Anti-oxidant FAQ

[Stout1]

posted by Lozgod:

What are anti-oxidants?

Anti-oxidants are substances that prevent or reduce the rate of oxidation. Anti-oxidants usually work by giving up their electrons more easily than do the tissues we want to protect. By donating electrons to substances that have been oxidized they act as "reducing" agents.

Visualize it:
When the surface of a sliced apple turns brown, this is called oxidation, which is caused by oxygen found in the air. A little lemon juice, which contains vitamin C and other anti-oxidants, will retard this browning. Other examples of oxidation in action can be seen in the flames of fires and in the rusting of iron.

Slow oxidation is the body's energy source as we "burn" food in our cells. In chemistry, oxidation refers to changes in atoms and molecules in which the electrical charge of the unit becomes more positive through the loss of one or more electrons. The nucleus of atoms is positively charged with protons, whereas electrons orbiting around the nucleus (as planets orbit around the sun) are negative. It is the nature of these orbits to usually be more stable when the electrons are in pairs. An atom or molecule is said to be "oxidized" as it loses its electron(s), whereas if it regains its electron(s), it is said to be "reduced." Although many other compounds can also act as oxidizers, oxygen, which is present everywhere in the air, is the most active "oxidizing" agent.


What are free radicals?

Free radicals are highly reactive atoms or molecules that have at least one negative electrical charge as a result of having one or more unpaired electrons.

The term "radical" refers to the ability of these reactive compounds to initiate a series of damaging changes in other substances. Free radicals are very unstable and tend to rob surrounding molecules of electrons in order to replace their own losses. Oxygen itself is commonly turned into various free radicals. These are called oxygen-free radicals or reactive oxygen species. Free radicals tend to activate chain reactions in which series of thefts and donations of electrons take place. In this chain reaction process, stable compounds are robbed of electrons, become unstable, steal electrons in turn, and so forth.

Although the body uses both oxidation and free radicals for many purposes, such as in energy production in aspects of immune function, free radicals must be controlled in order to protect our tissues from inflammation and other types of damage.


What are some of the most common anti-oxidant nutrients?

The body makes use of a great variety of anti-oxidants and free radical scavengers for different purposes and to protect tissues with different needs.

Vitamins A, C, and E have important anti-oxidant functions. The B vitamins, although not technically anti-oxidants, often act as co-factors with anti-oxidants. The vitamin-like compounds alpha-lipoic acid and coenzyme Q-10 are powerful anti-oxidants.

The body uses the minerals copper, magnesium, manganese, selenium, and zinc to produce powerful anti-oxidant compounds.

Anti-oxidants include beta-carotene and other similar brightly colored pigments found in foods, such as lycopene in tomatoes and the anthocyanidins in grapes and other berries. Certain colorless compounds, including the catechins found in green tea and the proanthocyanidins found in the coats of grape seeds and in some (mostly red) wines are especially noteworthy as anti-oxidants. Other anti-oxidants include ellagic acid in strawberries, resveratrol found in some red wines, and the isoflavones found in soybeans and in members of the cabbage family.

Finally, even some amino acids, such as taurine, can act as anti-oxidants.


Which is the best anti-oxidant?

There is no one "best" anti-oxidant and here's why.

Water-soluble anti-oxidants like vitamin C are best at protecting those tissues that contain water-soluble compounds, such as proteins. Fat-soluble anti-oxidants like vitamin E are best at protecting fat-based tissues, such as the membranes of all cells. Most studies have shown far superior results when a mixture of many different anti-oxidants is used instead of more of any single anti-oxidant.

A case can be made, however, that anti-oxidants that protect both types of tissues and which may improve the results of other anti-oxidants are especially useful as supplements. Such "team" players include alpha-lipoic acid and proanthocyanidins.


What foods contain anti-oxidants?

Most anti-oxidants in the diet come from fruits and vegetables. Because fruits and vegetables are our best sources of anti-oxidants, most authorities recommend that we eat five or more servings per day. The payoff is worth it.

Let's consider some of the compounds you miss if you don't eat your vegetables. The carotinoids not only are anti-oxidants, but they encourage cells to differentiate and to mature properly, something which cancer cells do not do. Bright yellow and orange fruits and vegetables, such as carrots and sweet potatoes, but also deep green vegetables, such as parsley and kale, are good sources.

Catechins, components of grape seed extracts, are also found in green tea and many berries.

The flavonoids, found in brightly colored fruits and vegetables, are anti-oxidants that block the receptor sites of some hormone-sensitive cancers.

The indoles, found in all members of the cabbage family, induce the body to produce protective enzymes.

The isothiocyanates, found in mustard, horseradish and radishes, also induce the body to produce protective enzymes.

Lycopene is a special member of the carotene family that protects the prostate and that is an especially powerful anti-oxidant; it is common in tomatoes and red grapefruit.

