Lipids Flashcards

Flashcards on Lipids from Naturopathic Nutrition Year 1

What is the body composition of a lean, healthy man?

Roughly 16% fat

Besides energy, what are fats essential for?

Part of every cell and vital for physiological and biological processes like hormone production

How have farming and food processing affected the amount and types of fat in human diets?

Increased the amount and types of fat, most notably trans fats and vegetable oils

What did Ancel Keys declare in the 1950s regarding saturated fat?

Eating a high saturated fat diet would increase serum cholesterol and consequently lead to heart disease

What type of diet did the American Heart Association recommend?

A diet low in total fat, especially saturated fat and cholesterol, and high in carbohydrates from grains, substituting animal fats for seed oils

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

The secretion of hormones, growth factors, enzymes, and cytokines; the protection of organs; a form of energy storage; and to provide insulation against temperature extremes

What forms do lipids exist in the body?

Individual fatty acids, triglycerides, phospholipids, cholesterol and steroid-based compounds, sphingolipids, glycolipids, cerebrosides, fat-soluble vitamins

What are the functions of lipids?

Energy (ATP) production, storage of energy reserves, cell membrane structure, thermal insulation and protection around organs

What steroid hormones are derived from cholesterol?

Progestogens, androgens, glucocorticoids, mineralocorticoids, and oestrogens

What are eicosanoids?

Signalling molecules involved in processes such as blood coagulation and inflammation

What fatty acids is the brain rich in?

Arachidonic acid (AA) and docosahexaenoic acid (DHA)

What types of fatty acids travel directly to the liver?

Short-chain (up to 5 Carbons) and medium-chain fatty acids (6-12 Carbons)

What is butyrate important for?

Colon health, primary energy source for colonocytes, supports intestinal tight junctions, anti-inflammatory effect

What happens when unsaturated fats are saturated by hydrogenation?

Turns the natural fatty acid into unnatural forms (i.e. trans fats) which are damaging to health

Describe saturated fatty acids

Contain no C-C double bonds and are solid at room temperature

Describe unsaturated fatty acids

Contain one or more double bonds between carbons and are liquid at room temperature

How do trans fats affect cell membranes and health?

Stiffen cell membranes, alter blood triglyceride and cholesterol profiles, and are linked to increased risk of cardiovascular disease, insulin resistance and cancer

Describe the cis configuration of fatty acids

The H atoms are on the same side of the double bond, found in majority of natural fats

Describe trans configuration of fatty acids

The H atoms are on separate sides of the double bond, unsaturated but behave like saturated fats

What are triglycerides (TGs)?

The major form of dietary fat and the form in which fat is stored in the body

Excess dietary energy is converted to triglycerides via what process?

Lipogenesis

What stimulates lipolysis?

Adrenaline, noradrenaline, adrenocorticotropic hormone (ACTH), glucagon and growth hormone, thyroid-stimulating hormone (TSH) and thyroxine

What role does carnitine play in fatty acid breakdown?

Facilitates the transport of fatty acids across the mitochondrial membrane

When carbohydrate levels are low, what becomes the primary fuel for energy production?

Ketones

The digestion of triglycerides is aided by what emulsifying action?

Bile

What are the UK Government’s Scientific Advisory Committee on Nutrition (SACN) Review (2019) recommendations regarding lipids?

SACN recommended that saturated fats should not exceed >10% of energy, low-fat dairy options, choose unsaturated oils and spreads, and eat in small amounts

What did the PURE study in 2017 find regarding high carbohydrate and high fat diets?

Found that high carbohydrate diets led to the highest mortality rates and high fat diets led to reduced mortality

What are examples of healthy dietary fat food sources?

Fruit, seeds, seed oils, nuts, coconut oil, grass-fed meat, oily fish

What did a recent review by the Journal of the American College of Cardiology find regarding saturated fats?

There was inadequate scientific evidence to keep advising against foods high in saturated fats, including coconut, unprocessed meat, eggs and dark chocolate

Why is coconut oil considered a healthy saturated fat?

