What Are Antioxidants
Antioxidants are molecular compounds that play an essential role in protecting biological systems from the damaging effects of free-radical compounds. Free-radicals are highly reactive atoms or molecules that have a charge due to the presence of one or more unpaired electrons. The imbalance of electrons makes free-radicals highly unstable molecules that will scavenge for molecular structures to either grab electrons from or donate electrons to. When present in excess, they can cause many damaging effects within our bodies, including: interference with normal cellular processes, damage to cell membranes and structures, as well as damage and breakage of DNA strands.
Free-radicals are generated continuously within our bodies during normal metabolic processes such as oxidation. It is through aerobic respiration that the most biologically significant free-radicals are produced - reactive oxygen species (ROS). Reactive oxygen species (ROS) play a role in the development and progression of many chronic diseases, such as: cancer, heart disease, atherosclerosis, cerebral ischemia, Alzheimer's disease, and play a major role in the general processes of ageing. The amount of free radicals increases greatly during exercise, when exposed to UV light, when we are ill, as we age, and when we are exposed to chemical pollutants, such as exhaust fumes, or cigarette smoke – every inhalation of cigarette smoke, releases millions of free-radicals within your body. Once a free radical oxidizes a molecule, it can start a chain reaction of oxidation that won’t stop until it meets an antioxidant.
Antioxidants protect against the damage casused through oxidation
Antioxidants help to block the process of oxidation, by donating one of their own electrons, this disarms and reduces the damaging free-radical molecule so that it is no longer able to cause damage. However, during this process the antioxidants themselves become oxidized. In some cases the antioxidant can be regenerated by another antioxidant, in other cases it must be excreted by the body.
There are many different types of antioxidants that help to protect biological systems from the damage caused by oxidation. Each antioxidant works slightly differently and protects against different types of free radicals. Some antioxidants are water- soluble, some are fat soluble and some are both fat and water soluble. However, most of these antioxidants work in synergy with one or more different antioxidants.
Antioxidants work better in synergy
Most antioxidants work in synergy, meaning they work better when in the presence of one, or more, different antioxidants. Examples of synergistic antioxidants include vitamin C, Vitamin E and Alpha-Lipoic Acid. Vitamin E is fat soluble, residing in the cell wall where it protects the cell from free-radicals seeking to access the cell, vitamin C is water soluble and resides within the cell plasma, whereas alpha-lipoic acid is both water- and fat-soluble and functions in all compartments of the body to neutralise free radicals. When vitamin E comes into contact with a free-radical it donates one of its own electrons and neutralises the free-radical. The vitamin E molecule is now oxidized and must be rejuvenated by either Vitamin C or alpha-lipoic acid, once rejuvenated it is free once again to neutralise another free-radical. Alpha-lipoic acid is also capable of rejuvenating vitamin c. The combined antioxidant effect of Vitamin C, Vitamin E and Alpha-Lipoic Acid is far superior to their individual antioxidant potential.
Antioxidants produced by your own body
Your body naturally produces a large number of different antioxidants, including: Catalase, Co-Enzyme Q10, Glutathione, and Superoxide Dismutase. Both Superoxide Dismutase and Catalase are examples of antioxidants working in synergy together. The natural synergy shown between Superoxide Dismutase and Catalase is considered to be our best line of natural defence against free-radical damage. Superoxide Dismutase breaks down oxidants into hydrogen peroxide. Whilst Catalase breaks down hydrogen peroxide into water and oxygen.
Dietary sources of antioxidants
A large amount of antioxidants are obtained through our diet, and eating five servings of fruit and vegetables a day is a good way to achieve a good antioxidant intake. The best natural sources of antioxidants are fruits, vegetables, seeds, nuts, spices, herbs and oils.
Vitamin A > Liver, Dairy Products, Fish
Vitamin C > citrus fruits, broccoli, tomatoes, peppers
Vitamin E > vegetable oils, walnuts, peanuts, almonds, seeds, olives, avocado
Selenium > Brazil Nuts, Meats, Tuna
Beta-Carotene > peppers, spinach, kale, squash, sweet potatoes, and apricots
Carotenoids (e.g., lycopene, lutein, zeaxanthin) > Tomatoes, carrots, watermelon, kale, spinach
Curcumin > Turmeric
Diallyl sulfide, Allyl methyl trisulfide > Garlic, Onions, Leeks
Flavanols (Catechins, Epicatechins, Procyanidins) > tea, cocoa, chocolate, apples, grapes
Phenols, polyphenols, phenolic compounds > Grapes, blueberries, strawberries, cherries, grapefruit, cranberries, raspberries, blackberries, tea
Proanthocyanidins > cranberries, cocoa, apples, strawberries, grapes, wine, peanuts, cinnamon