Antioxidants are compounds that help prevent
free-radical damage are known as antioxidants or "free-radical scavengers".
These protective compounds are common in our foods such as Vitamins A,
C, E and Coenzyme Q10. Also carotenes such as beta-carotene, which is high
in carrots, and the trace mineral selenium, are well known antioxidants.
Lycopene, which gives tomatoes their colour, is a powerful antioxidant.
Grape seed, maratime pine bark and green tea extracts contain catechins
that have potent antioxidant properties and have become popular natural
medicines.Antioxidants have benn shown to play an important role in disease
As many of these protective compounds are abundant
in fresh fruit and vegetables it is wise to make sure we eat plenty of
them each day. People with cancer are usually recommended to also have
fresh fruit and vegetable juices each day as their body's needs are greater
and juicing provides the extra nourishment, including minerals, with minimum
energy wasted on digestion. For people that are weak and have a lack of
appetite, juicing can provide high quantities of essential antioxidants,
vitamins and minerals that are easily absorbed. It is also possible that
a supplment may be needed.
These are highly reactive molecules that contribute to cell damage
and disease. Although the body produces free radicals our load is increased
with environmental exposure such as chemicals, radiation and X rays and
also ingested compounds in our food and drinks. Some sources are air pollution,
insecticides, radiation such as from computers, and mobile phones, fried
or burnt foods, alcohol and coffee. Cigarette smoke has extremely high
levels of free radicals. Free radicals are toxic because they damage the
body’s cells and DNA and oxidize vital compounds in the body. A familiar
example of oxidation is an apple slice that turns brown--when an apple
is cut into slices and left on the counter for 30 minutes, it begins to
turn brown. But if the slices are coated with lemon juice immediately after
cutting, they will remain their original color. The vitamin C (an antioxidant)
in the lemon juice prevents oxidation, or the browning process. In the
body, this oxidative damage by free radicals is a major contributor to
causing cancer. Free radicals may also play a role in the promotion of
heart disease, Alzheimer’s disease, age-related macular degeneration and
cataracts, and decreased immune function. To make the situation worse,
free radicals accumulate in the body over time and may also convert stable
compounds in the body into free radicals. This may be one reason why cancer
and these other diseases are more prevalent with age.
Antioxidants are needed?
scientists agree that vitamins C and E, beta-carotene, and selenium play
a role in prevention of various degenerative diseases. However, new research
indicates that there may be many other antioxidants that are also important
for maintaining good health. Each antioxidant has its own job to do in
the body, and some even work together. Lutein and zeaxanthin (found in
green leafy and yellow vegetables) are concentrated in the lens and retina
of the eye and have been associated with a reduced risk of cataracts and
(found in tomato products) is concentrated in the prostate gland in men
and may play a role in prevention of prostate cancer. Vitamin C (found
in citrus fruits and some green vegetables) is a water-soluble antioxidant
and works in the watery areas of the body. On the other hand, vitamin E
(found in vegetable oils, nuts, and seeds) is a fat-soluble antioxidant
and works in fat-containing parts of the body, such as the outer lining
(membrane) of cells. Vitamin C can also help regenerate the antioxidant
activity of vitamin E after vitamin E has been used as an antioxidant in
the body. Probably the best prevention plan is a variety of antioxidants
from a variety of sources.
a variety of antioxidants is also important because each antioxidant targets
certain types of damaging free radicals--getting a variety will help cover
all of your health bases.
C: Vitamin C is a water-soluble antioxidant nutrient. It has been shown
to be a factor in reducing risk of various types of cancer, reducing risk
for heart disease, improving immune function (especially in combination
with vitamin E), and reducing risk for cataracts.
E: Vitamin E is a fat-soluble antioxidant nutrient and is the primary
antioxidant found in the lipid-containing tissues of the body (such as
cell membranes, or linings). Vitamin E’s antioxidant activity may be protective
against atherosclerosis (a condition in which arteries narrow and may lead
to heart attack), nervous system disorders, and progression of the human
immunodeficiency virus (HIV) that leads to AIDS. The natural form of vitamin
E (d-alpha-tocopherol) is at least twice as biologically active as the
synthetic form (dl-alpha-tocopherol). Therefore, when using a dietary supplement,
the natural form is preferred.
