The world of nutrition has evolved hugely over the last few decades as interest in the topic has grown. Basic dietary advice is no longer enough for many people as they seek out other ways to optimise their health, combat ageing, lose weight and maximise exercise performance.
The desire to learn more has helped drive this evolution but has also exposed us to information that may be lacking in reliable science.
One topic that has always been popular is that of free radicals and antioxidants. These terms are frequently chucked around and often oversimplified as being either good or bad for us but is it really that simple?
A little too much knowledge can be dangerous
One of my old bosses many years ago once said to me that a little bit of knowledge can be a dangerous thing and this is something that always rings true when I listen to people talk about nutrition.
How has dietary advice evolved over the last couple of decades?
Not long after I started out as a nutritionist the Department of Health had just launched the five-a-day campaign (2003) to promote the health benefits of eating more fruits and vegetables in the diet. This campaign was driven by the science which proved fruits and vegetables had a key role to play in the prevention of cardiovascular diseases, cancers and diabetes.
The conversation around diet and nutrition at this time was heavily focused on key public health messaging to help tackle obesity and heart disease.
In 2007 the Food Standards Agency launched the ‘Eatwell Plate’ to help people to understand how the five key food groups form the basis of a balanced diet. This has since been replaced with the updated ‘Eatwell Guide’ (1).
When did the conversation start to change?
After this is when the conversation began to change as more people took an interest in the topic of nutrition.
Reporting in the media began to focus more on research findings linking diet to disease (many of which were contradictory), food companies started to coin phrases such as ‘superfoods’ and many books and TV shows on the topic became hugely popular.
During this time the quality of advice given out was questioned by qualified health professionals and authors such as Ben Goldachre putting much of it down to bad science. This also saw the demise of well-known ‘health experts’ who dominated our screens at this time.
Around this time was also when the food industry became more regulated as they had to provide evidence to support any health claims made on their products (2008).
In 2007 the UK regulator Ofcom introduced regulations banning the advertising of foods high in fat, salt and sugar on children’s TV channels. Bans were also introduced on the advertising of these foods on non-children’s channels during, before and after programmes aimed at those aged between four and fifteen.
The UK was the first country to introduce statutory scheduling restrictions of food advertisements to children.
The birth of social media
Around the same time came the social media explosion with the birth of Twitter in 2006 and Instagram in 2010.
These social media platforms are now home to many health and wellness ambassadors who churn out advice and represent food and wellness brands in the media. This has raised many issues as to the quality of nutrition and diet advice as people turn to unqualified influencers for information over experts (although there are now many trusted voices on these platforms).
The topic of free radicals and antioxidants
As our interest in the nitty gritty of nutrition has grown one of the topics that has continued to come up is that of free radicals and antioxidants. The terms are chucked around willy nilly and while most people may be familiar with them, very few actually know what they are.
The problem of oversimplification
The science behind free radicals and antioxidants is actually quite complex. One problem with delivering these concepts to people has been an oversimplification of the science which has led them to be classed as either being good or bad for you.
The idea that free radicals are bad and antioxidants are good is one that is used to sell myriad of products in the wellness market, but the science is not that straight forward. Antioxidants are normally depicted as the superhero defending our body against ageing and chronic disease risk caused by free radical damage.
There is of course truth in this depiction but unfortunately biology is never that simple.
What are free radicals?
Free radicals are very reactive chemicals, which are created when an atom or molecule (chemical that has two or more atoms) either gains or loses an electron. The most common type of free radicals produced in living tissue are called reactive oxygen species or ROS for short and these contain oxygen.
We produce free radicals naturally through chemical processes that occur in the body such as the breakdown of food and its transformation into energy used by cells.
We are perfectly equipped to deal with free radicals but they may become an issue when they build up in high concentrations. This can put the body in a state of oxidative stress (when free radicals outweigh antioxidants), which has the potential to damage every major component of cells when it occurs over a prolonged period of time. The most significant damage is that caused to DNA, which is thought to play a role in the development of many health conditions including heart disease and cancer (2).
