They’re in virtually every health food on the market, packed into berries and supplements of all kinds and jacking up the prices of seemingly mundane food items. Eating them as much as possible is supposed to provide better overall health, greater levels of energy, and even an extended our lifespan. But do you really know what antioxidants do?In a broad sense, antioxidants work to prevent one major cause of damage to cells. As the name implies, they resist the action of molecules known as oxidants — those substances that oxidize other molecules, or steal away an electron. Most oxidants are quite weak and only take electrons that are readily available. Some, however, are very strong and can rip electrons away from molecules that need them to function properly. This can lead to a chain reaction of electron stealing that will eventually cause a molecule to be destroyed.The antioxidant can lose an electron to this radical without becoming unstable.An antioxidant is any molecule which can stop that chain reaction. For the most part, they are just molecules that can be stable in either of two distinct electronic states — one before oxidation, and one after. This means that the oxidant is neutralized without creating another dangerous molecule in the process. The most advanced antioxidants are structured so that, after neutralizing a dangerous molecule, their shapes change to make them much easier to excrete. This means they only stay in the body until their job is done.The main source of dangerous oxidants is the cell’s own natural process of respiration. When using oxygen as a driver of cellular respiration, oxygen atoms can occasionally be modified incorrectly, leaving the process not as harmless H2O, but as so-called Reactive Oxygen Species (ROS), like peroxides. These are very strong oxidants. In a healthy body these are created at a fairly predictable rate, and the body’s own antioxidants tend to be enough to keep them in mostly check.However, oxidants can be created in much higher volumes if there is some problem with the cell respiration process, or in the presence of some outside pressure like a chemical contaminant. In these cases, dietary antioxidant supplements can be very helpful. Too-high levels of ROS can cause major damage to DNA and other vital cellular organs, causing everything from depressed function to cancer to cell death.Foods high in antioxidants.There is little hard evidence about just how effective it is to take antioxidants without such an excess of oxidants in need of resistance, however. Those who need help fighting unusual circumstances, whether that circumstance is a virus or a contaminant or a genetic predisposition, can certainly benefit from some help fighting the good molecular fight. Those producing normal levels of ROS, however, derive far less benefit from them. An antioxidant is only as good as the oxidant it neutralizes, so an excess of countermeasures would seem to provide little benefit.Still, there is some evidence to suggest that regular intake of antioxidants is good for overall health — though that could easily be due to the fact that the molecules are almost always present in health foods. Extricating the effects of dietary antioxidants from the effects of the generally nutritious molecules that are taken in along with them is difficult. While the claims made by health food labels are often downright outrageous, foods rich in antioxidants are a strong part of a healthy, well-rounded diet.