Nutrition, Diet and bodyweight Flashcards
What is metabolism?
Chemical processes that occur to maintain life
Catabolic vs anabolic
Catabolic:
- Break down larger molecules into smaller ones (intermediary metabolites)
- Release large amounts of free energy
- Oxidative (release H atoms) - ‘reducing power’
Anabolic:
- Build larger molecules from smaller ones (from intermediary metabolites)
- Use energy released from
catabolism (ATP) - Reductive (use H released in catabolism)
What is energy?
Name the types of work
What energy do cells use to drive energy-requiring activities?
Capacity to do work
Biosynthetic, Mechanical, Transport (movement of ions & nutrients across membranes), Electrical and Osmotic
Cells use Chemical bond energy to drive energy-requiring activities
ATP and ADP cycle
ATP + water –> ADP +Pi + Energy
ADP + Pi + Energy –> ATP + water
Units for food energy
Kilojoule
1kcal = 4.2KJ
Consumption of food per year?
500kg
Carbohydrates
• General formula (CH2O)n
• Contain aldehyde (-C=OH) or keto (-C=O) group
• Multiple –OH groups
9 essential amino acids
(If learned, this huge list may prove truly valuable)
Isoleucine
Leucine
Tryptophan
Histidine
Lysine
Methionine
Phenylalanine
Threonine
Valine
Describe what is meant by conditionally essential.
In normal circumstances, these amino acids are produced by the body in amounts sufficient enough to meet the body’s requirements, but for growing children, during pregnancy, in disorders like CVD and physiological stress, biosynthesis may be inadequate, so these amino acids will need to be taken through the diet.
Conditionally essential amino acids in children/pregnant women
Arginine
Tyrosine
Cysteine
Plant origin proteins vs animal/meat origin proteins
Plant origin proteins lower quality - deficient in 1 or more essential amino acid
Animal/Meat Origin proteins contain all essential amino acids so are higher quality
Fat functions
absorb fat soluble vitamins (ADEK)
Lots of hydrogen (less oxygen) so high energy
Mineral function
establish ion gradients - maintain water balance
calcium + phosphorus for structure
calcium for signalling
ENZYME CO FACTORS
Iron for haemoglobin
Electrolytes
Sodium
Potassium
Chloride
(Iv fluids = 1mmol/kg/day)
water = 30ml/kg/day
Minerals
Calcium
Magnesium
Phosphorus
Sulphur
Iron
Trace minerals
Copper
Zinc
Iodine
Selenium
Ultratrace
Chromium
Manganese
Molybdenum
Fat soluble vitamins and deficiency problems
A - Xerophthalmia
D - Rickets
E - Neurological abnormalities
K - Defective blood clots (factor 7, 9, protein C, and protein S)
Water soluble vitamins and deficiency
B1 - Beriberi
B12 - Anaemia
B6 - Dermatitis/Anaemia
Biotin - Alopoecia, scaly skin, CNS defects
C - Scurvy
Choline - Liver damage
Folate - Neural tube defects/Anaemia
Niacin - Pellagra (skin lesions)
Pantothenic acid - Fatigue
Riboflavin - Ariboflavinosis
Dietary fibre sources
Cereal foods / fruit and veg
(cellulose, lignin, pectin, gums)
Why is cellulose fibre?
Contains B 1-4 linkages, humans cannot digest as do not possess the enzymes
High fibre diet does…
Reduces risk of diabetes and lowers cholesterol
Low fibre risks
Constipation
Bowel cancer
EAR
LRNI and RNI
EAR - estimated average requirement (requirements for 50% of group, 50% will need more)
RNI - reference nutrient intake (ensures 97.5% needs met)
LRNI - lower RNI (enough for only 2.5% of people who have low requirements)
Daily expenditure =
Basal metabolic rate
Voluntary physical activity
Diet induced Thermogenesis (energy to process food)
Male vs female DE
males - 12,000KJ per day
females - 9500 KJ per day
Factors affecting BMR
Body size (SA)
Gender
Environmental temp
Endocrine status
Body temp
How is body weight determined
Energy intake vs energy expenditure
BMI
weight (kg) / (height(m) squared)
BMI values
<18.5 - underweight
18.5 - 24.9 - ideal weight
25 - 29.9 - overweight
30 - 34.9 - obese
>35 - severely obese
What else is important with bmi?
Waist to hip ratio
Distribution of fat - upper body and abdomen = higher risk
Low protein diet cause
Kwashiokor
(insufficient blood proteins synthesised, lower capillary oncotic pressure, water moves to interstitium = oedema)
