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Nutrition And Diet Flashcards

(76 cards)

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1
Q

What are the essential components of the diet?

A

Carbohydrates, proteins, fats, minerals, vitamins, water, fibre

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2
Q

Carbohydrate general formula and types of chemical groups?

A

General formula = (CH2O)n
Aldehyde groups + ketone groups, multiple - OH bonds

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3
Q

Monosaccharides

A

Single units eg. Hexose sugars 3-9 Carbon atoms

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4
Q

Disaccharides

A

2 units

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5
Q

Oligosaccharides

A

3-12 units eg. Dextrins (product of longer polysaccharide breakdown)

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6
Q

Polysaccharides

A

10 - 1000’s units (eg. Starch, glycogen, cellulose)

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7
Q

Major dietary carbohydrates?

A
  • Fructose
  • sucrose
  • maltose
  • lactose
  • glucose
  • starch
  • glycogen
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8
Q

Energy content of carbohydrates?

A

17 kJ/g

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9
Q

Requirement of glucose in diet?

A

No requirement for glucose in diet, body makes glucose from certain amino acids+ glycerol (from hydrolysed triglycerides) during gluconeogenesis. Glucose also synthesised from dietary sugars eg. Galactose + fructose

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10
Q

Structure of proteins?

A

Composed of liner chains of amino acids joined pep via peptide bonds

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11
Q

How many different amino acids used for protein synthesis?

A

20 different amino acids

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12
Q

How many essential amino acids?

A

9 essential amino acids cannot be synthesised (must be obtained from diet)

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13
Q

If learnt this huge list may prove truly valuable

A

Isoleucine, lysine, threonine, histidine, leucine, methionine, phenylalanine, tryptophan, valine

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14
Q

Quality of proteins?

A

Animal protein high quality, plant protein lower quality - vegetarians need to ensure variety in diet to meet protein requirements

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15
Q

Conditionally essential proteins?

A

Children + pregnant women= ↑ protein synthesis, need additional arginine, tyrosine and cysteine in diet

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16
Q

Turnover of tissue proteins?

A

Continuous turnover, 400g/day in adult males -turnover = breakdown + resynthesis of tissue proteins

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17
Q

How many grams are further degraded and now are they excreted?

A

35 g/day lost by further degradation + must be replaced in diet - nitrogen of degraded AA excreted in urine as urea

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18
Q

Energy from metabolism of proteins?

A

17 kJ/g

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19
Q

Average daily requirement to maintain zero nitrogen balance (N2 intake = N2 loss)?

A

Adult male= 35g protein (0.5g/kg) - growing children+ women during pregnancy need proportionally more ( show positive nitrogen balance → N2 intake > N2 loss )

In starvation = nitrogen balance negative

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20
Q

Structure of fats?

A

Triacylglycerols (3 fatty acids esterified onto 1 glycerol) → less oxygen than carbs/proteins, yields more energy when oxidised

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21
Q

Use of fats in body?

A

Needed for absorption of fat soluble vitamins → A, D, E, K from gut

Provides essential fatty acids eg. Linoleic and linolenic acids
Cannot be synthesised in body - structural components of cell membranes + precursors of regulatory molecules (eicosanoids)

Energy yield 2.2 times greater than carbs or protein so would need twice the amount of food in a fat free diet

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22
Q

Energy content of fats?

A

37 kJ/g

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23
Q

Uses of minerals?

A

Electrolytes establish ion gradients across membranes +maintain water balance

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24
Q

Calcium & phosphorus uses?

A

C+ P essential for structure (bones + teeth), calcium also important signalling molecule

