General Information & Selected Studies

Antioxidant Vitamins and Zinc Reduce Risk of Vision Loss from Age-Related Macular Degeneration
High levels of antioxidants and zinc significantly reduce the risk of advanced age-related macular degeneration (AMD) and its associated vision loss. These findings from a nationwide clinical trial are reported in the October 2001 issue of Archives of Ophthalmology. The clinical trial, called the Age-Related Eye Disease Study (AREDS), was sponsored by the National Eye Institute (NEI). The National Eye Institute (NEI) is part of the National Institutes of Health (NIH) and is the Federal government's lead agency for vision research.

Scientists found that people at high risk of developing advanced stages of AMD, a leading cause of vision loss, lowered their risk by about 25 percent when treated with a high-dose combination of vitamin C, vitamin E, beta-carotene, and zinc. In the same high-risk group, which includes people with intermediate AMD, or advanced AMD in one eye but not the other eye, the nutrients reduced the risk of vision loss caused by advanced AMD by about 19 percent.
(NEI News Release, October 12, 2001)

NCI Fact Sheet: Antioxidants
Antioxidants are substances that may protect cells from the damage caused by unstable molecules known as free radicals. Antioxidants interact with and stabilize free radicals and may prevent some of the damage free radicals otherwise might cause. Examples of antioxidants include beta-carotene, lycopene, vitamins C, E, and A, and other substances.

Antioxidants neutralize free radicals as the natural by-product of normal cell processes. Free radicals are molecules with incomplete electron shells, which make them more chemically reactive than those with complete electron shells. Exposure to various environmental factors, including tobacco smoke and radiation, can also lead to free radical formation. In humans, the most common form of free radicals is oxygen. When an oxygen molecule (O2) becomes electrically charged or "radicalized" it tries to steal electrons from other molecules, causing damage to the DNA and other molecules. Antioxidants are often described as "mopping up" free radicals, meaning they neutralize the electrical charge and prevent the free radical from taking electrons from other molecules.

Antioxidants are abundant in fruits and vegetables, as well as in other foods including nuts, grains and some meats, poultry and fish. Food sources of common antioxidants include:

	Beta-carotene is found in many foods that are orange in color, including sweet potatoes, carrots, cantaloupe, squash, apricots, pumpkin, and mangos. Some green leafy vegetables including collard greens, spinach, and kale are also rich in beta-carotene.
	Lutein, best known for its association with healthy eyes, is abundant in green, leafy vegetables such as collard greens, spinach, and kale.
	Lycopene is a potent antioxidant found in tomatoes, watermelon, guava, papaya, apricots, pink grapefruit, blood oranges, and other foods. Estimates suggest 85 percent of American dietary intake of lycopene comes from tomatoes and tomato products.
	Selenium is a mineral, not an antioxidant nutrient. However, it is a component of antioxidant enzymes. Plant foods like rice and wheat are the major dietary sources of selenium in most countries. 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, meats and bread are common 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 rich in vitamin A include liver, sweet potatoes, carrots, milk, egg yolks and mozzarella cheese.
	Vitamin C is also called ascorbic acid, and can be found in high abundance in many fruits and vegetables and is also found in cereals, beef, poultry and fish.
	Vitamin E, also known as alpha-tocopherol, is found in almonds, in many oils including wheat germ, safflower, corn and soybean oils, and also found in mangos, nuts, broccoli and other foods.

Vitamin E: What is it?
Vitamin E is a fat-soluble vitamin that exists in eight different forms. Each form has its own biological activity, the measure of potency or functional use in the body. Alpha-tocopherol is the most active form of vitamin E in humans, and is a powerful biological antioxidant. Antioxidants such as vitamin E act to protect your cells against the effects of free radicals, which are potentially damaging by-products of the body’s metabolism.
(National Institutes of Health, Office of Dietary Supplements)

Lutein
Research indicates that because of its antioxidant properties, lutein consumption may play a role in maintaining the health of the eyes, heart and skin as well as the breasts and cervix in women. Additional lutein research is currently under way at a number of universities to expand on these findings.

Lutein and the Skin
Ongoing research by internationally recognized skin cancer experts from Scripps Memorial Hospital in La Jolla, California, demonstrates the presence of lutein and other antioxidants in the skin, with the hypothesis that antioxidant levels can actually protect the skin from sun damage and the onslaught of the aging process. Further supporting evidence from a 1998 paper in the Journal of Dermatology found that lutein and beta-carotene seemed effective in protecting the cells from UVA damage.

Lutein and the Heart
Lutein is found in HDL, or 'good' cholesterol and researchers think it may prevent LDL cholesterol from oxidizing. Evidence from a 1994 study in Circulation suggested that one of the reasons the French have a low risk of heart disease is that they consume foods high in lutein content like spinach and collard greens.
(Lutein Information Bureau, 2003)

Antioxidant Properties of Edible Berry Anthocyanins
Anthocyanins are common components of fruits and vegetables, in particular berries, which provide pigmentation (color) and serve as natural antioxidants. Fruits and vegetables are rich sources of a variety of nutrients, including vitamins, trace minerals, dietary fiber and many other classes of biologically active compounds. Several studies have shown that berries, which are rich in anthocyanins, possess potent antioxidant, anti-aging, and anti-diabetic properties. Anthocyanins also protect DNA integrity, provide cardiovascular protection, improved brain function and mental clarity, healthy vision, urinary tract health and dermal health. Thus, the broad spectrum of current research supports the hypothesis that edible berries rich in anthocyanins provide a wide range of health benefits.
(Bagchi M, Sen CK, Kothari SC, Preuss HG, Stohs SJ, Bagchi D, Antioxidant and Anticarcinogenic Properties of Edible Berry Anthocyanins, The Original Internist, 10:6-14, 2003.)

Coenzyme Q10
Coenzyme Q10 (also known as CoQ10, Q10, vitamin Q10, ubiquinone, or ubidecarenone) is a compound that is made naturally in the body. A coenzyme is a substance needed for the proper functioning of an enzyme, a protein that speeds up the rate at which chemical reactions take place in the body. The Q and the 10 in coenzyme Q10 refer to parts of the compound’s chemical structure.

Coenzyme Q10 is used by cells to produce energy needed for cell growth and maintenance. It is also used by the body as an antioxidant, which is a substance that protects cells from chemicals called free radicals. Free radicals are highly reactive chemicals that can damage important parts of cells, including DNA (deoxyribonucleic acid.) DNA is a molecule inside cells that carries genetic information and passes it from one generation to the next.)

Coenzyme Q10 is found in most body tissues. The highest amounts are found in the heart, liver, kidneys, and pancreas. The lowest amounts are found in the lungs. Tissue levels of coenzyme Q10 decrease as people get older. Coenzyme Q10 was first identified in 1957. Its chemical structure was determined in 1958.
(National Cancer Institute, 2002.