Lipids Flashcards
What are the functions if white adipose tissue?
It is a complex metabolically active endochrine tissue with the following functions-
- Secretion of-
-hormones
-enzymes
-cytokines - Protection of organs
- Provides insulation
Name the different lipids that exist in the human body
Fatty Acids
Triglycerides
Phospholipids
Cholersterol
Steroid compounds (eg. oestrogen)
Sphingolipids (found in nerve cell membranes e.g. Myelin)
Glycolipids (lipids +carbohydrate) involved in cell identity
Cerebrosides (in the brain)
Fat doluble vitamins A, D, E, K
How many calories does each gram of fat provide?
9 kcal
Give 5 functions of lipids
- Energy (ATP production)
- Energy storage
- Cell membrane structure
- Thermal insulation (subcutaneous fat)
- Organ protection (visceral fat)
Define what it meant by a short chain fatty acid
One with fewer that 6 carbon atoms
Name the 3 most common SCFAs
Acetate, propionate and butyrate
Why is Butyrate particularly important for colon health
It is the primary energy source for colonocytes and supports intestinal tight junctions
It has an anti-inflammatoy effect on the colon
What is a Fatty Acid?
Hydrocarbon chains with an acid group at one end and a methyl group on the other
What are the properties of a medium chain fatty acid
-Has 6-12 carbon atoms
-Can travel directly to the liver where they can be used to create energy or ketones
-good source of energy before excercise
What are the properties of a long chain fatty acid?
-Have 14-22 carbon atoms
-Used the build cell membranes
What are the properties of Saturated fatty acids?
-Contain no CC double bonds
-All the carbons are completely saturated with hydrogen bonds
-Solid at room temperature
-Stable oil
-Best oil to cook with at high temperatures
What are the proerties of Unsaturated Fatty Acids?
-Contain 1 or more double bonds between carbons
-Liquid at room temperature
How many double bonds do Mono unsaturated fatty acids have?
One
How many bonds do Polyunsaturated Fatty Acids have and how does this affect it’s stability?
Several double bonds. This makes it more unstable as the more double bonds the less stable and the more susceptible to oxidisation it becomes.
What are trans fats and why are they to be avoided?
Unsaturated fats that are made saturated by the addition of hydrogen (hydrogenised).
To be avoided because-
-They stiffen cell membranes, making them prone to oxidation, and alters their permeability, impeding normal cell function
-They alter blood triglyceride and cholesterol levels which increases risk of CV disease, insulin resistance and cancer.
Explain the difference between a Cis fat and a trans fat?
Cis- The hydrogen atoms are on the same side as the double bond
Trans- The H atoms are on seperate sides of the double bond.
What is a Triglyceride?
Lipid mollecules made up of 1 unti of glycerol and 3 fatty acids.
They are the major form of dietary fat and the form in which fat is stored.
Why are high trglycerides considered bad?
Linked to atherosclerois.
What triggers the body to synthesise triglycerides?
Whenever caloric intake exceeds energy requirements.
Excess energy is converted to trglycerides in a process known as lipogenesis and excess ingested fat is taken up by adipose tissue
Where does Lipogenesis take place?
In adipose tissue and the liver
Define Lipogenesis?
The process through which acetyl-Co-A is converted to tryglycerides for storage in fat.
Define Lypolysis
When dietary energy is limited, the fatty acids from triglycerides are mobilised from adipocytes into circulation
What is Lipolysis stimulated by?
-Adrenaline and noradrenaline
-Adrenocorticotropic hormone (ACTH)
-Glucagon
-Growth hormone
-TSH and thyroxine
What is Lipolysis inhibited by?
Insulin
Insulin resistance=central adiposity
Describe the process of the convertion of fatty acids to energy
Fatty acids can cross the cell membrane, traverse the cytosol and reach the motochondria
What amini acid is needed to transport the fatty acid across the cell membrane?
