Oxidative stress — what you need to know

Oxidative stress is the term for damage that destructive oxygen molecules called free radicals cause. Here's what you need to know about it.

Our bodies produce free radicals naturally when we breathe, digest food and neutralize alcoholic drinks and drugs of any type, and when cells convert fat and carbohydrates into energy. When free radicals attack low-density lipoprotein (LDL) or "bad" cholesterol, they convert it into the form that promotes atherosclerosis.

The body's natural antioxidant system usually eradicates free radicals. If that protective system is overwhelmed, free radicals begin to damage cells and other molecules, leading to atherosclerosis, cancer, mental decline and other health problems.

A lack of fruit and vegetables, an excess of stress and too little exercise all overwhelm your natural antioxidants.

The more of the following risks you have, the higher the odds that free radicals are damaging your cardiovascular system.

• Smoking
• Being overweight
• Metabolic syndrome or diabetes
• Too little exercise
• A diet that doesn't include at least five servings of fruit and vegetables daily
• Mental or emotional stress

Free radicals' attacks on LDL cholesterol convert it into a form that triggers or worsens atherosclerosis. The new form can also contribute to plaque bursting; it is this burst plaque that can cause blood clots that block blood flow to the brain or heart.

Mental and emotional stress can boost oxidative stress; relaxation can lower it.

Unfortunately there is no test available to determine the level of oxidative stress going on in your circulatory system. But, lifestyle choices pretty much tell the story. Being overweight, having a diet low in fruit and vegetables, smoking and a lack of exercise all raise your risk of oxidative stress.

Each year Canadians spend millions of dollars on over-the-counter vitamin and mineral supplements — including popular antioxidants such as vitamins A, C, E and beta carotene, and the mineral selenium. However, research has yet to prove conclusively that these supplements work.

Instead you should try natural antioxidants: exercise, stress reduction, colourful fruits and vegetables.

Easy food switches that will boost your daily antioxidant intake include drinking apple or grape juice instead of soft drinks, adding broccoli to your salad — and even eating canned vegetables: despite the canning process, they generally retain many of the antioxidants that can be lost from fresh vegetables during storage. Be vigilant, though — vegetables are often canned in salt water, so check the label for sodium.

Remember this information about oxidative stress to help you to understand the basics. And, if you have questions, you can use this information to start a conversation with your doctor.