Lecture 15 Flashcards
What are minerals and trace elements?
Essential, non-organic elements that DO NOT PROVIDE ENERGY. Required in small amounts
If minerals/trace elements are low in the body, what happens?
Symptoms of deficiency may appear
What is a mineral?
An element found in the body in a quantity of >5grams e.g. Na/K/Ca
What is a trace element?
An element found in the body in a quantity of <5grams e.g. Fe/I/Zn
What is the composition of sodium in the diet?
10% is inherent = naturally occurring in food
15% is discretionary = at consumers discretion to add more
75% is salt added during food processing
What did the NZ Total Diet Study show?
- Didn’t look at discretionary sodium
- Saw a decrease in intake from the 80’s
- > food companies slowly decreasing amount of salt in packaged foods
From the NZ Total Diet Study, what was the highest source of sodium?
Grain
Describe sodium absorption
- Well absorbed, but not regulated
- Plasma levels controlled by the kidney
What % of sodium is excreted in the urine?
> 90%
Is sodium deficiency common?
No it is rare from the diet, can become depleted from losses (sweat, diarrhoea, vomiting)
What happens to the kidneys with age?
The capacity to excrete sodium declines with age
At what age does GFR start to decline?
30
What is GFR at by age 80?
40%
What does the decrease in GFR mean for blood pressure?
A smaller increase in salt intake can cause increased BP
What is hypertension?
A disease where someone has higher than normal BP
What is the effect of hypertension?
Can damage blood vessels which increases risk of heart and renal disease
Describe the DASH1 diet
- Used an RCT with three conditions
1. Control (typical diet)
2. Fruit and vegetables
3. F/V + low fat dairy products
What were the results of the DASH1 diet?
- Sodium intake across the groups was very similar
- After 8 weeks, a decrease in BP was seen for both intervention diets
Describe the DASH2 diet
- Another RCT with 2 conditions
1. Control diet
2. DASH diet
What were the findings of the DASH2 diet?
- Regardless of Na+ levels, in both types of DASH diet results ALWAYS showed a decrease in blood pressure compared to the standard diet
- When you decrease Na+ in the diet, BP decreases
- When combining DASH with less sodium, this has the best effect
What was the overall conclusion from the DASH2 diet?
Fruit and vege, calcium, and reduced sodium has the best effect at decreasing blood pressure
