What are free radicals? Why should I avoid free radicals and what can foods with a high ORAC-value do for me?

What are free radicals?

The body is under constant attack from oxidative stress. Oxygen in the body splits into single atoms with unpaired electrons. Electrons like to be in pairs, so these atoms, called free radicals, scavenge the body to seek out other electrons so they can become a pair. This causes damage to cells, proteins and DNA.

Free radicals are associated with human disease, including cancer, atherosclerosis, Alzheimer's disease, Parkinson's disease and many others. They also may have a link to aging, which has been defined as a gradual accumulation of free-radical damage.

Substances that generate free radicals can be found in the food we eat, the medicines we take, the air we breathe and the water we drink. These substances include fried foods, alcohol, tobacco smoke, pesticides and air pollutants.

Free radicals are the natural byproducts of chemical processes, such as metabolism. Free radicals can be seen as as waste products from various chemical reactions in the cell that when built up, harm the cells of the body.

Yet, free radicals are essential to life. The body's ability to turn air and food into chemical energy depends on a chain reaction of free radicals. Free radicals are also a crucial part of the immune system, floating through the veins and attacking foreign invaders.

The danger of free radicals

Once free radicals are formed, a chain reaction can occur. The first free radical pulls an electron from a molecule, which destabilizes the molecule and turns it into a free radical. That molecule then takes an electron from another molecule, destabilizing it and tuning it into a free radical. This domino effect can eventually disrupt and damage the whole cell.

The free radical chain reaction may lead to broken cell membranes, which can alter what enters and exits the cell. The chain reaction may change the structure of a lipid, making it more likely to become trapped in an artery. The damaged molecules may mutate and grow tumors. Or, the cascading damage may change DNA code.

Oxidative stress occurs when there are too many free radicals and too much cellular damage. Oxidative stress is associated with damage of proteins, lipids and nucleic acids. Several studies have suggested that oxidative stress plays a role in the development of many conditions, including macular degeneration, cardiovascular disease, certain cancers, emphysema, alcoholism, Alzheimer's disease, Parkinson's disease, ulcers and all inflammatory diseases, such as arthritis and lupus.

Free radicals are also associated with aging. Free radicals can damage DNA's instructional code, causing our new cells to grow incorrectly, leading to aging.

Symptoms of oxidative stress

There are no officially recognized symptoms of oxidative stress. According to naturopathic doctors, symptoms include fatigue, headaches, noise sensitivity, memory loss and brain fog, muscle and joint pain, wrinkles and gray hair, vision trouble and decreased immunity.

It is not possible to directly measure the amount of free radicals in the body. While indirect methods do exist, these aren't acknowledged because they aren't very accurate.

Antioxidants and free radicals

Antioxidants keep free radicals in check. Antioxidants are molecules in cells that prevent free radicals from taking electrons and causing damage. Antioxidants are able to give an electron to a free radical without becoming destabilized themselves, thus stopping the free radical chain reaction. Antioxidants are natural substances whose job is to clean up free radicals. Just like fiber cleans up waste products in the intestines, antioxidants clean up the free radical waste in the cells. Well-known antioxidants include beta-carotene and other carotenoids, lutein, resveratrol, vitamin C, vitamin E, lycopene and other phytonutrients.

Our body produces some antioxidants on its own, but an insufficient amount. Oxidative stress occurs when there is an imbalance of free radicals and antioxidants with too many free radicals and too few antioxidants.

Antioxidants can be acquired through diet. Antioxidants are plentiful in fruits and vegetables, especially colorful fruits and vegetables. Some examples include berries, tomatoes, broccoli, spinach, nuts and green tea.

Antioxidants became well known in the 1990s when scientists began to realize the possible effects of free radicals on cancer development, atherosclerosis and other chronic conditions. During the subsequent decades, scientists have conducted many studies on the effects of antioxidants with mixed results.
A six-year trial, the Age-Related Eye Disease Study (AREDS), found that a combination of vitamin C, vitamin E, beta-carotene and zinc offered some protection against the development of advanced age-related macular degeneration.

On the other hand, a beta-carotene trial among Finnish men who were heavy smokers found an increase in lung cancer among those taking beta-carotene supplements, probably due to the antioxidants turning into pro-oxidants with so many smoke particles in the body.

Free radicals and exercise

Intense aerobic exercise can induce oxidative stress. Burning fuel in high-intensity cardio exercise causes chemical reactions that make free radicals form at a faster rate. This isn't an excuse to skip the gym, however.
Frequent exercise training seems to reduce the oxidative stress initially brought on by exercise. This is because regular physical exercise enhances antioxidant defenses.

Spurred by the concern that intense exercise could cause oxidative stress, several studies were conducted to look at the effects of antioxidant supplementation for athletes. It turned out that regular exercise alone was enough to build up antioxidant defenses against the initial exercise-induced oxidative stress.

Therefore, out of shape and infrequent exercisers who do a spontaneous bout of intense physical activity may invoke oxidative stress, while those who are consistently active should not worry.

What are ORAC Values?

ORAC stands for Oxygen Radical Absorbance Capacity, a measure of the ability of a food or any other substance to quench oxygen free radicals in a test tube.

The less free radical damage there is, the higher the antioxidant capacity of the test substance.
Over time, many different foods were tested, resulting in a long list of fruits, vegetables and spices. As you might expect, high scores were awarded to brightly colored fruits and vegetables including blueberries and raspberries, some types of apples, and beans.
While ORAC and antioxidant are different, eating a combination of foods that have demonstrated high ORAC scores has also boosted blood antioxidant scores.

ORAC researchers suggest that increasing daily intake to between 3,000 and 5,000 ORAC units seems to have a significant impact on plasma and tissue antioxidant capacity.

You may choose your foods based on the ORAC scale, but it’s only part of the picture in a healthy diet. While healthy foods tend to have high ORAC scores, simply having high scores in a lab does not necessarily indicate high antioxidant activity in the body. Instead, try to aim for a diet that is as varied and colourful as possible.

Recommended are
- green vegetables (which contain carotenoid antioxidants like lutein, zeaxanthin and astaxanthin, that can protect aging eyes from developing cataracts and macular degeneration): spinach, collards, kale.
- cruciferous vegetables (contain antioxidants and other phytonutrients like glucosinolates and DIM, that reduce cancer risk): broccoli, cabbage, Brussels sprouts, cauliflower, turnips.
- orange/yellow fruits and vegetables (rich in carotenoids that protect the immune system): sweet potatoes, carrots, mangoes, apricots.
- red pigmented fruits (contain lycopene, a powerful antioxidant that helps fight heart disease and some types of cancer, particularly prostate cancer):tomatoes, watermelon, papaya, pink grapefruit.
- blue/purple fruits and vegetables (these hues come from anthocyanins, phytochemicals that protect against carcinogens and may help prevent heart disease): blueberries, purple grapes, red cabbage, beets, plums.

And let's not forget about green and white tea, (green) coffee, dark chocolate and red wine, which all rank very high on the ORAC-value chart and have a high antioxidant activity.
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