What are antioxidants?

Antioxidants are compounds that keep you healthy by neutralising chemicals in your body, known as free radicals. Antioxidants are produced naturally by your body and are also commonly found in fruits and vegetables. Antioxidants work by 'mopping up' free radicals. Some common antioxidants include vitamin C, vitamin E, and beta-carotene

Vitamin C

A water-soluble vitamin essential for the formation of connective tissue. It also aids in fighting bacterial infections. Also known as ascorbic acid.

Carotene

An orange, red, yellow or brown pigment found in plants such as carrots. Beta-carotene is an important antioxidant that is converted to vitamin A in the body.

What are free radicals?

Free radicals, also known as oxidants, are formed naturally in your body when food is broken down. Free radicals are also formed in our skin and eyes by sunlight and are also in the air we breathe. Smoke, air pollution, stress and alcohol can lead to an increase in the production of free radicals. They can be highly reactive with anything they interact with, which can lead to cell membrane, protein and DNA damage.

Over time, damage caused by excess free radicals can contribute to a number of medical conditions including heart and liver disease and some cancers including those of the bowel, stomach, oesophagus and mouth. Free radicals are also thought to be involved in the gradual deterioration of your body that occurs with ageing and have been linked to vision loss, joint inflammation and nerve cell damage in the brain. There is also evidence of them being involved in atherosclerosis, which is the hardening of arteries due to the lodging of cholesterol in the inner walls of the arteries.

Arteries

A blood vessel carrying blood saturated with oxygen from the heart to the body's tissues.

Atherosclerosis

Fatty deposits within arteries of the body.

Cell membrane

The membrane that separates the cell from its outer environment, which regulates the flow of material into and out of the cell. It is composed mainly of fats, with embedded proteins contributing important regulatory functions.

Cholesterol

A type of fat produced by the body that is necessary for metabolism.

DNA

The genetic material of all living cells and some viruses. The full name is deoxyribonucleic acid.

Heart

The muscular organ in the chest that pumps blood through the body by rhythmic contraction and dilation.

Liver

A large, internal organ of the body, located on the upper right-hand side of the abdomen. The liver has hundreds of distinct functions, including producing bile, regulating the body's metabolism and detoxifying the blood.

Nerve cell

The basic cell of the nervous system. A specialised cell that generates and transmits nerve impulses.

Protein

1. One of the three macronutrients in foods that supply the body with energy. Food rich in proteins include meats, legumes and dairy foods. 2. Large molecules, such as antibodies and albumin, that are found in the blood.

Antioxidants and disease prevention

Research into antioxidants and their role in disease progression is constantly evolving. Currently there are studies that indicate that a diet rich in antioxidants is associated with longevity and good health. There is also some evidence indicating that antioxidants can help prevent certain diseases. These include a lower risk of heart disease and some cancers for people who eat a diet high in fruit, vegetables and whole grains.

Moderate intake of red wine (no more than one standard glass per night) has also been shown to have a cardioprotective (heart-protecting) effect. A series of studies have indicated that antioxidants in red wine, including flavonoids and resveratrol, may be involved in preventing the start or reducing the progression of atherosclerosis.

Macular degeneration, a common cause of blindness in elderly people, has also been studied. Antioxidants including lutein and zeaxanthin, commonly found in fruits, vegetables and egg yolk, can protect against further macular degeneration.

Atherosclerosis

Fatty deposits within arteries of the body.

Heart disease

A class of diseases that involves the dysfunction of the heart and/or the blood vessels.

Heart

The muscular organ in the chest that pumps blood through the body by rhythmic contraction and dilation.

Sources of antioxidants

Common compounds that function as antioxidants and their sources are:

  • Vitamin C - commonly found in citrus fruits, green leafy vegetables, berries and papaya;
  • Vitamin E - commonly found in seed-like cereal grains, plant oils, nuts and eggs;
  • Beta-carotene - commonly found in dark green leafy and orange-coloured vegetables;
  • Selenium - commonly found in fish, lean meats, grains and brazil nuts;
  • Anthocyanins - commonly found in berries, grapes and eggplant;
  • Copper - commonly found in cocoa, wheat bran and yeast;
  • Ubiquinone - commonly found in fish, meat and peanuts;
  • Flavonoids - commonly found in berries, tea and coffee;
  • Resveratrol - commonly found in dark-skinned grapes and red wine and;
  • Phytochemicals - commonly found in soy beans, tea, apples, onions, cocoa and herbs.

Vitamin C

A water-soluble vitamin essential for the formation of connective tissue. It also aids in fighting bacterial infections. Also known as ascorbic acid.

Carotene

An orange, red, yellow or brown pigment found in plants such as carrots. Beta-carotene is an important antioxidant that is converted to vitamin A in the body.

Antioxidant supplements

Antioxidants can also be taken in the form of supplements, which can be taken orally in pill or liquid form. It makes sense to think that taking a large quantity of antioxidants would help reduce free radicals that cause damage to cells and DNA, leading to unwanted medical conditions. However, this is not the case, as research has shown that high doses of antioxidant supplements may be linked to health risks. Antioxidant supplements have been shown to reduce the efficiency of some chemotherapy drugs in treating cancer. This is because chemotherapy drugs cause the formation of free radicals that target and kill cancerous cells. Antioxidants mop these free radicals up before the free radicals can reach the cancerous cells. Interestingly, supplementation with beta-carotene can actually increase the incidence of lung cancer in people who smoke.

DNA

The genetic material of all living cells and some viruses. The full name is deoxyribonucleic acid.

Carotene

An orange, red, yellow or brown pigment found in plants such as carrots. Beta-carotene is an important antioxidant that is converted to vitamin A in the body.

Eating healthy

It is clearly understood that antioxidants neutralise harmful free radicals in your body. It has been shown that eating fresh fruit and vegetables, rather than taking antioxidant supplements, works better to prevent disease. Fruit and vegetables also contain many other elements other than antioxidants that can help to keep you healthy. Overall, it is best to eat a healthy diet with a wide variety of fruit, vegetables, lean meats, whole grains and dairy products each day to stay healthy.

A healthy diet consists of fruit, vegetables, grains, meat and fish.A healthy diet provides antioxidants that neutralise harmful free radicals.