Lipids Flashcards
What are fat cells called?
Adipocytes
What is BAT & WAT?
Brown and white adipose tissue
What did Ancel Keys declare in the 1950’s?
High saturated fat would increase serum cholesterol.
What is WAT?
A complex metabolically- active endocrine tissue.
Name 4 forms of lipids in the body?
Triglycerides
Phospholipids
Cholesterol
fat soluble vitamins
What are 4 functions of lipids?
Energy production (ATP)
Storage of energy reserves
Cell membrane structure
Steroid hormones
What are short & medium chain fatty acids used for in the body?
Used in the liver to create energy or ketones.
What are long chain fatty acids used to build?
Cell membranes.
Name 3 SCFA?
Acetate
Propionate
Butyrate
Why is butyrate important?
It supports the intestinal tight junctions.
What is the process of hydrogenation?
Unsaturated fats become saturated with the addition of hydrogen e.g. oils made into solid spreads.
Explain saturated fats and give example?
All carbons are completely saturated with hydrogen bonds, solid at room temperature
E.g. margarine
Explain unsaturated fatty acids and give 1 example.
The contain 1 or more double bonds and are liquid at room temperature
E.g Olive oil
Explain monounsaturated fatty acids and give 1 example.
The have 1 double bond in the chain
E.g sunflowers oil
Explain polyunsaturated fatty acids and give 1 example.
The have several double bonds
E.g vegetable oil
How are trans fats produced?
By hydrogenation and high temperatures.
Where are trans fats found?
In margarine, processed foods and refined vegetable oils.
What are the negative effects of trans fats?
The stiffen cell membranes which makes them prone to oxidation and impedes normal cell function.
The alter blood triglyceride and cholesterol profiles increasing the risk of cardio vascular disease, insulin resistance and cancer.
What are cis fats?
They are natural fats with H atoms on the same side
What are triglycerides?
Triglycerides are the major form of dietary fat, they circulate in the blood when released for energy.
What are triglycerides made up of?
1 unit of glycerol and 3 fatty acids
What are high blood triglyceride levels related to?
Atherosclerosis
What is the process of converting dietary energy to triglycerides?
Lipogenesis
Where does lipogenesis take place?
In adipose tissue and the liver
Why does lipogenesis take place?
When there is an excess of carbohydrates
Acetyl-CoA is converted to triglycerides for storage in fat
What is lipolysis?
Fatty acids from triglycerides are mobilised when dietary energy is limited.
What stimulates lipolysis?
Adrenalin, noradrenalin
Adrenocorticotrophic hormone (ACTH)
Glucagon and growth hormone
Thyroid stimulating hormone (TSH) and thyroxine
How does carnitine assist energy production?
Carnitine facilitates the transport of fatty acids across the mitochondrial membrane.
What is ketosis?
Ketosis is the process by which fat becomes the primary fuel for energy production
Ketones are made when glucose is in short supply
When does ketosis take place?
When carbohydrates are restricted to 40g daily
What are the health benefits of ketosis?
Weight loss
Management of epilepsy
Parkinson’s
Alzheimer’s Disease
Which 2 enzymes assist lipid digestion?
Gastric lipase- stomach
Pancreatic lipase- duodenum
What is the purpose of bile?
It emulsifies the fat.
The remaining 2 fatty acids and monoglyceride are packaged into chylomicrons and transported in the lymph to the blood stream.
Identify 4 ways to optimise lipid digestion.
Increase bile production by optimising stomach acid with zinc and B6 rich foods.
Add choleretics like dandelion, artichoke and turmeric to increase bile flow.
Ensure good hydration to support bile flow.
Increase glycine and taurine with legumes, sea veg, spinach and eggs.
List 3 foods, rich in Vit E to support fat-soluble antioxidants.
Sunflower seeds
Almonds
Wheatgerm
List 4 benefits of a diet high in healthy fats.
Greater satiety value
Source of Essential fatty acids
Source of choline
Source of fat soluble vitamins
List 4 food sources of healthy dietary fats.
Avocado
Chia seeds
Oily fish
Walnuts
What are MCT’s and what oil might you find them in?
Medium chain triglycerides
In coconut oil
Why might you cook with coconut oil and ghee?
Due to their high smoke point and tolerance of heat.
Why would you choose to consume polyunsaturated oils in their raw, cold pressed form?
Because they oxidise when heated producing free radicals.
They should be stored in dark coloured bottles in cool areas as they can become rancid.
What are the dangers of rancid oil?
Rancid oil becomes oxidised and produces malondialdehyde which is a potential mutagen.
What makes fats more prone to oxidation?
If they are high in polyunsaturated fat
If they are exposed to prolonged heat
If they are naturally low in antioxidants
If they are refined or heavily processed
Which fats are considered more stable?
Saturated fatty acids e.g. coconut oil due to their lack of double bonds.
What are the two essential fatty acids?
Linoleic acid (omega 6 fatty acid) Alpha-linolenic acid (omega 3 fatty acid)
What does the enzyme Delta-6 desaturase do?
It creates the chemical reaction to create other fatty acids from LA and ALA
Does the typical western diet tend to be more abundant in Omega 3 or 6?
Omega 6.
We tend to eat more plant oils, grain fed meat and dairy than flax seeds, pumpkin seeds and oily fish.
What are conditionally essential nutrients?
The are nutrients which they body can make but is unable to convert so they become essential.
They are EPA & DHA and can be consumed in oily fish.