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Nutrition Year 1 > LIPIDS > Flashcards

LIPIDS Flashcards

1
Q

How much fat as % of body weight is considered too much for man and woman?

A

25% for man and 33% for woman

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2
Q

Which American physiologist in 1950’s declared that a high saturated fat diet would increase serum cholesterol and lead to heart disease? Changing the world view on Fat

A

Ancel Keys

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3
Q

What are the 6 functions of white adipose tissue (WAT)?

A
  • secretion of hormones
  • growth factor
  • enzymes and cytokines
  • protection of organs
  • a form of energy storage
  • provides insulation against extreme temperatures
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4
Q

Lipids include:
Triglycerides
Phospholipids
Cholesterol and steroid-based compounds
Sphingolipids
Glycolipids
Cerebrosides
Fat soluble vitamins

Describe each one

A

Triglycerides - 3 fatty acids bound to a glycerol
Phospholipids - cell membrane function and communication
Cholesterol and steroid-based compounds - oestrogen, progesterone, testosterone
Sphingolipids - myelin (found in nerve cell membrane)
Glycolipids - cell identity
Cerebrosides - found in the brain
Fat soluble vitamins - A D E K

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5
Q

Name 3 functions of lipids and explain?

A
  1. Energy (ATP) production - each gram of fat supplies 9cal.
  2. Storage of energy reserve - efficient form of storage
  3. Cell membrane structure - phospholipids and cholesterol stabilise cell membranes. Phospholipid (communication, diffusions and absorption). Cholesterol acts as a buffer for temperature change. Too high sat. fat decrease cell membrane fluidity
  4. Thermal insulation and organ protection
  5. Steroid hormones derived from cholesterol - progesterone, androgens, glucocorticoids, oestrogen, testosterone
  6. Growth and development - AA and DHA for the brain => EFA essential for foetal development. brain, vision
  7. Constituent of nervous tissues - sphingolipids for myelination of nerve fibres
  8. Aid cell-signalling processes
  9. required for absorption of fat soluble vitamins
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6
Q

what is a fatty acid?

A

A fatty acid is a Hydrogen and Carbon chain with an acid group at one end and a methyl group on the other end

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7
Q

What are SCFA ? How many carbons? How are they produced? Can we find them in the diet?

A

Short chain fatty acids have up to 5 carbon atoms in the chain
SCFA are produced when fibre is fermented by the colon
Can be found in the diet in small doses in breast milk, cow milk and coconut oil

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8
Q

what are the 3 most common SCFA?

A

Butyrate
Acetate
Propionate

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9
Q

why is SCFA butyrate important/role for colon health?

A

Butyrate is the source of energy of colonocytes => supports the intestinal tight junctions and mucous production
Anti inflammatory effect on the colon (increase glutathione), support mucous production

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10
Q

how many carbon atoms in a medium, long and very long chain fatty acid?

A

medium chain fatty acid = 6 to 12 carbons => go straight to liver to create ketones cross the BBB
Long chain fatty acid = 14 to 22C => build cell membrane
Very long chain fatty acid = > 22C => build cell membrane

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11
Q

explain the omega nomenclature system for arachidonic acid 20:4 w6

A

20 carbons
4 double bonds
w6 first double bond happens at the 6th carbon

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12
Q

explain the bonds for saturated fatty acids, unsaturated fatty acids, monounsaturated fatty acids and polyunsaturated fatty acids

A

saturated fatty acids = no carbon double bond - all carbons are saturated with hydrogen - solid at room temp

unsaturated fatty acids = one or more double carbon bonds - liquid at room temp

monounsaturated fatty acids = one double carbon bond - olive oil

polyunsaturated fatty acids = several double bonds - flaxseed (ALA)

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13
Q

what happen to stability when polyunsaturated fatty acids have many double bonds?

A

The more double bonds the less stable they are and are prone to oxidation - each double bond in a point of reaction

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14
Q

what does the process of hydrogenation does to fatty acids ?

A

hydrogenation is the process to add hydrogen to solidify an unsaturated fatty acid. it creates an unnatural trans fatty acid.

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15
Q

where can trans fat be found? what is the issue with trans fat?

A

margarine, processed food, refined vegetable oils
stiffen cell membrane making them prone to oxidation, impair normal cell function
trans fat alter blood triglycerides and cholesterol profile => risk of CVD, insulin resistance and cancer
There is no safe levels of trans fat

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16
Q

What is the difference between a Cis and a Trans polyunsaturated fatty acid?

A

Cis fatty acid => H atome on the same side. the majority of natural fats are Cis
Trans fatty acid => H atoms are on separate sides

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17
Q

Give an example of a natural Trans Fat ?
Which food?
What does it do to the body?

