ANTIOXIDANTS

 

Before discussing their role in maintaining good health, we must first clarify what antioxidants are. "Antioxidant" is a classification of several organic substances, including vitamins C and E, vitamin A (which is converted from beta-carotene), selenium (a mineral), and a group known as the carotenoids. Carotenoids, of which beta- carotene is the most popular, are a pigment that adds color to many fruits and vegetables -- without them, carrots wouldn't be orange, for example. Together as antioxidants, these substances are thought to be effective in helping to prevent cancer, heart disease, and stroke.

At the molecular and cellular levels, antioxidants serve to deactivate certain particles called free radicals. In humans, free radicals usually come in the form of O2, the oxygen molecule. The oxygen molecule wants to be oxidized, and this oxidation process can sometimes be carcinogenic. Free radicals are the natural by-products of many processes within and among cells. They are also created by exposure to various environmental factors, tobacco smoke and radiation, for instance.

If allowed to go unattended, these free radicals can cause damage to cell walls, certain cell structures, and genetic material within the cells. In the worst case scenario and over a long time period, such damage can become irreversible and lead to disease (e.g., cancer). This is where antioxidants come into play.

Antioxidants play the housekeeper's role, "mopping up" free radicals before they get a chance to do harm in your body. Researchers have postulated that antioxidants prevent the possible carcinogenic effects of oxidation. Despite numerous studies carried out on the role of antioxidants in cancer and heart disease prevention, the jury is still out as to which groups of people, if any, benefit from taking antioxidant supplements.

Some studies have shown that smokers with diets high in carotenoids have a lower rate of lung cancer development than their smoking counterparts whose carotenoid intake is relatively low. Other research efforts have suggested that diets high in carotenoids may also be associated with a decreased risk of breast cancer. Vitamin C has been found to prevent the formation of N-nitroso compounds, the cancer-causing substances from nitrates and nitrites found in preserved meats and in some drinking water.

Many researchers claim that elderly people, especially those who have reduced their food intake, frequent aspirin users, heavy drinkers, smokers, and people with impaired immune systems may benefit from taking antioxidant supplements daily. In terms of heart disease and stroke, it is possible that higher levels of antioxidants slow or prevent the development of arterial blockages, a complicated process involving the oxidation of cholesterol. Moreover, antioxidants may deter the collection of plaque on arterial walls.

Free radicals

Free radicals are highly reactive molecules. Although they are important for normal biological processes, they become destructive when they are out of control, and are the major cause of aging. They can be detrimental by bonding with life-giving protein tissue, so that the tissue no longer performs its rejuvenating tasks. Free radicals attack cell membranes, accumulate in fat cells, and damage nucleic acids (RNA and DNA).


 

Where do free radicals come from?

— All forms of radiation produce free radicals. This includes radiation from computers, radios, TV screens, microwaves, x-rays, radioactive fallout, and food irradiation.
— Any stress — whether caused by infection, emotions or physical trauma — results in an increase of free radicals, which ultimately wastes oxygen.
— Ground meats, such as hamburgers, hot dogs and sausages, are at risk of peroxidation (the breakdown of fat in their membranes), thereby causing free radicals. The same is true of foods that contain a high oil content (nut butters, salad oils and dressings, whipped topping mixtures, foods fried in oil — potato chips, French fries, doughnuts).
— Sunlight, smog, ozone and other environmental pollutants (photochemicals, cigarette smoke, herbicides) are additional causes of free radical formation. Even normal metabolism causes "internal radiation," resulting in free radicals.

The point is that free radicals abound, and they have an intimate relationship with oxygen. Free radicals, because they react with oxygen, may reduce your oxygen supply. And reduced oxygen may cause free radical damage. The exact mechanisms for reduced oxygen vary with the causes.

 

Antioxidants

Not every toxin taking a trip through your blood stream affects your cellular health. You do have a built-in protection system. Antioxidants are compounds or enzymes that oppose the enemy. (Among the antioxidants are vitamins A, C and E; the minerals selenium and zinc; and the enzyme SOD, super oxide dimutase). You need antioxidants for guard duty, to control the oxidative reactions that burn food and create energy. When the free radicals and the antioxidant are out of balance problems arise. Then cells cannot operate in the normal fashion of healthy, aerobic respiratory metabolism.

