Final Section 3: Sodium and Public Health Flashcards
function of electrolytes
fluid compartment balance, acid-base balance, muscle contraction (Ca-Mg), conduction of nerve impulses
water intake recommendation
1-1.5ml /kcal/energy expenditure
2.7L for women, 3.7L for men
increased for pregnancy/lactation, diarrhea, vomiting, fever, heavy exercise, hot environments, diabetes (glucose and water), bleeding
what is thirst?
slow response, can lag behind - when you feel thirst you are already dehydrated
mouth sensations, stomach, hypothalamus
fluid intake and output
always matched, increased intake will increase output
intake from fluids, food and metabolic processes
output through kidneys (obligatory 500mL), skin, lungs, feces
sodium as an electrolyte
extracellular cation, blood volume regulation, Na-K ATPase
Potassium as an electrolyte
intracellular cation, blood volume regulation, high blood volume leads to cardiac arrest, deficiency due to vomiting/diarrhea, or diuretics (for hypertension)
regulation of fluid balance
GI tract handles 10L per day of fluid secretion reabsorption
Kidneys regulate fluid balance with Renin-Angiotensin-Aldosterone System to regulate water and sodium excretion
how a nephron works
working unit of kidney
glomerulus is filtering site passing waste products into tubule
tubule is site of reabsorption of fluid and nutrients
Renin-Angiotensin-Aldosterone System
- Kidneys respond to reduce blood flow by releasing renin
- Renin initiates activation of angiotensinogen protein to angiotensin
- Angiotensin signals adrenal glands to secrete aldosterone and causes blood vessels to constrict, raising BP (and signals pituitary release of ADH)
- Aldosterone and ADH signal kidneys to retain Na and water to increase blood volume
ADH system
- hypothalamus responds to high Na in blood and stimulates pituitary
- pituitary releases ADH
- ADH signals kidneys to retain Na and water to raise blood volume
normal and hypertensive BP
normal: 120 mm Hg over < 80 mm Hg
elevated: 120-129 mm Hg over < 80
stage 1 HT: 130-139 mm Hg over 80-89 mm Hg
stage 2 HT: >/=140 mm Hg over >90mm Hg
systolic - pressure in left ventricle contracting
diastolic - pressure in left ventricle relaxing
evidence with Na
linked high Na intake to hypertension
linked hypertension to CVD and stroke
no direct link of Na intake to CVD and stroke
consequences of high BP
stroke, memory loss, loss of vision, heart attack, kidney damage
modifiable risk factors for hypertension
non modifiable risk factors for hypertension
smoking, secondhand smoke, excess weight, physical inactivity, unhealthy diet and stress
genetics, family history, ethnicity, older age, male sex, psychosocial stress
increased risk with comorbidities: heart diease, dyslipidemia, diabetes, insulin resistance, kidney disease, sleep apnea, obesity
hypertension treatment
DASH (Dietary Approach to Stop Hypertension) high K diet, decreased sodium intake, physical activity, weight control, stress management, diuretics medications
ACE inhibitors - angiotensin converting enzyme inhibitor
DASH diet
high fruit/veg, high K
30% kcal from fat (nuts, fish, whole grains, low fat dairy)
vegetarian protein
low sugar
nutrient dense
increase K, decrease Na, high Mg, and Ca
lowers cholesterol and LDL specifically
Na AI and CDRR, K AI and UL
stats
Na AI: 1500 mg/day, CDRR 2300 mg/day
K AI: 4700 mg/day, UL none
90% men, 60% consume above CDRR of Na (mostly women over 70)
most people consume less than 50% of K AI
goal of Health Canada Sodium Working Group?
get people to average AI intake of 1500mg per day Na
hypertension stats
20% hypertensive, 20% pre-hypertensive
reduced Na intake to 1800mg/day would save 3 billion in health care costs
CDRR is contained in
% intake sources
1 tsp of salt, 6g
10% is table salt, processed and fast foods is 75% intake
salt functional properties in food industry
microbial food preservation, texture, flavor, color, controlled fermentation of bread and cheese
breads are highest source of added Na
why didn’t bill pass in 2010?
Bill did not pass because parliament was worried people would just add the salt back on their own food
Difficult to show direct link between Na and CVD
how to increase sodium literacy
consumer education is new target
change DV to AI instead of CDRR (higher %DV)
adding no salt added labels
moving Sodium to bottom of label (stands out more)
ACE inhibitors are
angiotensin converting enzyme inhibitor
