Oxidative stress occurs when free radicals accumulate faster than the body's antioxidant systems can neutralize them. This imbalance has been linked to chronic inflammation, cellular damage, age-related decline, and a wide range of chronic diseases.
This article explains how these processes are connected and what the research shows.
What is Oxidative Stress?
Oxidative stress happens when there is an imbalance between free radicals and antioxidants in the body.
Free radicals are something you probably haven't thought much about since high school chemistry...
A free radical is a molecule that has an unpaired electron. Electrons HATE being unpaired, and these free radicals will "steal" electrons from other molecules, wreaking all kinds of havoc.
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Such species are mostly unstable and reactive, but they also can accept and donate electrons, therefore becoming oxidants and reductants.
They have a role in essential metabolic processes:
In low concentrations, they are involved in defending against microbial pathogens.
They are an important defense mechanisms for white blood cells, so while they can be harmful in some circumstances, they're also essential!
Our cells also use free radicals as important signalling molecules, but these typically exist in balance with naturally occurring antioxidants.
However, free radicals can also enter our body from the external environment. Smoking, pollution, ultraviolet light, and common (but toxic!) chemicals can all promote the accumulation of these free radicals- at greater levels than what our bodies are designed to handle.
So, while the production of free radicals is usually a natural process, external factors and genetics can cause an unnatural build-up of free radicals in your body.
External factors and genetics can cause a build-up of free radicals in the body. Smoking, pollution, ultraviolet light, and nasty chemicals can all promote their accumulation.
Antioxidants, on the other hand, are stable molecules that can donate one of their electrons to the free radical, making it less damaging.
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Antioxidants naturally occur in many vegetables and fruits – another great reason to add more fruits and vegetables into your diet!
What's the Connection Between Oxidative Stress and Inflammation, Cancer, and Aging?
So now you may be wondering:
How are these free radicals related to inflammation, or even cancer?
No worries:
Now we're going to discuss exactly how free radicals can harm our bodies.
Let’s dive deeper into how cellular oxidation, inflammation, and cancer are all connected:
When the immune system interacts with antigens (harmful molecules that trigger the immune system response), reactive species (free radicals) are generated in response.
This leads to the production of cytokines and chemokines, which are important signaling molecules that can communicate with immune cells.
These are also precursor molecules for the inflammation response, which is the organism’s reaction to pathogens and physical damage. Once it is activated, the immune system keeps producing signaling molecules that trigger further free radical production.
These free radical species that contain oxygen are the main influencers of the inflammatory response. Inflammation reactions continue until the damage is repaired and pathogens are no longer present, at which point free radical production is turned off.
However, if the inflammation becomes chronic, due to the long-term exposure to damaging environmental factors or an illness, free radicals are produced at a constant and unsustainable rate, exhausting your body’s antioxidant defense system.
This leads to DNA damage, mutations in dividing cells, antioxidant depletion and an increase in growth factor production.
Repetitive mutation can lead to mutations in oncogenes (genes with the potential to cause cancer) and tumor growth, while growth factors can affect the growth pathways in cancer cells- leading to the uncontrolled growth of cells.
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Chronic inflammation is closely linked to free radical production and has been extensively studied for its role in tumor formation and cancer development.
Chronic inflammation is closely related to free radical production and is considered as a precursor for cancer development.
A major free radical-producing organelle in the cell is the mitochondria (cell’s power generator) – yet, in an ironic twist of biology, mitochondria are also the organelle most susceptible to oxidative damage.
Free radicals in a cell can also target and damage the cell membrane, proteins, and DNA.
Mitochondrial DNA is ten times more susceptible to such damage than nuclear DNA, and it has recently been discovered that mitochondria might be involved in carcinogenesis (the start of cancer formation), as it has been observed that mutations in some regions of mitochondrial DNA have been linked to various cancers.
If they attack nuclear DNA, free radicals can also activate proto-oncogenes (potential oncogenes) and inactivate tumor suppressor genes.
They are also known to be a contributing factor to tumor vascularization. (Growing a blood supply is a crucial (and bad) step in tumor growth.)
Ok...so what’s the good news?