Carnitine
Describe the process of Beta-oxidation
Fatty acids are broken down into 2-carbon blocks as acetyl CoA which is oxidised via the Krebs cylce to CO2 and H2O. Energy is then generated using the electron transport chain.
What triggers ketone production?
Glucose being in short supply
What is Ketogeneis?
acetyl-CoA is converted to the ketones-
acetoacetate or B-hydroxybutyrate
For most adults what is the maximum carbohydrate level in grams that will allow you to get into ketosis
40 g per day
Name 4 theraputic used of ketosis
-weightloss
-epilepsy management
-Parkinsons and Alzheimers disease
Describe the process of lipid digestion
-Gastric lipase in the stomach and pancreatic lipase in the duodenum separate the glycerol from the fatty acids
-The resulting 2 fatty acids and monoglyceride are transported into enterocytes where they are rebuilt in the cell, packaged into chylomicron and transported via the lymphatic system to the blood stream where they are used for energy or stored in adipose tissue.
How does Bile facilitate fat digestion?
Emulsifies the fat to increase the surface area
Name 3 things you can do to support fat digestion
- Chew food and avoid liquid aroung meal times
- Increase bile production by optimising stomach acis
- Good hydration to increase bile flow
What can you do to increase stomach acid levels?
-Zinc
-B6
-Eat bitter food before a meal (chicory, rocket)
-stress management
Which 2 amino acids are components of bile? Name some good sources
Glycine and Taurine
Sources- legumes, sea vegetables, spinach and eggs.
Which oil can stimulate bile secretion?
Olive oil
Why are the current dietary fat reccommendations problematic?
-the fat in low fat diets is often replaces with refined carbohydrates and sugar
-Fat is satiating limiting it can lead to overeating
-It fails to distinguish the types of fat
Name 3 benefits/theraputic uses for cocnut oil
-Contains MCTs which increase the number of calories burned
-Contains 50% lauric acid which helps form monolaurin. Both have antibacterial, antiviral and antifungal properties
-Can increase HDL and lower LDL
-Preliminary studies show positive outcomes in epilepsy and AZ disease.
Name a form of Buryric acid (4-C)
Butter, dairy
Name a source of Caprylic acid (8-C)
Coconut, palm kernal, breast milk
Name a source of Lauric acid 12-C
Coconut
How many carbon chains does the saturated fat Palmitic acid have?
16
Name 3 food sources of Stearic acid
Red meat, cocoa butter and butter
Name 3 food sources of Omega 7 (Palmitoleic acis)
Coconut, macadamia nuts and sea buckthron berries
Name 3 food sources of Omega 9 (Oleic acid)
Fruits-Olive, avocado
Nuts-almond, peanut, pistachio, brazil nut, peacan, cashew, hazlenut, macadamia
Fat- Butter
Name the 4 main categories of Omega 3 fats and give a food source for each of them.
ALA (Alpha-linolenic acid)- Flaxseeds, chia seeds, hemp seeds, dark green leaves, pumkin seeds and walnuts
Stearidonic Acid (SDA)
Blackcurrent seeds
EPA and DHA-
Cold water fish oil
Salmon, trout, tuna , anchovies, mackerel, sardines, herring, spirulina and chlorella
Name the 3 main categories of Omega 6 fats and give a food source for each of them.
Linoleic Acid-LA
-Sunflower, walnut, pumpkin seed, sesame, almond chia, cashew, avocado, brazil nuts
Gamma linolenic acid- GLA
-Borage oil, evening primrose oil, hemp oil, blackcurrant seed oil
Arachidonic Acid (AA)
-Meat and other animal products
-
What are the best fats for cooking at high temperatures?
Saturated fats-
coconut oil, butter, ghee, lard
Why is it okay to cook with monounsaturated fats and lower temperatures?
They have naturally occurring anti-oxidents
What is the maximum temperature you should heat monounsaturated fats to before they get damaged?
