Antioxidants Are True Superheroes
What are Antioxidants?
In the world of molecules, antioxidants are true superheroes. They are our bodies’ first line of defense against free radicals, which are unstable molecules that can wreak all kinds of havoc on cells, proteins and DNA. In order to understand why antioxidants are so important, we need to get acquainted with their enemies:
Free Radicals
Free radicals are formed within our bodies as by-products of normal aerobic respiration, metabolism, and inflammation. They also arise from environmental factors such as pollution, sunlight, or smoking.
Free radicals come in many shapes, sizes, and chemical configurations, but they all have at least one unpaired electron, making them highly unstable and reactive. They scavenge the body …show more content…
to grab electrons, damaging cells and interfering with their normal function. This damage is called oxidation, and it’s essentially the same process that causes a cut apple to turn brown, or iron to rust.
Over time, all this damage to cells can accumulate, potentially causing or contributing to many health problems such as heart disease, macular degeneration, diabetes, and cancer.
Antioxidants to the Rescue
Antioxidants prevent or slow the oxidative damage to our body by generously giving electrons to free radicals—neutralizing them—without turning into electron-scavenging substances themselves.
In doing so, the antioxidants themselves become oxidized, which is why there is a constant need to replenish our antioxidant resources.
Antioxidants work in one of two ways to neutralize free radicals: chain-breaking or chain-prevention. When a free radical steals an electron, a second radical is formed, beginning a chain reaction that will continue to generate unstable molecules until termination occurs—either the free radical is stabilized by a chain-breaking antioxidant, or it eventually decays. Other antioxidants work by scavenging “chain-initiating” free radicals, neutralizing them before an oxidative chain reaction can even begin.
Antioxidants are nutrients (vitamins and minerals) as well as enzymes (proteins in the body that assist in chemical reactions). Each one has unique chemical behaviors and biological properties. Antioxidants are not all the same, and they are not interchangeable. The effectiveness of any given antioxidant in the body depends on which free radical is involved, how and where it is generated, and where the site of damage is. In fact, technically the term “antioxidant” refers not to the substance itself, but to a chemical property (i.e. the ability to act as an electron donor) and a substance that in some cases acts as an antioxidant might in other circumstances have no effect at all, or even act as a “pro-oxidant” or electron
grabber.
Antioxidant Enzymes
The first line of defense that the body has against free radicals is the enzyme known as superoxide dismutase(SOD), which works together with the enzyme catalase (CAT) to keep superoxides (common free radicals that are highly reactive forms of oxygen) under control.
Glutathione peroxidase is another important antioxidant enzyme. Cell membranes consist primarily of lipids (fats), which are very susceptible to damage by a group of free radicals called peroxides. Glutathione peroxidase prevents destruction of cell membranes by removing several classes of these peroxide radicals.
Antioxidant Nutrients
There are thousands of different nutrients that can act as antioxidants. Listed below are some of the most familiar ones:
Vitamin E (Alpha-tocopherol) is a fat-soluble vitamin. It plays an important role in safeguarding cell membranes (which are largely composed of fatty acids) from damage by free radicals. Alpha-tocopherol also protects the fats in low-density lipoproteins (LDL, or “bad” cholesterol) from oxidation. It is found in almonds and other nuts and seeds, whole grains, vegetable oils, and green leafy vegetables.
Vitamin C, also known as ascorbic acid, is a water-soluble vitamin. It is well-suited to the environment inside cells and works synergistically with vitamin E to extinguish free radicals. Vitamin C also helps protect the fat-soluble vitamins A and E, as well as fatty acids, from oxidation. Sources of vitamin C include citrus fruits, green leafy vegetables, broccoli, strawberries and tomatoes. It’s easy to illustrate vitamin C’s antioxidant properties: remember the cut apple? What happens when you cover one half with lemon juice?
Carotenoids are natural plant pigments found in deeply colored fruits and vegetables, and are powerful antioxidants. Beta-carotene is the most widely studied of the 600 or so carotenoids identified to date. It is thought to be the best scavenger of singlet oxygen (a form of oxygen that is toxic to cells). Beta-carotene sources include cantaloupe, mangoes, papaya, pumpkin, peppers, spinach, kale, squash, sweet potatoes, and apricots. Lutein, best known for its association with healthy eyes, is abundant in green, leafy vegetables such as collard greens, spinach, and kale. Lycopene is the potent antioxidant found in tomatoes (especially in concentrated forms such as tomato paste), watermelon, and pink grapefruit.
