Oxidative stress might not be something you can see or feel — but over time, it can quietly erode your health at the cellular level. Caused by an imbalance between harmful free radicals and the antioxidants that neutralise them, oxidative stress damages DNA, proteins, and cell membranes. This ongoing cellular strain plays a key role in the ageing process and contributes to a wide range of chronic conditions, from heart disease and diabetes to neurodegenerative disorders and inflammation. Understanding how oxidative stress affects the body is essential if you want to support long-term health, energy, and resilience.
Oxidative Damage At the Cellular Level
Oxidative damage begins at the cellular level but has widespread effects that can contribute to ageing, inflammation, and the development of many chronic diseases. Here’s a layered explanation, starting from what's happening inside your cells and expanding to broader health consequences.
Oxidative damage occurs when there’s an imbalance between free radicals (also called reactive oxygen species, or ROS) and the body’s ability to neutralise them with antioxidants.
Free radicals are highly reactive molecules that contain unpaired electrons. They are naturally produced in cells during normal metabolic processes — especially in the mitochondria, where your cells generate energy (ATP). External factors like pollution, cigarette smoke, UV radiation, and poor diet can also increase free radical production.
When ROS are not neutralised effectively, they can damage key cellular components:
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Lipids (Fats)
Free radicals can attack the fatty acids in cell membranes, especially polyunsaturated fatty acids. This process is called lipid peroxidation, which weakens the membrane’s structure and fluidity, making the cell more permeable and vulnerable. It also produces toxic by-products like malondialdehyde (MDA) and 4-hydroxynonenal (4-HNE) that further damage cells and tissues.
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Proteins
ROS can oxidise amino acids in proteins, altering their structure and function. This can deactivate enzymes, damage receptors, and disrupt structural proteins like collagen and elastin. In some cases, oxidised proteins form aggregates that the cell struggles to remove.
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DNA
Oxidative stress can cause mutations by damaging the DNA in the cell nucleus and mitochondria. This includes strand breaks, base modifications (e.g. 8-oxo-guanine), and cross-linking of DNA with proteins. If the damage overwhelms repair mechanisms, it can lead to errors in cell replication or trigger cell death (apoptosis).
Oxidative Damage At the Tissue and Organ Level: How This Leads to Symptoms or Disease
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Inflammation
Oxidative stress and inflammation go hand in hand. Damaged cells release signals that attract immune cells, which then produce more ROS in the process of trying to neutralise threats. This creates a feedback loop that can drive chronic low-grade inflammation, damaging tissues over time.
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Cellular Ageing (Senescence)
Accumulated oxidative damage is a key driver of cellular senescence — when cells stop dividing and enter a dysfunctional but still active state. Senescent cells secrete pro-inflammatory molecules and enzymes that degrade surrounding tissue, contributing to tissue ageing and loss of function.
Oxidative Damage At the Whole-Body Level: Diseases and Conditions Linked to Oxidative Damage
Oxidative stress is not a disease itself, but it plays a central role in the development or progression of many chronic conditions.
🧠 Neurodegenerative Diseases
Alzheimer’s disease: Oxidative stress contributes to the formation of beta-amyloid plaques and tau tangles. Parkinson’s disease: Damaged neurons in the substantia nigra are particularly vulnerable to mitochondrial oxidative damage.
❤️ Cardiovascular Disease
Oxidative damage to LDL cholesterol makes it more likely to form plaques in arteries (atherosclerosis). Damaged endothelial cells (lining blood vessels) lose their ability to regulate blood pressure and prevent clotting.
🦠 Cancer
DNA mutations caused by oxidative stress can activate oncogenes or disable tumour suppressor genes, initiating cancer. Chronic inflammation fuels further mutation and tumour progression.
🩸 Diabetes
High blood sugar increases ROS production. Oxidative damage impairs insulin signalling and damages blood vessels, accelerating complications like neuropathy, retinopathy, and kidney disease.
🫁 Lung Disease
In conditions like COPD and asthma, oxidative stress damages airway cells and worsens inflammation triggered by pollutants or allergens.
🦴 Arthritis and Joint Degeneration
ROS degrade cartilage by breaking down collagen and activating enzymes that damage connective tissue. In autoimmune arthritis, oxidative stress fuels the inflammatory response.
🧬 General Ageing
The free radical theory of ageing suggests that cumulative oxidative damage to DNA, proteins, and lipids contributes to the gradual decline in physiological function over time. Mitochondrial dysfunction, driven by ROS, is considered a hallmark of ageing.
The 6 Proven Antioxidants That Can Help
When it comes to protecting your cells from oxidative stress, six nutrients stand out with scientifically recognised roles: Copper, Riboflavin (vitamin B2), Selenium, Vitamin C, Vitamin E, and Zinc. These essential micronutrients don’t just have theoretical antioxidant potential — they’re officially approved by health authorities like the European Food Safety Authority (EFSA) for their contribution to the protection of cells from oxidative damage.
Each one supports the body’s defence systems in a unique way: copper and zinc are crucial for antioxidant enzymes like superoxide dismutase; riboflavin helps regenerate glutathione, a major intracellular antioxidant; selenium enables the activity of glutathione peroxidase; vitamin C scavenges free radicals in watery environments and regenerates vitamin E; and vitamin E protects cell membranes from lipid peroxidation. Together, they form a robust, multi-layered defence network to keep oxidative stress in check.
Conclusion
Oxidative stress is more than just a biochemical buzzword. It’s a real and measurable process that affects nearly every cell in the body. By damaging core cellular structures and fuelling chronic inflammation, it accelerates ageing and contributes to the development of major health issues.
The good news is that the body has powerful built-in defences, and with the right support - through nutrition, lifestyle, and scientifically backed antioxidants - it’s possible to reduce oxidative damage and promote cellular health from the inside out.
