Nutrition, Diet and body weight Flashcards
Catabolic processes
break down of molecules to release energy in the form of reducing power
the reducing power can be used in anabolic processes
Anabolic processes
uses energy and raw materials to make larger molecules for growth and maintenance
What is biosynthetic work?
synthesis of cellular components
What is mechanical work?
muscle contraction
What is electrical work?
nervous contraction
What form of energy do cells use to drive energy-requiring activities?
chemical bond
SI unit of food energy
kj
What is 1 kcal?
amount of energy needed to raise temperature of one kilogram of water by one degree celsius
4.2 kilojoules
Why cant we break down cellulose?
we do not have the enzymes to break the cellulose beta 1,4 glycosidic bond
Why do we need to maintain plasma glucose?
red blood cells cannot make glucose as they have no mitochondria
What are the 9 essential amino acids?
if learned this huge list may prove truly valuable?
isoleucine lysine tryptophan histidine leucine methionine phenylalanine threonine valine
What are the conditionally essential amino acids?
tyrosine and cysteine and arginine
What is high quality protein?
protein of animal origin all essential amino acids
What are lower quality proteins?
proteins from plant origin- most are deficient in more than one essential amino acid
What are essential fatty acids?
linoleic and linolenic acids- cannot be synthesised in the body
What are fibres essential for?
cant be broken down by human digestive enzymes but essential for normal functioning of gastrointestinal tract
fibres also reduce cholesterol and a risk of diabetes
What are the consequences of a low fibre intake?
constipation and bowel cancer
How much energy does 70kg male need?
58kg woman?
12,000kj
9500kj
What is basal metabolic rate?
energy we need to keep our body system going
- ion transport across membranes
- biochemical reactions
30% is used by skeletal muscle
How to calculate BMI?
Weight/height squared
kg/m squared
What the desirable weight? underweight overweight obese severely obese
<18.5 18.5 - 24.9 25 - 29.9 30 - 34.9 >35
What are the risks of having a greater fat distribution in the upper body compared to the hips?
insulin resistance hyperinsulinsm type 2 diabetes hypertension hyperlipidaemia stroke premature death
What are the components of daily energy expenditure?
Basal metabolic rate
Diet induced thermogenesis- energy required to process food
Physical activity level-
What is basal metabolic rate
The rate at which the body uses energy while at rest to maintain such as vital functions such as keeping warm and breathing
RNI
Reference nutrient intake
EAR
Estimated average requirement of energy
LRNI
Lower reference nutrient intake
Values below the LNRI are insufficient for most people
What are the fat soluble vitamins
A D E K
Deficiency in A
Dryness of eyeballs
Xerophthalmia
Deficiency in D.
Rickets
Soft bones due to abnormal calcium metabolism
Vit D regulates the number of phosphate and calcium
Deficiency in E
Nerve and muscle damage
Vit E is required for the protection of oxidative damage
Deficiency in K
Defective blood clotting
What can a deficiency in vitamin B12 lead to
Anaemia
Macrolytic
What causes muscle wasting
- Lack of energy intake/ glucose from diet
- glycogen stores already being mobilised
- fat stores too are constantly being mobilised releasing fatty acids
- fatty acids are being converted into ketone bodies via B oxidation
- Ketone bodies are important to supply energy needed for red blood cell production and the maintenance of the CNS
- Once these above energy stores are exhausted as a result of depletion, muscle protein is broken down to release amino acids for gluconeogenesis to occur
what is refeeding syndrome?
Marasmus is due to insufficient food (including protein). Due to the lack of necessary nutrients, esp protein, liver cannot synthesise albumina and lipoproteins.
this leads to the downregulation of enzymes involved in the urea cycle. This, in turn, means protein cannot be digested (hydrolysed) completely therefore toxic levels of ammonia buildup in the body
What is a dietary source of fibre
cellulose
gums
pectin
lignins
