Lipids are among the fundamental structural component of living cells. They separate from water with a tendency to form bilayers, constituting the biological membranes that surround all living cells and also provide partitions between the organelles within.
Cell membranes are essentially bilayers of fatty acids esterified onto glycerol headgroups at the surfaces. Oleic acid (illustrated oncover) is 18 carbons long, typ and is #monounsaterated, having a single C=C double bond. Other common C-18 acids are stearic (no C=C), linoleic (2 × C=C)and linolenic (3 × C=C) acids. They differ in fluidity, with the mix of these and other components giving optimal membrane fluidity for ambient temperatures.
Now in previous weekly leaves I have devotes significant attention to the importance of antioxidants. Membrane lipids are targets for oxidation damage that can compromise membrane integrity and function. Polyunsaturated acids, linoleic and linolenic, are particularly prone. Saturated and monounsaturated acids (e.g. stearic and oleic acids) are much less susceptible. Fatty acid oxidation can also occur in the frying pan, and harmful oxidation products can accumulate. This is particularly true of polyunsaturated vegetable oils.
The human body can make most of its own fatty acids, though some are essential. Dietary fatsseem to affect the profiles of blood lipids and cholesterol. Polyunsatured andmonounsaturated oils are considered healthy (in moderation due to highcalorific content). In contrast, a diet rich in unsaturated fats raises healthconcerns. Also scorned are the trans-fats that are prominent in industrialhydrogenated oils, with the configuration of the remaining C=C bonds twisted from“cis” to “trans” – see molecular sketch in cover.
Olive oil is mostly monounsaturated, containing 50-80% oleic acid, mostly esterified as glycerides. A signature ingredient of the Mediterranean diet, it is anever-popular choice for both cooking and health.
As typical in these posts, I bring up cosmetics. Olive oil is very widely used in skincareproducts, natural and easily absorbed. Though itself resistant to oxidation, itis an excellent carrier for lipophilic antioxidants, including many of thephytochemicals present in the extracts we make at Green Mountain Biotech
Further reading
Dietary Fat, Victoria State Health Dept. https://www.betterhealth.vic.gov.au/health/healthyliving/fats-and-oils
