Free radicals have received a lot of attention over the last few decades. Too many free radicals affect the body in many ways, resulting in oxidative stress if the body is no longer able to regulate them. These unstable atoms are believed to cause many disorders, and they have the power to alter proteins, fats, and DNA.

Unpaired Electrons

Free radicals are molecules that can exist independently and have an unpaired electron in their orbit. The main thing to understand about free radicals is that this unpaired electron makes them very reactive and highly unstable: they can either give away or accept an electron.

Free radicals target and attack other cells, causing disruption and damage.


Where Free Radicals Come From

Free radicals form in many ways. They can develop naturally in the body from various reactions and processes, including normal metabolic processes and factors like inflammation, exercise, and ischemic damage.

Free radicals also come from external sources, like cigarette smoke, pesticides, pollutants, radon, ozone, and radiation. Some viruses can produce them, as well.


Oxidative Stress

The accumulation of free radicals and the damage they cause leads to oxidative stress. Scientists believe that oxidative stress plays a big part in the development of degenerative changes and a variety of diseases.

The human body produces antioxidants to counteract the effects of free radicals, preventing and repairing the damage they have caused.



Research suggests that free radicals promote aging, and some people believe that using antioxidants to limit or inhibit this damage can slow the rate of aging.

Although evidence shows that antioxidants are beneficial for reversing the damage of free radicals as they relate to various conditions, there is no evidence to suggest that they can prevent age-related changes.


Free Radicals and Cancer

Cancer is a complex process, and research has established that oxidative damage to DNA from free radicals is responsible for its development.

This damage causes gene mutations that change the programming of cells, altering normal cell growth. For example, tobacco smoke can change the DNA of lung cells, leading to lung cancer.


Free Radicals and Heart and Lung Diseases

Free radicals also affect the heart and lungs. Research shows that cardiovascular disease has complex causes, including high blood pressure, poor diet, smoking, and high cholesterol, and recent studies indicate that oxidative stress from free radicals is a contributing factor.

The current debate centers not on whether free radicals cause cardiovascular disease but whether they are a primary or secondary factor. Studies also show that inflammatory diseases, like asthma and COPD, result from oxidative stress.


Free Radicals and Neurological Diseases

Free radicals and the oxidative stress they cause have also been investigated as causes of neurological diseases such as depression, Alzheimer's, multiple sclerosis, and Parkinson's disease.

Numerous studies revealed that oxidative damage contributes to the loss of neutrons in Alzheimer's disease and the progression to dementia. The toxic peptide produced in people with Alzheimer's, ß-amyloid, is believed to form due to oxidative stress.


Other Diseases

Free radicals contribute to many other diseases and conditions. They play a role in the chronic inflammation of rheumatoid arthritis, renal diseases — like chronic renal failure — and eye problems — like macular degeneration, cataracts, and retinal damage.

Free radicals can cause issues with pregnancy and fetal development, too, inducing conditions like preeclampsia and intrauterine growth restriction.



Antioxidants are the best defense against free radicals. These molecules are stable enough to lose an electron to a free radical, essentially reducing the free radical's ability to cause damage. The body produces some antioxidants during normal metabolism, but many antioxidants are only available in foods and supplements.


Actions of Antioxidants

Antioxidants use two mechanisms of action to neutralize free radicals. The first method is to suppress the production of free radicals, though how they do so is not yet understood. The second method that antioxidants use is scavaging free radicals. Research shows that vitamin E is the most potent free radical scavenger.


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