A

Conjugated Linoleic Acid (CLA).
Found in grass fed meat and dairy products.
CLA helps increase lean muscle mass

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18
Q

What are triglycerides ?

A

Triglycerides are the major form of dietary fats
Triglycerides are the form fat is stored in the body in adipose tissues
TG = 3 fatty acids + 1 glycerol

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19
Q

what is the problem with high blood triglycerides?
what cause that?

A

Linked to atherosclerosis
triglycerides are packed in very LDL cholesterol in the liver
high refined carbs, alcohol, obesity

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20
Q

what are the co morbidities of high serum triglycerides?

A

insulin resistance and type 2 diabetes

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21
Q

Through which process are triglycerides synthesised?

A

When caloric intake exceeds energy requirements, excess dietary energy is converted to triglycerides via LIPOGENESIS

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22
Q

Where does lipogenesis takes place?

A

In adipose tissue (adipocytes acquire triglycerides from circulating lipoproteins chylomicrons and very LDL) and the liver

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23
Q

Explain the process of lipogenesis

A

lipogenesis is the process through which acetyl-CoA is converted to triglycerides for fat storage when there is an excess of carbs.
Acetyl-CoA is created from glucose during glycolysis

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24
Q

explain the process of lipolysis

A

when dietary energy is limited, the fatty acids from triglycerides are mobilised from adipocytes in circulation => triglycerides are hydrolysed by lipase into fatty acids and glycerol for use in the body.

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25
Q

name 3 hormones that stimulate lipolysis ?
and one hormone that antagonise them?

A
  • adrenaline and noradrenaline
  • adrenocorticotropic hormone
  • glucagon and growth hormone
  • TSH and thyroxine

INSULIN antagonise the lipolytic effect of these hormones

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26
Q

what hormone antagonise the Lysol

A
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27
Q

Why is insulin is the fat storing hormone? What pb does it causes in insulin resistance patients?

A

Insulin inhibits lipolysis in adipocytes and promotes triglyceride storage

BUT in insulin resistance leads to increased levels of lipolysis because cell cannot pick up the insulin signal and the mechanism to switch off lipolysis does not work. This creates a continued and dysregulated breakdown of triglycerides into fatty acids which have nowhere to go and pack around the central abdomen => central adipose tissue

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28
Q

what is the process in which fatty acids is broken down to produce energy?

A

fatty acids catabolism.
1. fatty acids cross into cell membrane to mitochondria and enter the mitochondria with the help of CARNITINE and B5
2. in mitochondria, the fatty acid undergo beta oxidation (needs B2, B3 and Sulphur) and is broken down into 2 carbon blocks and Acetyl CoA
3. Acetyl CoA enters the Krebs cycle to CO2 and H2O
4. Energy is generated using the ETC

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29
Q

Explain Ketosis? and the process of ketogenesis

A

when carbs are low, fat become the primary fuel for energy production => ketone is synthesise as brain cannot metabolise fatty acids ==> can’t cross the BBB.

Ketogenesis = acetyl coa is converted to ketones

30
Q

in which pathology can you can you get a build up of ketones?

A

Diabetes => acetones build up give a sweet smell to breath

31
Q

How much carb restriction to trigger ketosis?

A

less than 40g a day = 2 slices of bread, 1 medium orange, 60g of oats

32
Q

explain the difference between nutritional ketosis and ketoacidosis?

A

Ketoacidosis is a dangerous condition that happens in type 1 diabetes where there is insufficient insulin response to regulate ketones => generate a shift in blood pH and can create acidosis

33
Q

how are lipids / triglycerides digested ?

A

Gastric lipase the stomach and Pancreatic lipase in duodenum ==> separate the glycerol from the fatty acids

The process is facilitated by the emulsifying action of bile (produced in liver and stored in gallbladder) => increase surface area for lipase to act

This results in 3 fatty acids and a monoglyceride which are packed into Chylomicrons and transported via the lymphatic system in the blood stream

Fatty acids are either used or stored in adipose tissues

34
Q

Give 3 tips to optimise fat digestion

A
  • chew well
  • avoid drinking with meals
  • increase bile production with bitter greens => choleretics and cholagogues
  • optimise stomach acid levels with B6 and Zinc rich foods
  • stress management
  • increase glycine and taurine which are bile components (legume, sea vegetables, spinach and eggs)
  • Olive oil can stimulate bile secretion
35
Q

Explain the issue with government dietary guidelines on lipids recommendation?

A

the uk guidelines recommends to chose low fat options and chose unsaturated oil and spread in small amounts.
No mention of healthy fats like olive oil, avocado, fatty fish etc.
low fat options often contains high sugar
no mention of the importance of quality of fats
not enough fat in the diet make people less satiated resulting in overeating

36
Q

benefits of including healthy fats in the diet?