Ellagic acid, found in abundance in strawberries, helps to prevent the formation of the carcinogen called nitrosamine in our digestive system.

Anti-oxidants can also be found in some otherwise unlikely places. The soybean, for instance, contains substances called isoflavones. Genistein is the best known of these. It is an anti-oxidant that also has a number of special anti-cancer properties. Genistein or a precursor to genistein may be found in some members of the cabbage family, as well.


What kinds of damage do free radicals cause? How can free radicals contribute to cancer, heart disease, arthritis, and other health problems?

Free radicals can attack the membranes of cells, proteins and fats in the blood stream, the collagen that lies beneath the skin and many other tissues. In general, they interfere with cellular processes.

Much recent work on the causes of cardiovascular disease suggests that fats in the blood become damaging to the arteries primarily as a result of having undergone oxidation. These damaged fats become embedded in the lining of the arteries, poison the immune cells, which attempt to remove them, and lead to the production of aortic plaques.

Oxidized blood fats, similarly, have been linked to diabetes in research that has shown that oxidized blood fats interfere with the actions of the hormone insulin.

Free radical damage is associated with most or all degenerative diseases. In arthritis, free radicals are active in the chronic inflammation that causes pain and stiffness and damages the joints. The results of free radical damage account for most aging and for most of the obvious signs of aging we experience before we approach our genetic or biological limit at the age 80 or 90 years.

Cancers, too, are largely the result of free radical damage. Free radicals can attack and alter the genetic code in the cells and transform normal cells. Free radical scavengers, substances that act as electron donors and receptors without becoming reactive or toxic themselves, offer protection against these types of damage.


Can anti-oxidants prevent heart attacks, stress, protect the lining of the arteries, and prevent high blood pressure?

Very strong scientific evidence shows that anti-oxidants offer protection against unwanted changes in the body. Many disease conditions are associated with low levels of anti-oxidants in the blood and in the tissues.

Clinical trials routinely find significant health benefits when the anti-oxidant intake from the diet is increased.

The vitamins C and E help to protect fats in the blood against damage, prevent the formation of foam cells in the artery lining, and improve the body's ability to utilize insulin to control blood sugar levels. These are important factors in preventing heart disease and hypertension. Vitamin E is even a natural minor blood "thinner" and it improves the amount of blood pumped by the heart.

Plant compounds (known as polyphenols, including anthocyanidins and proanthocyanidins) found in many fruits, are given in Europe to support the health of the veins and arteries. A number of plant anti-oxidants help normalize blood pressure and prevent oxidized materials from the blood from "sticking" to the artery walls and causing damage. In the scientific literature, such matters are discussed in terms of improving the production of the compound nitric oxide by cells in the lining of the arteries, reducing the release of the blood clotting compound known as platelet activating factor (PAF), inhibiting angiotensin-I converting enzyme (ACE), and so forth. In everyday language, these medical terms mean that various anti-oxidants relax the walls of the arteries, reduce the tendency to build plaques in these arteries, and inhibit the retention of sodium by the kidneys.

To give one example, in animal experiments, grape seed extract had reduced elevated blood pressure by as much as 20 percent. Moreover, such important health benefits come without side effects.


How do anti-oxidants protect against cancer?

Cancers very rarely appear in the body without an extended period of time during which cells change internally. Researchers call this the "initiation" phase of cancer development.

For a cell to become cancerous, important alterations must occur in the genetic "blueprint" found in the nucleus of that cell. Free radicals attack this genetic map for cell growth and development in several ways. Sometimes guardian genes, which normally cause cancerous cells to "autodestruct" in a process called apoptosis, are turned off. At other times, genes, which should only be active during the first few months of life, are reactivated in cells. In other instances, normal genes are damaged such that they begin to act abnormally.

Anti-oxidants help to prevent all of these types of damage to the genetic codes of the cells. Some anti-oxidants act directly inside the cells to prevent free radicals from gaining access to the genes and to even encourage genetic repair mechanisms. The versatile compound S-adenosyl-L-methionine (SAMe) is a good example of such an anti-oxidant. Anti-oxidants also act indirectly by preventing the formation of toxic compounds and even by improving the body's ability to excrete toxins. The indoles and other phytonutrients (plant nutrients) found in members of the cabbage family, for instance, strongly support the detoxification processes of the liver through which toxic compound are bound up and removed from the system. Finally, cancerous cells always suffer from defects in energy production, and some powerful anti-oxidants, including alpha-lipoic acid and coenzyme Q-10, improve cellular energy production.


How do anti-oxidants boost immunity?

To understand how anti-oxidants boost immunity, one must first realize that a prominent internal source of free radicals is the activity of the immune system itself. The immune cells classified as phagocytes, such as the large white cells called macrophages and neutrophils, are early defenses against bacterial and yeast invasion of the tissues. Their active presence at the site of an infection is often characterized by inflammation. These large leukocytes typically destroy invaders by the release of what is termed an "oxygen burst." This burst begins with superoxide radicals (O2 -), which are released through the action of the enzyme NADPH (reduced nicotinamide-adenine dinucleotide phosphate) as it donates an electron. The superoxide is then very quickly transformed into hydrogen peroxide and hydroxyl radicals.