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25
Minerals involved in enzyme co-factors?
Iron, magnesium, manganese, cobalt, copper,zinc, molybdenum
26
What component is iron essential for?
Haemoglobin
27
Electrolyte elements?
Sodium, potassium, chloride
28
Minerals elements?
Calcium, magnesium, phosphorus, sulfur, iron
29
Trace mineral elements?
Copper, zinc, iodine (for thyroid hormone synthesis), selenium (for anti-oxidative pathways)
30
Ultratrace elements?
Chromium, manganese, molybdenum (all for enzyme use)
31
Routine maintenance of electrolytes (IV fluids)
Na+, K+, Cl- → water → 1 mmol/kg/day 30ml/kg/day
32
Amount of vitamins required?
Microgram or milligram quantities (toxic if in excess from supplements) → deficiency diseases if inadequate intake
33
Fat soluble vitamins?
A→ D→ E→ K
34
Water soluble vitamins?
B1 (thiamin), B12, B6, biotin, C, choline, folate, niacin, pantothenic acid, riboflavin
35
Vitamins & minerals with important antioxidant properties?
Vitamin C, vitamin E, selenium
36
Where is dietary fibre found?
Cereal foods (ie. Beans, bread, fruit + veg)
37
Types of dietary fibre?
Lignin, pectins, cellulose, gums
38
Why is fibre not digested?
Humans do not possess enzymes to hydrolyse 1,4 beta glucose glycosidic bonds in cellulose
39
Low fibre intake...?
Bowel cancer/constipation
40
High fibre intake...?
Reduced cholesterol+ reduced risk of diabetes
41
Recommended avg. Intake =?
18g/day → women=12.8g/day → men= 14.8g/day
42
Dietary reference values (DRVs) include...
Reference nutrient intake (RNI) Estimated average requirement (EAR) Lower reference nutrient intake (LRNI) Safe intake when insufficient data
43
RNI…?
Used for proteins/ vitamis/minerals Avg. need over no. of days
44
EAR…?
Used for energy or a nutrient - amount any stated group of people will need Avg. need over no. of days
45
Variables for dietary reference values?
Values depend on age, gender, amount of physical activity, and often higher during pregnancy of lactation
46
Daily energy expenditure...?
Basal metabolic rate(BMR) + diet induced thermogenesis(DIT) + physical activity level(PAL)
47
Variations in daily energy expenditure due to…?
-age -sex -body composition -physical activity
48
Basal metabolic rate measure?
Measure of basal energy required to maintain life - maintains resting activities of the body
49
Factors affecting BMR?
-body size (surface area) -gender (males higher BMR than females as females = more adipose tissue which is less metabolically active than lean muscle tissue) -environmental temperature ( ↑when cold) -endocrine status ( ↑during hyperthyroidism) -body temperature ( 12% ↑per degree) -pregnancy and lactation increases BMR
50
Major tissues contributing to BMR?
Skeletal muscles → 30% CNS → 20% Liver → 20% Brain → 20% Heart →10% Other →20 %
51
How to calculate rough estimate of BMR?
Multiply body weight in kg by 100 (only in non- obese individuals) unit = kJ/24hrs
52
Voluntary physical activity energy expenditure?
Energy required by skeletal- cardiac muscles for voluntary physical activity Reflects energy demands of cardiac, skeletal and respiratory muscles
53
Rough estimates of VPA..?
Sedentary → 30 kJ/kg/day Moderate (~2hrs of exercise) → 65kJ/kg/day Very active → 100kJ/kg/day
54
Diet induced thermogenesis (DIT) measure?
Increase in metabolic rate as energy required to digest, absorb, distribute and store nutrients Energy required = 10% energy content of ingested food
55
Where are energy stores situated?
Short term energy for a few seconds → muscle Stores for immediate use (minutes or hours) → carbohydrates Long term stores ~ 40 days worth of → adipose Extreme conditions → muscle proteins
56
Obesity definition?
Excessive fat accumulation in adipose tissues which impair health, usually measured using body mass index >30 → result of energy intake > energy expenditure
57
Diseases associated with obesity?
↑ risk of hypertension, heart disease, stroke, type 2 diabetes, certain cancers, gall bladder disease, osteoarthritis
58
Clinical importance of distribution of fat?
Obese persons → greater proportion of fat within upper body (especially in abdomen) = ↑ risk of insulin resistance, hyperinsulinism, type2 diabetes, hypertension, hyperlipidaemia and stroke as well as premature death
59
Body mass index BMI measure?
Estimate of desired weight Equation: BMI = weight (kg) / height^2 (m)
60
Body mass index BMI measure?
Estimate of desired weight Equation: BMI = weight (kg) / height^2 (m)
61
Range of BMI values?
Underweight = <18.5 Desired range = 18.5 - 24.9 Overweight = 25 - 29.9 Obese = 30 - 34.9 Severely obese = >35 All for both men and women
62
Alternative to body mass index?
Waist to hip ratio (waist circumference divided by hip circumference) >0.9 = abnormal for men >0.85 = abnormal for women
63
Maximum rate of weight loss? (Assuming 12000 kJ stops eating and energy requirement by met mobalisation of fat from adipose tissue )
12000/37 = 324g/day = 2.3kg/week
64
Why is initial weight loss larger than 2.3 kg/ week?
Starvation = reduction in liver glycogen stores which are required to provide glucose to brain, glycogen stores contain more water than fat therefore weight loss = rapid
65
Why is total s starvation not a preferred method for weight loss?
Protein metabolism ↑ to maintain blood glucose via gluconeogenesis, therefore lean body mass lost Liver begins to convert fatty acids to ketone bodies (ketosis) which fuels CNS but disturbs blood pH → dehydration
66
Malnutrition condition definition?
Inbalance b/w what an individual eats and what they require to maintain health
67
Causes of malnutrition?
Eating too little (under-nutrition) or eating too much (over-nutrition), also caused by incorrect balance of nutrients
68
Causes of malabsorption conditions?
Failure to digest/absorb ingested nutrients → eg. Celiac or Crohn
69
Causes of under nutrition?
Eating disorders eg. Anorexia nervosa or bulimia nervosa OR more commonly from ↓ food source in many developing countries
70
2 types of protein - energy malnutrition?
Marasmus OR kwashiorkor
71
Marasmus clinical presentation?
Child looks emaciated wl obvious signs of muscle wastage + loss of body fat (no odema) - hair = thin+ dry, diarrhoea common wl anaemia
72
Kwashiorkor causes?
Child displaced from breastfeeding and fed a diet wl some carbohydrates but very low protein content
73
Clinical presentation of kwashiorkor?
Apathetic child, lethargic, anorexic, generalised oedema (usually 'pitting oedema' → when indentation left after pressure applied), abdomen swollen (distended)due to hepatomegaly ( enlarged liver), ascites (fluid accumulation in peritoneal cavity), anaemia common as serum albumin ↓
74
Why does oedema occur in kwashiorkor?
Insufficient amino acids for liver to synthesise blood proteins eg.albumin,↓ plasma oncotic pressure,↑ net flow of fluid from capillaries → oedema
75
Why is it important to re-feed slowly?
Can cause re-feeding syndrome, rapid ingestion of energy rich food = ↑ rapidly of blood sugar + insulin = glycogen/fat / protein synthesis = utilise depleted stores of phosphate, magnesium and sodium =electrolyte abnormalities eg. Hypophosphotaemia
76
Rate of re-feeding?
5-10 kcal/kg/day , raise gradually to full needs within a week

Metabolism (4 decks)

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