Carotenoids are the pigments that provide the red, yellow, orange, and
green colors of fruits and vegetables--more than 500 carotenoids have been
identified! The primary dietary carotenoids include beta-carotene, alpha-carotene,
lycopene, lutein, zeaxanthin, and beta-cryptoxanthin. Beta-carotene, alpha-carotene,
and beta-cryptoxanthin can be converted into vitamin A in the body, but
only in amounts that are required by the body. In other words, there is
no risk for vitamin A toxicity by eating too many carrots--only a risk
for an orange glow to the skin.
is a fat-soluble antioxidant that is a member of the carotenoid family
and may play a role in reducing risk for heart disease and prostate cancer.
Observational research has associated beta-carotene with a decreased risk
of various types of cancer; however, two studies indicated that smokers
who supplemented with beta-carotene had an increased risk for lung cancer
versus smokers who did not supplement. Research has not yet discovered
why beta-carotene supplementation produced these unexpected results, but
scientists have proposed several possible explanations: that beta-carotene
may act negatively in the lungs when a carcinogen (tobacco smoke) is present,
and/or that beta-carotene may have an anti-cancer effect only when consumed
with other carotenoids or other antioxidants. More research is needed to
determine the cause of these research results. Until those answers are
available, it’s recommended that smokers avoid supplementing with high
amounts of isolated beta-carotene. For more information on beta-carotene,
see the Health Data Bank paper “Beta-carotene.”
Lycopene, a member of the carotenoid family, is a fat-soluble pigment responsible
for the red color of certain fruits and vegetables. Its pigment protects
the plant from damage by oxygen and light. Lycopene’s antioxidant activity
may play a role in protection against prostate cancer and heart disease.
and zeaxanthin: Lutein and zeaxanthin, members of the carotenoid family,
are fat-soluble pigments responsible for the yellow or green color of certain
fruits and vegetables. Their pigment protects the plant from damage by
oxygen and light. They are found in the lens and macula of the eye and
thought to be protective against age-related macular degeneration (ARMD)
and age-related cataracts.
Selenium is an essential trace mineral, which means that it must be consumed
in the diet for good health. Selenium is also an antioxidant and may play
a role in reducing risk for heart disease and cancer, including prostate,
colorectal, lung, and possibly other types of cancer. Selenium works with
vitamin E in fighting free radicals and is also required for the function
of an important antioxidant enzyme (glutathione peroxidase) in the immune
system. It may even be involved in slowing the progression of the human
immunodeficiency virus (HIV), which leads to AIDS.
Q10 (CoQ10): CoQ10 is a member of the ubiquinone family. This fat-soluble
antioxidant also takes part in energy production in the body’s cells. The
body produces CoQ10, but production decreases with age. Research indicates
that supplementation with CoQ10 may be beneficial for heart health problems
including recovery after congestive heart failure or heart attack. It may
also play a role in reducing the effects of periodontal disease.
acid: Alpha-lipoic acid is produced in the body and found in animal
and plant sources. It’s a highly potent antioxidant that may help protect
against atherosclerosis and may help slow progression of diabetic neuropathy
and HIV. Alpha-lipoic acid has a double benefit by recycling other important
antioxidants, such as vitamin C, vitamin E, coenzyme Q10, and glutathione.
seed extract: Grape seed extract contains compounds called oligomeric
proanthocyanidins (OPCs), or sometimes called procyanidolic oligomers (PCOs).
These compounds are potent antioxidants that may protect against heart
disease and cancer. OPCs have also been shown to have an anti-inflammatory
bark extract: Pine bark extract contains compounds called flavonoids.
