Several chemical substances found in foods are called antioxidants because of their ability to prevent harmful chain reactions caused by free radicals. The most important natural antioxidants are:
Free radicals
Free radicals are unstable compounds formed mainly from oxygen.
They are produced during the normal functioning of the body, but their production can be increased by, for example, pollution, cigarette smoke or prolonged exposure to the sun.
Because of their chemical structure, they damage other atoms by "oxidising" them.
However, they are more or less controlled by the body's natural antioxidants.
However, some factors can upset this balance.
When free radicals exceed the body's ability to neutralise them, they can contribute to the development of several diseases, including cardiovascular disease, certain cancers and other diseases associated with ageing.
The TAC Index
The Total Antioxidant Capacity (TAC) index indicates the overall antioxidant activity of a food or plant, i.e. its ability to neutralise free radicals in the human body.
The higher the TAC of a food, the more antioxidant it is.
The unit of measurement is the micromole (µmol).
- Weak (or slightly antioxidant): TAC index between 0 and 499 µmol
- Moderate antioxidant: TAC index between 500 and 999 µmol
- High (or strong antioxidant): TAC index from 1000 to 1999 µmol
- Very high (or very powerful antioxidant): TAC from 2000 to 14000 µmol
Our daily antioxidant needs
There are no official recommendations for specific antioxidants.
On the other hand, there are some for the main source of antioxidants, which are fruits and vegetables: 7 to 10 servings a day.
Berries are the richest in antioxidants: blueberries, blackberries, cranberries, raspberries, strawberries, currants and plums.
Vegetables include beets, artichokes, asparagus, broccoli, purple cabbage, yellow peppers and potatoes (especially those with coloured flesh).
And don't forget pulses, especially white beans.
The super antioxidants
The most powerful antioxidants are those that are not nutrients, but molecules produced by plants to protect themselves from aggressors and to respond to hostile conditions in their environment.
They are also responsible for the colour of food.
They are called "phytochemicals".
These molecules are very powerful: more than half of the chemotherapy drugs used today, which save many human lives, come directly from plants. So here's where you can find them:
- Berries: strawberries, raspberries, blueberries, blackberries, currants, cranberries, etc.
- Pulses: soya beans, beans, pinto beans, kidney beans, black beans
- Fruit: apple, cherry, plum, pomegranate
- Cruciferous vegetables: broccoli, cauliflower, cabbage, etc.
- Garlic, onion, spring onion, leek
- Citrus fruits: orange, grapefruit, clementine, lemon, lime, etc.
- Tomatoes
- Spices and herbs: saffron, turmeric, ginger, oregano, thyme, etc.
- Green tea and cocoa