Antioxidants seem to be everywhere; in superfoods and skincare, even chocolate and red wine. Products containing antioxidants are marketed as essential for good health, with the promise of fighting disease and reversing aging.
But are they really as good for us as we are led to believe?
What are antioxidants?
The term antioxidant covers a wide range of molecules (atoms held together by chemical bonds) that protect other molecules from a chemical process called oxidation. Oxidation can damage vital molecules in our cells, including DNA and proteins, which are responsible for many bodily processes.
Molecules such as DNA are necessary for cells to function properly, so if too many molecules are damaged, the cell can malfunction or die. This is why antioxidants are important. They can prevent or reduce this damage. In the body, uncontrolled oxidation is usually caused by highly reactive molecules called free radicals.
What is oxidation?
Oxidation is a common chemical reaction where electrons are transferred from one molecule to another. Electrons are one of the subatomic particles (smaller than an atom) that make up just about everything. When electrons move during an oxidation reaction, bonds can be broken and the structure of molecules changed.
Not all oxidation reactions are bad. They are essential for life and involved in many important processes. In cellular respiration, glucose (a sugar from the food we eat) is oxidized by oxygen (from the air we breathe), producing carbon dioxide, water and energy to fuel our bodies. Household bleaches oxidize colored stains into colorless molecules.
Less desirable oxidation reactions include rusting of metals and oxidative spoilage of foods.
What are free radicals?
Free radicals are simply molecules with one or more unpaired electrons. Electrons like to be in pairs, so unpaired electrons can result in unstable and highly reactive molecules. To become stable, the free radical must steal an electron from another molecule (or donate one). When a molecule loses an electron, this molecule has been oxidized and itself becomes a free radical.
This new free radical can steal an electron from another molecule, setting off a chain reaction. This process permanently alters the structure of molecules, causing irreversible damage.
But if an antioxidant is present, it can donate an electron to the free radical, stabilizing it and stopping the chain reaction. The antioxidant sacrifices itself and oxidizes instead of the other molecule, becoming a free radical. But unlike most molecules, the antioxidant is able to stabilize the unpaired electron and does not become highly reactive. This process deactivates the antioxidant.
Free radicals aren’t always bad for you. Their highly reactive and destructive nature is utilized by the body’s immune system. Certain white blood cells, called phagocytescan engulf foreign particles, such as bacteria, then seal them in and release free radicals to destroy them.
Free radicals are naturally generated by our body, but can be increased by lifestyle factors such as stress, poor diet, pollution, smoking and alcohol. Our body can handle some free radicals, but if it forms too many, it can overwhelm the body’s normal defenses.
Free radical damage is thought to be one of the causes of aging and contributes to various diseases. For example, free radical damage to DNA can cause genetic mutations and promote cancer.
Not All Antioxidants Are Created Equal
So if free radicals are dangerous and cause aging and disease, and antioxidants can neutralize them, then getting more antioxidants should be good for you, right? Unfortunately, it’s not as simple as that. Yes, high antioxidant levels and low oxidative stress are associated with good healthbut not all antioxidants are created equal.
Antioxidants come from many sources. Some are naturally produced in the body and some occur naturally in food we eat. Antioxidants (natural or synthetic) can also be added to food which do not normally contain it, either for their (supposed) health value, or to preserve food (antioxidants also prevent the oxidation of food).
A Balanced diet is the most effective way to get the antioxidants your body needs. Fruits, vegetables, grains, eggs and nuts are all useful sources of antioxidants. Despite the hype, the antioxidants found in so-called superfoods are no more effective than those found in regular fruits and vegetables, so it’s better to save your money.
But that’s a different story when it comes to antioxidant supplements. Research has shown that antioxidant supplements can cause more harm than good. A meta-analysis 2012 over 70 trials have found antioxidant supplements to be ineffective or even detrimental to health. The reasons are unclear, but the additional nutritional benefits of consuming antioxidants in a healthy diet are likely to contribute. Additionally, the high concentrations of antioxidants associated with supplement use can lead to problems.
Too much of a good thing
There are a number of reasons why high concentrations of antioxidants can be harmful. In high concentrations, antioxidants can:
There’s no magic pill, but a healthy diet can provide you with all the antioxidants you need to fight free radical damage.
