FNH 250: Bone Health

Bones

Rigid organ that serves as the body’s main form of structural support. Alcohol is also toxic to this organ

Osteoid

Protein-collagen matrix that bones are made of. Contains nerves, cartilage, and connective tissue

Hydroxyapatite

Crystal deposited onto the protein collagen matrix of bone

Cortical Bone

Ivory-like, extremely dense bone. Most small bones and the outer surface of long bones contains it. Slow turnover and makes up 80% of the skeleton

Trabecular Bone

Lace-like bone. Very dynamic and found on the ends of bones, the spine, inside flat bones, and pelvis bones. Sensitive to hormones that regulate deposits

Osteoblast

Cells that build bone

Osteoclast

Cells that crumble (break down) bone

Bone Growth

Bone development phase where we make more bone than we break down. Size and length of bones increase

Bone Modelling

Phase in bone development where bones take on a specific shape

Bone Remodelling

Phase in bone development where bones break down and are rebuilt over time, affecting bone density

Blood Calcium

Closely regulated by hormones, and does not reflect the body calcium concentration

Calcitriol

Hormone that activates vitamin D, which increases blood calcium levels. Stimulated by the parathyroid hormone

Parathyroid Hormone

Hormone that activates calcitriol and acts on osteoclast cells to raise blood calcium

Calcitonin

Hormone secreted by the thyroid gland that decreases the action of osteoclasts, reducing calcium in blood

DEXA

Measurement of bone density via using low x-rays across the entire body. Bone density can then be measured at specific sites and compared to a healthy 30-year-old person

T-Score

Indicator of bone density. Anything past -1 is low bone mass

Ultrasound

Sound waves used to measure bone density in the heel. Non-invasive, painless, and quick, but only used as a screening tool to check for more severe readings

pDEXA

A weaker version of DEXA only used in the heel, wrist, or finger. Also non-invasive, painless, and quick, but also used as a screening tool

Calcium

Mineral of greatest amount in the body. Differs from most other nutrients in that hormones tightly regulate blood calcium concentration so it stays constant.

Phosphorous

Second most abundant mineral in the body found in hydroxyapatite crystals. Also served as the major intracellular anionic electrolyte, which helps to maintain proper electrical and fluid balance

Vitamin D

Vitamin that comes from 2 different sources: either through hormones, or when consumed in the diet. Increases blood calcium and bone mineralization, works in the intestine, bone, and kidneys

Bone Formation and Maintenance

Function of dietary calcium and phosphorous where they are used in the formation of hydroxyapatite crystals, which are deposited into the osteoid and provide strength and rigidity to bones

Crystal Substitution

The use of different minerals for crystals instead of calcium or phosphorous, such as magnesium, sodium, or carbonate

Nerve Transmission and Muscle Contraction

Function of calcium where action potentials travel down the cell to muscles which causes the calcium ion channels to open, leading to contraction.

Tetany

Spasmodic relaxation caused when cell calcium levels fall below normal

Rigour

Inability for muscles to relax due to cellular calcium levels being higher than normal

Blood Clotting

Function of calcium where it leads to the formation of fibrin and clots

Hypertension

High blood pressure. There is an inverse relationship between this and calcium intake

Osteoporosis

Naturally occurring degenerative bone disease characterized by decreased bone density, increased bone fragility, and increased risk of fractures. Often found in age, so building peak bone mass early in life can reduce the risk of effects.

Non-Dietary Osteoporosis Factors

Factors that influence people’s risk for osteoporosis outside of diet. Includes gender, age, hormones, genetics, and physical activity

Dietary Osteoporosis Factors

Factors that influence people’s risk for osteoporosis from diet. Includes body weight, smoking and alcohol, and calcium nutrition

Rickets

Deficiency of vitamin D in children. Caused by poor mineralization, which leads to bowed legs and malformed ribs.

Osteomalacia

Improper mineralization of osteoids that can lead to progressive weakness and increasing pain. Typically caused from kidney, liver, and intestinal diseases, low vitamin D intakes, or repeated pregnancies

Calcium Food Sources

Food sources of calcium. Includes most dairy products, but nuts, bone-in sardines, broccoli, and cabbage are also good sources

Fluoride

Mineral involved in bone health that helps mineralize bone and teeth.

Fluorapatite

Stronger crystal found in bones and teeth made when fluoride replaces the hydroxyl group

Fluorosis

White specks, mottling, or brown streaks in teeth associated with fluoride toxicity

Dental Caries

Symptom of low fluoride that can lead to inability for proper chewing.

Fluoride Sources

Brewed tea, tap water, and most seafood. Some non-food items such as chewing gum and toothpaste also help.