What are Antioxidants?
Antioxidants are both natural and man-made substances that may prevent or delay some types of cell damage caused by free radicals. The body makes some of the antioxidants it uses to neutralize free radicals, while the rest come from the food we eat or from supplementation. The term Antioxidant refers to a chemical property where the substance has the ability to donate an electron. Each Antioxidant is different because of the unique chemical and biological properties. This supports the reason why research has problems classifying the benefits of Antioxidants. It is an elaborate network that evolved with no one Antioxidant doing the same job. Antioxidants are chemicals that interact and neutralize free radicals, causing them to no longer be harmful to the body.
Page Contents - Quick Links
- What are Antioxidants?
- Examples of Antioxidants Include:
- Vitamin C
- Vitamin A & Beta-Carotene
- Vitamin E
- Lutein & Zeaxanthin
- What are Free Radicals?
- You are exposed to free radicals:
- Causes of High Concentrations of Free Radicals
- Top 7 Health Benefits of Antioxidants
- Top 10 Foods That Provide the Most Antioxidants
- Simple tips to incorporate more Antioxidants into your diet
- What diseases or sicknesses can Antioxidants prevent?
- Do Antioxidant Supplements Work?
- Are Antioxidants Safe?
Antioxidants are found in many fruits, teas, wine, and vegetables, as well as available in dietary supplements.
Examples of Antioxidants Include:
How does it work
Humans cannot make Vitamin C so it needs to be obtained from diet or supplements. Vitamin C is a water-soluble Antioxidant that regenerates other Antioxidants in the body, including Vitamin E. In addition to being an Antioxidant, it is used for immune function. Vitamin C can limit the formation of carcinogens, modulate immune response and potentially repair oxidative damage that leads to cancer. Studies have shown that high doses in research selectively kill cancer cells. Age-Related Macular Degeneration has some links with Vitamin C, where it may slow progression in those with a high risk of developing the disease. Vitamin C supplementation is also linked with decreased risk of coronary heart disease.
Negative Effects of High Doses
Vitamin C has low toxicity with most common issues with gastrointestinal problems such as nausea, cramps, and diarrhea. Those with kidney disorders can have a higher risk of kidney stone formation with high doses of Vitamin C.
The highest concentrations of Vitamin C can be found in
- red peppers
Vitamin C supplements come in dissolving tablets, pills, and powder form, providing versatility in how it is taken.
How does it work
This fat-soluble vitamin is involved in immune health, cell growth, and vision. There is mixed evidence on the relationship between Beta-Carotene and prostate cancer. Age-Related Macular Degeneration has been linked to Beta-Carotene supplements, in that it lowered risk of advanced stages of the disease. Beta-Carotene found in fruits and vegetables decreases the risk of breast cancer in premenopausal women. Postmenopausal women can find a reduced risk of ovarian cancer with eating a Beta-Carotene rich diet.
Negative Effects of High Doses
In people that smoke, taking Beta-Carotene supplements may increase the risk of colon, lung, and prostate cancer. Beta-Carotene may increase the risk of cancer in those that have been exposed to asbestos.
- sweet potatoes
Vitamin A is available in multivitamins as well as by itself, usually as retinyl acetate or retinyl palmitate. Vitamin A is also available in the Beta-Carotene form.
Orlistat, a weight loss treatment can decrease the absorption of fat-soluble vitamins. Retinoids increase the risk of hypervitaminosis A when taken with Vitamin A supplements. Taking Beta-Carotene, Vitamin C, Vitamin E and Selenium together can decrease the effectiveness of cholesterol lowering medications.
How does it work
Vitamin E is a fat-soluble vitamin that protects cell membranes from oxidations and recycles free radicals. It is involved in immune health and regulates cell signaling, gene expression, and metabolic processes. Vitamin E has both Antioxidant and anti-inflammatory properties. This Vitamin is linked with inhibiting bad cholesterol from adhering to walls of the heart, which causes atherosclerosis. Vitamin E may also prevent blood clots from forming that can lead to heart attacks and thromboembolisms, as well as lowering risks of heart disease. Vitamin E may block the formation of carcinogenic components in the stomach as well as protect from cancer by boosting the immune system. Taking Vitamin E supplements reduced the risk of bladder cancer according to The American Cancer Society studies. Age-Related Macular Degeneration risk is lowered with high dietary intakes of Vitamin E. Vitamin E is related to delayed brain deterioration due to age.
Negative Effects of High Doses
Due to its blood-thinning properties, it increases the risk of hemorrhagic strokes. Large doses of Vitamin E supplements may increase the risk of prostate cancer.
Foods high in Vitamin E include
There are usually only supplements of the alpha-tocopherol version, although there are some that have mixed products containing other versions.
Anticoagulant medications, chemotherapy, and radiotherapy can interactions with Vitamin E.
