Free Radicals

Definition: Free radicals are highly reactive molecules or atoms that have unpaired electrons in their outer shell. This instability makes them seek out and react with other molecules, potentially causing cellular damage. Free radicals can be generated through various processes, including normal metabolic reactions, environmental factors (such as pollution and radiation), and certain lifestyle choices (like smoking).

Importance

• Cellular Damage: Free radicals can damage cellular components, including DNA, proteins, and lipids, leading to oxidative stress. This stress is implicated in the development of various diseases, including cancer, cardiovascular diseases, and neurodegenerative disorders.
• Role in Aging: The accumulation of free radical-induced damage over time is thought to contribute to the aging process and age-related diseases.
• Physiological Functions: Despite their damaging potential, free radical also plays roles in normal physiological processes, such as immune response and cell signaling.

Sources

1. Endogenous Sources: Produced during normal metabolic processes, particularly in the mitochondria during ATP production.
2. Exogenous Sources: Environmental factors such as UV radiation, pollution, tobacco smoke, and certain chemicals can increase free radical production.

Antioxidants and Defense Mechanisms

The body has developed several mechanisms to counteract the effects of free radicals:

• Antioxidants: Molecules that neutralize free radicals by donating an electron without becoming unstable themselves. Examples include vitamins C and E, glutathione, and various phytochemicals found in fruits and vegetables.
• Enzymatic Defenses: Enzymes such as superoxide dismutase (SOD), catalase, and glutathione peroxidase help detoxify free radicals.

Conclusion

Free radicals are a double-edged sword; while they can cause significant cellular damage leading to various health issues, they also play essential roles in normal biological functions. Understanding their impact on health is crucial for developing strategies to mitigate oxidative stress through lifestyle choices and dietary interventions.

References

1. Halliwell B, Gutteridge JMC. “Free Radical in Biology and Medicine.” 5th ed. Oxford University Press; 2015.
2. Sies H. “Oxidative Stress: A Concept in Redox Biology and Medicine.” Redox Biology. 2015; 4: 180-183. Available from: https://doi.org/10.1016/j.redox.2015.01.001
3. Valko M, Leibfritz D, Moncol J, Cronin MT, Mazur M, Ruzicka R. “Free Radical and Antioxidants in Normal Physiological Functions and Human Disease.” International Journal of Biochemistry & Cell Biology. 2007; 39(1): 44-84. Available from: https://doi.org/10.1016/j.biocel.2006.07.001