Lipids are a group of compounds which are characterised by their hydrophobic nature which makes them soluble in organic-type solvents e.g. alcohol, but generally immiscible in water. They are usually long-chain fatty acids and their esters.
The group includes naturally-occurring:
- ketone bodies
Lipid ingestion is typically around 60-100 g/day in butter, margarine, milk, meat and eggs. Triglycerides constitute the majority of this input but phospholipids, cholesterol and cholesterol esters are also absorbed.
They are vital for cell function:
- energy source
- precursors of hormones
- structural elements e.g. cell membrane
- necessary for the absorption of dietary elements e.g. vitamins A, D, E and K
Lipid production, degradation or storage may all be affected by disease; the majority are inherited.