Nutrition, Diet And Body Weight Flashcards
Catabolic and anabolic processes definitions
Catabolic processes: break down molecules to release energy in the form of reducing power
Anabolic processes: use energy and raw materials to make larger molecules for growth and maintenance.
In the body, cells use what type of energy in energy requiring activities?
Chemical bond energy
Although energy exists in inconvertible forms, other forms (eg heat) would prove dangerous to the body
What are the units of food energy?
SI unit: Kilojoules (kJ)
Calorie may also be used everyday (this refers to kilocalories, 1000 calories)
1 Kcal = 4.2kJ
What are the essential components of a normal health diet?
Carbohydrate (mostly supplies energy) Protein; energy and amino acids Vitamins Minerals Water; hydration Fat; energy and essential fatty acids Fibre; function in the GI tract
How can carbohydrates be classified?
(All either contain a keto (c=o) or aldehyde (-c=OH))
Monosaccharides (3-9 C atoms)
Disaccharides (2 units)
Oligosaccharides (3-12 units)
Polysaccharides (10-1000s units)
What are ‘essential’ amino acids
Essential amino acids cannot be synthesised be the body and must be obtained from the diet.
Isoleucine Lysine Threonine Histidine Leucine Methionine Phenylalanine Tryptophan Valine
If Learned This Huge List May Prove Truely Valuable
What does it mean for amino acids to be ‘conditionally essential’
?Amino acids which are more ‘essential’ in certain individuals
Eg children and pregnant women have a high rate of protein synthesis and need some arginine, tyrosine and cysteine
Why must vegetarian diets include a wide variety of plant sources
Protein of animal origin contain all essential amino acids, whilst plant protein is mostly deficient in one or more essential amino acids.
To prevent deficiency in one or more essential amino acids, a variety of plant protein must be consumed
Why are fats essential in the diet?
- energy source; contain less oxygen that carbohydrates or protein so more is reduced so yields more energy when oxidised
- absorption: required for the absorption of fat-soluble vitamins (A,D,E and K) from the gut
- provide essential fatty acids; eg linoleic and linolenic (these can’t be made in the body)
Why are minerals important in the diet
- act as electrolytes; establish ion gradients, maintain water balance
- structure; calcium and phosphorus in bones and teeth
- signalling molecules; calcium
- enzyme co factors; iron, magnesium, magnese, cobalt, copper, zinc and molubdenum
- iron for Hb
What’s found in IV fluids
Na+,K+,Cl- all 1mmol/kg/day each
water at 30ml/kg/day
Recommended fibre intake for adults
Recommended average intake for adults = 18g/day
Average intake for women 12.8g/day
Average intake for men 14.8g/day
Why is fibre important in the diet
Low fibre intake linked to bowel cancer and constipation
High fibre content lowers cholesterol and diabetes risk
DRVs
Dietary Reference Values
Estimates of the amount of energy and nutrients needed by different groups of the healthy UK population. Depends on age, gender and activity
RNI
Reference Nutrient Intake (97.5%)
For protein, vitamins and minerals
Enough to ensure the needs of 97.5% are being met. Many within the group will need less.
EAR
Estimated average requirement (50%)
Used for energy
LRNI
Lower Reference Nutrient Intake (2.5%)
(Values below LRNI are insufficient for most people)
Enough for only the small number of people who have low requirements (2.5%) the majority need more
What’s the daily energy expenditure for a 70kg adu;t male and 58kg adult female?
70kg adult male; 12,000kj/day
58kg adult female 9,500kj/day
Energy requirements vary between individuals depending on Age Sex Body composition Physical activity
What is BMR and what factors may effect it
Basal metabolic rate
Factors affecting BMR:
- body size
- gender (males higher than females)
- environmental temperature (increases in cold)
- endocrine status (increased in hyperthyroidism)
- body temperature (12% increase per degree)
Why is basal metabolic rate important
It maintains resting activities of the body
Maintenance of cells including ion transport across membranes, and biochemical reactions
Function of organ, 30% BMR skeletal muscle
Maintaining body temperature
What’s voluntary physical activity and what are the rough values for a
- sedentary person
- individual with moderate activity
- very active individual
VPA; energy required depends on intensity and duration of activity
It reflects energy demands of skeletal muscle, heart muscle and respiratory muscles
Sedentary person 30kJ/Kg/day
Moderate activity 65kJ/Kg/day
Very active individual 100Kj/Kg/day
Which foods have greatest theoretical energy content ?
In the typical British diet, which foods have greatest energy intake?
Greatest theoretical energy content;
- Fat
- Alcohol
- Protein
- Carbohydrate
Greatest total % energy intake
- Grains/carbohydrates
- Meat
- Drinks
- Milk and products
What are the body’s energy stores
- glycogen and fat act as very short term stores of energy rich molecules in muscle (few seconds worth)
- carbohydrate stokes for immediate use - minutes or hours depending on activity
- long term stores in adipose - 40 days worth
- under extreme circumstances, muscle proteins can also be converted to energy
How does obesity occur and what are some associated risks?
- excessive fat accumulation in ADIPOSE tissue
- usually measured using BMI (>30)
- when energy intake>expenditure for many years
-associated risks: cancers, cardiovascular disease, type 2 diabetes
