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 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...
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