Free radicals are highly reactive molecules that contain one or more unpaired electrons. They are formed naturally in the body during various metabolic processes but can also be introduced from external sources such as tobacco smoke, environmental pollutants, and radiation. Free radicals play a dual role in biological systems, as they can be both beneficial and harmful. On the positive side, they are used by the immune system to fight off pathogens and by cells to communicate with each other. However, when free radicals accumulate, they can cause oxidative stress, leading to cell damage and contributing to the aging process and various diseases, including cancer and cardiovascular diseases.
The chemistry of free radicals is centered around their unpaired electrons, which make them highly unstable and reactive. They seek to stabilize themselves by either donating or accepting an electron from other molecules, causing a chain reaction of radical formation. This can result in significant damage to cellular components such as DNA, proteins, and cell membranes. Antioxidants are substances that can donate an electron to a free radical without becoming destabilized themselves, thus breaking the chain reaction. Common antioxidants include vitamins C and E, glutathione, and certain enzymes that scavenge free radicals and mitigate the damage they cause.
Environmental factors can significantly increase the production of free radicals, leading to an imbalance between free radical production and the body’s ability to counteract their harmful effects. This imbalance is referred to as oxidative stress. Prolonged oxidative stress is linked to the development of a range of disorders, including Alzheimer’s disease, cancer, atherosclerosis, and diabetes. Additionally, exposure to ultraviolet light, air pollution, and toxic chemicals can increase free radical production beyond the body’s antioxidant capacity, exacerbating oxidative stress and its associated risks.
In response to the threats posed by free radicals, there is a growing interest in the development of dietary and lifestyle strategies to reduce oxidative stress. These include consuming a diet rich in antioxidants, leading a physically active lifestyle, and avoiding known environmental contaminants. Foods particularly high in antioxidants are often referred to as superfoods and include berries, nuts, dark green vegetables, and green tea. The ongoing research into free radicals and antioxidants highlights the complex interactions within our bodies and the environment, underscoring the importance of maintaining a balance to promote optimal health and longevity.