The most likely cause of excess free radicals in the body are due to a combination of environmental, lifestyle and dietary factors which include pollution, stress, smoking, alcohol, sun exposure, infection and overconsumption of foods high in bad fats and sugar.
What are antioxidants?
Antioxidants are essential for the survival of all living things. These chemicals are able to interact with free radicals and neutralising them without getting damaged or becoming a free radical themselves. Whilst the body relies on external source of antioxidants, which are gleaned from the diet, it’s also able to make some such as the cellular antioxidant glutathione.
Dietary antioxidants are found in fruits, vegetables and grains, which are all a rich source. Examples of dietary antioxidants include lycopene and beta carotene found in red, orange and green vegetables as well as vitamins A, C, E and minerals such as selenium. Plants also contain compounds such as polyphenols, which act as antioxidants and are found in foods such as berries and raw cacao.
Are free radicals always bad for us?
Most people equate free radicals to poor health but there is more to the story as they also play an important role in many normal cellular responses.
The immune system uses free radicals to help kill foreign invaders (phagocytes) in the body, which are just one of many ingredients in a cocktail of chemicals released in this defence mechanism, which is known as an oxidative burst.
Another interesting example of where free radicals may be beneficial is linked to exercise, particularly amongst athletes. Free radicals may play a key role in the benefits gained from exercise, which goes against much of the information provided on this topic.
One of the benefits of exercise is that it helps to improve insulin sensitivity, which is a good thing as the body becomes more attuned to maintaining blood sugar levels. Insulin resistance has the opposite effect resulting in higher insulin and blood sugar levels, which form part of the aetiology of diseases such as diabetes.
Research has shown that the oxidative stress (excess free radicals vs antioxidants) induced by exercise actually promotes insulin sensitivity and triggers an internal mechanism to protect the body against the potential damage from free radicals (3). Interestingly, the same research has also shown that flooding the body with antioxidants (mostly in the form of supplements) may inhibit this health benefit from occurring.
These and similar findings have prompted experts in the field of sports nutrition to question the use of antioxidant supplements as part of their prescribed diet regime.
Are antioxidants always good?
The reputation of antioxidants has evolved over the decades into something of a panacea for good health. Early research many decades ago identified their role in the ageing process and their association with health has stuck.
There is no doubt that antioxidants have a key role to play in the aetiology of disease and cell ageing, but this doesn’t mean that overdosing on them will help you to live longer, stop you getting sick or prevent wrinkles.
Supplements containing antioxidants have always been popular but the evidence to support their use in the reduction of disease risk is often lacking and often contradictory.
Supplements have their place and as the name suggests this is to supplement the diet to make up for any shortfalls that may exist when your diet may be compromised for whatever reason. Public Health England currently recommend we supplement our diet with vitamin D during the winter months in the absence of sunlight and it has long been advised that women take folic acid during the early stages of pregnancy.
Supplements are also useful for young children, older adults and those following strict diets such as veganism. In such cases there may be a greater risk of deficiency.
In some cases, supplements could do more harm than good and especially high doses of antioxidants.
One example is the link between beta carotene supplements and lung cancer as shown in the World Cancer Research Fund/American Institute for Cancer Research Third Expert Report Diet, Nutrition, Physical Activity and Cancer: a Global Perspective. This report found that there was strong evidence to show that taking high-dose beta carotene supplements increased the risk of lung cancer in both current and former smokers (4).
It’s all about balance
Adopting a healthy diet which includes plenty of plant-based foods, especially brightly coloured fruits and vegetables, will ensure a good intake of antioxidants. Leading a healthy lifestyle which involves being active, maintaining a healthy body weight, not smoking and addressing stress and sleep issues can help to reduce excess free radicals.
I get that this may be easier said than done and behaviour change is a tricky thing that often challenges our ability maintain a healthy way of living. However, focusing on the information and advice which is supported by science is always going to be a better long-term option than seeking out quick-fix fads. A faddy approach to your health is not only likely to be short-lived but may in fact be more detrimental to your health.