Some Information on Lipids
What are lipids? Let's start by looking at some lipid facts and lipid definitions. This will include some information on lipid structure and lipid function. Then you can learn about lipid oxidation and why it is relevant to your well being.
Lipids are a group of molecules all sharing one property: they are hydrophobic. Lipids include:
- fats
- oils
- waxes
- phospholipids
- steroids
- other related compounds
Fats, like oils, contain:
- glycerol, a type of alcohol with a hydroxyl group on each of its 3 carbon atoms
- 3 fatty acids, joined by dehydration synthesis
Because fats and oils have 3 fatty acids, they are known as triglycerides. Fats differ from oils in that fats are solid at room temperature, while oils are liquid at room temperature.
The terms saturated, mono-unsaturated and poly-unsaturated refer to the number of hydrogen atoms attached to the hydrocarbon tails of the fatty acids, compared to the number of double bonds between the carbon atoms in the tail.
Saturated Fatty Acids
Saturated fatty acids are so called because each carbon atom in the chain holds all the maximum number of hydrogen atoms it can. The hydrocarbon chains are therefore fairly straight and can pack close together. As a result, these lipids tend to be solids at room temperature and are often found in the organs of the body, acting as cushions. The only bonds present between carbon atoms are single bonds.
Unsaturated Fatty Acids
Unsaturated fatty acids don't have all the hydrogen atoms they can possibly hold. This is because there is occasionally a carbon-carbon double bond. This causes bends in the molecule so they can't pack as closely to each other. As a result, they tend to be liquids at room temperature. They are generally found in skin deposits.
Most people have heard that unsaturated fatty acids are 'healthier' than saturated fatty acids.
Cis- and Trans- Unsaturated Fatty Acids
There are two ways that the pieces of the hydrocarbon tail can be arranged around a carbon=carbon double bond in unsaturated fatty acids:
- cis bonds - the two pieces of the carbon chain on either side are either side of the double bond are both "up" or both "down", so that they're on the same side of the molecule
- trans bonds - the two pieces of the carbon chain are on opposite sides of the double bond, so one is "up" and one is "down", on different sides from each other
Naturally occurring unsaturated vegetable oils have almost all cis bonds. Frying converts some of these cis bonds to trans bonds. If the oil is constantly reused, many are converted to trans bonds. The concern here is because fatty acids with trans bonds are carcinogenic.
Phospholipids
Phospholipids are made from glycerol, 2 fatty acids and a phosphate group (with another molecule attached to its other end). The hydrocarbon tails of the fatty acids are still hydrophobic, but the phosphate group is hydrophilic. This means phospholipids are soluble in both water AND oil. Because of this property, phospholipids can act as emulsifying agents, enabling water and oil to mix.
One well-known phospholipid is lecithin, which is found in egg yolk and soybeans. Egg yolk is mostly water but has a lot of lipids (especially cholesterol) which are needed by the developing chick. So, lecithin is used to emulsify the lipids and hold them in water as an emulsion. Lecithin is the basis of mayonnaise!
Our cell membranes are mostly made of phospholipids arranged in a double layer, with the tails from both layers on the "inside". They face each other and their tails face out into the watery environment on either side.
Lipoproteins
Lipoproteins are clusters of proteins and lipids all mixed together. Lipoproteins act as carriers of lipids, around our blood stream.
There are low density lipoproteins (LDL) and high density lipoproteins (HDL).
LDL has the bad reputation because its associated with depositing cholesterol on the walls of our arteries. HDL has the good reputation because its associated with carrying cholesterol out of our blood system.
Arachidonic Acid
Why is Arachdonic acid so important? Well it's important because it's the fatty acid precursor for prostaglandin and leukotriene biosynthesis. Prostaglandin and leukotriene are eicosanoids, compounds that regulate the process of inflammation.
Dietary Lipids
Food Lipids are primarily triacylglycerides, phospholipids and sterols found naturally in most biological materials consumed as food and added as functional ingredients (see functional foods) in many processed foods.
As a class, lipids contribute many desirable qualities to foods, including attributes of texture, structure, flavour and colour.
Lipid Oxidation
Lipids are one of the most chemically unstable food components and will readily undergo free-radical chain reactions that not only deteriorate the lipids but also:
- produce oxidative fragments, some of which lead to rancidity
- degrade vitamins A, D and E
- degrade essential fatty acids)
- possibly form compounds
In a nutshell, this explains why Lyprinol's patented stabilisation process is so vital. The benefits seen by coastal Maori populations in New Zealand are due to the fact that they consume Green Lipped Mussel absolutely fresh.
The longer Green Lipped Mussels are out of the water, the more the important lipids within oxidise and degrade. Similarly, there are many Green Lipped Mussel extract products on the market. But by what process have the essential lipids been extracted? Chances are, without stabilising the important lipids, all beneficial effects will have been eradicated. Why? Because the lipids will have oxidised and degraded.
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