
VITAMIN D RESPONSIVE GENE
TRANSCRIPTION START SITE
FUNCTION OF VITAMIN D
PARATHYROID HORMONE (PTH) PHYSIOLOGY
CALCIUM, PTH, AND VITAMIN D FEEDBACK LOOPS
CALCIUM FEEDBACK TO REGULATE PTH SECRETION
CALCIUM SENSING RECEPTOR: CLINICOPATHOLOGIC CORRELATES
PTH RECEPTOR CLINICOPATHOLOGIC CORRELATES
ORGAN PHYSIOLOGY AND CALCIUM METABOLISM
GI PHYSIOLOGY
RENAL PHYSIOLOGY
BONE PHYSIOLOGY
MEASUREMENT OF BONE TURNOVER
HYPERCALCEMIA: SIGNS AND SYMPTOMS
CAUSES OF HYPERCALCEMIA
PRIMARY HYPERPARATHYROIDISM
TREATMENT OF PRIMARY HYPERPARATHYROIDISM
HYPERVITAMINOSIS D
HYPERVITAMINOSIS D: CLINICAL CHARACTERISTICS
NON-HORMONAL HYPERCALCEMIA
RENAL FAILURE-ASSOCIATED HYPERCALCEMIA
DRUG-INDUCED HYPERCALCEMIA
HYPOCALCEMIA: SIGNS AND SYMPTOMS
CAUSES OF HYPOCALCEMIA
HYPOCALCEMIA: HYPOPARATHYROIDISM
HYPOPARATHYROIDISM: TREATMENT
HYPOPARATHYROIDISM: TREATMENT SUMMARY
HYPOCALCEMIA: HYPOVITAMINOSIS D
DEFECTIVE VITAMIN D FUNCTION
NON-PARATHYROID HYPOCALCEMIA: SECONDARY HYPERPARATHYROIDISM
HYPERPARATHYROIDISM: PRIMARY vs. SECONDARY
SECONDARY HYPERPARATHYROIDISM
RICKETS AND OSTEOMALACIA
RICKETS AND OSTEOMALACIA: CLINICAL MANIFESTATIONS
RICKETS AND OSTEOMALACIA: CAUSES

CALCIUM METABOLISM.ppt

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Vitamin Deficiency Disorders

Vitamin Deficiency Disorders
By:Abdelaziz Elamin, MD, PhD, FRCPCH
Professor of Child Health, College of Medicine
Sultan Qaboos University, Muscat, Oman

BACKGROUND

* Vitamins are organic substances that are essential for several enzymatic functions in human metabolism
* Thiamine was discovered in 1912 & was thought to be a vital amine compound & thus the term vitamin was invented

VITAMINS
* Vitamins are classified according to solubility into fat soluble & water soluble.
* 13 vitamins are known, 4 fat soluble (KEDA) & 9 water soluble (C, Folate & the B group).

VITAMIN A
* Vitamin A is a generic term for many related compounds.
* Retinol (alcohol), Retinal (aldehyde) are often called preformed vitamin A. Retinal can be converted by the body to retinoic acid which is known to affect gene transcription.
* Body can convert b-carotene to retinol, thus called provitamin A.

FUNCTIONS
* Vision: integrity of eye & formation of rodopsin necessary for dark adaptation.
* Regulation of gene expression: vital to cell differentiation & physiologic processes
* Growth & development
* Immunity: important for activation of T lymphocyte, maturation of WBC & integrity of physiological barrier.

Nutrient Interactions
* Zinc deficiency interfere with vitamin A metabolism in several ways:
o It decreases the synthesis of retinol binding protein, which transports retinol to tissues.
o It decreases the activity of the enzyme retinyl palmitate, which is necessary for release of retinol from the liver.
o Zn is needed for the enzyme that convert retinol into retinal.
* Iron & vitamin A.
o Vitamin A deficiency may exacerbate IDF
o Vitamin A supplementation improves iron status among children & pregnant women.
o Combining vitamin A with iron controls IDA more quickly & effectively than using iron alone.

VITAMIN A UNITS
* 1 mg of retinol = 6 mg of b-carotene.
* 3 mg of retinol = 10 international units of vitamin A.
* 100 mg carrots contain 10 mg of b-carotene.

Recommended Allowance
Papaya
Fish & meet
Apricot
Milk & cheese
Spinach
Butter
Cantaloupe
Egg
Carrots
Liver & kidney
Sweet potato
Cod liver oil
Plant Foods
Animal Foods
RICH DIETARY SOURCES

Vitamin A deficiency
* Deficiency of vitamin A leads to:
o Night blindness & xerophthalmia
o Growth retardation
o Acquired immune deficiency
o Keritinization of epithelia in RT, GIT & UT with increased risk of RTI, malabsorption & UTI.

THERAPEUTIC USES
* Vitamin A deficiency
* Boosting immunity of infants
* Skin disorders
* Acute promyelotic leukemia
* Cancer prevention (lung & breast)

TOXICITY
* Vitamin A in excess leads to:
o Dermatitis with xanthosis cutis
o Hepatosplenomegaly
o Bone pain & increased risk of fracture
o Pseudotumor Cerebri

VITAMIN D
* Vitamin D comprises a group of sterols; the most important of which are cholecalciferol (vitamin D3) & ergosterol (vitamin D2).
* Humans & animal utilize only vitamin D3 & they can produce it inside their bodies from cholesterol.
* Cholesterol is converted to 7-dehydro-cholesterol (7DC), which is a precursor of vitamin D3.
* Exposure to the ultraviolet rays in the sunlight convert 7DC to cholecalciferol.
* Vitamin D3 is metabolically inactive until it is hydroxylated in the kidney & the liver to the active form 1,25 Dihydroxycholecalciferol.
* 1,25 DHC acts as a hormone rather than a vitamin endocrine & paracrine properties.

FUNCTIONS
* Calcium metabolism: vitamin D enhances ca absorption in the gut & renal tubules.
* Cell differentiation: particularly of collagen & skin epithelium
* Immunity: important for Cell Mediated Immunity & coordination of the immune response.

Vitamin D deficiency
* Deficiency of vitamin D leads to:
o Rickets in small children.
o Osteomalacia
o Osteoporosis

GROUPS AT RISK
* Infants
* Elderly
* Dark skinned
* Covered women
* Kidney failure patients
* Patients with chronic liver disease
* Fat malabsorption disorders
* Genetic types of rickets
* Patients on anticonvulsant drugs

Sources of Vitamin D
* Sunlight is the most important source
* Fish liver oil
* Fish & sea food (herring & salmon)
* Eggs
* Plants do not contain vitamin D3

THERAPEUTIC USES
* Rickets & Osteomalacia
* Osteoporosis
* Psoriasis
* Cancer prevention (prostate & colorectal)
* Autoimmune diseases

TOXICITY
* Hypervitaminosis D
causes hypercalcemia, which manifest as:
o Nausea & vomiting
o Excessive thirst & polyuria
o Severe itching
o Joint & muscle pains
o Disorientation & coma.
RICKETS

Vitamin Deficiency Disorders.ppt

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