When the Fats in Our Cells Oxidise

When the Fats in Our Cells Oxidise

Lipid peroxidation and why health starts at the cell membrane

Every cell in the human body is surrounded by a membrane. It is not just a wrapper but a dynamic boundary through which the cell takes in nutrients, recognises hormones, exchanges signals, communicates with the immune system and gets rid of waste products.

To perform these functions, the membrane has to be both stable and flexible. This flexibility is largely provided by unsaturated fatty acids. But the very structure that makes them so valuable also makes them more vulnerable to oxidative damage.

When free radicals attack the fats in the membrane, a chain reaction called lipid peroxidation can begin. If the body's own defence systems do not stop it in time, it spreads to neighbouring fat molecules and forms reactive products that can damage proteins, DNA, receptors and mitochondria.

This is not a separate disease, but a mechanism that may play a part in ageing and in the development of a number of chronic conditions.

How the chain reaction begins

Saturated fats are relatively resistant to oxidation. Monounsaturated fats, such as the oleic acid in olive oil, are also fairly stable. Polyunsaturated fatty acids contain more double bonds and are more sensitive to attack by free radicals.

This is where an important biological paradox appears. The omega-3 fatty acids EPA and DHA are valuable for the brain, vision, the cardiovascular system and the control of inflammation, but they oxidise easily. That does not make them harmful. It shows that their benefit also depends on the quality of the source, proper storage and the available antioxidant resources.

Lipid peroxidation roughly takes place in three stages:

1. A free radical attacks a vulnerable fatty acid and turns it into a new unstable radical.
2. The damaged molecule attacks a neighbouring fat, and the reaction spreads like a row of falling dominoes.
3. The chain is broken by antioxidants and specialised enzymes before it affects a large part of the membrane.

One of the most important defences is the enzyme glutathione peroxidase 4, or GPx4. It uses glutathione and depends on adequate selenium to neutralise oxidised lipids right in the membrane. Vitamin E can also stop the reaction from spreading, and coenzyme Q10 helps protect mitochondrial membranes.

When damaged fats become even more dangerous

If oxidised lipids are not neutralised, they break down into secondary reactive substances. Among the most studied are 4-HNE, malondialdehyde and acrolein.

These molecules can bind to proteins and change their function, disrupt cell signalling and form compounds with DNA. This does not mean their presence automatically leads to a specific diagnosis. They are part of a dynamic process in which the amount produced, the rate of detoxification and the body's overall repair capacity all matter.

Isoprostanes are among the most reliable markers of free-radical oxidation of fatty acids. Oxidised LDL is another practically interesting marker, because oxidised LDL particles take part in inflammatory processes in the artery wall. However, this does not reduce the importance of LDL levels, ApoB, blood pressure, blood sugar control, smoking and the other cardiovascular risk factors.

The link with chronic disease

Lipid peroxidation is found in atherosclerosis, fatty liver disease, diabetes, neurodegenerative processes and some cancers. The key is not to confuse involvement with being the sole cause.

The brain is especially sensitive because it uses a lot of oxygen, contains a significant amount of DHA and, in certain areas, contains iron, which can speed up oxidative reactions. In the liver, accumulated fat provides the material for oxidation, while inflammation and metabolic overload make it easier. In diabetes, high and widely fluctuating blood sugar increases the formation of reactive oxygen species.

There is also a process called ferroptosis – a form of cell death linked to iron, the loss of protection from GPx4 and uncontrolled lipid peroxidation. It is an important area of research, but it is not yet a reason for anyone to start antioxidant or iron-lowering protocols on their own.

What increases the oxidative load

The problem is rarely one specific fat. More often, several factors combine:

• smoking and air pollution;
• chronic inflammation and infections;
• unstable blood sugar and insulin resistance;
• excessive alcohol;
• frequent consumption of fried and repeatedly heated fats;
• stale or improperly stored oils, nuts and fish products;
• excessive or poorly distributed iron;
• insufficient intake or absorption of protein, selenium and other cofactors;
• heavy exertion without enough energy, sleep and recovery.

Not all vegetable oils have the same composition, quality and use. The problem is not solved by mechanically eliminating them, nor by uncontrolled replacement with large amounts of butter, ghee or coconut fat. It is more sensible to limit ultra-processed and deep-fried foods, avoid overheating fats and choose the type of fat according to the temperature and purpose.

How we assess this process at Agaia

In our practice we do not look for “oxidative stress” as a stand-alone label. We look at the environment that creates it and the resources the body has available.

Testing may include a standard lipid profile, ApoB, glucose, insulin and HbA1c, liver markers, a full blood count, ferritin, transferrin saturation and markers of inflammation. When there is a specific need, F2-isoprostanes, oxidised LDL or other specialised markers may be discussed. MDA is widely used but is sensitive to the method and sample handling, so the result should not be interpreted in isolation.

Selenium and ferritin also require context. High ferritin may reflect iron overload, but it can also be raised in inflammation, liver problems or metabolic dysfunction. Low or high serum selenium should not be corrected towards a universal target without assessing diet and actual need.

To these data we add body composition, intra- and extracellular water, phase angle, muscle reserves, metabolic profile, digestion and recovery. The cell membrane is not protected by an antioxidant alone. It needs the right fatty acids, amino acids, minerals, energy and an environment in which the inflammatory load is under control.

Practical protection for cell membranes

The foundation is simpler than a long list of supplements:

• use fresh extra virgin olive oil for cold dishes and moderate cooking;
• limit fried and ultra-processed foods;
• do not reuse the same fat repeatedly;
• store sensitive oils, nuts and seeds away from light, air and heat;
• eat oily fish according to individual tolerance and goals;
• include colourful vegetables, berries, spices and wholesome food sources of antioxidants;
• get enough protein and amino acids for glutathione synthesis;
• manage blood sugar spikes, sleep, stress and recovery;
• do not take iron, selenium or high doses of antioxidants without a proven need.

Vitamin E, NAC, glycine, CoQ10, astaxanthin, alpha-lipoic acid, sulforaphane and other substances may be useful in certain situations. But “more antioxidants” does not automatically mean more protection. High doses can disrupt normal redox signalling, interact with medications and be unsuitable during certain therapies. In athletes, excessive suppression of reactive oxygen species may even blunt part of the adaptation to training.

We don't remove healthy fats – we build protection

The goal is not for the cell membrane to become as saturated and oxidation-proof as possible – it would lose some of its fluidity and function. We do not eliminate omega-3 and all omega-6 fats, because they are needed for structure, signalling and the inflammatory response.

The goal is balance: quality fats in the right amount, as few already-oxidised products as possible, stable blood sugar, sufficient tissue and antioxidant resources, and timely management of inflammation.

The cell membrane is where nutrition meets hormones, immunity and energy metabolism. When it is well built and protected, the cell communicates and adapts better. And when we measure the causes of its overload instead of simply adding yet another antioxidant, we are working on what really matters – the environment, the resources and the body's ability to recover.