25: Minerals & Mineral Deficiencies

Question 1

What are the energy releasing B vitamins?

Answer 1

Energy releasing = B1 - B7:

•   Thiamine (B1)
•   Riboflavin (B2)
•   Niacin (B3)
•   Pantothenic acid (B5)
•   Pyridoxine (B6)
•   Biotin (B7)

Question 2

What are the hematopoetic B vitamins?

Answer 2

Hematopoietic

•   Folate (B9)
•   Cobalamin (B12)

Deficiencies give anemias

Question 3

Describe B9 Folate function & deficiency

Answer 3

Function: precursor for tetrahydrofolate, which is co-enzyme involved in generating precursors for DNA & protein synthesis.

Deficiency:

• -neural tube defects in newborns of deficient mothers
• -macrocytic anemia
• • hyperhomocysteinemia (cardiovascular risk)

Susceptible groups:

• -pregnant women*, elderly, alcoholics, patients with certain long-term drug treatments
• -people with genetic polymorphisms in folate metabolism

Question 4

Describe neural tube defects & their relationship with B9, Folate.

Answer 4

Folate supplementation can prevent certain neural tube defects. Inadequate folate early in pregnancy appears to be associated with neural tube defects. Mothers may have inadequate folate without symptoms of deficiency.

Demand for folate is very high throughout pregnancy and lactation.

Grain products enriched in folate have lowered the risk of deficiency, but folate supplements are still routinely recommended for women of child-bearing age.

Question 5

Describe B12 Cobalamin function & deficiency

Answer 5

•  Function:

• -coenzyme in methionine synthesis and in conversion of methylmalonyl CoA to succinyl CoA
• -needed in folate metabolism

•  Deficiency: Pernicious anemia (megaloblastic
anemia) with demyelination–gives neuralogic issues

•  Susceptible groups: Elderly, patients with malabsorption diseases, long-term vegetarians.

Question 6

Describe the structure & breif physio of Cobalamin

Answer 6

•  Cobalamin contains a cobalt.

•  B12 in food must be released from protein
by acid hydrolysis in the stomach. It then must
bind to intrinsic factor to be absorbed in the
ileum.

•  Lack of intrinsic factor is a the most common form of B12 deficiency.

Question 7

______ and _____ deficiencies result in megaloblastic anemias.

Answer 7

Folate and B12 deficiencies result in megaloblastic anemias.

Both the terms “megaloblastic” and “macrocytic” refer to the large size of RBCs in the presence of Folate/Vitamin B12 deficiency.

This condition arises from a deficiency in nucleotides, leading to decreased DNA and RNA synthesis. Cells increase in size without dividing, and large immature* RBCs do not carry sufficient oxygen.

Pernicious anemia refers specifically to a B12-deficient anemia arising from lack of intrinsic factor

Question 8

What are minerals?

Answer 8

Minerals are:

•  Inorganic compounds critical for human
physiology. Remember that vitamins are ORGANIC. Minerals are typically ions.

•  Many minerals are enzyme cofactors, but
they can also play structural roles in proteins or on their own

•  Categorized as macrominerals and
microminerals based on level required
(doesn’t correlate with importance–DO NOT NEED TO KNOW FOR TEST).

•  Often work in parallel with vitamins, so
supplements often contain both.

Question 9

Describe Calcium function & deficiency

Answer 9

Functions: 
•  Major component of 
bone 
•  Signaling 
•  Coagulation 
•  Muscle contraction 
•  Neurotransmission

Deficiency:
Mild: muscle cramps, osteoporosis
Severe: rickets (vitamin D-Calcium connection). This is why milk (full of calcium) is fortified with vitamin D, so it can be absorbed.

Susceptible groups:
Children, adult women, elderly

Question 10

Calcium comes solely from ____ and its distribution is highly regulated

Answer 10

Calcium comes solely from diet and its distribution is highly regulated

•  98% of calcium is in bone and teeth
–Hydroxyapatite is the basic mineral component of bones and teeth: Ca5(PO4)3OH

–bone is the body’s calcium reservoir: bone releases Ca2+ if serum levels are insufficient

•   2% of calcium in rest of the body
•   Low serum calcium signals enhanced intestinal absorption and stimulates bone resorption

Question 11

Describe Osteoporosis

Answer 11

Osteoporotic bone from calcium deficiency is porous. It is essentially a resorption of bone due to loss of balance between osteoclasts & osteoblasts.

Calcium intake during period when bone is reaching maximum density (age 10-35
in women) is important to prevent osteoporosis.

Even higher levels of calcium intake are required to maintain bone mass in postmenopausal women. (Exercise also helps maintain bone density).

Question 12

Describe Magnesium function & deficiency

Answer 12

Functions:
•  Essential for many enzymes using MgATP as substrate (Mg ATPases)
•  Present at high levels in bone

•   Deficiency: Weakness, tremors, cardiac arrhythmia
•   Susceptible groups:
• -Alcoholics
• -Patients taking diuretics, or experiencing severe vomiting and diarrhea

Question 13

Describe Phosphorous function & deficiency

Answer 13

Functions:

• Mostly present in phosphates
• Major component of bone–hydroxyapatite
• Constituent of nucleic acid & membrane lipids
• Required in ALL energy producing runs

•  Deficiency: Rare (since quite abundant in food supply )—can result in rickets, muscle weakness and breakdown, seizures. Note that any deficiency of anything that has to do with bone can give rickets.

Question 14

Describe Iron function & deficiency

Answer 14

•  Function:

• -O2/CO2 transport in hemoglobin
• -oxidative phosphorylation
• -cofactor in several nonheme iron proteins and cytochromes (redox properties of iron are important)

•  Deficiency: Microcytic hypochromic anemia, decreased immunity. MOST COMMON NUTRITIONAL DEFICIENCY IN THE US & WORLD.