An antioxidant is like the screen in front of your fireplace. It quenches the sparks as they form. If the fire in the fireplace is out of control, the screen is useless.
Another analogy: antioxidant/free radical metabolism is that of the automobile engine and its cooling system. The engine runs on the burning (or oxidation) of fuel, creating energy and heat, giving your car power to move. If the process is uncontrolled the engine destroys itself because of the heat it has generated. The cooling system keeps the temperature within a normal operating range. The oxidative reaction is the burning of the fuel; the antioxidant is the cooling system. Balance between these two functions is the critical factor, both for your car and for you.

So you see that oxygen is double-dealing. It can be flower or serpent, blowing hot or cold, supporting the very life it could destroy. The fireplace can provide warmth and comfort, but when the fire is out of control, the house may burn down.

 

Free radicals are molecules, or portions of molecules, with 1 electron less than normal. Those molecules are highly reactive so they easily capture an atom from other molecules, starting a chain reaction.

Free radicals, acting on fats of the cellular membranes and the forming of a nucleus in proteins, cause severe damage to cells, disintegrating membranes and nuclei. Free radicals form continuously in human organism for the effect of the oxidative process, to attack viruses and bacteria. Furthermore, smoking, radiation and pollution contribute to create those substances.


Free radicals are the main factor for ageing, tumors, arteriosclerosis and hypertension. The most important of them are: super-oxide-anion O2, hydrogen peroxide H2O2 and hydroxyl OH.


The first is not only the most widespread but also the most dangerous one because it destroys nitric oxide, increasing hypertension level. The reactions with free radicals tend to be perpetual, without anti-oxidizers. Today, free radicals are considered the main factor for inflammation and of ischemic heart disease. A hyper caloric diet increases the production of free radicals, while a hypo caloric one tend to reduce them. For example, a diet of 2400 calories needs 660 g of oxygen, used at 90 - 95% for breathing, the remaining 5 -10% produces the reactive form of oxygen (free radicals and non radicals).

Diseases linked to free radicals are Cancer, Infarct, Arteriosclerosis, Hypertension, Alzheimer, Parkinson, Cataracts, Pigmented Retinitis, and Arthritis.

The cellular zone where oxygen is more active is the mitochondria, endoplasmic reticulum, and membranes. During the normal metabolic processes free radicals form and damage mitochondria and cellular membranes. Those are renewed every 5-6 days. In cancer or ischemia the oxidative damage is so high that the repairing processes are insufficient, and the membranes are damaged out of repair. Sodium and calcium penetrates the cell, killing it. With age the speed at which mitochondria and membrane are repaired decreases, so there is a progressive deterioration of their functions.
Smoking produces a great amount of free radicals (every cigarette induces the formation of 1,000 free radicals).

Free radicals hinder high quality training:

When a sedentary athlete begins to exercise, free radical production increases from 12 to 20 times their resting rate. (Brooks 1984) The faster or longer the athlete exercises, the more proportionate the oxygen-induced free radicals are produced causing definitive tissue damages, fatigue, and pain. The "Univalent Reduction Pathway" produces superoxides, hydroperoxides, and hydroxyl free radicals. The conversion of a sugar, glycogen, and fat occur by oxidation. During this process pairs of hydrogen atoms are released like guided missiles causing a small "micro-membrane-level war and destruction" to underlying tissues and cells.

Damages "felt" from non-neutralized free radicals are stiffness, soreness, lethargy, and lack of motivation the following day or the days following an intense effort. For 95% of all O2 inhaled, no free radicals are released during fuel-conversion, but 5% of them are "dirty".(Ernster 1986) Every 5 minutes during cycling or running, 15-20 breaths out of every 350-400 inhaled breaths releases 100% free radical components in cellular tissues, where body stores of antioxidants must meet and neutralize them as they are produced. As body stores of antioxidants are spent or recruited, regardless of pace or speed or duration, free radicals are permitted free reign, creating more free radicals, which circulate within the athlete's exercising muscle tissues.

Human tissues naturally store three antioxidants for this purpose, Catalase, Super Oxide Dismutase, and Glutathione Peroxidase. Unfortunately, we endurance athletes tend to abuse our physiology to the extent that antioxidant stores are overcome with too much Free Radical build up, and we are forced to either "Rest" or face the likelihood of injury.

Other sources raising free radical activity are as follows.

Free radicals get into to all of us from air pollution, water pollution, herbicides, pesticides, food biodegradation, fat rancidity, ultra-violet radiation, and electro-magnetic pollution.

Free radicals can be neutralized by oral supplementation:

 

 

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