What Are Free Radicals?
In general, free radicals are molecules or compounds that possess one or more unpaired electrons. Because of this feature, free radicals can undergo changes in chemical activity.
Due to their unpaired electrons, free radicals circulate in the body and cause damage to healthy cells. Oxygen intake partially drives free radicals formation. Although our survival depends on adequate oxygen, a small portion (1–3%) of the oxygen we breathe is not used for energy production. Together with certain metals in the body, this unused oxygen leads to new radical molecules.
What Do Free Radicals Do in the Body?
Free radicals are unstable and highly reactive because they have an odd number of electrons. They can arise from various sources and can “steal” electrons from other cells or molecules, creating a chain reaction. If a molecule loses an electron, it becomes another free radical—a cascade effect that can have serious consequences.
By doing so, free radicals can damage cell membranes and DNA, altering their structure. Their formation is commonly linked to unhealthy diets, pollution, tobacco smoke, excessive sun exposure, and other radiation. Stress hormones like cortisol or adrenaline also contribute.
Additionally, free radicals are believed to play a decisive role in the development of chronic illnesses. They can damage fat tissue, causing harmful substances to leak into surrounding areas. This disrupts cell function and may lead to cell death. Free radicals also play a central part in conditions such as cancer, inflammatory joint disorders, asthma , diabetes, and kidney diseases.[1]
How Can We Counteract Free Radicals Formation?
Antioxidants are the body’s “protectors,” neutralizing harmful free radicals. Both free radicals and antioxidants can be produced in the body; however, we should ensure we also get antioxidants from our diet. Eating fruits and vegetables (e.g., citrus fruits containing vitamin C) supports free radical defense. Vitamin C is known to fight free radicals and slow processes that contribute to aging.
The Strongest Antioxidants
Among the most potent antioxidants are vitamin C, beta-carotene, and vitamin E. Vitamin C is especially effective at helping reduce stomach and intestinal cancer risk and is thought to lower the likelihood of heart disease. Beta-carotene can curb cancer cell growth and is essential for eye health. Vitamin E helps prevent hardening of the arteries (atherosclerosis). Another powerful antioxidant is glutathione, critical for protein synthesis and also effective against free radicals. Antioxidants are thus vital for healthy immune system function and overall well-being.[2]
Do Secondary Plant Compounds Help?
Many secondary plant compounds are antioxidants or have antioxidant-like effects. We find them in virtually all plant-based foods we eat. Not only can they positively affect human health, but they also help protect the plants themselves from damage.
Although found in relatively small quantities, these compounds (including carotenoids, indoles, flavonoids, and alkyl sulfides) are surprisingly potent. Secondary plant compounds can support hormone regulation, help guard against heart disease and aging, and even reduce inflammation. Often, they exhibit antimicrobial properties, aiding the body in fending off pathogens. For example, carotenoids possess antioxidant capacity, contributing to free radical neutralization.
References
- [1] Rintu Das, “Role of free radicals in human inflammatory diseases,” American Institute of Mathematical Sciences (AIMS), AIMS Biophysics, 2017
- [2] Lavrent Khachatryan, “Formation and stabilization of persistent free radicals,” Proceedings of the Combustion Institute, 2007
- Lavrent Khachatryan, “Free Radicals in Tobacco Smoke,” Mini-Reviews in Organic Chemistry, 2011
- Samaneh Khodadadi, “Free radicals and antioxidants: an updating review”