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- Free radicals are atoms that attach to healthy cells in your body, damaging them in the process.
- You can encounter free radicals in the environment from things like smoke and alcohol.
- Combat the damaging effects of free radicals by consuming foods rich in antioxidants.
- Visit Insider's Health Reference library for more advice.
You probably know smoking cigarettes, drinking alcohol, and being exposed to pollution can contribute to aging and disease. But have you ever wondered why?
The answer, in part, can be explained by free radicals.
What are free radicals?
Free radicals are created naturally in the body during your day-to-day, like when you metabolize food, but they're also generated by external sources, says Alexis Parcells, MD, a plastic surgeon and founder of the anti-aging clinic, SUNNIE.
External sources of free radicals include:
- Air pollution
- Alcohol
- Cigarette smoke
- Pesticides
- Processed meats
How free radicals damage the body
Free radicals damage the body because they attach to healthy cells, which disrupts the cell's usual life-sustaining functions.
The reason free radicals attach to cells in the first place is because free radicals are a particular type of atom, called an unstable atom.
Generally speaking, atoms make up just about everything, from your skin cells to the food you eat. And those atoms are surrounded by electrons.
Now, when an atom has enough electrons, it's called a stable atom, and when it's missing some electrons, it's unstable. Here's the important part: Unstable atoms want to become stable.
Therein lies the problem with free radicals: They are unstable atoms and, as a result, seek out stable atoms in healthy cells and steal those atom's electrons, damaging the cell in the process.
Making matters worse is that when free radicals steal electrons from multiple atoms, they create more unstable atoms, setting off a harmful chain reaction.
And when free radicals attack important molecules in the cell such as DNA, proteins, carbohydrates, and fats, it leads to large-scale cell damage and subsequent disease, says Neilank K. Jha, MD, a neurosurgeon and founder of private concussion clinic Konkussion.
How antioxidants protect against free radicals
The good news is your body has an antioxidant defense system to protect you from free radicals.
An antioxidant is any stable compound able to give up an electron of their own to neutralize, or "turn off" free radicals. This also stops free radicals from producing more free radicals.
"When antioxidants encounter free radicals ... the antioxidants bind to them, immediately delivering their extra electron to the free radical, returning them to balance before they can harm your cells," Parcells says.
What is oxidative stress?
Sometimes, there are more free radicals than antioxidants in the body which results in a condition known as oxidative stress.
"Oxidative stress is a condition in which oxidative damage occurs in the cell because of an unfavorable balance between free radicals and antioxidants," Jha says. "Short-term oxidative stress can occur due to injury and infection while the long-term results from poor diet and lifestyle choices."
Oxidative stress is believed to be involved in several diseases, including:
- Kidney disease
- Cancer
- Cardiovascular disease
- Diabetes
- Alzheimer's
- Chronic Obstructive Pulmonary Disease (COPD)
- Osteoarthritis
- Dementia
How to prevent oxidative stress
The good news is, you can combat oxidative stress by increasing the amount of antioxidants in your body. While you naturally produce antioxidants like glutathione and melatonin, you can also get them from foods and beverages.
In fact, plant-based foods, like fruits and vegetables, add a significant amount of antioxidants to your diet thanks to their high amount of phytochemicals.
Examples of phytochemicals include vitamin C in oranges, carotenoids in tomatoes and kale, and flavanols in blueberries, green tea, apples, and onions.
You can also buy antioxidant supplements. However, research has not found a clear benefit from supplementing antioxidants and suggests that they could even be harmful.
For example, recent large scale randomized clinical trials indicate that neither vitamin E nor vitamin C supplementation reduces the risk of major cardiovascular events in middle-aged and older men, healthy women, or postmenopausal women.
"When it comes to consuming antioxidants, I would recommend opting for natural dietary sources as opposed to supplementation," Jha says. "By eating antioxidant-rich foods such as fruits and vegetables, you not only get the benefit of free-radical defense, but other vitamins, minerals, and fiber as well."
Insider's takeaway
Free radicals are unstable atoms that increase signs of aging and contribute to the development of chronic diseases.
While free radicals are naturally produced by your body, they're also created by outside factors like cigarette smoke and pollution.
The good news is, your body naturally produces some antioxidants to combat these damaging molecules, and you can boost this defense system by eating antioxidant-rich foods like fruits, vegetables, and spices.
"You're exposed to free radicals every day, so while you can't avoid them entirely, you can turn to powerful antioxidants to help protect your skin and health," Parcells says.