Coconut oil contains medium-chain triglycerides (MCTs), which the body uses as a source of fuel or turns them into ketones, increases the number of calories burned compared to long-chain fatty acids, contains 50% lauric acid with antibacterial, antiviral, and antifungal properties

What types of fats are best for cooking?

Coconut oil, butter, ghee, olive oil, avocado oil, macadamia

What oils should only be used in their raw, cold-pressed form?

Vegetable oils like flaxseed oil

How do fatty acids within triglycerides go rancid?

Release of fatty acids from glycerol and oxidation of double bonds

What are the two essential fatty acids required in the diet?

Linoleic acid (an omega-6 fatty acid) and alpha-linolenic acid (an omega-3 fatty acid)

Humans lost the ability to introduce double bonds into fatty acids between the carbon atoms 6‒7 and 3‒4. What impact does this have?

Making LA and ALA essential in the diet

Name some ALA sources

Flaxseeds, pumpkin seeds

Name some EPA / DHA sources

Oily fish

What are the function of EFAs

Maintaining membrane fluidity, affecting transport of substances into and out of the cell, key components of organelle membranes, necessary for cell-to-cell communication, essential for foetal and child brain development, precursors of eicosanoids

What are some food sources of ALA?

Flaxseeds, hempseeds, soybeans, walnuts and dark green leaves

List some therapeutic uses of ALA

Decreases the risk of myocardial infarctions, atherosclerosis development and strokes, reduces C-reactive protein levels, anti-arrhythmic and anti-hypertensive effects, lowers LDL cholesterol

What are some food sources of EPA and DHA?

Oily fish and human breast milk

List some therapeutic uses for EPA and DHA

Can significantly reduce blood triglyceride levels, can lower blood pressure, preventative against the formation of atherosclerosis, lower blood fibrinogen levels

How can a vegetarian or vegan diet meet EPA / DHA needs?

Include good sources of alpha-linolenic acid, support EFA conversion, moderate the use of oils rich in omega-6 fatty acids, and consider algal EPA / DHA supplements

What are some food sources for Linoleic Acid (LA)?

Vegetable oils safflower, sunflower, soybean, and corn oils and nuts, seeds and some vegetables

What are some food sources for Gamma-Linolenic Acid (GLA)?

Evening primrose oil, blackcurrant seed oil, hemp and borage oils

What are some therapeutic uses for GLA?

Reduces joint pain, swelling and morning stiffness in RA, immune-regulatory and anti-inflammatory effects and reduction in NF-kB activity, improves attention and impulsivity, reduced inflammation and improves eczema skin symptoms

What are some uses of Evening Primrose Oil in reference to female fertility?

Decreases and optimises cervical mucus, to sustain sperm during conception

What are some sources of Arachidonic Acid (AA)?

Animal products such as meat, eggs and dairy, especially when those animals are intensively raised on grain

What are eicosanoids involved in?

Inflammation, blood vessel permeability and constriction, blood coagulation, immune cell behaviour, lipid accumulation and central nervous system signalling

How can other omega-6 and omega-3 fatty acids be synthesised from ALA and LA respectively?

Desaturation (addition of a double bond) or elongation (addition of two carbon atoms)

Why is cholesterol considered an important compound?

Cholesterol is essential for the synthesis or action of vitamin D, cortisol, aldosterone, sex hormones, bile salts and acids, membrane integrity, lipoproteins

What is the role of LDL in transporting cholesterol?

Takes cholesterol from the liver to cells

What is the role of VLDL in transporting cholesterol?

Takes triglycerides to cells

What is the role of HDL in transporting cholesterol?

Collects cholesterol from cells to transport back to the liver

What is required for atherosclerosis to occur?

Requires LDL cholesterol to deposit in the arterial wall and become oxidised and it is an inflammatory disease. In the absence of inflammation or injury to the endothelium, cholesterol does not deposit

What are phospholipids?

The structural basis of all cell membranes

What are therapeutic uses of key phospholipids?

Improve insulin sensitivity, improve neuronal membrane functioning and cognitive function, neuro- and hepato-protective, and supplies choline for the synthesis of the neurotransmitter acetylcholine