As more people jump on the health eating bandwagon for the start of 2022, a Charles Sturt chemistry academic weighs in on the myths, importance and relevance of antioxidants, as discussed in the new book he co-edited.
By Associate Professor in Chemistry in the Charles Sturt University School of Agricultural, Environmental and Veterinary Sciences Paul Prenzler.
It is a new year and for many, the promise of a ‘new you’. But while people scramble to clean up their eating habits, it is important not to get caught up on buzz words.
Antioxidants, for example, are something most people will have heard of and, given their positive effects on the body, would assume you can’t get enough of. But while antioxidants have their place in a balanced and nutritious diet, more does not necessarily mean better. We sort the good from the bad from the myths to get you on track.
What are antioxidants and what do they do?
Despite the word itself being widely known, few people outside of the science and health fields have an accurate understanding of precisely what antioxidants are and what they do.
Antioxidants are substances – natural or synthetic – that protect against oxidation. Oxidation is a process we see everywhere in our daily lives. It is what causes rust on metal, powers the batteries in our devices such as mobile phones, and keep plants and animals alive through photosynthesis and respiration. Where oxidation is a problem, antioxidants counter the effects of the oxidants. In our bodies, natural processes such as digestion and respiration produce free radicals, which are strong oxidants, and antioxidants can neutralise the free radicals and protect the cells in our bodies from harm.
Why is it important to measure antioxidants?
There are different areas where antioxidants are important and so measuring their activity is necessary. In the human body, antioxidants are necessary because we use oxygen to keep us alive, but the process of respiration generates by-products that could cause us harm. The way our body protects itself is by using antioxidants – some we generate in the body and some we need to consume in our diet. In another area of human physiology, oxidants and antioxidants are now being studied in terms of how cells communicate with one another, e.g., there is an interest in antioxidants in terms of diseases, such as Alzheimer’s. In the food we eat, antioxidants are important to protect food from spoilage. For example, rancidity is a process that involves oxidation, so measuring things that inhibit oxidation (i.e. antioxidants) is vital to ensure food quality and safety. A very interesting area of practical use of antioxidants is in food packaging. Here, preventing oxidation by including antioxidants in the packaging helps to preserve food, keeping it fresh, without adding something to the food itself.
What is the most valuable way to measure the antioxidants in terms of positive human health?
There is no clear answer to this question. According to some authors in the book, there is a measurement called the total antioxidant capacity (TAC) assay, which may be of use. These authors point to studies whereby large numbers of people are surveyed about their diet and their health, then the TAC of the diet is correlated with health outcomes. This approach is showing some promising results in the relationship between dietary antioxidants and health, but this research is not at a stage where we can predict whether a particular antioxidant is going to be helpful to prevent a specific disease.
The pitfalls of taking a simplistic approach to an antioxidant measure, examples of how that has happened in food marketing or packaging?
One of the pitfalls is that some consumers think that if some antioxidants are good, then a lot must be better. There have been cases where people have done themselves harm by over-consuming antioxidant supplements. Another potential pitfall is always chasing the next “superfood”. In the past, food companies were guilty of misusing an antioxidant measurement called “ORAC” to try and outdo each other for the “best” antioxidant. This was when the US FDA started compiling a database of food ORAC values. In the end it had to stop because (or partly because) the database was being misused.
Another potential pitfall is in paying a lot of money for supplements that may not have any proven efficacy.
What should the everyday consumer be looking for when it comes to antioxidants? Eg, what foods and what numbers/measurements should we be looking at?
My personal view is that the best way to consume antioxidants is to have a diet that is rich in fresh fruit and vegetables and whole grains. The antioxidants in apples are different to those in oranges, so having different types of fruit and different types of vegetables would be important. I’d be wary of any terms like “super-food”. I’d also be wary of claims that compare the antioxidant activity of a food with vitamin C. Some time ago it was popular to say something was 10 times or 100 times more effective an antioxidant than vitamin C. Those claims don’t have connection, as far as I’m aware, with any real health benefits. Another thing that can happen is that a food or beverage gets promoted as healthy on the basis of very little evidence. Some studies are done with a very limited number of people and the findings may be misused to promote health claims.
Why this book is important for future recommendations and research into antioxidants?
I think this book will be very helpful for researchers in antioxidants. Firstly, it provides the fundamental chemistry of antioxidants so that researchers who don’t have this background can understand the chemical principles not only of how antioxidants work, but also how the antioxidant activity tests work. Better informed researchers mean better research can be conducted. Secondly, the book takes a balanced view on antioxidants. It critiques both those researchers who say there is nothing to be gained from measuring antioxidant activity, and those who take the simplistic view that antioxidants equals health. Another feature of the book is that it brings together antioxidant research from a wide variety of domains. Some of the negativity about antioxidants comes from the diet-health domain, but there are many other areas where antioxidants are important, so if a new researcher only hears “there is nothing worthwhile in antioxidant research” then they may be misled into thinking that that applies to every situation. Also, because antioxidant research, particularly in the human body, is complex, the book introduces ideas and techniques that may assist researchers dealing with this complexity.
How do we separate the hype surrounding antioxidant as a buzzword from its actual benefits?
The key is to obtain information from reliable sources. Food companies will hype their products, which is their job. Some food companies do good research, but it is preferable to get information from independent sources – government advice on diet is good and CSIRO produce good information on diet also. Beware of the word “super-food”. Don’t buy products where there is claim about something being 10 times stronger in antioxidants than vitamin C, just because of that claim. It might be a good product, but don’t be swayed by the advertising.
Associate Professor Paul Prenzler co-edited the book with fellow Charles Sturt academics Dr Danielle Ryan and Professor Kevin Robards.