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Medical Cell Biology And Genetics > Topic 4: Diet And Nutrition > Flashcards

Topic 4: Diet And Nutrition Flashcards

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1
Q

What are the essential components of the diet

A

Carbohydrate - energy
Protein - energy and amino acids (can convert to ATP)
Fat - energy and essential fatty acids
Minerals - essential
Vitamins - essential
Water - hydration
Fibre normal GI function and lowering cholesterol

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2
Q

Define the components of daily energy expenditure

A

Vary between age, sex, body composition and physical activity

70kg adult male - 12000KJ/day
58kg adult female - 9500 KJ/day

It is the sum of basal metabolic rate, diet-induced thermogenesis, physical activity level

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3
Q

Describe the factors involved in regulation of body weight

A

Physical activity -
Reflects energy demands of skeletal muscle, heart muscle and respiratory muscles

Sedentary - 30kJ/kg/day
Moderate - 65 kJ/Kg/day
Active - 100 kJ/Kg/day

When overweight - down ro lipds/adipose tissue

Energy intake bigger than energy expenditure - more fat, measured in BMI

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4
Q

Explain the clinical consequences of protein and energy deficiency

A

Require stores of energy’usualky as adipose
Under extreme conditions muscle proteins can be converted to energy

Low protein intake can result in insufficient blood protein synthesis (albumen) leading to a decrease in plasma on droid pressure and oedema - in disease Kwashiorkor

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5
Q

What is metabolism

A

The chemical process that occur within a living organism in order to maintain life

  • oxidative pathways, food into energy
  • fuel storage - when not eating, eg: fat and glycogen
  • bio synthetic pathways - produces basic building blocks for cells
  • detoxification pathways - remove toxins, eg: P450 in liver
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6
Q

What are catholic processes

A

Break down to release energy

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7
Q

What are anabolic processes

A

Uses energy and raw materials to make larger molecules for growth and maintainence

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8
Q

Why do we need energy

A

Bio synthetic work- synthesis cellular components
Transport work - movement of ions and nutrients across membranes
Mechanical work - muscle contraction
Electrical work - nervous conduction
Thermogenesis
Detoxification

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9
Q

What type of energy do our cells use

A

Chemical bond energy

ATP

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10
Q

Energy is procured by oxidation fo what

A

Lipids
Carbs
Proteins
Alcohol

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11
Q

ATP-ADP cycle

A

ATP -> ADP + Pi

-> CO2 and H2O and heat

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12
Q

What are the units of food energy

A

Kilojoules
Calorie is also used - kilocalorie - 1000 calories

1kcal - amount of energy required to raise the temperature of 1kg of water by one degree Celsius
1kcal= 4.2kJ

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13
Q

Key information of carbohydrate

A

(CH20)n
Contains aldehyde and keto group
Multiple OH groups

Monosaccharides - single sugar
Disaccharides - two sugar like lactose, sucrose
Oligosaccharides 3-12 units, eg: dextrin
Polysaccharides - 10-1000 units like glycogen, starch, cellulose

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14
Q

Starch

A
  • amylose and amylopectin
    In plants
    Polymer of glucose
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15
Q

Sucrose

A

Glucose and fructose
Table sugar
Disaccharide

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16
Q

Lactose

A

Galactose and glucose
Milk sugar
Disaccharide

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17
Q

Fructose

A

Fruit sugar

Monosaccharide

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18
Q

Glucose

A

Sugar in human blood
Red blood cells don’t have mitochondria so rely on glucose for glycolysis as can’t do ETC
If glucose conc falls below Km of glucose transporter then glucose can’t be transported to brain = coma

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19
Q

Maltose

A

Glucose - glucose disaccharide

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20
Q

Glycogen

A

Storage molecule

Polymer of glucose

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21
Q

What is digestion

A

Coverts larger carbohydrates to monosaccharides which are absorbed into blood

22
Q

Protein

A

Composed of amino acids
Enter blood
20 different amino acids used for protein synthesis in body
9 essential ones can’t be synthesised so must be obtained from diet

23
Q

What are the 9 essential amino acids

A 
Isoleucine
Lysine
Threonine
Histidine
Leucine
Methionine
Phenylalanine
Tryptophan
Valine

(If learned this huge list may prove truly valuable)

Deficiency in some of these amino acids in plant origin

24
Q

Which amino acids are conditionally essential

A

Children and pregnant women possess a high rate of protein synthesis so require also some ARGININE, TYROSINE and CYSTEINE in diet

25
Q

Fat

A

Lipid composed of triacylglycerols (3 fatty acids esterified to one glycerol)
Can be saturated, unsaturated and trans (unsaturated by H bonds on either side - increases shelf life)
Less oxygen so more rescued so yield more energy when oxidised
Used for absorption of fat soluble vitamins from gut
Provides essential fatty acids such as linoleic and linolenic - plasma membrane and prostaglandins
Omega 3 - 3 carbons down there is a double bond

26
Q

Minerals

A

Electrolytes establish ion gradients across membrane
Maintain water balance
Ca and P - structure
Ca - signalling
Enzyme co factors - Fe, Mg, Manganese, Co, Cu, Zn and molybdenum)
Fe - haemoglobin

27
Q

Electrolytes

A

Sodium
Potassium
Chloride
1mmol/kg/day each

28
Q

Minerals

A 
Calcium
Magnesium
Phosphorus
Sulphur.  Without no cysteine etc so no thymine so can not start protein synthesis 
Iron
29
Q

Trace minerals

A

Copper
Zinc
Iodine - to make thyroid hormone
Selenium - protect against oxidative stress