A
  • greater satiety value
  • source of EFAs
  • Source of choline (cell membrane)
  • source of essential fat soluble vitamins and phytonutrients
  • flavour enhancement in cooked food
37
Q

Example of healthy fat sources

A

fruits and fruits oil - avocados, olives
seeds and seeds oil - chia, flax, pumkin, hemp
nuts: almonds, cashew, walnuts, Brazil
oily fish - SMASH
coconut oil
grass fed meat

38
Q

Explain the benefits of coconut oil, a medium chain triglycerides (MCT) and also a saturated fat

A
  • MCT increase the number of calories burned compared to long-chain fatty acids
  • Coconut contains 50% Lauric acid which is antibacterial, antiviral and anti fungal
  • coconut oil lower LDL and increase HDL
39
Q

Name 3 saturated fats in food and associated food source

A
  • butyric acid = produce in colon also small amount in butter and dairy
  • Caprylic acid = coconut, palm kernel and Breast milk
  • Lauric acid = coconut
  • Stearic acid = beef, pork, lamb, butter, cocoa
40
Q

Name the two types of monounsaturated fatty acids and food sources

A

omega 7 = coconut, palm, macadamia
omega 9 = olive, avocados, nuts

41
Q

Name the 3 types of polyunsaturated fatty acids OMEGA 3 and food sources

A

ALA = flaxseeds, chia, hemp, dark leafy green, walnuts
SDA = blackurrant seeds
EPA and DHA = SMASH, spirulina, chlorella, algae

42
Q

Name the 3 types of polyunsaturated fatty acids OMEGA 6 and food sources

A

LA - sunflower, hemp, pumpkin walnuts avo
GLA - evening primrose oil and borage oil
AA - meat and animal products

43
Q

which oil should you prefer for cooking and why?

A

Coconut oil and Ghee are saturated fat and have a higher smoke point => better for cooking
- extra virgin olive oil can be used for low temperature cooking below 180 degrees
ideally you want to stir fry in water and add the oil at the end

polyunsaturated oil should only be used cold pressed and raw

44
Q

what causes toxicity and rancidity in fats?

A
  • if they are high in polyunsaturated fats
  • are exposed to prolonged heat light or oxygen
  • are refined
45
Q

what is the limiting enzyme in ALA conversion to EPA and DHA?

A

delta 6 desaturase because will favour LA (omega 6)

46
Q

Name 3 functions of EFA ?

A
  • vital component of cell membranes, help maintain fluidity
  • components of organelles membranes like mitochondria
  • necessary for cell to cell communication
  • essential for foetal and brain development
47
Q

Name 3 clinical indicator of EFA requirement

A

SKIN
- dry flaky chapped lips
- hyperkeratosis
- delayed wound healing
- dry brittle, red and swollen cuticles
- dry/oily hair, split ends
- acne, eczema, psoriasis, dermatitis

ENDOCRINE:
- weight imbalance
- PMS, painful cramps, sore breast
- excess insulin

REPRODUCTIVE
- infertility / impotence / repeated miscarriage
- ovarian cysts / fibrotic breast disease

CIRCULATORY
- Frequent nose bleed / bleeding gum
- easy bruising
- delayed recovery from exercice

MUSCULO SKELETAL
- chronic joint pain / arthritis
- delayed recovery from injury

IMMUNE
- susceptibility to infection

NEUROLOGICAL
- dementia / alzheimers
- Parkinson’s disease
- irritability / nervousness
- tingling arms and legs
- CFS

48
Q

What are ALA food sources?

A

flaxseeds, chia seeds, hempseed, walnuts, soybeans, dark leafy greens

49
Q

What are ALA therapeutic uses ? x3

A
  • CVD
    Decrease risk of myocardial infarction and atherosclerosis development
    Reduce C-reactive protein levels
    anti arrhythmic effect
    anti hypertensive
  • Neurological
    promotes vasodilatation to prevent strokes
    promote brain derived neurotropic factor which plays a role in neuronal maintenance, learning and memory + mood boosting effet (good for depression)
  • Anti inflammatory = IBS, asthma and AI conditions (effect depends on its conversion to EPA and DHA….
50
Q

ALA drug interaction?

A
  • Blood thinning medication - omega 3 increase anticoagulant effect of aspirin and warfarin
  • Statins - increase reduction of cholesterol
51
Q

EPA and DHA therapeutic uses x 4

A
  • CVD
    Reduce blood triglyceride levels
    lower blood pressure via series 3 prostaglandins
    prevent atherosclerosis formation
    reduction of myocardial infarction
    decrease inflammation and increase insulin sensitivity => stimulate lipase activity (switch off lipolysis and decrease blood triglycerides levels)
  • Anti inflammatory => arthritic conditions like OA, RA, IBD, Eczema, Lupus
    inhibits NFkB and TNF-alpha and interleukin-6
  • Neurological health => depression. Alzheimers, ADHD
    Neuroprotective properties and increase brain derived neurotropic factor
    Dosage = EPA 0.6 - 3g / day DHA 0.15 -2g / days
  • Foetal health => pregnancy support
    Support foetal brain development
    Dosage = EPA 0.8g DHA 0.4g /day
52
Q

which nutrients support ALA conversion to EPA and DHA in vegetarian diet?

