Sodium 1 Flashcards
What are minerals and trace elements?
Essential, non organic elements that do not provide energy. If absent or low in the diet, symptoms of deficiency may appear. Required in small amounts
What are the main dietary sources of sodium?
10% Inherent means sodium that’s in food naturally
13% Discretionary is the sodium that is at your discretion (sauce, table salt etc.)
~75% Processing is the sodium typically in the form of NaCl
How could you measure sodium intake?
Best way to measure sodium intake is to measure sodium excretion - about 90% of intake is excreted in urine
AI and SDT for sodium
AI is 460-930mg/day
SDT is <2000mg/day, more than 2000mg can lead to chronic disease
Sodium absorption and function
Well absorbed, not regulated, plasma levels controlled by kidney
Functions: principal cation in ECF, primary regular of ECF volume, maintain acid-base balance, nerve impulse transmission, muscle contraction
Sodium, excretion, deficiency and toxicity
E: urine >90% sodium excreted in urine, sweat
D: rare from diet, depletion from losses (sweat, diarrhoea, vomit)
T: acute is rare, chronic is common
Na and Blood pressure
Kidneys capacity to excrete sodium declines with age, GFR declines form age 30 yr, 40% at 80 yr, smaller increases in salt intake, increased blood pressure
Hypertension
Disease whereby someone has higher than normal blood pressure which can damage blood vessels increasing risk of heart disease and renal disease
Causes of hypertension
Age increase, blood pressure increase
Increased BMI, increased blood pressure
Smoking increasing blood pressure
Increased exercise, decrease blood pressure
Stress increases blood pressure
Alcohol, caffeine and sodium increase blood pressure, potassium, calcium and magnesium decrease blood pressure
Intersalt and meta-analysis study
Intersalt used information from 52 countries and measured sodium excretion, were able to correlate blood pressure with weight, alcohol, age and sodium intake
Meta-analysis used information from 78 trials, found that decreased sodium levels resulted in small decrease in blood pressure, twice as effective in older people
What is DASH 1?
Clinical intervention trial that randomly placed people in three diet groups, weren’t looking at impact of sodium but were looking at other dietary factors
What is DASH 2?
Dietary approach to stop hypertension with a sodium arm - two diet groups at three levels of sodium
DASH diet - combination diet of high fruit and veges and two serves of low fat
Amount of sodium changed in the diet
Findings in DASH 1 and 2
Blood pressure always reduced in DASH diet
If you lower sodium content in either control or DASH diet blood pressure drops hence there is an impact of sodium in relation to sodium
Lowest blood pressure is people on the DASH 2 diet with low sodium
Limitations of DASH 1 and 2
Limitations of DASH 1 and 2 include the trials only being done over 8 weeks - short term intervention studies that are only measuring blood pressure, doesn’t show impacts on stroke or heart disease
