The human body derives its energy from the utilization of nutrients and oxygen as fuel. It also utilizes oxygen to help the immune system destroy foreign substances and combat disease. The byproducts of this and other metabolic processes can lead to the development of molecular agents that react with body tissues in a process called oxidation. While this process is a natural consequence of the energy generation system, its byproducts called free radicals can damage healthy cells. Antioxidants work in several ways: First, they may reduce the energy of the free radical. Second, they may stop the free radical from forming in the first place. And finally antioxidants interrupt the oxidizing chain reaction to minimize the damage caused by free radicals.

Many members of the medical and scientific communities believe that free radicals are major factors leading to more than sixty different health problems including aging, cancer, and atherosclerosis. Reducing exposure to free radicals and increasing intake of antioxidant nutrients has the potential to reduce the risk of health conditions caused by free radicals.

Our bodies produce several antioxidant enzymes, including superoxide dismutase (SOD), glutathione peroxidase, and catalase, that destroy many types of harmful free radicals. Supplements of these enzymes are available for oral administration. However, supplementing with the building blocks the body uses to make SOD, catalase, and glutathione peroxidase may prove to be more effective. These building block nutrients include the minerals manganese, zinc, and copper for SOD, and selenium for glutathione peroxidase.

In addition to enzymes, many vitamins and minerals such as vitamin C, vitamin E, beta-carotene, lutein, lycopene, vitamin B2, coenzyme Q10, and cysteine (an amino acid) act as natural antioxidants. Herbs, such as milk thistle, aloe vera, cascara sagrada, bilberry, turmeric (curcumin), grape seed or pine bark extracts, and ginkgo can also provide powerful antioxidant protection for the body and help inhibit many of the health problems associated with free radicals.

Consuming a wide variety of antioxidant enzymes, vitamins, minerals, and herbs is recommended as the best way to provide the body with the most complete protection against free radical damage.

There are a number of user submitted antioxidant product reviews and ratings available at NutritionalTree.com.

Natural Sources of Antioxidants

Natural antioxidants are most abundant in fruits and vegetables, as well as in other foods including grains, nuts, and some red meats, poultry and fish. The list below describes food sources of common antioxidants.

• Beta-carotene can be found in many foods that are orange in color, including carrots, sweet potatoes, cantaloupe, apricots, squash, pumpkin, and mangos. Some green leafy vegetables are also rich in beta-carotene. Some of these include collard greens, spinach, and kale .
  
  
• Lycopene is a potent antioxidant most commonly found in tomatoes, watermelon, papaya, guava, apricots, pink grapefruit, blood oranges, and other foods. It is estimated that nearly 85 percent of American dietary intake of lycopene comes from tomatoes and tomato based products.
  
  
• Lutein, well known for its association with healthy eyes, is found in green, leafy vegetables such as spinach, collard greens, and kale.
  
  
• Selenium is a mineral, not technically an antioxidant in its own right. However, it is an important component of most antioxidant enzymes. Plant foods like rice and wheat are the the most common dietary sources of selenium in most countries. The concentration of selenium in soil, which varies by region, determines the amount of selenium in the foods grown in that soil. Consequently, animals that eat grains or plants grown in selenium-rich soil have higher levels of selenium in their bodies. In the United States, breads and meat are typical sources of dietary selenium. Brazil nuts also contain large quantities of selenium.
  
  
• Vitamin A is found in three main forms: retinol (Vitamin A1), 3,4-didehydroretinol (Vitamin A2), and 3-hydroxy-retinol (Vitamin A3). Foods will a lot of vitamin A include liver, carrots, sweet potatoes, egg yolks, milk and mozzarella cheese.
  
  
• Vitamin C is a well known antioxidant that can be found in high concentrations in many fruits and vegetables. It can also be found in cereals, beef, poultry and fish products.
  
  
• Vitamin E, also known as alpha-tocopherol, is found in many oils including wheat germ, corn, safflower and soybean oils, and is also found in mangos, nuts (almonds), broccoli and other foods.