Lutein & Zeaxanthin
How does it work
Found in the human eye, Lutein and Zeaxanthin protect the eye from the damage of free radicals created by blue light. Both Antioxidants are involved in protection against Age Related Macular Degeneration. An increase of Lutein and Zeaxanthin in diet and supplements lowers the risk of cataracts.
- leafy green vegetables
There are many Lutein supplements available alone and with Zeaxanthin. There are also supplements with just Zeaxanthin.
How does it work
This non-toxic Antioxidant is found in fruit and vegetables. Its job as an Antioxidant is to protect cells in the body from damage. Lycopene supplements are used for prevention against atherosclerosis. Research has shown that oral Lycopene supplements improved sperm quality in men with fertility issues, as well as healing ulcers and swelling in the mouth. Risk of developing pancreatic cancer has been lowered in diets high in lycopene from tomatoes.
Fruits and vegetables that are high in Lycopene include:
- pink grapefruit
Cooking foods that contain Lycopene actually increase the concentration.
Lycopene is available as a supplement, with daily supplements containing up to 120 mg to have been used safely for up to one year.
Some people are allergic or intolerant to Lycopene, leading to diarrhea, nausea, stomach pain, gas, vomiting and loss of appetite. Lycopene may worsen established prostate cancer, so it is advised to avoid this supplement.
How does it work
This mineral element is thought to be an Antioxidant, but the effects are most likely due to the antioxidant activity of selenium-containing proteins. Doctors usually suggest that people with HIV and Crohn’s disease use selenium supplements, while the average healthy person usually does not have a deficiency. Some promising research has found that Selenium can prevent cancer, although the mechanisms are not understood. It is speculated that it prevents DNA damage and reduces oxidative stress. Selenium supplements can improve inflammation in the thyroid, where the highest amount of Selenium in the body is located.
- brazil nuts
- saltwater fish
Selenium is available as a supplement.
Normal dosage does not have side effects. High doses of Selenium may cause fever, nausea, bad breath, kidney, liver and heart problems. Selenium supplements are associated with increased skin and prostate cancer risk.
Selenium can interact with antacids, chemotherapy drugs, corticosteroids, niacin, and birth control pills.
How does it work
Manganese is involved in the formation of connective tissue, bones, blood-clotting factors and sex hormones. It also is important for brain and nerve function as well as being a component of the Antioxidant enzyme Superoxide Dismutase that fights free radicals. Many Americans have a deficiency in Manganese due to refined grains. Those with arthritis have low levels of Superoxide Dismutase, so studies are underway to see if manganese and glucosamine can reduce pain.
- whole grains
- leafy vegetables
Manganese supplements are available.
Manganese supplements may interact with antipsychotics, high blood pressure medicine, antacids, laxatives, tetracycline antibiotics, and quinolone antibiotics.
What are Free Radicals?
Free radicals are highly reactive and unstable chemicals that have the ability to harm cells in our body. They are formed when an atom or molecule gains or loses an electron. Free radicals are formed naturally in the body and are some are used in a positive way. At higher concentrations, they can be hazardous to the body causing damage to DNA, cells, proteins, and cell membranes. Damage to the DNA, by free radicals or other means, can lead to cancer and other diseases. Exercise uses more oxygen; therefore it increases the amount of free radicals created in the body.
You are exposed to free radicals:
- As a result of body processes such as creating energy, exercising, and digesting food.
- When the body breaks down medications.
- Pollutants such as air pollution, sunlight, and cigarette smoke.
- Reactive Oxygen Species: free radicals that are the most common type created in the body.
Oxidative stress is an imbalance between the production of free radicals and ability to counteract the harmful effects of antioxidants. Diseases caused by oxidative stress include
- cardiovascular disease
- age-related macular degeneration
Studies show that these diseases might occur because of oxidant damage to tissues and that diets high in fruits and vegetables lower the risk of these diseases and increase lifespan.
Causes of High Concentrations of Free Radicals
- Ionizing radiation
- Environmental toxins: Cigarette smoke, metals, and high-oxygen atmospheres contain large amounts of free radicals or stimulate the body to produce more free radicals.
When free radicals steal electrons they can alter the function of proteins in the body by changing their structure.If the cell membrane is affected, what enters and leaves the cell may be affected. The role of the antioxidant is to donate electrons to free radicals without adverse effects.
Studies regarding the effects of single Antioxidants as disease prevention are still inconclusive. Although, most of the trials have been conducted over a short time span and on people that had existing diseases. One study looked at the effects of beta-carotene on cognitive function for 18 years with positive outcomes. Evidence suggests that eating fruits, vegetables, and whole grains that are rich in antioxidant and their assisting molecules will provide protection against aging symptoms.
Top 7 Health Benefits of Antioxidants
Free Radical Neutralization
Antioxidants neutralize or remove free radicals from the body by donating an electron to satiate the free radical.