180 degreesC
What is the best way to consume and store Poluunsaturated fats
-In it’s raw, cold-pressed form
-store in dark glass bottles in the fridge
-know the pressing date if possible
Which 2 fatty acids cannot be made by the body?
Linoleic Acid (Omega 6)
Alpha-Linoleic Acid (Omega 3)
What enzyme is needed to convert ALA and LA to other forms?
Delta-6-desaturase
Why is the high prevalence of Omega 6 in the Western diet problematic for Omega 3 levels?
They both compete for the use of the Delta-6-desaturase enzyme.
What is the
a. typical
b. Ideas
Omega 6 to 3 ratio?
Typical 1:16
Ideal 1:1-1:3
What population group is able to convert ALA to DHA and EPA more efficiently. Why might this be?
Women of reporductive age.
Because of higher oestrogen levels.
Name 5 functions of Essential Fatty Acids
- Components of cell membranes and help to maintain membrane fluidity
- They act with cell membrane proteins to aid the transport of substances in and out of the cell.
- They are key components of organelle membranes (eg. the mitochondria)
- Neceassy for cell to cell communication
- Essential for foetal and child brain development
- Pre-cursors of eicosanoids (Local hormones)
Name a symptom of EFA deficiency related to the skin
Dry flaky lips
Hyperkeratosis pilaris
Delayed wound healing
Dry brittle nails
Name a symptom of EFA deficiency related to the endocrine system
PMS-cramps, sore breasts
Hyperinsulinaemia
Name a symptom of EFA deficiency related to the reproductive system
Infertility, frequent miscarriages
Name a symptom of EFA deficiency related to the circulatory system
Frequent nosebleeds
bleeding gums
Easy bruising
Name a symptom of EFA deficiency related to the musculoskeletal system
Chronic joint pain/arthritis
delayed recovery from injuries
Name a symptom of EFA deficiency related to the immune system
Frequent infections
Name a symptom of EFA deficiency related to the Neurological system
Dementia
Parkinson’s disease
Irritability/ nervousness
Tingling arms and legs
CFS/ME
Name 3 theraputic uses of ALA in relation to CV disease
- Decreased the risk of myocardial infarctons, atherosclerosis and strokes
- Reduces C-reactive protein
- Help heart arrhythmias, ALA in cell membranes f cardiomyocytes modifies ionic channel currents and therefore stabalises electrical activity
- Lowers LDL cholesterol
- Anti-hypertensive (lowers ACE activity)
How does ALA help prevent strokes?
Promotes vasodilation in the brain and increases BDNF
What is the role of BDNF in the brain?
Critial role in neuronal maintenance, learning and memory
mood boosting effects
What are EPA and DHA formed from?
ALA
What are the theraputic benefits of EPA and DHA for CV disease?
-Can reduce blood triglyceride levels
-Reduces blood pressure
-Prevents atherosclerosis
By what mechanism does EPA and DHA reduce inflammation?
Inhibit NFkB, TNF-a and Interlukin-6
Effects the cell membranes
Which co factors aid in the convertion of ALA to DHA and EPA?
Zinc, magnesium and B6
What co-factors are needed to convert LA to GLA
B3, B6,Vit C magnesium and zinc,.
Name 3 theraputic uses of GLA
- Rheumatoid arthritis
- ADHD
- Eczema
Name 3 theraputic uses of Evening Primrose Oil
- PMS
- Breast pain (cyclical mastagia)
Female Fertility (optimises cervical mucous)
What is an Eicosanoid?
Manufactured when omega 3 and 6 oxidise, they are hormone-like signaling molecules?
Name 5 Eicosanoids
1 Prostaglandins
2. Leukotrriens
3. Thromboxanes
4. Resolvins
5. Protectins
Which EFAs are Eicsanoids made from?
AA- Arachandonic Acid
EPA Eicoapentaeoic Acid
DGLA-dihmo-y-linlenic Acid
What are the functions of Series 1 Prostaglandins?