Selenium is a mineral (a nutrient that is essential, but only needed in very small quantities) that is a component of several antioxidant enzymes including glutathione peroxidase. The amount of selenium in soil, which varies by region, determines the amount of selenium in the foods grown in that soil. Animals that eat grains or plants grown in selenium-rich soil have higher levels of selenium in their muscle. In the United States, red meat and bread are common sources of dietary selenium. Other sources include Brazil nuts, fish and shellfish, eggs, and garlic. Similar to selenium, the minerals manganese and zinc are other trace elements that form an essential part of various antioxidant enzymes.
Other Antioxidants
In addition to enzymes, vitamins, and minerals, there appear to be many other nutrients and compounds that have antioxidant properties. Among them are coenzyme Q10, which is essential to energy production, and uric acid, a product of DNA metabolism. Additionally, substances in plants called phytochemicals (which include the carotenoids) are being investigated for their antioxidant activity and health-promoting potential.
Do Antioxidants Improve Health?
Since antioxidants counteract the harmful effects of free radicals, it might logically follow that we should consume large quantities of them. This is true to a degree: hundreds of observational studies suggest that eating a diet high in antioxidant-rich fruits, vegetables, whole grains, beans and legumes is associated with a lower risk for many chronic diseases like cancer, heart disease, stroke, cataracts, Parkinson’s, Alzheimer’s, and arthritis.
However, taking an antioxidant out of its natural context and packaging it into a supplement may not help. Large, long-term studies (randomized, controlled trials) have mostly found that antioxidant supplements have no beneficial effects. Although supplements containing antioxidants are generally considered safe, there are some concerns that consuming mega-doses of antioxidants could be harmful due to their potential toxicity and interactions with medications.
If You Are Thinking About Using Antioxidant Supplements: * Do not use antioxidant supplements as a replacement for a healthful diet or conventional medical care, or as a reason to postpone seeing a doctor about a medical problem. * Consult your health care provider before deciding to use antioxidant supplements. * Look for published research studies on antioxidant supplements for the health condition that interests you. * Tell all of your health care providers about any complementary and alternative practices you use.
Despite the disappointing findings of trials so far, scientists remain certain of the many potential benefits of dietary antioxidants. There is plenty of additional research under way, including studies supported by the National Center for Complementary and Alternative Medicine (NCCAM) and other components of the National Institutes of Health (NIH).
Best Food Sources of Antioxidants
A supplement may contain a single type of antioxidant, or even several types. However, food contains thousands of types of antioxidants—vitamin A alone has several hundred forms—and it’s not known which of these substances are able to confer benefits. Many scientists believe that antioxidants in food form chemical networks that interact with our own cellular and genetic intricacies. In addition, other nutrients may be present in fruits and vegetables that work in sync with antioxidants and are necessary to provide a protective effect.
When it comes to antioxidant intake, no one food or food group should be the exclusive focus. It’s best to include a wide variety of foods as part of a healthy, well-balanced diet. Some of the best sources of antioxidants include: * Berries—blueberries, blackberries, raspberries, strawberries and cranberries are among the top sources of antioxidants. * Beans—small red beans and kidney, pinto and black beans are all choices rich in antioxidants. * Fruits—many apple varieties are high in antioxidants, as are avocados, cherries, green and red pears, fresh or dried plums, pineapple, kiwi, acai berries, and others. * Vegetables—those with the highest antioxidant content include broccoli, tomatoes, artichokes, spinach, red cabbage, red and white potatoes (include the peel), and sweet potatoes. In many cases, cooking vegetables (especially tomatoes) increases the availability of their antioxidants. * Beverages—green tea, coffee, red wine and many fruit juices such as pomegranate. * Nuts—walnuts, pistachios, pecans, hazelnuts and almonds are some of the top nuts for antioxidant content. * Herbs & Spices—these may be unexpected sources, but ground cloves, cinnamon and ginger, dried oregano leaf and turmeric powder are all packed with antioxidants. And don’t forget garlic, which along with onions, chives and leeks, contains an important class of antioxidant phytochemicals called allyl sulfides. * Grains—in general, oat-based products are higher in antioxidants than are those derived from other grain sources. * Dark Chocolate—and for dessert, dark chocolate is chock-full of antioxidant flavonoids!