In other words, the body generates its own free radicals and the immune cells must have their own protection against the free radicals they generate. This protection comes from protective anti-oxidants, anti-oxidant enzymes, and free radical scavengers. Vitamin C levels, for instance, drop dramatically in white blood cells during infections because the cells use the vitamin for their own protection.

Anti-oxidants are known to perform yet other immune-boosting functions. Some anti-oxidants increase the production of interferon and other immune components, and a number of anti-oxidants are themselves directly toxic to viruses and/or prevent viruses from gaining entry into cells for replication.


Can anti-oxidants help me live longer?

Let's ask this question differently: Are anti-oxidants important in the diets of human populations known for longevity? The answer here is clearly "yes!" In two areas of the world known for longevity for good health into old age, anti-oxidant consumption is a common factor.

Both the Mediterranean and the Japanese diets are associated with good health and longevity. The first is a diet relatively high in fats and the second is a diet relatively low in fats, therefore fat content is not a common factor. However, both of these otherwise very different cuisines emphasize the consumption of wide variety of foods, including whole fruits and vegetables, and both stress that food must be fresh. Compared to the typical American, the typical individual in southern France or in Japan will consume more and a greater variety of anti-oxidants on a daily basis.


Can anti-oxidants really create younger looking skin?

Absolutely. It is sometimes said that the skin is the outer reflection of inner health, and there is much truth to this. One reason why this is true is that the same collagen "building blocks" used to construct and maintain the skin, also help maintain the integrity of much of the rest of the body.

Collagen fibers are constructed from chains of amino acids, which are woven together to form the strands. These fibers are the primary structural proteins of the body and they take various shapes to match the body's needs. Thin layers form the skin, similar layers of collagen in the form of elastin line the veins and arteries, rope-like structures form the tendons, a collagen webbing filled with proteoglycans constitutes the cartilage of the joints, and yet another shape supplies the basic scaffolding of the bones. As this suggests, collagen is the most abundant protein found in the body. It consists not only of amino acids, but also of specialized sugars that influence its strength. In addition to these, the synthesis of collagen requires vitamin C and the minerals copper, iron, manganese, silicon, and zinc. Anti-oxidants create younger looking skin by reducing the sources of inflammation and by inhibiting enzymes, such as hyaluronidase, which break down collagen-based tissues. Proanthocyanidins inhibit hyaluronidase, for instance. Some anti-oxidants, such as N-acetyl-cysteine (NAC), even improve the rate at which collagen is created.


Can anti-oxidants improve fertility?

Yes, for men and women. The case is clearer in men, for whom vitamins C, E and the mineral selenium, which supports important anti-oxidant functions, can improve the number and the viability of sperm. High levels of free radicals are found in the semen of at least forty percent of infertile men. In women, selenium probably has the best record of improving fertility. It should be kept in mind that fertility in both sexes is strongly tied to overall health. Therefore, for best results, anti-oxidants are best utilized as part of a general program for maintaining and improving health.


Can anti-oxidants protect against Alzheimer's disease?

The cause of Alzheimer's disease is not known, although there are many elements that are strongly linked statistically with this condition. On the one hand, higher levels of the metals aluminum and mercury are found in the brains of Alzheimer's patients, and it is known that these metals are toxic. On the other hand, levels of anti-oxidants are typically depressed in the brains of Alzheimer's patients. Moreover, there also may be an immune system component to this condition and anti-oxidants help to control excessive immune activity in many tissues. The bottom line is that adequate anti-oxidant intake may be of benefit, but the cause of Alzheimer's disease remains elusive.


What is a more comprehensive anti-oxidant program?

Keep in mind that the body uses many different anti-oxidants for many different purposes. A comprehensive anti-oxidant program should:
1) Look to the diet and increase the number of vegetables and whole fruits consumed every day.
2) Include supplementary anti-oxidants that cover a wide spectrum of water-soluble and fat-soluble anti-oxidants in generally moderate doses. Aside from anti-oxidant vitamins, such as C and E, vitamin-like anti-oxidants should be considered, such as alpha-lipoic acid and coenzyme Co-Q-10, and anti-oxidant-related minerals should also be supplemented, such as magnesium, manganese, selenium, and zinc. Just as important, plant anti-oxidant mixtures can be added to these to broaden their benefits. Well-known and proven herbal anti-oxidants include Ginkgo biloba extracts, grape seed extracts, and Pycnogenol. Some of the most famous Chinese longevity-promoting herbs, for example, Ho shu wu, are good sources of powerful anti-oxidants, including proanthocyanidins and resveratrol.