Supporting the body's natural antioxidant defenses may help reduce oxidative stress and limit some of the cellular damage associated with chronic inflammation.
Molecular hydrogen has been studied for its potential relationship to Nrf2 pathway activation, one of the body's key cellular defense mechanisms against oxidative stress.
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Do Free Radicals Make Us Age Faster?
Two theories explain the aging process: damage-accumulating and genetic.
The damage-accumulating theory has several possible reasons; however, the free radical theory remains one of the most widely discussed explanations for biological aging.
The rationale is based on the fact that radicals produced during oxygen metabolism are accumulated over time.
Electrons that leak from the electron transport chain (how your cells make energy) interact with oxygen, producing radicals, which can further damage mitochondria, DNA, and lipids (fats).
Mitochondrial DNA damage can accumulate over time and has been proposed as one factor that may contribute to cellular aging.
To add credibility to the theory, the correlation between oxygen consumption and aging has been noticed in a variety of instances:
• Queen bees live 50 times longer than working bees that fly actively and consume more oxygen
• Larger animals that consume less oxygen per body unit live longer than smaller ones
• Pigeons live 10 times longer than rats due to the slower generation of reactive species by their mitochondria
• Some long-lived species appear to possess more robust antioxidant defense systems.
In humans, oxidative DNA damage can be measured by urinary tests and regulated with dietary and caloric adjustments.
This is one of the reasons that fasting may be associated with longevity. It has been observed in many animals that enzymes from younger animals are more active and stable than those found in their older counterparts.
The same pattern can be seen in mitochondria: they contain many enzymes involved in energy production, and it has been reported that the activity of those specific enzymes also decreases with age.
Such changes can be linked to prolonged oxidative stress, and additional studies in animals report a decrease in antioxidant activity with increased age.
These findings all help support the conclusion that protein damage by free radicals contributes to aging.
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The Bottom Line
I hope that you were able to learn some fun new facts, but if you’re totally overwhelmed by all the scientific jargon, here are the key take-home messages to keep in mind:
• Reactive species are molecules with far-reaching effects
• Their accumulation and imbalance with antioxidants can lead to oxidative stress
• Oxidative stress has been extensively studied in relation to inflammation, tumor formation, and cancer biology and is considered a potential contributing factor in the development of certain cancers.
• Reactive species may also have a significant role in aging.
To minimize the negative effects of oxidative stress, it’s always a good idea to:
Incorporate some healthy greens and antioxidant-rich foods into your diet!
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Minimize the exposure to harmful environmental factors like smoking, pollution, EMF exposure, etc.;
Molecular hydrogen has attracted significant scientific interest for its relationship to oxidative stress and the Nrf2 pathway, one of the body's most important cellular defense mechanisms.
Learn more about how molecular hydrogen works as a selective antioxidant.
Shop Molecular Hydrogen Tablets
Other useful resources:
Nrf2 and Molecular Hydrogen: A Simple Aid to a Complex Problem
References:
Khansari, N., Shakiba, Y. and Mahmoudi, M. (2009). Chronic Inflammation and Oxidative Stress as a Major Cause of Age-Related Diseases and Cancer. Recent Patents on Inflammation & Allergy Drug Discovery, 3(1), pp.73-80.
Reuter, S., Gupta, S., Chaturvedi, M. and Aggarwal, B. (2010). Oxidative stress, inflammation, and cancer: How are they linked?. Free Radical Biology and Medicine, 49(11), pp.1603-1616.
Lobo, V., Patil, A., Phatak, A. and Chandra, N. (2010). Free radicals, antioxidants, and functional foods: Impact on human health. Pharmacognosy Reviews, 4(8), p.118.
Aaronson, S. (1991). Growth factors and cancer. Science, 254(5035), pp.1146-1153.
Honma, T., Tsuduki, T., Sugawara, S., Kitano, Y., Ito, J., Kijima, R., Tsubata, M., Nakagawa, K. and Miyazawa, T. (2013). Aging decreases antioxidant effects and increases lipid peroxidation in the Apolipoprotein E deficient mouse. Journal of Clinical Biochemistry and Nutrition, 52(3), pp.234-240.