30
Q

Ultra trace

A

Chromium
Manganese
Molybdenum

31
Q

Vitamins

A 
Required in micro or milligram
Fat or water soluble
Deficiency diseases
Excess vitamins also a problem 
See PP slides for deficiency
32
Q

Dietary fibre

A

Made of cellulose, lignin, pectins and gums
(Do not have enzymes to break down cellulose)
Recommended intake - 18g/day but currently below this
Low intake x constipation and bowel cancer
Reduces cholesterol and risk of diabetes

33
Q

What are dietary reference values

A

Series of estimates of the amount of energy and nutrients needed by different groups of healthy Uk population

  • Reference nutrient intake - proteins, mineral and vitamin , eniugnt o ensure needs of 97.5% are being met
  • estimated average requirement - energy, 50% will require more
  • lower reference nutrient intake - proteins, mineral and vitamin. For those who have low requirements (2.5%)
  • Safe intake (used when insufficient data)

Depend on age, gender and level of activity

34
Q

Basal metabolic rate

A

Maintains resting activities if the body
Maintenance of cells - ion transport and biochemical reactions

Function of organs - skeletal muscle (30% BMR)
liver, brain (20%)
Heart - 10%
Other - 20%

Affected by body size, gende, temperature, endocrine status, body temp

35
Q

How to measure body mass index

A

Weight (kg) / height^2 (m^2)

Measure height without shies
Weight with minimal clothing
Major weakness - very muscular individuals
Could measure instead waist/hip ratio

Male (kg/m2) Female (kg/m2) Classification
Male < 18.5 18.5 - 24.9 25 - 29.9 30 - 34.9 >35
Female < 18.5 18.5 - 24.9 25 - 29.9 30 - 34.9 >35
Classification Underweight Desirable weight Overweight Obese Severely obese

36
Q

Diseases associated with body fat in upPer body (abdomen)

A 
Insulin resistance 
Hyperinsulinism
Type 2 diabetes
Hypertension
Hyperlipidaemia
Stroke
Premature death
37
Q

Clinical consequences of severe protein deficiency in children

A

Growth failure (height and weight below normal).
• Impaired physical development (tiredness, weakness and
p1
poor exercise tolerance due to reduced muscle mass).
• Impaired mental development (low IQ).
• Negative nitrogen balance due to Nin < Nout
• Oedema due to reduced albumin synthesis in the liver.
• Increased risk of infection due to reduced immunoglobulin
synthesis.
• Anaemia due to reduced haemoglobin synthesis.
• Fatty liver due to reduced lipoprotein synthesis.

38
Q

Define obesity

A

Obesity is a chronic condition characterised by excess body fat. It is usually defined on the basis of determination of the Body Mass Index (BMI). A individual with a BMI of ≥30 is considered to be obese. Obesity is a risk factor for the following chronic conditions: hypertension, cardiovascular disease, type 2 diabetes, gall bladder disease, osteoarthritis & cancer.

39
Q

How much water do you need each day

A

2.5 litres

40
Q

What is used for screening malnutrition

A

MUST tool

  1. BMI
  2. unplanned weight loss
  3. Acute ill

If more than 3 - high risk

41
Q

What is dietary fibre needed for

A

Reduce cholesterol
Better digestion
Need 18g

42
Q

What are the two types of malnutrition

A

Marasmus

Kwashiorkor

43
Q

What is marasmus

A 
Insufficient energy intake 
Negative energy balance so mobilisation of fat stores and muscle proteins broken down for amino acids 
Nutritional deficiencies - energy, protein, vitamins and minerals, dehydration 
Typically in children 
Chronic slow onset
Severe weight loss
Muscle wasting, protruding rubs
Diarrhoea 
No protruding abdomen
Insuffience protein intake
No oedema
44
Q

What is kwashiorkor

A 
Insuffient protein intake
Deficit of essential amino acids
Rapid acute onset
Some weight loss
High mortality
Poor appetite
Typically when displaced from breast milk as toddler - carbohydrate rich diet when new baby arrives
Found in developing countries 
Bilateral pitting oedema 
Hair changes (brownish, scanty, straight)
Flaky skin
Protuberant abdomen - enlarged liver 
Anemia - not enough amino acid to make Hb
45
Q

What is bilateral pitting oedema

A

Normal thumb pressure applied to both feet for 3 secs

Shallow pit remains on both after lifted - oedema

46
Q

What causes oedema

A

Net flow of fluid from plasma into interstitutial fluid
Decreased plasma protein - net flow of fluid into interstitium (oedema). As in kwashiorkor unable to make essential amino acids, limits ability of liver to produce serum albumin so net flow increases

47
Q

Net flow=

A

Different in on oncotic - diffference in hydrostatic

48
Q

Why does a fatty liver occur in kwashiorkor

A

Liver functions to synthesise lipoproteins to transport this fat around body but without this ability of the liver, lipds accumulate in liver as can’t be transported - fatty liver - hepatic dysfunction

49
Q

How do you reintroduce food to someone with marasmus and kwashiorkor

A

Marasmus - slowly, small, monitored
Kwashiorkor - can not be given protein rich foods as no enzymes present in urea cycle so can lead to build up of ammonia which is toxic. So small amounts of protein at regular intervals

50
Q

What is re-feeding syndrome

A

Rapid influx of food
Can lead to confusion, coma, convulsion and death
Usually by ammonia toxicity as no urea cycle,, ammonia build up
Or by rapid increase in metabolism, chemical pathways work very quickly, which requires phosphate, run out of phosphate eas already depleted, so hypophosphataemia
Re feed at 5-10 kcal/kg/day over 1 week

Medical Cell Biology And Genetics (36 decks)

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