As you make your way down supermarket aisles, you can see shelves stocked with antioxidant supplements, antioxidant cookies, and even antioxidant soft drinks. Antioxidants seem to be what many supplement and food manufacturers want us to take to prevent all sorts of health problems.

But what is oxidation, what is oxidative stress, and do we need antioxidant supplements?

Oxidation is a little like rust. On a car, rust caused by oxygen can affect a number of parts. Small rust spots may appear here and there without much in the way of consequences initially. But if no anti-rust treatment is applied, the process spreads, weakening the whole structure.

The situation is not so straightforward in our cells. The oxidation reactions caused by oxygen are important and even essential for cells to work properly and for immune-system functioning. Since the body needs oxidation, it must not be completely blocked, as that could be harmful to the body. When oxidation reactions get to a certain level in a cell, its natural antioxidant systems are overwhelmed, leading to a situation called oxidative stress, when too much oxidation occurs. In the presence of oxidative stress, damage starts to occur in the cells, and all the structures (cell wall, genetic code, etc.) can be affected. The damage can become irreparable, with the consequences described above. (Figure 5).

How does oxidative stress impact health?

We have seen that excess oxidation and oxidative stress damage cells. If the damage becomes irreparable, the cells are pushed to the edge of the abyss. As explained in the preceding chapter, such cells risk becoming cancerous; they are also at greater risk of becoming senescent and causing the body to age prematurely.

The premature aging caused by excess oxidation contributes to conditions associated with premature aging:

• various cancers

• atherosclerosis

• aging of the skin (pigment irregularities, wrinkles)

• macular degeneration

• presbycusis (hearing loss)

• chronic bronchitis

• dementias and Alzheimer’s disease

• erectile dysfunction

• Parkinson’s disease

• cataracts

What causes excess oxidation?

We have seen that the oxidant–antioxidant balance is important for cells to work properly and that problems begin when excessive oxidation occurs. Let’s look at some factors that can lead to excessive oxidation.

First of all, one of the greatest producers of oxidative stress — ultraviolet radiation — has special significance for the skin and eyes. It damages skin cells, causes the skin to age more quickly, and increases the risk of cancer. As for the eyes, it increases the risk of cataracts and macular degeneration. One of the other causes that must not be overlooked is smoking, which generates major oxidative stress in the lungs and throughout the body.

While ultraviolet radiation and smoking can easily be avoided, other causes are much harder to steer clear of. Among the most insidious causes of oxidative stress are atmospheric pollution, heavy metals, certain types of radiation, excess calories and sugar, and even psychological stress! Since all the sources of excess oxidation cannot be avoided, adopting protective habits that counteract oxidative stress would seem justified.