As a bonus, almost all of the above are plant-based whole foods which offer many health benefits in addition to their antioxidant content. And of course, getting regular exercise, reducing stress, and abstaining from harmful practices like smoking are also essential parts of a healthy lifestyle.
Benefits of antioxidants
Numerous studies with plant phytochemicals show that phytochemicals with antioxidant activity may reduce risk of cancer and improve heart health.
Antioxidants reduce the risk of cancer
Not all results are conclusive but many studies show that antioxidants may reduce the risk of cancer. A large randomized trial on antioxidants and cancer risk was the Chinese Cancer Prevention Study (1993). This study showed that a combination of the antioxidants beta-carotene, vitamin E and selenium significantly reduced incidence of cancer. However, the Alpha-Tocopherol / Beta-Carotene Cancer Prevention Study (1994) showed that intake of beta-carotene increased lung cancer rates of male smokers.
Antioxidants protect the heart
Everyone knows that cholesterol causes heart diseases and tries to limit cholesterol intake. But a more important cause of fatty buildups in the arteries is the oxidation of low-density lipoprotein cholesterol. The use of dietary supplements of antioxidants could reduce the risk of cardiovascular disease, but there is no hard evidence. At this stage, studies only show that the intake of foods, naturally rich in antioxidants reduces this risk.
Adverse effects
Relatively strong reducing acids can have antinutrient effects by binding to dietary minerals such as iron and zinc in the gastrointestinal tract and preventing them from being absorbed. Notable examples are oxalic acid, tannins and phytic acid, which are high in plant-based diets. Calciumand iron deficiencies are not uncommon in diets in developing countries where less meat is eaten and there is high consumption of phytic acid from beans and unleavened whole grain bread.
In the world of molecules, antioxidants are true superheroes. They are our bodies’ first line of defense against free radicals, which are unstable molecules that can wreak all kinds of havoc on cells, proteins and DNA. In order to understand why antioxidants are so important, we need to get acquainted with their enemies:
Free Radicals
Free radicals are formed within our bodies as by-products of normal aerobic respiration, metabolism, and inflammation. They also arise from environmental factors such as pollution, sunlight, or smoking.
Free radicals come in many shapes, sizes, and chemical configurations, but they all have at least one unpaired electron, making them highly unstable and reactive. They scavenge the body …show more content…
to grab electrons, damaging cells and interfering with their normal function. This damage is called oxidation, and it’s essentially the same process that causes a cut apple to turn brown, or iron to rust.
Over time, all this damage to cells can accumulate, potentially causing or contributing to many health problems such as heart disease, macular degeneration, diabetes, and cancer.
Antioxidants to the Rescue
Antioxidants prevent or slow the oxidative damage to our body by generously giving electrons to free radicals—neutralizing them—without turning into electron-scavenging substances themselves.
In doing so, the antioxidants themselves become oxidized, which is why there is a constant need to replenish our antioxidant resources.
Antioxidants work in one of two ways to neutralize free radicals: chain-breaking or chain-prevention. When a free radical steals an electron, a second radical is formed, beginning a chain reaction that will continue to generate unstable molecules until termination occurs—either the free radical is stabilized by a chain-breaking antioxidant, or it eventually decays. Other antioxidants work by scavenging “chain-initiating” free radicals, neutralizing them before an oxidative chain reaction can even begin.
Antioxidants are nutrients (vitamins and minerals) as well as enzymes (proteins in the body that assist in chemical reactions). Each one has unique chemical behaviors and biological properties. Antioxidants are not all the same, and they are not interchangeable. The effectiveness of any given antioxidant in the body depends on which free radical is involved, how and where it is generated, and where the site of damage is. In fact, technically the term “antioxidant” refers not to the substance itself, but to a chemical property (i.e. the ability to act as an electron donor) and a substance that in some cases acts as an antioxidant might in other circumstances have no effect at all, or even act as a “pro-oxidant” or electron
grabber.
