2. Chain reaction of lipid peroxidation plays a major role in aging and disease

Every cell in our body, and multiple compartments inside of those cells have elaborate barrier structures, called lipid membranes, built of such oxidisable lipid molecules, referred to as omega-3 and omega-6 polyunsaturated fatty acids (PUFA). And most cells in our body handle oxygen (respiration). So, what happened to that bottle of oil, and to the painting, also happens to us all the time: Lipid Peroxidation.

Oxygen: the universal oxidizer

Of the 100 billion people who ever lived on this planet, only the ones killed in battle or accident did not see oxygen play a prominent role in their demise. Oxygen can oxidise whole planets (just look at Mars). What chance do tiny cells, choke-full of “flammable” biomolecules, have to resist it?

They try their best: there is an arsenal of antioxidants, multiple detoxifying enzymes, and garbage removal systems, and a lot of energy available to keep things in the intact form. These tools are somewhat effective in protecting various types of biomolecules.

The domino effect in lipid membranes

But there is an insidious side to lipids. Tightly packed in membranes like dominoes, multiple lipid molecules also fall like dominoes, when hit with a single activated oxygen molecule. This represents the only non-enzymatic chain reaction in life.

An initial hit generates multiple damage, which makes this similar to a slow explosion.