Free Radicals and Antioxidant Vitamins

A lot of health claims are made for dietary antioxidant vitamins, the main one being that they can delay the effects of aging, or prolong youth. It is easy to see why the belief arose.

What are the health benefits of antioxidants?

Antioxidants such as butylated hydroxyanisole and butylated hydroxytoluene are used in food processing, to prevent foods such as fats and oils reacting with oxygen and becoming rancid. In the same way, sulfur dioxide is used in fruit processing to delay spoilage.

Before we go any further, it would be well to define what an “Antioxidant” nutrient is and where are antioxidants found. Antioxidants are natural substances produced in the body or obtained from the food we eat.

Antioxidants act like scavengers in our bloodstream neutralizing the oxidized by-products of our body cells activities. Vitamins A, C and E are antioxidant vitamins common in the human diet, and they play a role in scavenging what are called “free radicals“.

Free radicals are volatile molecules which try to stabilize themselves by taking electrons from other molecules. Molecules which are vulnerable to attack include the polyunsaturated fatty acids contained in the membranes surrounding body cells.

Once the molecules have relinquished an electron to a free radical, the tissue becomes damaged. The free radicals are believed to play a role in several degenerative diseases, such as heart disease and some cancers, and are thought to be involved in aging.

The appropriate use of just the right antioxidants can prevent cancer cell development and even reverse many forms of serious diseases whose primary cause is excess oxidation (free radical damage to cells). It also helps protect red blood cells from rupture by oxidizing agents.

Biochemically, Vitamin E certainly helps prevent oxidation in situations where it should not occur. It helps protect cell membranes, and also protects Vitamin A and polyunsaturated fatty acids as they are transported through the blood stream.

Which nutrients make up the antioxidant arsenal then? A number of natural substances have antioxidant potential, but the main ones we should be trying to eat everyday include Vitamins A, C and E, the mineral Selenium and Zinc, and the enzyme called simply “Coenzyme Q10”.

Vitamin A

Vitamin A is familiar to us in yellow and orange vegetables and from fish oils such as cod liver oil. The best antioxidant form of Vitamin A, however, is called “Beta-Carotene” which is derived, as you might guess, from vegetable sources such as carrots, apricots and mangoes.

Beta-Carotene is actually a “pro-Vitamin” or in other words it is the raw material from which our bodies can manufacture its own Vitamin A. Beta-Carotene also has no toxicity at high levels unlike other vitamin A sources which can be toxic in large doses.

Beta-Carotene exerts a particularly protective antioxidant effect on cells from various cancers. Beta-Carotene also reduces incidence of coronary heart disease and improves HDL cholesterol.

Recommended Dietary Allowances (RDAs) for Vitamin A
0–6 months*400 mcg RAE400 mcg RAE
7–12 months*500 mcg RAE500 mcg RAE
1–3 years300 mcg RAE300 mcg RAE
4–8 years400 mcg RAE400 mcg RAE
9–13 years600 mcg RAE600 mcg RAE
14–18 years900 mcg RAE700 mcg RAE750 mcg RAE1,200 mcg RAE
19–50 years900 mcg RAE700 mcg RAE770 mcg RAE1,300 mcg RAE
51+ years900 mcg RAE700 mcg RAE

* Adequate Intake (AI), equivalent to the mean intake of vitamin A in healthy, breastfed infants.


Vitamin C

Vitamin C is the next antioxidant hero – one of the most important of all the vitamins and one of the most easily lost or destroyed by improper food preparation or storage. Vitamin C, like Beta-Carotene, has a major role to play in preventing cancer cell development.

Recommended Dietary Allowances (RDAs) for Vitamin C
0–6 months40 mg*40 mg*
7–12 months50 mg*50 mg*
1–3 years15 mg15 mg
4–8 years25 mg25 mg
9–13 years45 mg45 mg
14–18 years75 mg65 mg80 mg115 mg
19+ years90 mg75 mg85 mg120 mg
SmokersIndividuals who smoke require 35 mg/day
more vitamin C than nonsmokers.

* Adequate Intake (AI)


Vitamin E

Vitamin E is next, a powerful antioxidant vitamin with a recently acknowledged track record for reducing the incidence of heart disease and atherosclerosis.

As a fat soluble vitamin, Vitamin E is particularly important in protecting our body cells from rancid fats the breakdown of which results in free radicals from rapid and highly toxic oxidization.

Oxidized free radicals in the walls of arteries which are the real cause of plaque formation that contributes to hardening of the arteries – not cholesterol as such. This fact has only recently been acknowledged as the culprit in cardiovascular disorders.

Vitamin E is found in the following foods: fruit, vegetables and whole grain breads and cereals. Foods are rich in Vitamin E include many vegetable oils, including sunflower, soy and peanut oils, whole grains, wheat germ, leafy green vegetables and liver.

Recommended Dietary Allowances (RDAs) for Vitamin E (Alpha-Tocopherol)
0–6 months*4 mg
(6 IU)
4 mg
(6 IU)
7–12 months*5 mg
(7.5 IU)
5 mg
(7.5 IU)
1–3 years6 mg
(9 IU)
6 mg
(9 IU)
4–8 years7 mg
(10.4 IU)
7 mg
(10.4 IU)
9–13 years11 mg
(16.4 IU)
11 mg
(16.4 IU)
14+ years15 mg
(22.4 IU)
15 mg
(22.4 IU)
15 mg
(22.4 IU)
19 mg
(28.4 IU)

*Adequate Intake (AI)


NOTE: There are easier methods of warding off the visible physical signs of aging. Staying out of the sun, eating a balanced diet, stopping smoking and limiting alcohol consumption are the biggies.

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