Antioxidant Enzymes
The first line of defense that the body has against free radicals is the enzyme known as superoxide dismutase(SOD), which works together with the enzyme catalase (CAT) to keep superoxides (common free radicals that are highly reactive forms of oxygen) under control.
Glutathione peroxidase is another important antioxidant enzyme. Cell membranes consist primarily of lipids (fats), which are very susceptible to damage by a group of free radicals called peroxides. Glutathione peroxidase prevents destruction of cell membranes by removing several classes of these peroxide radicals.
Antioxidant Nutrients
There are thousands of different nutrients that can act as antioxidants. Listed below are some of the most familiar ones:
Vitamin E (Alpha-tocopherol) is a fat-soluble vitamin. It plays an important role in safeguarding cell membranes (which are largely composed of fatty acids) from damage by free radicals. Alpha-tocopherol also protects the fats in low-density lipoproteins (LDL, or “bad” cholesterol) from oxidation. It is found in almonds and other nuts and seeds, whole grains, vegetable oils, and green leafy vegetables.
Vitamin C, also known as ascorbic acid, is a water-soluble vitamin. It is well-suited to the environment inside cells and works synergistically with vitamin E to extinguish free radicals. Vitamin C also helps protect the fat-soluble vitamins A and E, as well as fatty acids, from oxidation. Sources of vitamin C include citrus fruits, green leafy vegetables, broccoli, strawberries and tomatoes. It’s easy to illustrate vitamin C’s antioxidant properties: remember the cut apple? What happens when you cover one half with lemon juice?
Carotenoids are natural plant pigments found in deeply colored fruits and vegetables, and are powerful antioxidants. Beta-carotene is the most widely studied of the 600 or so carotenoids identified to date. It is thought to be the best scavenger of singlet oxygen (a form of oxygen that is toxic to cells). Beta-carotene sources include cantaloupe, mangoes, papaya, pumpkin, peppers, spinach, kale, squash, sweet potatoes, and apricots. Lutein, best known for its association with healthy eyes, is abundant in green, leafy vegetables such as collard greens, spinach, and kale. Lycopene is the potent antioxidant found in tomatoes (especially in concentrated forms such as tomato paste), watermelon, and pink grapefruit.
Selenium is a mineral (a nutrient that is essential, but only needed in very small quantities) that is a component of several antioxidant enzymes including glutathione peroxidase. The amount of selenium in soil, which varies by region, determines the amount of selenium in the foods grown in that soil. Animals that eat grains or plants grown in selenium-rich soil have higher levels of selenium in their muscle. In the United States, red meat and bread are common sources of dietary selenium. Other sources include Brazil nuts, fish and shellfish, eggs, and garlic. Similar to selenium, the minerals manganese and zinc are other trace elements that form an essential part of various antioxidant enzymes.
Other Antioxidants
In addition to enzymes, vitamins, and minerals, there appear to be many other nutrients and compounds that have antioxidant properties. Among them are coenzyme Q10, which is essential to energy production, and uric acid, a product of DNA metabolism. Additionally, substances in plants called phytochemicals (which include the carotenoids) are being investigated for their antioxidant activity and health-promoting potential.
Do Antioxidants Improve Health?
Since antioxidants counteract the harmful effects of free radicals, it might logically follow that we should consume large quantities of them. This is true to a degree: hundreds of observational studies suggest that eating a diet high in antioxidant-rich fruits, vegetables, whole grains, beans and legumes is associated with a lower risk for many chronic diseases like cancer, heart disease, stroke, cataracts, Parkinson’s, Alzheimer’s, and arthritis.
However, taking an antioxidant out of its natural context and packaging it into a supplement may not help. Large, long-term studies (randomized, controlled trials) have mostly found that antioxidant supplements have no beneficial effects. Although supplements containing antioxidants are generally considered safe, there are some concerns that consuming mega-doses of antioxidants could be harmful due to their potential toxicity and interactions with medications.
