Posts Tagged ‘Vitamin A’
Understanding Free Radicles
What is a free radical?
A free radical is any atom or molecule that is missing an electron from it’s outer shell, making it unstable. Free radicals float around until they stabilize. They stabilize by attacking an other molecule and steeling an electron. There are a wide variety of molecules from which they can steal an electron. The molecule that has been attacked by a free radicle, is now missing an electron and has become another free radical. This creates a chain reaction.
Free radicals are a necessary part of life.
Oxidation reactions are necessary part of life, unfortunately they can also be damaging. Our body produces free radicals almost constantly. Free radicals are by-products of a basic metabolic process called oxidation. Immune cells will also release free radicals in order to fight invading viruses and bacteria in, making them an important part of the body’s defenses.
Environmental sources of free radicals
The second source of free radicals is the environment. Free radicals from your environment can be ingested, inhaled or absorbed into the body. Air pollution, tobacco smoke, herbicides, and pesticides all form free radicals. UV rays, from sun exposure are also a cause of free radicals.
Whats the damage?
Damage caused by free radicals include aging, destruction of DNA and clogging of arteries. It is also believed that free radicles may play a role in cancer, strokes, and heart disease. Oxidative stress may also damage or kill cells. Free radicals cause damage to your skin’s structural support and decrease its elasticity, resilience, and suppleness.
Free Radical Theory of aging
The free-radical theory of aging (FRTA) states that organisms age because cells accumulate free radical damage over time. There is evidence that reducing oxidative damage can extend life span. Dr. Denham Harmon, M.D., Ph.D., first proposed a theory of aging in the 1950’s, it is now considered a major theory of aging. Dr. Harmon’s theory also implies that antioxidants will slow the aging process.
What is an antioxidant.
Antioxidants stop the chain reactions of free radical, and inhibit other oxidation reactions. An antioxidant is a molecule capable of inhibiting the oxidation of other molecules.
Antioxidants have an extra electron, so they can their extra electron to a free radical. When antioxidants donate an electron to a free radical, they neutralize that free radical.
Exogenous and Endogenous
Endogenous antioxidants are made by the body, compared to Exogenous antioxidants which are obtained from our diet. Unfortunately, as we age the body produces less endogenous antioxidants. It is believed that the decrease in endogenous antioxidants leads to premature aging. The body is incapable of producing enough endogenous antioxidants to combat free radicals on their own, so it is essential to get additional antioxidants through diet.
The body makes five types of endogenous antioxidants:
superoxide dismatuse (SOD), alpha lipoic acid (ALA), coenzyme Q10 (CoQ10), catalase and glutathione peroxidase. Catalase and glutathione peroxidase are important, because the body can produce more of them when certain free radicals are present.
Oxygen Radical Absorbance Capacity (ORAC) is a method of measuring antioxidant capacities of food.However, because the ORAC method is derived only in test tube experiments it cannot be applied to human biology. Currently there aren’t any food compounds other than, antioxidant vitamins (vitamins A, C and E ) that have been proven with antioxidant efficacy in vivo. Antioxidant from non-nutrient compounds in foods, such as polyphenols, which have high antioxidant capacity in vitro can provide an artificial index of antioxidant strength with the ORAC measurement. Many of these ORAC values remain unconfirmed and are not scientifically credible, and may mislead consumers. The FDA has published guidance disallowing food product labels to claim an antioxidant benefit, when no evidence currently exists. Numerous health food and beverage companies have promoted products claimed to be “high in ORAC”.
Is more, better?
Researchers are still learning about the effects of an excessively high intake of antioxidants, some studies are showing that excessive amounts may have negative effects, like inhibiting key enzymes in the body.
You need a variety of antioxidants.
Any molecule that protects your cells against oxidation is technically an antioxidant, but not all antioxidants operate the same way. Antioxidants are not interchangeable, each has a unique set of chemical behaviors and biological properties. Antioxidants work together as part of a network, and no single antioxidant can do the work a group. Some antioxidants may excel at fighting certain types of free radicals, or only work in certain parts of a cell. There are even some that are only effective under the right conditions. Antioxidant diversity is important.
Sources of Antioxidants
All plants produce antioxidants. Even meat, dairy products, and eggs contain some antioxidants, which mainly come from the nutrient-rich plants the animals fed on. Plants and animals maintain complex systems of multiple types of antioxidants, such as glutathione, vitamin C, and vitamin E as well as enzymes such as catalase, superoxide dismutase and various peroxidases.
Antioxidant enzymes made by the body:
superoxide dismutase (SOD)
Coenzyme Q10 (CoQ10) and Glutathione
Vitamin A and Carotenoids
Carrots, squash, broccoli, sweet potatoes, tomatoes, kale, collards, cantaloupe, peaches and apricots (bright-colored fruits and vegetables)
Citrus fruits like oranges and lime etc, green peppers, broccoli, green leafy vegetables, strawberries and tomatoes
Nuts & seeds, whole grains, green leafy vegetables, vegetable oil and liver oil
Fish, shellfish, red meat, grains, eggs, chicken and garlic
Flavonoids / polyphenols
soy, red wine, purple or Concord grapes, pomegranate, cranberries, tea
Tomato, tomato products, pink grapefruit, watermelon
dark green vegetables such as kale, broccoli, kiwi, brussels sprout and spinach
flax seed, oatmeal, barley, rye
My conclusion is simple:
– Eat a healthy diet with a variety of fruits and vegetables.
– Don’t depend on any single “super” antioxidants, a variety of antioxidants are needed.
– Just because you read that red wine, tea or chocolate is high in antioxidants, you don’t want to depend on them as your main source of antioxidants. Remember currently only antioxidants from food compounds with vitamins (vitamins A, C and E ) have been proven with antioxidant efficacy in vivo.
– Avoid environmental factors that produce free radicals.