HTHSCI 3BB3 - F2023 - 8A - Minerals and Bone Health

major minerals

- calcium, chloride, magnesium, phosphorus, potassium, sodium, sulfur

- needed in amounts > 100 mg/day or which make up < 0.01% of body weight

trace elements

those minerals needed in amount < 100 mg/day or which make up > 0.01% of body weight

mineral bioavailability

- not destroyed during processing, but can be lost

- supplements can provide a source of single or multiple minerals

- Toxicity can occur and bioavailability must be considered

- Some minerals prevent the absorption of others

- Life stage can also impact mineral absorption

mineral function in the body

- cofactors for enzymes and help to stabilize molecules

- Minerals also provide structure and support such as in bone and teeth

- Minerals can also serve a regulatory function in the body

sources of calcium

daily products, canned fish, fruits, vegetables and plant-based proteins

Calcium is absorbed by which kind of transport?

active and passive

Calcium Passive transport

Primarily when calcium intake is high

Calcium Active transport

- Vitamin D triggers expression of a calcium transporter in the mucosal cells

- Leads to more calcium absorbed from dietary intake

- Requires ATP (energy)

How is the amount of calcium absorbed changes based on life stage and need

- infancy increases

- young adults increases

- young adults with low vit D decreases

- older adults decreases

- post menopause decreases

- pregnancy increases

What is a function of calcium in blood?

calcium is necessary in blood clotting

where is calcium located in the body?

- 99% in bone

- 1% in body

Calcium functions in the body

- regulates muscle contractions, blood pressure, enzymes

- coagulation, release of neurotransmitters

Calcitonin

reduces calcium absorption, and increased calcium deposition in bones

parathyroid

increases calcium absorption, decreased calcium excretion and increased bone resorption. Together these increase levels of calcium in the blood

Osteoblasts

bone forming cells

osteoclasts

Bone-destroying cells

Calcium toxicity

- Kidney Stones (formed from calcium

oxalate or calcium phosphate)

- Can interfere with iron, zinc, magnesium and phosphorus absorption

What bone is at higher risk to lose density and fracture later in life

Trabecular bone, due to its increased surface area

Osteoporosis

A condition in which the body's bones become weak and break easily.

- from loss in the protein matrix and mineral (calcium) deposits of the bone

- responsible for at least 80% of fractures in people over 60 years of age

Influences on osteoporosis risk:

• Age

• Gender

• Hormone levels

• Genetics

• Exercise

• Smoking and alcohol use

• Diet

t or f: parathyroid hormone stimulates the kidneys to excrete calcium

false

Are leafy greens a good source of calcium?

yes

T or F

Males and females have equal risks for osteoporosis

Phosphorus in the body

- mostly in bones and teeth

- makes up about 1%of human body weight

- found bound to oxygen as phosphate

T or F: Readily absorbed in the GI tract (60-70% of dietary phosphate is absorbed)

True

What enhances phosphorus absorption

vit D

What molecules in phosphorus found in

Phospholipids (cell membrane)

ATP (adenosine triphosphate, energy)

Creatine phosphate (energy)

Phosphorylation of proteins (activates/deactivates proteins)

RNA/DNA

Regulation pH within a cell

______________________ is a component of chlorophyll, unsurprising it is plentily in leafy greens

magnesium

Magnesium in the body:

- half of the magnesium in the diet is absorbed

- Vitamin D can increase magnesium absorption slightly

- High dietary calcium can decrease absorption

What regulates magnesium levels by controlling excretion in the urine?

kidneys

How does magnesium help stabilize?

- molecules such as ATP

- cofactor for >300 enzymes including the sodium

- potassium ATPase pump

- important for DNA, RNA and protein synthesis

The nurse instructs a primigravid (a person who is pregnant for the first time) client to increase their intake of food high in magnesium because:

Synthesis of protein, nucleic acids and fats

T or F: spinach and kale are good sources of magnesium

true

How is sulfur obtained?

- Obtained from organic molecules such as sulfur containing amino acids and vitamins and some inorganic food additives

- in methionine, cystine, thiamin, and biotin