Beta-Carotene, Lutein, and Zeaxanthin are beneficial to eye health by protecting the eye from free radicals caused by blue light. Vitamin C, Vitamin E, Beta-Carotene, and Zinc are associated with reducing the risk of Age-Related Macular Degeneration.
Vitamin C, Vitamin A, and Vitamin E all boost the immune system. Antioxidants also help the body to recover from sickness such as viral and bacterial infections.
Prevention: Since free radicals cause mutations in the DNA, which can lead to cancer, Antioxidants are helpful in aiding our immune system and increase our chances of preventing cancer.
Slow down Aging
By neutralizing free radicals in the body, you can offset the effects of aging. Vitamin C and Vitamin E may also prevent or reverse memory loss. Antioxidants like Vitamin E and Vitamin C can also delay the aging processes in the skin.
Some Antioxidants, like those found in tea, prevent the oxidation of fats that create inflammation. Vitamin E is also known for reducing inflammation in the body.
Heart Disease Prevention
The inflammation caused by free radicals as well as oxidation of bad cholesterol can cause heart disease. Antioxidants can reduce the population of free radicals and lower the risk of heart disease.
Top 10 Foods That Provide the Most Antioxidants
- Red Kidney Bean
- Pinto Bean
- Artichoke Hearts
- Red Delicious Apple
Vegetables and fruits are considered to be rich sources of antioxidants. There is an abundance of evidence that supports that eating fruits and vegetables can lower risks of certain diseases, however, scientists don’t know if this is because of the Antioxidants, the combination of certain Antioxidants or something else present in the foods. No concerns have been raised involving amounts of Antioxidants present in foods.
Simple tips to incorporate more Antioxidants into your diet
- Eat a healthy diet consisting of 5 servings of fruits and vegetables each day.
- Drink black and green tea for added Antioxidants
- Consider using an Antioxidant supplement
What diseases or sicknesses can Antioxidants prevent?
Age-Related Macular Degeneration
A combination of Vitamin C, Vitamin E, Beta-Carotene and Zinc offer protection against macular degeneration.
Lutein is also found to protect vision as a cause of age.
Laboratory studies have found that increased presence of antioxidants found in diet and supplements can prevent free radical damage that is linked with cancer development. These studies have only been performed in animals. Vitamin C can limit the formation of carcinogens, modulate immune response and potentially repair oxidative damage that leads to cancer.
Beta-Carotene reduces the decline of brain function associated with age.
Vitamin E is linked with inhibiting bad cholesterol from adhering to walls of the heart, which causes atherosclerosis.
There needs to be more done in research to understand the complex interactions of Antioxidants, Vitamins, and Minerals in food. In addition to understanding interaction, there also needs to be more information regarding factors that influence uptake and distribution of Antioxidants in the body.
Do Antioxidant Supplements Work?
- Antioxidants alone such as those in supplement form may not be the only factor to providing the health benefits. There could be other substances present in the foods, or lifestyle choices rather than the sole effect of the specific Antioxidant.
- There can be differences in chemical composition of Antioxidants present in foods from those in supplements, which may change the effects. Some Antioxidants have more than one chemical form present in food, while supplement will typically include only one form. This can lead to one form being more effective to treat a disease than another.
- The Antioxidant supplements in scientific studies may not have been given long enough to prevent chronic diseases like cancer and cardiovascular diseases.
- There is still a lot to learn about the interaction of free radicals and health. Antioxidants may help prevent disease in those who are under increased oxidative stress rather than people that are not.
Are Antioxidants Safe?
Antioxidants found in food do not pose any health threat, however, high doses of certain supplements of Antioxidants may be linked to health risks. Like other dietary supplements, there may be medication interactions. There is some concern about excessive doses of Antioxidant supplements and health.
Possible Side Effects of Consuming Too Much Antioxidants
- Beta-Carotene: High doses of supplemental Beta-Carotene may increase the risk of lung cancer in smokers.
- Vitamin E: Using supplements in high doses of Vitamin E may increase risks of prostate cancer and hemorrhagic stroke. Medication interactions include a risk of bleeding in those taking anticoagulant drugs.
- Antioxidant Supplements and Cancer: There is conflicting evidence regarding Antioxidant supplementation and cancer. The National Cancer Institute suggests that those being treated for cancer discuss supplementation with their doctors before taking anything.
If You Are Considering Antioxidant Supplements
- Antioxidant supplements should not be used to replace a healthy diet or conventional medical care
- If you have age-related macular degeneration, consult your doctor to determine if supplements will be appropriate for you.
- If you are pregnant, nursing, or looking to give a supplement to a child, it is especially important to discuss with your doctor.
- Keep in mind that there may be interactions with dietary supplements and that not all ingredients may not be listed on the label.
Supplements that are rich in Antioxidant