3BB3 Week 8: Minerals and Bone Health

Minerals

inorganic elements

Stability of vitamins vs minerals

- minerals are very stable, unlike vitamins
- not destroyed by heat, oxygen, or acid

Are minerals lost in processing?

no, but they can still be lost other ways

How are minerals categorized?

Major and Trace

What are Major Minerals?

minerals needed in large amounts ( > 100 mg/day, or making up > 0.01% of body weight)

What are Trace Elements?

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

What are the major minerals in the diet?

Sodium, Magnesium, Phosphorus, Sulfur, Chlorine, Potassium, Calcium

Examples of trace elements:

Lithium, Beryllium, Fluoride, Aluminum, Silicon, Vanadium, Chromium, Manganese, Iron, Nickel, Copper, Zinc, Germanium, Arsenic, Selenium, Bromine, Rubidium, Molybdenum, Cadmium, Tin, Iodine, Lead

how can minerals be lost?

taking skin off of f+v for example

supplements

can be a source of single or multiple minerals

toxicity

can occur with minerals, bioavailability must be considered

interactions between different minerals

some minerals prevent the absorption of others
ex: calcium and iron

food sources of minerals?

- f+v
- whole grains
- protein foods

life stage and minerals

age and stage can impact mineral absorption (ex: calcium absorption changes with age)

mineral function in the body

- many serve as cofactors for enzymes and help stabilize molecules
- structure and support in bone and teeth (solidify protein scaffolding)
- can also serve a regulatory function in the body

Major minerals in the diet with particular deficiency risk:

- Mg
- Ca

electrolytes

- sodium, potassium, chlorine

Calcium RDA adults 9-18

1300mg/day

Calcium RDA adults 19-50

1000mg/day

Calcium RDA Females 51+

1200 mg/day

Good food sources of calcium

- dairy products
- canned fish
- fruits, veggies
- proteins

how is calcium absorbed in the body?

active and passive transport

Passive transport of Calcium

- doesn't use energy
- primarily when calcium intake is high

Active transport of Calcium

- takes energy (ATP)
- against conc. gradient usually
- Vit. D triggers expression of a calcium transporter in the mucosal cells
- leads to more calcium absorbed from dietary intake

amount of calcium absorbed changes based on these factors:

- life stage
- need (growth)

Calcium absorption in Infancy

60% --> high growth need

Calcium absorption in Young adults

25% of calcium --> lots of bone growth

Calcium absorption in Young adults with low vit. D

10% of your calcium is absorbed

Calcium absorption in Older adults

decreased due to lower levels of vitamin D

Calcium absorption in Post-menopause

calcium absorption decreases due to lower estrogen levels
--> estrogen is important to activate vitamin D

Calcium absorption in Pregnancy

50% of calcium is absorbed. Absorption increases because of higher estrogen levels
--> high estrogen = more calcium, more vitamin D

what is a function of Calcium?
a) necessary in blood clotting
b) promotes muscle relaxation
c) elevates BP
d) causes nerve cells to fire spontaneously

a) necessary for blood clotting

99% of calcium is in here

bone

the other 1% of calcium

in the rest of the body, critical

Calcium and muscle contraction

- regulates contraction
- release of Calcium triggers actin and myosin to work

Calcium and BP control

possibly regulated contraction of BVs
- net effect of decreased BP

Calcium and enzyme activity

regulates it

Calcium and coagulation

- needed for blood coagulation
- activates clotting factors (X, Thrombin)

Calcium and NTs

regulates the release of NTs and is important for nerve impulses

Regulation of blood calcium by these two hormones

- Calcitonin
- Parathyroid hormone

Calcitonin

reduces calcium absorption, uptake by kidneys, and increased calcium deposition in bones

Parathyroid hormone

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

these lil guys break down bone constantly

osteoclasts

lil guys that constantly build up bone

osteoblasts

Balance of osteoblast/clast activity

breakdown and buildup of bone based on calcium needs in the body

Trabecular bone

spongy bone, high surface area for cells to work on

Cortical bone

compact bone

Calcium deficiency

results in loss of bone mass/density

Calcium toxicity

- kidney stones (from calcium oxalate or calcium phosphate)
- can interfere with iron, zinc, magnesium, and phosphorus absorption
- UL = 2000-2500 mg/day

Osteoporosis cause

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

What kind of bone is more at risk for OP and why?

