Most people are familiar with the word “stress”; and most human beings experience some sort of it daily. Simply put, psychological stress is a normal reaction to changes or challenges (aka stressors) to which the body adapts with physical and mental responses. The stress response is positive in that it can help you push through stress-provoking events. However, too much stress over time can negatively affect long-term mental and physical health. Psychological stress is increasingly recognized as a factor leading to another less familiar type of stress known as “oxidative stress” — which happens intracellularly and can damage cells, proteins and DNA. But what is oxidative stress? In a nutshell, oxidative stress plays a role in the development of a wide range of health conditions, including those that are metabolic.

What is oxidative stress?

Within cells, a structure called the mitochondria works to generate energy from nutrients and oxygen through a sophisticated series of metabolic steps. During this process, tiny negatively-charged particles called electrons form a stable and non-reactive pair. On occasion, an electron breaks free of its pair and binds to other molecules, causing what is referred to as a reactive oxygen species (ROS) and generating what is called a free radical. This is a normal and necessary process called oxidation, and it is nothing to worry about provided the body’s antioxidant defense system is in good working order.

In case we lost you at antioxidant, most people are familiar with the word, but many people don’t really know what an antioxidant is or what it does. Antioxidant simply means a substance that inhibits oxidation, hence “anti-” oxidant. Within cells, antioxidants neutralize or remove free radicals by donating an electron. When there are more free radicals present than can be kept in balance by antioxidants, a phenomenon called oxidative stress occurs. In summary: Oxidation is a result of normal metabolic processes within the cells — while oxidative stress is a disruption of equilibrium or an imbalance of free radicals and antioxidants.

What causes oxidative stress?

Fortified with an extra electron, ROS become capable of interacting with other molecules, which causes a potentially dangerous downstream effect on cells, protein and DNA. The body is able to maintain a balance between antioxidants and free radicals, but too many or too little ROS can derail cellular robustness. 

There are multiple factors that contribute to oxidative stress and excess free radical production, some of which include:

• Diets high in fat, refined carbohydrates, added sugar, salt and ultra-processed foods
• Lack of exercise
• Environmental factors such as cigarette smoke, pollution, radiation, pesticides, alcohol and certain medications
• Obesity

Oxidative stress can also be triggered temporarily by the body’s natural immune response. This type of stress causes mild inflammation that resolves when the immune system fights off immune invaders or repairs an injury. Exercise also increases the formation of free radicals leading to temporary oxidative stress in muscle tissues, an action that stimulates antioxidant production and regulates tissue growth. Oxidative stress caused by exercise or mild inflammation is normal and part of the body’s natural process for keeping itself healthy. 

Why is oxidative stress a concern?

In the 1950s, the Free Radical Theory of Aging proposed that an accumulation of oxidative damage over time causes cellular aging and contributes to the onset of age-related disease. The theory implied that mitigating oxidative damage could possibly slow physical and mental decline. Fast forward to modern times, we now know that the uncontrolled imbalance of free radicals and antioxidants known as oxidative stress can indeed lead to cell and tissue damage. As detailed in this 2017 review, a large body of scientific evidence confirms that long-term oxidative stress is a contributor to the onset or progression of a wide range of disease states (i.e., cancer, diabetes, metabolic disorders, cardiovascular disease and neurodegenerative diseases) and an accelerator of the aging process. 

How are oxidative stress and metabolic health linked? 

Metabolic syndrome (MetS), a cluster of conditions that increase the risk of heart disease, stroke and diabetes, is diagnosed by the presence of three of the following conditions:

• Obesity
• Insulin resistance
• High blood pressure
• Impaired glucose tolerance or diabetes
• Hyperinsulinemia and dyslipidemia

Several studies have reviewed the research and concluded that oxidative stress plays a key role in the pathogenesis of MetS. Research has suggested that both acute glucose fluctuations and chronic hyperglycemia lead to oxidative stress and are driving factors behind common complications linked to diabetes — such as vision loss, nerve damage, impaired kidney function and accelerated risk for artery disease. There is also evidence suggesting that ROS contribute to the development of insulin resistance and that levels of ROS are increased in obesity.

What can we do to manage stress?

The good news is that you can make lifestyle choices and take dietary measures to minimize the negative impact of oxidative stress on the body. Here are a few tips:

• Commit to engaging in a regular, moderate exercise routine.

• Minimize exposure to environmental factors that impact oxidative stress (i.e., smoke, chemicals, radiation).

• Eat a wide variety of fiber-rich prebiotics (fruits, vegetables, whole grains) and other antioxidant-rich foods, while limiting ultra-processed foods and foods with added sugar and excess unhealthy (saturated) fats.

• Watch your portion sizes and don’t graze. Shoot for eating small to moderate portions at spaced intervals. Overeating and constant eating have been linked to oxidative stress!

• Try to get adequate sleep. Animal studies have shown that lack of sleep or poor sleep quality can increase ROS levels.

Learn more: Can Stress Cause Illness?

Key takeaways

Oxidative stress occurs when there is a disruption of equilibrium or an imbalance of free radicals and antioxidants. The damage to cells, proteins and DNA caused by long-term oxidative stress contributes to a wide range of health conditions, including metabolic health. Maintaining a healthy body weight in addition to committing to healthy lifestyle and dietary habits can lower the impact of oxidative stress, potentially reducing the risk for many chronic disease states while decelerating the inevitable process of aging.