Free Radicals — The Good, The Bad, and The Ugly

What Is a Free Radical?

Free radicals are molecules with an unpaired electron, naturally produced in your cells as a byproduct of energy production. These unstable molecules seek out an electron from nearby molecules to stabilize themselves — causing damage to cells, proteins, and DNA in the process. Free radicals are also known as Reactive Oxygen Species (ROS), and include superoxide anions (O2·−), hydroxyl radicals (OH·), and peroxyl radicals (ROO).

Not All Free Radicals Are Bad

Some free radicals help cells communicate, eliminate harmful microbes, and facilitate the immune response. Free radicals like Hydrogen Peroxide (H2O2) and Nitric Oxide (NO•) have important functions inside your cells. For example, hydrogen peroxide is used by your immune cells to kill bacteria, and nitric oxide is a signaling molecule that relaxes your blood vessels.

The Most Dangerous Free Radical

At low levels, free radicals are useful. A burst of superoxide or hydrogen peroxide attracts nearby neutrophils — the immune system's first responders — to fight microbes, remove damaged tissue, and begin the inflammation process.

Hydrogen peroxide also stimulates the production of antioxidant enzymes and can trigger apoptosis (programmed cell death). It's an important molecule that needs to be at optimal levels at all times as a way for cells to communicate with one another and the immune system.

The problem is that hydrogen peroxide has the potential to convert into the deadliest free radical — the hydroxyl radical (OH•). In a process called the Fenton reaction, hydrogen peroxide reacts with free-floating iron to form hydroxyl radicals. There's a delicate balance that needs to be maintained to keep your cells working well while preventing hydroxyl radical production.

Oxidative Stress Is the Root Cause of Many Health Issues

The issue isn't free radicals themselves — it's when there are too many of them. Your antioxidant defense system usually neutralizes free radicals before they cause damage, but excess free radical production can overwhelm your natural defenses. Oxidative stress is this imbalance: more free radicals being produced than your body can handle, leading to hydroxyl radicals causing widespread cellular damage.

Research shows that most chronic diseases are associated with oxidative stress, including:

• Cancer 1, 2
• Cardiovascular Disease 3, 4
• Alzheimer's 5, 6
• Asthma 7
• Rheumatoid Arthritis 8, 9
• Diabetes 10, 11
• Allergies 12
• Aging 13

Factors That Increase Free Radicals

Environmental and lifestyle factors can significantly increase free radical production. Here are the main ones you can control:

• Chronic Stress. Some stress is necessary and healthy, but chronic stress contributes to excess free radical production. Stress hormones like cortisol and adrenaline increase metabolism, leading to increased free radical production. When this happens regularly, your antioxidant enzymes get depleted and oxidative stress sets in.
• Alcohol. After excessive drinking, your cells work hard to remove toxins. Glutathione peroxidase (GSH) is a key player in this effort and helps keep your hydrogen peroxide levels in check. When alcohol depletes GSH, H2O2 levels rise — leading to hydroxyl radical production.
• Processed Food. Packaged pastries, microwave meals, and processed meats are major contributors to free radical production. These foods are full of preservatives and lack the nutrition your cells need. The biggest culprits are vegetable oils (canola, corn, sunflower, grapeseed) — fats that become oxidized when exposed to light, air, or heat. Cook with healthy fats like avocado oil, coconut oil, grass-fed butter, or olive oil when possible.
• Environmental Toxins. You're constantly exposed to chemicals in laundry detergents, soaps, shampoos, makeup, and skincare. If you live in a city, carbon monoxide and industrial pollution are affecting you more than you think. When these chemicals build up, your cells become inefficient and produce more free radicals. Switching to non-toxic alternatives and drinking clean, filtered water are practical first steps.

Keep Free Radicals in Check

Free radicals are going to be part of your life no matter what. Knowing what drives excess production is an important step toward managing oxidative stress. Beyond reducing exposure to the factors above, you can strengthen your natural defense system by incorporating antioxidants into your diet. Read more about it here.