Micronutrients: Vitamins and Minerals

Question 1

What are vitamins?

Answer 1

Essential organic compounds:
-small amount needed
-do not provide energy
-many help in metabolism (coenzyme)
Most are ingested, but:
-Vitamin D synthesized by skin
-Vitamins B and K –> intestinal bacteria
Sensitive to heat

Question 2

What are lipid-soluble vitamins?

Answer 2

Vitamins A, D, E, K:
-Absorbed with chylomicrons
-Accumulation possible in adipose tissue and liver
-Risk of hypervitaminosis (extreme)

Question 3

What are water-soluble vitamins?

Answer 3

Vitamins Bs and C:
-Absorbed with water
-Not stored, excess eliminated in urine

Question 4

What is vitamin A (retinol)?

Answer 4

-Synthesized from a pigment present in fruits and vegetables (beta-carotene)
-Facilitates eyesight; photoreceptors on the retina (composed of visual pigment rhodopsin; retinal + opsin)
-Deficit may cause night blindness (first cause of child blindness)

Question 5

What is vitamin D?

Answer 5

-Obtained from diet and production initiated in the skin upon sunlight exposure
-Increases calcium and phosphorus absorption (bones main building materials)
-Critical in children (insufficient intake causes rickets; weak/soft bones)

Question 6

What is vitamin E?

Answer 6

-Antioxidant
-Neutralizes peroxides and free radicals (cause damage to cells and enzymes)

Question 7

What is vitamin K?

Answer 7

Blood clotting:
-Helps the synthesis of prothrombin (becomes active thrombin)
-Deficiency = clotting problem
No link with hemophilia (genetic disorder)

Question 8

What are vitamins B?

Answer 8

-Many different forms: B1, B2, B3, B5, B6, B9, B12
-Act as coenzymes: join enzymes to make them functional + thus, essential for metabolic processes

Question 9

What is vitamin C?

Answer 9

Ascorbic acid:
-Citrus fruits are a good source
-Used as a food preservative, antioxidant or color stabilizer
Promotes iron absroption:
-Increases iron solubility in small intestine
-Hence, increasing absorption
Symptoms of defiency appear after 3 months:
-Hair loss, bleeding gum, skin lesions or bruising
-Scurvy (scorbu)

Question 10

What are minerals?

Answer 10

-Inorganic compounds (no carbon)
-Must come from the diet; impossbile to synthesize
-Many are enzymes cofactors

Question 11

What are the major minerals?

Answer 11

-Potassium (K) - Electrical impulses
-Sodium (Na) - Blood pressure
-Calcium (Ca) - Bone structure
-Phosphorus (P) - Bone structure and ATP
-Magnesium (mg) - Cofactor
-Chloride (Cl)

Question 12

What are trace minerals?

Answer 12

-Iron (Fe) - Oxygen transport
-Zinc (Zn)
-Copper (Cu)
-Iodine (I) - Thyroid function
-Sulfur (S) - Certain amino acids

Question 13

What are the pathologies linked to minerals?

Answer 13

Anemia (Fe):
-Iron is hard to absorb
-Needed to make hemoglobin
-Not enough RBCs or RBCs without hemoglobin
-Oxygen delivery is impaired = weakness and fatigue
Goiter (I):
-Enlargement of thyroid gland (low iodine)
-Impairs hormone production causing cretinism (mental and physical retardation)