Antioxidants help to reduce the risk of heart disease and premature ageing. But what are they? Learn all about antioxidants and the role they play in stabilising pesky free-radical particles.
Antioxidants are the body’s first line of defence against illness and disease. They are naturally produced by the body to defend against free radicals and are believed to prevent certain types of cell damage that lead to heart disease and cancer. The discovery of antioxidants is still relatively new in biochemistry terms. They were first identified in the 1990’s so much of the research is still ongoing or in its early stages. In order to fully understand the role of antioxidants, we first need to know a bit more about free radicals.
When reading about or shopping for antioxidant-rich foods you will often see references to free radicals. But what are they and why do they have such a bad reputation?
Stable atoms have eight electrons, which are carried in pairs. Unfortunately, atoms can be damaged by the oxidation process (exposure to oxygen) which causes them to lose electrons and become unstable free radical particles. When this occurs, unstable atoms steal electrons from neighbouring cells, which radically alters their structure and function. As this process continues, it creates a chain reaction as cell after cell becomes affected and damaged. Occasionally cells are permanently damaged which accelerates the ageing process and increases the risk of certain diseases.
Unfortunately, we can’t avoid free radicals completely; they are naturally produced by the body’s oxidation process and conversion of food into energy. Environmental factors can also play a part, such as cigarette smoke, exercise. pollution, cosmetics, and sunlight.
In simple terms, oxidation is the process of things breaking down, for example, oxidation occurs when iron rusts or an apple goes brown. Oxidation is an essential part of many bodily functions, such as burning energy and making new cells, all of which produce free radicals. Oxidative stress occurs when free radicals run rampant with insufficient antioxidants to halt the chain reactions. Essentially, if the body fails to produce sufficient antioxidants, the damage continues to spread.
We aren’t defenceless against free radicals - the body naturally produces antioxidants to counteract them and keep their numbers in check. The term antioxidant refers to the way in which certain compounds work. Antioxidant compounds have the ability to donate spare electrons to free radicals to stabilise them and prevent them from causing further damage to neighbouring cells. Because antioxidants remain stable even when they are missing electrons, they don’t become free radicals themselves when giving electrons away.
There are hundreds of different types of substances that act as antioxidants, such as vitamins C and E, beta-carotene, selenium, Coenzyme Q10, lipoic acid, and polyphenols. Each one is different and so supports the body in its own way. This is why many different types of antioxidants are needed from the diet because one type simply won’t be that effective on its own.
Over the past few years, there has been plenty of hype surrounding the potential health benefits of antioxidants. While some of the claims are completely unfounded, it does appear that adding more antioxidants to the diet offers some health benefits, particularly in relation to age-related conditions. Here are a few of the ways that antioxidants are thought to support health:
The antioxidants that the body produces naturally aren’t enough, and so the body needs a constant supply of antioxidants from the diet. Different types of antioxidants can be broken down into five categories; enzymes, vitamins, minerals, proteins and phytochemicals.
There is strong evidence to show that diets rich in antioxidants can lower the risk of heart disease, stroke, cancer, and age-related eye disease. While fruits and vegetables contain a wide array of antioxidant compounds, their colour often indicates their main antioxidant content. The different colours provide different types of antioxidants, which is why it’s important to ‘eat the rainbow’ instead of limiting yourself to one or two types of fruit and veg.
Fruits and vegetables with high levels of antioxidants are often referred to as ‘superfoods’. Currently, there are no set criteria for what is deemed a superfood and so the term has been criticised for being more of a marketing tool. But there are foods that are known to provide a high concentration of antioxidants and are beneficial for health.
The antioxidants in fruits and vegetables can be damaged by cooking or processing, so they are best eaten raw. If cooking, opt for steaming to preserve the delicate antioxidant content as much as possible. Antioxidant supplements may offer added protection, however, they should never be taken as an alternative to a healthy diet or medication.
ORAC units were introduced to measure the antioxidant capacity of foods, so you may have come across them when reading about the nutritional benefits of superfoods. However, there has been controversy concerning their use. The units can vary depending on the amount of food which is measured; a flaw that was abused by a number of food marketers. So we prefer not to reference ORAC values when writing about antioxidant rich foods.
This is where the evidence becomes problematic. We know that antioxidants are beneficial, but we don’t know how many antioxidants are needed for certain health benefits. It is clear that eating a diet rich in different fruits and vegetables can help and many of us are familiar with the ‘5 a day’ mantra, which most experts believe is sufficient to get all the antioxidants you need.
The UK government’s recommendations for a healthy balanced diet are highlighted in the Eatwell Plate below, which suggests that fruits and vegetables should make up one-third of your meal. While this doesn’t need to be every meal, it should balance out over the day or week.
However, there are differing opinions regarding how many portions of fruits and vegetables we should all eat on a daily basis. Some suggest '5 a day', while others suggest '7 a day' (5 veg and 2 fruit). While the jury is still out, simply try to incorporate as many different types and colours as you can. Antioxidants don’t survive in the body for long, so a regular daily supply is required.
Antioxidant-rich fruits and vegetables pose few, if any, safety risks. However, questions have been raised over the safety of super strength doses of certain antioxidant supplements. There is some evidence to suggest that high doses of beta-carotene in supplement form may increase the risk of lung cancer in smokers so high-strength supplements are not recommended. It has also been suggested that super high doses of vitamin E may increase the risk of prostate cancer in men. Research is ongoing.
Antioxidant supplements may also interact with certain prescription medications, for example, high dose vitamin E supplements may increase the risk of bleeding, so should not be taken in combination with anti-coagulant medication. If you are concerned about a specific supplement, speak to your GP or pharmacist who will be able to provide medical advice to suit your individual needs.
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