Fluid and Electrolytes Focus on Hypertension and Bone Health

Question 1

water

Answer 1

• carries nutrient and waste products
• assists in metabolic reactions
• regulates body temperature
• maintains BP and structure of large molecules
• lubricates and cushions many body parts

Question 2

body water content

Answer 2

• 60% of body weight
• dependent on body composition
• 3/4 weight in lean tissue
• 1/4 in fat tissue
• proportion of water is smallest in: females, obese, elderly as they are associated with < lean tissue

Question 3

water sources and losses

Answer 3

total water sources = total losses
for adequate hydration

• dehydration can be evaluated on the colour of urine (pale yellow = adequate hydration)

Question 4

water recommendations

Answer 4

AI from food AND beverages:
2.7 L per day - women

3. 7 L per day - men
   - choose beverages with lower energy
   - can include caffeinated drinks (coffee/tea has lower diuretic than once thought)
   - alcohol does not count! (strong diuretic)

Question 5

water balance

Answer 5

• every cell contains and is surrounded by fluid
• 2/3 of fluid is intracellular
• 1/3 extracellular

Question 6

electrolytes

Answer 6

• electrolytes: are slats that dissolve in water and dissociate into ions (charged particles)
• electrolytes maintain fluid balance inside and outside of the cell and attract water by osmosis
• wherever electrolytes move, water will follow

Question 7

sodium

Answer 7

principal cation in extracellular fluids

prime regulator of fluid volume and BP

• maintains acid/base balance
• essential to nerve impulse transmission & muscle contraction

Question 8

sodium intake

Answer 8

people sensitive to high sodium intake have increased risk of hypertension
- risk factor for stroke, heart disease, kidney disease

high intake - increases calcium excretion
- effect on bone loss is uncertain

Question 9

sodium intake in Canada

Answer 9

mean = 2760 mg/day
AI = 1500 mg
UL = 2300 mg 

• we need salt in our diet, but too much = health risk

sources:
- 77% processed foods
- 12% naturally occurs in food
- 11% added by consumer

Question 10

potassium

Answer 10

principal cation in intracellular fluids

• works with sodium to: maintain fluid balance, regulate nerve impulses and muscle contractions

high potassium diet = lower BP

AI - 4700 mg

Question 11

Na & K - processed foods

Answer 11

processed foods: processing increases sodium content and reduce potassium

Question 12

diet & hypertension

Answer 12

• limit processed foods
• increase intake of potassium rich: fruits/veggies. legumes, dairy, fish/meat

- limit alcohol, healthy body weight
DASH Diet ( Dietary Approaches to Stop hypertension)

Question 13

potassium rich foods

Answer 13

potato, whole baked

yogurt, non-fat plain

tomato juice

halibut

Question 14

calcium

Answer 14

most abundant mineral in the body

99% in bones and teeth

• important part of bone structure providing a rigid frame
• serves as a calcium bank is calcium drops

1% circulates in body fluids

• regulates BP, blood clotting
• muscle contractions, nerve impulses
• hormone secretion
• MAY protect against hypertension and help weight management (findings are mixed)

Question 15

inadequate calcium intake

Answer 15

bones give up calcium to maintain stable blood calcium

Question 16

calcium balance

Answer 16

parathyroid hormone (released from parathyroid gland) = activation of vitamin d

calcitonin (released from thyroid gland) = inhibit vit. D activation

Vitamin D (acts on target tissues to ↑ or ↓ blood calcium).

Question 17

Calcium RDA

Answer 17

RDA: 1000 mg (19-50
yrs)
adolescents: 1300 mg
F > 50y = 1200mg

M>70y = 1200mg

Question 18

Calcium UL

Answer 18

2500mg

Question 19

calcium absorption

Answer 19

absorption is quite poor across most foods (and supplements), including dairy

absorption rates in non dairy sources of calcium - highly variable

Question 20

bone mineralization

Answer 20

process in which calcium and other minerals crystallize on the collagen matrix of a growing bone

Question 21

bone health

Answer 21

• bones gain and lose calcium continuously in a process called remodeling (role of osteoclasts - erode bone and osteoblasts- build new bone)
• bone mass influenced by:
  age, gender, genetics & ethnicity, lifestyle behaviours

Question 22

peak bone mass

Answer 22

highest attainable bone density for an individual
- achieved by ~ age 30

Attainment of peak bone mass in youth, serves as best protection against bone loss later in life

Question 23

vitamin D (calciferol) roles in body

Answer 23

maintains: blood concentrations of calcium and phosphorus

Question 24

Vitamin D food sources

Answer 24

fatty fish, beef, egg, liver, fortified milk/butter/cereals/juice

Question 25

sun exposure RDA

Answer 25

15 ug (600 IU)

Question 26

process of sunlight into Vitamin D

Answer 26

• ultraviolet sunlight activates 7-dehydrocholesterol on skin – converted to provitamin D3 – undergoes 2 hydroxylation reactions in liver and kidneys to produce 1, 25 dihydroxyvitamin D3 (Calcitriol = active form)

Question 27

Rickets and vit. D

Answer 27

symptoms vary with severity - defective bone growth and skeletal deformities in children
weak bones, can’t support weight - bowed legs
pain in the muscles and joints
softening of rib cage - respiratory problems (pneumonia)

fortification of milk and some breads has greatly reduced incidence of rickets

Question 28

osteoporosis

Answer 28

condition in older people often detected later in life

• bones become porous & fragile due to loss of calcium
• increase risk fractures (hips, wrist, spine)

Question 29

osteoporosis more common in

Answer 29

women > 50 y

associates with rapid loss of estrogen after menopause and reduced calcium absorption

Question 30

osteoporosis risks

Answer 30

smoking and alcohol consumption ↑ risk

PA ↓ risk: stress on bones (weight bearing activity) and muscle attachments (resistance training) - ↑ bone density

Question 31

DXA - Bone Mineral Density

Answer 31

Bone density test can detect early stages of bone loss (osteopenia) and osteoporosis, to determine risk for fractures.

Serves as a baseline measure and tracks response to treatment

This is a simple, quick non-invasive test usually recommended at age 65 - earlier in the presence of other risk factors.

Question 32

preventing osteoporosis

Answer 32

• attainment of peak bone mass in youth
• lifetime diet rich in calcium AND vitamin D
• regular physical activity
• no smoking, moderate (or no) alcohol

Question 33

calcium toxicity

Answer 33

calcium rigor, constipation, ↑ risk of kidney stones, ↓ absorption of other minerals (e.g. iron)

Question 34

high calcium absorption food (>50%)

Answer 34

cauliflower, cabbage, brussels sprouts