If You Are Thinking About Using Antioxidant Supplements: * Do not use antioxidant supplements as a replacement for a healthful diet or conventional medical care, or as a reason to postpone seeing a doctor about a medical problem. * Consult your health care provider before deciding to use antioxidant supplements. * Look for published research studies on antioxidant supplements for the health condition that interests you. * Tell all of your health care providers about any complementary and alternative practices you use.
Despite the disappointing findings of trials so far, scientists remain certain of the many potential benefits of dietary antioxidants. There is plenty of additional research under way, including studies supported by the National Center for Complementary and Alternative Medicine (NCCAM) and other components of the National Institutes of Health (NIH).
Best Food Sources of Antioxidants
A supplement may contain a single type of antioxidant, or even several types. However, food contains thousands of types of antioxidants—vitamin A alone has several hundred forms—and it’s not known which of these substances are able to confer benefits. Many scientists believe that antioxidants in food form chemical networks that interact with our own cellular and genetic intricacies. In addition, other nutrients may be present in fruits and vegetables that work in sync with antioxidants and are necessary to provide a protective effect.
When it comes to antioxidant intake, no one food or food group should be the exclusive focus. It’s best to include a wide variety of foods as part of a healthy, well-balanced diet. Some of the best sources of antioxidants include: * Berries—blueberries, blackberries, raspberries, strawberries and cranberries are among the top sources of antioxidants. * Beans—small red beans and kidney, pinto and black beans are all choices rich in antioxidants. * Fruits—many apple varieties are high in antioxidants, as are avocados, cherries, green and red pears, fresh or dried plums, pineapple, kiwi, acai berries, and others. * Vegetables—those with the highest antioxidant content include broccoli, tomatoes, artichokes, spinach, red cabbage, red and white potatoes (include the peel), and sweet potatoes. In many cases, cooking vegetables (especially tomatoes) increases the availability of their antioxidants. * Beverages—green tea, coffee, red wine and many fruit juices such as pomegranate. * Nuts—walnuts, pistachios, pecans, hazelnuts and almonds are some of the top nuts for antioxidant content. * Herbs & Spices—these may be unexpected sources, but ground cloves, cinnamon and ginger, dried oregano leaf and turmeric powder are all packed with antioxidants. And don’t forget garlic, which along with onions, chives and leeks, contains an important class of antioxidant phytochemicals called allyl sulfides. * Grains—in general, oat-based products are higher in antioxidants than are those derived from other grain sources. * Dark Chocolate—and for dessert, dark chocolate is chock-full of antioxidant flavonoids!
As a bonus, almost all of the above are plant-based whole foods which offer many health benefits in addition to their antioxidant content. And of course, getting regular exercise, reducing stress, and abstaining from harmful practices like smoking are also essential parts of a healthy lifestyle.
Benefits of antioxidants
Numerous studies with plant phytochemicals show that phytochemicals with antioxidant activity may reduce risk of cancer and improve heart health.
Antioxidants reduce the risk of cancer
Not all results are conclusive but many studies show that antioxidants may reduce the risk of cancer. A large randomized trial on antioxidants and cancer risk was the Chinese Cancer Prevention Study (1993). This study showed that a combination of the antioxidants beta-carotene, vitamin E and selenium significantly reduced incidence of cancer. However, the Alpha-Tocopherol / Beta-Carotene Cancer Prevention Study (1994) showed that intake of beta-carotene increased lung cancer rates of male smokers.
Antioxidants protect the heart
Everyone knows that cholesterol causes heart diseases and tries to limit cholesterol intake. But a more important cause of fatty buildups in the arteries is the oxidation of low-density lipoprotein cholesterol. The use of dietary supplements of antioxidants could reduce the risk of cardiovascular disease, but there is no hard evidence. At this stage, studies only show that the intake of foods, naturally rich in antioxidants reduces this risk.
Adverse effects
Relatively strong reducing acids can have antinutrient effects by binding to dietary minerals such as iron and zinc in the gastrointestinal tract and preventing them from being absorbed. Notable examples are oxalic acid, tannins and phytic acid, which are high in plant-based diets. Calciumand iron deficiencies are not uncommon in diets in developing countries where less meat is eaten and there is high consumption of phytic acid from beans and unleavened whole grain bread.