Trabecular bone, because of its increased surface area. It is more likely to lose density and fracture later in life

proportion of fractures in people 60+ related to OP

80%

annual cost of OP on the Canadian Health System every year

$2.3 Billion

Influences on Osteoporosis risk

- age
- gender
- hormone levels
- genetics
- exercise (LIFT BRO)
- smoking and alcohol
- diet

Total bone mass in kids

in growing kids, total bone mass increases as the bones grow larger

Bone mass in puberty

increases rapidly, sex differences in bone mass appear

Peak bone mass in men vs women

higher in men

age at which peak bone mass is attained

30-35 (eat ur calcium while ur young kids)

Age at which bone mass starts to decline for both sexes

35 ish

bone mass and menopause

- bone loss is accelerated for about 5 years after menopause
- no estrogen = weaker bones

how do we lose bone mass with age?

absorption decreases slowly, we rely on bones to maintain our blood calcium levels

which of the following is a good source of calcium?
- leafy greens
- lean meat
- whole grain and cereals
- nuts and seeds

LEAFY GREENS
(as per usual tbh)

Phosphorus RDA

700 mg/day

85% of phosphorus is found here

bones and teeth

most common form of phosphorus in the body

bound to oxygen as phosphate

how common is phosphate deficiency?

rare

how much of dietary phosphate is absorbed?

60-70%
- readily absorbed by the GI tract

this vitamin can enhance absorption of phosphorus

Vitamin D

phosphate sources in the diet

- it's in a lot of things tbh
- dairy
- canned fish
- chicken
- oatmeal, whole grains
- some in broccoli, carrots, potato

Phosphorus and Calcium

important for bone mineralization

Body molecules/processes that contain/need Phosphate

- phospholipids (cell membranes)
- ATP
- Creatine Phosphate
- Phosphorylation of proteins
- RNA/DNA
- regulation of pH in a cell

phosphate deficiency

- rare
- bone loss (bone b/d to maintain blood levels)

Phosphate toxicity

- rare
- increased bone resorption (b/d)

Magnesium RDA

400-420 mg/day men
310-320 mg/day for women, more in pregnancy

how much Mg is there in an adult human

25 mg

Why are leafy greens a good source of magnesium?

Magnesium is a component of chlorophyll

Good sources of Mg

- leafy greens
- nuts and seeds
- whole grains

how much of dietary Mg is absorbed?

50%

this vitamin can improve Mg absorption (slightly)

Vitamin D

high amounts of this ………. in the diet can decrease Mg absorption

Calcium

65% of Mg is found here

in the bone, it helps to maintain the structure

Magnesium and ATP

- helps stabilize structures in molecules

Mg as a cofactor

- cofactor for > 300 enzymes
- includes the Sodium-Potassium ATPase pump
- important for DNA, RNA, and Protein synthesis

How do the Kidneys regulate Mg levels?

controlling excretion in the urine

Magnesium deficiency

- rare, but does occur
- linked to OP and heart disease

Magnesium toxicity

- can occur from supplementation
- can occur in those with impaired kidney function

Magnesium UL

350mg/day from non-food sources

why should a pregnant patient increase their magnesium intake?

Magnesium's role in protein synthesis, synth. of nucleic acids, and fats

Sulfur RDA

there is none

How do we obtain sulfur?

- organic molecules
- sulfur containing amino acids, vitamins, and some inorganic food additives

Sulfur containing AAs

- methionine
- cysteine

Sulfur containing vitamins

- thiamin
- biotin

Sulfur deficiencies

none when protein needs are being met