6 - General Nutrition Flashcards
What is metabolism?
The chemical processes that occur within a living organism in order to maintain life
What are anabolic and catabolic processes?

Why do we need energy?
- Mechanical work
- Transport work
- Biosynthetic work
- Electrical work
How is ATP produced?
Oxidation of:
- Lipids
- Alcohol
- Carbohydrates
- Proteins

What is the SI unit of food energy?
kJ (1000J)
1kCal = 4.2 kJ
(when packets say 100 cal, they actually mean 100kCal)
What is the definition of a kCal?
Amount of energy required to raise the temperature of 1kg of water by one degree celsius
What do we need in our diet and what is essential?
- Carbohydrates - energy
- Protein - energy and aa
- Fat - energy and essential
- Minerals - essential
- Vitamins - essential
- Water
- Fibre - GI function
What is the general structure of carbohydrates?
(CH2O)
Contain ketone and aldehyde groups and multiple OH’s
What is a dextrin?
Oligosaccharide (3-12 units)
Why is cellulose essential and why can’t we digest it?
- Needed for GI function
- Used to lower cholesterol and risk of diabetes
- Low fibre intake associated with bowel cancer and constipation
- We don’t have enzymes to hydrolyse b 1-4 linkages
What are the three disaccharides and what are they made of?
- Sucrose (glucose and fructose)
- Lactose (glucose and galactose)
- Maltose (glucose and glucose)
What amino acids are essential?
If Learned This Huge List May Prove Truly Valuable
- Isoleucine
- Leucine
- Threonine
- Histidine
- Lysine
- Methionine
- Phenylalanine
- Tryptophan
- Valine
What are conditionally essential amino acids?
Not always essential but under certain circumstances they are (e.g illness and stress) as there is a high rate of protein synthesis
e.g pregnant women and children need some tyrosine, arginine and cysteine

Why do vegetarians sometimes have illness?
- Can’t get all essential amino acids from a single plant like you can with single bit of meat
- Need wide variety of plant sources as vegetarian
What are lipids composed off and why are they essential?
- Triacylglycerols
(more reduced than carbohydrates so release more energy)
- Needed for absorption of fat soluble vitamins (A,D,E,K)
- Provide essential FA, linolenic and linoleic acid
Why is linolenic acid essential?
Used to make phospholipids
What minerals are essential and what for?

To maintain water and electrolytes in the body what is recommended to administer IV?
Water: 30ml/kg/day
Na/K/Cl: 1mmol/kg/day each
What vitamins are essential and what do they cause if there is a deficiency?
In tiny quantities
- A: Xerophthalmia (dry eye)
- D: Rickets
- E: Neurological abnormalities
- K: Defective blood clotting
What is hypervitaminosis?
Intake of too much vitamins
Usually due to supplements
What are some water soluble vitamins?

What should be our daily intake of fibre?
18g a day
(usually lower than this on average in real population)
(found in veg, cereal foods)
What are dietary reference values (DRV)?
Estimates published by SACN of the amount of energy and nutrients needed by different groups of healthy UK population, replaced RDA

What is the Daily Energy Expenditure?
BMR(~1700) + DIT(~150) + PAL(~1000-3000)
- 58kg woman - 9,500 kJ/day
- 70kg man - 12,000 kJ/day
What does the BMR use energy for and what factors affect BMR?
Used for ion transport and biochemical reactions in cells
- Gender
- Environment
- Body size
- Body temperature (10% increase per 1 degree)
- Endocrine status (hyperthyroidism)
- Lactation and prengancy
How do PAL affect energy expenditure?
Sedentary- 30kJ/kg/day
Moderately active - 60kJ/kg/day
Very active - 100kJ/kg/day

What organs make up BMR?
Skeletal muscle - 30%
Liver - 20%
Brain - 20%
Heart - 10%
Other - 20% (maintaining body temp)
What is the theoretical energy component in each food group of our diet?

How do you calculate BMR?
If not overweight, 100 x weight (kg)
How do you work out DIT?
10% of the energy intake
Where are energy stores in the body?
- Creatine Phosphate in muscle (few seconds worth)
- Glycogen in liver100g and muscle300g
- Excess fat stored in adipose tissue (40 days worth)
- Protein last resort
What is the body weight made up of in a 70kg man and a 100kg man?

What is obesity?
Chronic disease where there is excess fat in adipose tissue that impairs health, BMI > 30
- Cancer
- Gallbladder disease
- Type II diabetes
- Hypertension
- CVD
- Osteoarthiritis
How do you calculate and interpret BMI?
What is an alternative measurement to BMI?
Waist:Hip ratio
>0.9 (m) >0.85 (f) obese
- More fat on waist than hips leads to risk of stroke, type 2 diabetes, hypertension

How would you work out the rate of weight loss for someone who has a daily energy expenditure of 12,000 kJ stopped eating?
Would mobilise fat stores (37kJ/g)
12,000/37 = 324g/day x 7 = 2.3kg/week
Who does the eatwell plate not apply to?
- Children under two
- Malnourished people
- Special dietary needs

What is malnutrition and how is it measured?
Imbalance between what an indiviual eats and what the individual requires for sustained health
MUST (high) - Inpatients, Outpatients, GP, care homes
Malnourished patients spend longer in hospital
What can malnutrition be caused by?
Undernutrition: Anorexia, Bulimia nervosa, Lack of food in developing countries
Malabsorption: Coeliac’s and Crohn’s disease
How much water do we need to drink a day?
- 2.5 litres lost to faces, urine and expiration
- Metabolism produces 350ml
- We need to drink the rest (2.2 litres)

How much is one unit of alcohol?
10mg alcohol
Half a pint, small glass of wine
14 units a week, over three days and at least two days alcohol free
What would you do if someone was malnourished in hospital?
- Allow them to eat lots of what they like at first
- Fortisip
What is Marasmus?

What is Kwashiorkors?

What are the differences between Marasmus and Kwashiorkor’s?

What is refeeding syndrome?
When you eat a lot after not eating for a while, leads to convulsions, coma, death, confusion. Due to ammonia toxicity as there is a downregulation in enzymes of the urea cycle
Refeed at 5-10kcal/kg/day over a week
- Cancer patients, anorexic patients, post surgery, alcoholics

How would you refeed someone with Kwashiorkor’s and Marasmus?
Marasmus: Slowly, small amounts carefully monitored
Kwashiorkor’s: Small amounts of proteins at regular intervals. Can’t have lots as there is a downregulation of enzymes in urea cycle so leads to build up of ammonia which is toxic
What is Starling’s law of the capillary?

What happens to excess amino acids in the blood?
Excreted in the urine
Why is there muscle wasting and fatigue in a child with Marasmus?
- Energy intake is less than energy requirement
- Protein from muscles is broken down into amino acids for gluconeogenesis
Why is there oedema in Kwashiorkor’s but not Marasmus?
Kwashiokor is a protein deficiency but Marasmus is a energy deficiency so Marasmus adapt and can produce lipo-proteins with low levels of everything. Kwashiokor cannot produce lipoproteins as low protein so lipids build up in the liver, leading to an enlarged liver and hypoalbuminimea
Why do malnourished people have a poor immun system?
Don’t have the amino acids to produce antibodies