What are they made from?
Are they inflammatory or anti-inflammatory?
Functions-
Keep blood platelets from sticking together
Remove excess sodium and water from the body
Relax blood vessels, promoting circulation
Made from-DGLA
Anti-inflammatory
What are the functions of Series 2 Prostaglandins?
What are they made from?
Are they inflammatory or anti-inflammatory?
Functions-
Promote platelet aggression
Promote sodium and water retention
Oppose functions of series 1 prostaglandins
What are the functions of Series 3 Prostaglandins?
What are they made from?
Are they inflammatory or anti-inflammatory?
Functions-
Weak platelet aggression properties
Prevent the release of AA from cell membranes
Made from EPA
Anti-inflammatory.
What is the most important limiting factor in inhibiting the inflammation induced by series 2 prostaglandin?
EPA
What is the consequence of too much omega 3 versus omega 6?
A depressed immune system
Poor wound healing
What percentage of ALA is converted to EPA?
1%-20%
What factors can effect convertion of ALA and LA to other Omega 3 and 6 enzymes?
Genetics
Sex and age (women of reproductive age 2.5 better than men (ALA-DHA)
Competition for the enymes (balance of Omgea 3 and 6)
The right nutrients
What might inhibit EFA metabolism?
Magnesium, B6 and zinc deficiency
Insulin resistance
Viruses
Refined sugars
Alcohol
Stress hormones
High intake of EPA/DHA
Excess trans fats and cholesterol
Which substances in the body are cholesterol needed to produce?
- Vitamin D and calcium metabolism
- Cortisol (amd related hormones)
- Alsosterone (for mineral and fluid balance)
- Sex hormones
- Bile salts and acids
- Lipopotiens
What diet and lifestyle factors might affect cholesterol levels?
- A diet rich in triglycerides stimulates cholesterol synthesis in the liver and small intestine
- Fibre improves the excretion of excess cholesterol
- Health gut microbes metabolism cholesterol leading to less reabsorbtion
- Optimal bile production (excess cholesterol is excreted in bile)
What other substances are carried in lipiproteins along with cholesterol?
CoQ10, beta-carotene and Vitamin E
Name the 3 main lipoproteins and state their function.
LDL (low density) takes cholesterol from the liver to cells
VLDL (very low density) takes triglycerides to cells
HDL (high density) collect cholesterol from cells and transports them back to the liver.
What might trigger high cholesterol?
Increased demand for-
cholesterol’s anti-inflammatory function
cholesterol to repair cell membranes
cholesterol to make hormones
What might be better measures of potential heart disease risk than cholesterol?
LDL particle size-
small and dense=increased risk
larger and fluffy may be protective
HDL particle size- Larger particles more effective and have anti-inflammatory and anti thrombotic effects. Promotes nitric oxide production in endothelial cells
Liprotein (a)-blood clotting agent. It is a key genetic factor in coronary artery disease.
LpPLA2- Enzyme that plays a role in endothelial inflammation and therefore atherosclerosis
Fibrinogen- raised levels rise for clot formation
C-reactive protein- inflammatory maker associated with heart disease
Lipid peroxides- High levels reflect oxidative damage to membranes
What is the predominate phospholipid in the body?
Phosphatidylcholine
Where is Lecithin synthesised and what is it’s role?
In the liver
Plays role in fat digestion
Increases the solubility of cholesterol and helps improve cognitive function
Name 3 key phospholipids
- Inositol
- Phosphatidylserine
- Phosphatidylcholine
What is the main therapeutic use for inositol?
Improves insulin sensitivity
What is the main therapeutic use for phosphotidal serine?
Improves neural membrane functioning and cognitive function.
It can be used for depression, insomnia and stress.
Phosphatidylcholine
Neuro and hepatoprotective. It supplies choline for the synthesis of the neurotransmitter acetylcholine.
It is important for cognition, memory, immunity and hormone function.