•  Susceptible groups: Common in children and
menstruating women, pregnant women, and
elderly

Question 15

Iron absorption and distribution in the body are _____ regulated.

Answer 15

Iron absorption and distribution in the body are tightly regulated.

Reduction of Fe3+ to Fe2+ is promoted by vitamin C in diet. (Vitamin C deficiency causes mild anemia.)

Low pH in stomach helps release Fe3+ from ligands and makes it bioavailable.

Uptake of iron in mucosal cells of small intestine is regulated in response to iron-deficient or overload states.

Iron is carefully “escorted” both in circulation and in cells because of the potential for inadvertent redox damage.

Question 16

List some characteristics of iron-deficient anemia

Answer 16

Microcytic anemia—small, pale red blood cells

–less hemoglobin is produced, and RBCs undergo more cell divisions in bone marrow waiting for hemoglobin synthesis

Patient symptoms: fatigue, pallor, weakness, dizziness

Question 17

List Iron toxicity: Long term and acute

Answer 17

1)  Long-term: Hemochromatosis
–iron overload leads to iron deposits in multiple
tissues. Leads to compromised liver, pancreatic,
and cardiac function.
–ultimately can compromise mitochondrial
function leading to lactic acidosis

2)  Acute: Iron overdose in children
–most common cause of death due to toxicity in children under 6*. Overdose comes from
consumption of adult iron supplements

Question 18

Describe Copper function & deficiency

Answer 18

Functions:
•  Assists iron absorption through ceruloplasmin
•  Cofactor for enzymes required in collagen (vitamin C ligand–think scurvy) synthesis, fatty acid metabolism, and elimination of reactive oxygen species

•  Deficiency: Quite rare. Symptoms include
anemia, hypercholesterolemia, fragility of large arteries, bone demineralization demyelination

•  Susceptible patients:

• Those with genetic disease Menkes’ syndrome, or consuming excessive zinc.
• Menkes disease comes from mutations in Cu transporter ATP7A leading to copper deficiency.
• Wilson’s disease comes from mutations in ATP7B, a relative of ATP7A, but results in copper overload. Copper is not sequestered properly, and accumulates in liver with severe liver and nervous system symptoms. Results in liver failure and liver cancer.

Question 19

Describe Zinc function & deficiency

Answer 19

Function:
•  Cofactor for over 300 metalloenyzmes
•  Plays a structural role in many proteins (Zn finger domains)

Deficiency: Poor wound healing, dermatitis,
reduced taste acuity, poor growth and
impaired sexual development in children. Dermatitis is the earliest symptom of zinc
deficiency.

Susceptible groups: alcoholics, elderly, people with malabsorption or kidney disease

Question 20

Describe Chromium function & deficiency

Answer 20

Function: Component of chromodulin— facilitates insulin binding to its receptor so involved in glucose tolerance.

Deficiency: Impaired glucose tolerance (from reduced insulin effectiveness)

•  Susceptible populations: Those with impaired glucose tolerance, but Cr3+ hasn’t yet proven helpful in treatment of type 2 diabetics

Question 21

Describe Iodine function & deficiency

Answer 21

•  Function: Incorporated into
triiodothyronine (T3) and thyroxine
(T4). Iodine Regulates basal metabolic rate.

Deficiency: Goiter—enlarged thyroid gland.

Hyperthyroidism or hypothyroidism are other consequences of iodine issues.

Question 22

Describe Goiter

Answer 22

Low iodine stimulates increased thyroid stimulating hormone TSH, results in enlarged thyroid characteristic of goiter

Question 23

Describe Selenium function & deficiency

Answer 23

Function:
•  Component of antioxidant enzymes (ex. glutathione peroxidase)
•  Component of deiodinase enzymes involved in T3 and T4 metabolism

•  Deficiency: Keshan disease (in areas with
little selenium in soil)—cardiomyopathy and
cretinism

Question 24

Summary: most common vitamin and nutrient deficiencies in the general population:

_______—iron and calcium

Answer 24

Summary: most common vitamin and nutrient deficiencies in the general population:

Children—iron and calcium. Iron is put into formula.

Question 25

Summary: most common vitamin and nutrient deficiencies in the general population:

_______—calcium and magnesium, possibly vitamin A, C, and B6

Answer 25

Summary: most common vitamin and nutrient deficiencies in the general population:

Teenagers—calcium and magnesium, possibly vitamin A, C, and B6

Question 26

Summary: most common vitamin and nutrient deficiencies in the general population:

_________—iron, calcium, magnesium, vitamin B6, folate

Answer 26

Summary: most common vitamin and nutrient deficiencies in the general population:

Women—iron (especially in menstruation), calcium, magnesium, vitamin B6, folate

Question 27

Summary: most common vitamin and nutrient deficiencies in the general population:

________—Vitamins B6, B12, D, possibly zinc and chromium

Answer 27

Summary: most common vitamin and nutrient deficiencies in the general population:

Elderly—Vitamins B6, B12, D, possibly zinc and chromium

Question 28

Summary: most common vitamin and nutrient deficiencies in the general population:

_________—susceptible to multiple deficiencies, but especially folate, B6, and thiamine

Answer 28

Summary: most common vitamin and nutrient deficiencies in the general population:

Alcoholics—susceptible to multiple deficiencies, but especially folate, B6, and thiamine due to compromised liver function.

Question 29

It is _______ whether or not we should take multivitamins.

Answer 29

It is not clear whether or not we should take multivitamins. There are pros & cons to both arguments & we need better data.

Note that her test questions will be vignette based.