Lecture 9: Micronutrients - Sodium & Potassium Flashcards
(18 cards)
What kind of elements are sodium and potassium and what kind are they?
They are minerals, specifically inorganic minerals that always retain their chemical identity
What is the role of sodium in the body?
Sodium balances fluids in the body (regulates extracellular fluid), maintains blood pH levels and carries electrical signals from nerves to muscles
What are 5 risks of too high sodium intake?
- high blood pressure
- heart disease (cardiovascular disease)
- chronic kidney disease
- stomach cancer
- increased calcium excretion (potentially bone loss; osteoporosis)
How does high sodium intake lead to negative health outcomes?
–> Increased water retention
–> Increased resistance of the arteries to blood flow
–> Alterations in cell function
–> Changes in artery structure and function (stiffness)
–> Modification of heart activity
–> Modification of the autonomic neuronal system in the cardiovascular system
What are the sodium intakes of NZ children?
- sodium intakes of most children were > WHO guidelines
- major food sources: bread, pies/pastries, bread/pasta dishes
What are the most common sources of sodium?
- Bread (18%)
- Discretionary (from added salt while cooking/table salt; 13%)
- Bread-based dishes (11%)
- Grains and pasta (7%)
- Pork (7%)
- Sausages and processed meats (5%)
What are the 2 most important ways of measuring sodium?
- Gold standard 24-hour urine collection (excretion)
- Spot urine sample
What does sodium deficiency look like?
Not very common; blood sodium may drop with vomiting, diarrhea or heavy sweating. During intense activities athletes can lose too much sodium, developing hyponatraemia which is characterized by headache, confusion, stupor, seizures, and coma. This is not caused by inadequate intake, only severe loss.
What are the 4 elements and 5 activities of the salt reduction strategy from the WHO?
Elements:
1. Political commitment
2. Programme leadership
3. Partnerships
4. Advocacy
Activities (SHAKE):
1. Surveillance (monitor and measure salt use)
2. Harness industry (reformulation)
3. Adopt standards for labelling and marketing
4. Knowledge (education and empower)
5. Environment (support settings)
What did the United Kingdom Salt Reduction look like and was it succesful?
They had a three-pronged national salt reduction programme:
- Public awareness campaign
- Food labelling changes
- Manufacturer targets
–> voluntary approach
Results:
- Just over half of all average targets set were met by the in-home sector (foods in supermarkets etc.)
- 81% of packaged products at or below maximum targets
- Out-of-home sector: 71% of products at or below maximum per serving targets
- Salt excretion dropped from 9.5g to 8.1g –> most recently (2019) a bit up again
What are the 2 main strategies for sodium reduction in NZ?
-
Voluntary targets developed and led by the Heart Foundation
- Collaboration approach with industry
- Aim: 80% of market share (by sales volume) of a food category meets the target -
Voluntary Health Star Rating front-of-pack nutrition label
- Sodium is one nutrient in the scoring system
- Currently present on ~35% of packaged foods and drinks
What is the role of potassium in the body?
Plays a major role in maintaining fluid and electrolyte balance and cell integrity, affects homeostasis of the body and assists with sodium during nerve impulse transmission and muscle contraction.
What are the consequences of high potassium intake and how is this possible?
High potassium intakes reduce the risk of hypertension, heart disease, stroke and related deaths. This is because high potassium diet signals the body to reduce the amount of sodium retained, and lowers blood pressure.
How much mg of sodium is 1 g of salt?
400 mg sodium
What are the major dietary sources of potassium in NZ?
Potatoes, kumara, taro (13%)
Vegetables (12%)
Non-alcoholic beverages (10%)
Milk (10%)
Fruit (10%)
What does the potassium intake of children in NZ look like?
- sodium intakes of most children were < WHO guidelines
- major food sources: dairy products, meat and poultry, fruit, bread, bread/pasta dishes
What are 2 examples of high potassium diets?
-
The DASH diet:
- Dietary approaches to stop hypertension
- Mediterranean style diet; high in fruit and veg, low fat milk products, wholegrains, nuts and legumes, poultry and fish; low in red meat, butter, other high fat foods
- Developed to lower BP without medication (evidence from trials)
- Supported by NIH -
Public health approaches:
- Remove GST from fruit and vegetables
- Fruit and vegetable vouchers
- Community cooking programmes
- Salt replacers also increase potassium intakes
What does potassium deficiency look like?
Characterised by increase in blood pressure, salt sensitivity, kidney stones and bone turnover. As it progresses it can lead to irregular heartbeats, muscle weakness and glucose intolerance.