More than 4,000 flavonoids have been identified in plants and many are
antioxidants. Pine bark extract may be heart protective and beneficial
in some vascular disorders (circulation problems). It may also have anti-inflammatory
tea: Green tea contains compounds called catechins that have antioxidant
activity. The most potent green tea catechin is called epigallocatechin
gallate (EGCG). Catechins may protect against cancer and atherosclerosis
and may have anti-inflammatory benefits.
Quercetin is a member of a group of compounds called flavonoids. Its antioxidant
activity may play a role in protection against cancer. Preliminary research
indicates it may have beneficial effects on immune function, allergies,
capillary health, stomach health, and diabetic complications such as cataracts
and neuropathy. It has also been shown to have anti-inflammatory properties.
cysteine: N-acetyl cysteine (NAC) is a derivative of the protein amino
acid L-cysteine. NAC has antioxidant activity and also may be converted
to L-cysteine in the body, which in turn may be used to form the antioxidant
glutathione. Glutathione is a potent antioxidant and important for healthy
immune function. NAC may play a role in benefiting liver and heart health,
immune function, and pulmonary and respiratory problems.
Turmeric contains compounds called curcuminoids, which are antioxidants.
Curcuminoids may have anti-cancer and anti-inflammatory benefits. Preliminary
research indicates it may also have antiviral and antifungal benefits and
possibly protect against atherosclerosis.
acid: Ellagic acid is a powerful antioxidant. Preliminary research
indicates it may protect against cancer.
Hesperidin is a member of the flavonoid family and has been shown to have
antioxidant activity. It may be beneficial for circulatory and heart health.
mushroom: Reishi mushroom extract has been shown to have antioxidant
effects. Compounds called triterpenes are thought to be responsible for
its antioxidant activity. Reishi mushroom may play a role in immune function
and possibly cancer prevention.
Sources of Antioxidants?
Fruits and vegetables are the most abundant sources
of antioxidants. Usually the more colorful fruits and vegetables, such
as the deep orange, yellow, green, red, and purple varieties, are the richest
sources of antioxidants.The problem is that many Americans are not eating
enough fruits and vegetables in their diet, they are not eating many of
the colorful antioxidant-rich fruits and vegetables, and they are not eating
a variety of antioxidant-rich foods. A recent study indicates that 30%
of all vegetables consumed by Americans are white potatoes, and one-third
of those potatoes are consumed in the form of French fries. Most of the
lettuce and tomatoes consumed are consumed as condiments. The most commonly
consumed fruits and vegetables in the American diet (iceberg lettuce, French
fries, bananas, tomatoes, and orange juice) do not provide a powerful array
of antioxidant ammunition for disease prevention. The following table provides
food sources of antioxidants:
About Antioxidant Supplements?
a wide variety of colorful fruits and vegetables, whole grains, nuts, and
seeds is the best route to getting antioxidants. This will provide not
only a variety of health-protecting antioxidants, but many other nutrients
and phytochemicals (plant chemicals) that may benefit health and help prevent
disease. The National Cancer Institute recommends at least five or more
servings of fruits and vegetables daily. Research indicates that a daily
intake of five to ten servings of fruits and vegetables is associated with
reduced cancer risk.
most Americans are not consuming the amount or quality of fruits and vegetables
to obtain potential disease-fighting benefits, supplements may help fill
in the gaps. Many nutrition-oriented healthcare professionals recommend
starting with a blend of the basic antioxidant vitamins and minerals. This
may include a daily intake of vitamin C (250-500 mg), vitamin E (200-400
IU), selenium (100-200 mcg), and beta-carotene (10,000-25,000 IU) taken
with other carotenoids such as alpha-carotene, lutein, and zeaxanthin.
Supplementation may be beneficial for those antioxidants that are not available
in significant amounts in foods (such as vitamin E) or those antioxidants
found in foods that may have other negative health effects (high-fat meats
or egg yolks may raise cholesterol). And some antioxidants, such as pine
bark extract, may only be obtained in supplement form.
is much more to learn and discover about antioxidants, but in the meantime,
one message is clear--reduce exposure to free radicals, eat more colorful
fruits and vegetables, and supplement when needed.