A

magnesium, zinc, B6 and vitamin C

53
Q

EPA and DHA supplements drug interaction:

A
  • anticoagulant
  • diabetes medication (make drugs stronger)
  • blood pressure medication (Lower blood pressure more)
54
Q

omega 6 LA food sources

A

sunflower, safflower, soybean, corn oil, nuts and seeds

55
Q

omega 6 GLA food sources

A

borage oil and evening primerose oil

56
Q

GLA therapeutic uses x3

A
  • RA
    decrease joint pain, swelling and orange stiffness
    anti inflammatory effect
    GLA converts to PG1 (prostaglandine 1) - immune regulatory and anti inflammatory (reduce NFkB
    Dosage 1.4g borage seed oil
  • ADHD - GLA + EPA combines
  • Eczema = reduction in inflammation dosage 320mg/day of GLA
57
Q

Evening primrose oil therapeutic uses x3

A
  1. PMS - GLA in EPO is a precursor to PG1 which inhibits prolactin
  2. Breast Pain - dosage 1000mg 3x day for 4-6 months
  3. Female fertility - increase and optimise cervical mucous to sustain sperm
    dosage = 1500-2000mg/day
58
Q

Why is evening primrose oil recommended in PMS
Dosage ?

A

GLA in EPO is a precursor to PG1 which inhibits prolactin

Prolactin disrupts hormones and create an imbalance between oestrogen and progesterone

Dosage = 1500mg/day

59
Q

which vitamin is to combines with Evening primrose oil in mood disorder in PMS?

A

B6

60
Q

Borage seed oil and GLA should not be used with which patients >

A

during pregnancy - may increase AA production

61
Q

Mechanism in which AA (omega 6) is pro inflammatory

A

AA is metabolised by Cox 1 and COX 2 to the inflammatory prostaglandin 2 PG2

62
Q

What are eicosanoids? what are they involved in ?

A

Eicosanoids are made by the oxidation of omega 3 and 6. They include prostaglandins, leukotriene, thromboxanes and protectins

Eicosanoids are involved in
- inflammation
- vasoconstriction
- immune cell behaviour
- lipids accumulation
- CNS signalling

63
Q

What are eicosanoids made off and what is the process?

A

Eicosanoids are made from AA, EPA and DGLA
Fatty acids from phospholipids are converted bu COX and LOX enzymes into eicosanoids
Depending on which fatty acid they are made off they can be pro or anti inflammatory

64
Q

Name 2 anti inflammatory prostaglandins and 1 pro-inflammatory prostaglandins
What are they made from
What action they have

A

PG1 from DGLA = anti-inflammatory
anticoagulant, remove excess sodium and water from body, relax blood vessels

PG3 from EPA = anti-inflammatory
prevent release of AA from cell membrane, limit PG2 production

PG2 - pro-inflammatory from AA
promote platelet aggregation, promote sodium and water retention (increase BP)

65
Q

Name 3 inhibitors of delta 6 desaturase

A
  • Magnesium, B6, zinc deficiency
  • insulin resistance
  • virus
  • alcohol
  • stress hormone
  • high intake of DHA and EPA
66
Q

Name 3 beneficial properties of cholesterol

A
  • vitamin D and calcium metabolism
  • cortisol and related hormone synthesis
  • aldosterone synthesis
  • sex hormone synthesis
  • cell membrane integrity
  • lipoprotein synthesis
67
Q

What dietary element can reduce cholesterol absorption from the diet?

A

Dietary fibres

68
Q

Explain the role of HDL LDL and Very LDL

A

LDL - takes cholesterol from liver to cells
Very LDL takes triglycerides to cells
HDL - collects cholesterol for cells back to the liver

69
Q

What are the CVD markers to look at ?

A

LDL particle size = small LDL particle => 3x more risk of CVD / large and fluffy ones can be protective

HDL particle size = larger HDL are more effective at removing cholesterol from the blood

70
Q

What markers are used to determine CVD risks? x5

A
  • Lipoprotein (a) - blood clotting agent
  • Lp-PLA2 - enzymes involved in endothelial inflammation
  • Fibrinogen - raised levels increase risk of clot
  • C-reactive protein - inflammation marker associated with CVD
  • Lipid peroxides - raised levels means oxidative damage to membranes

Nutrition Year 1 (10 decks)

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