Antioxidants are big business – the word is not only a scientific term but also a marketing tool. According to Euromonitor International, the overall market for antioxidants was valued at a whopping $12bn (€8.8bn) last year.
So the recent announcement by the Panel on Dietetic Products, Nutrition and Allergies (NDA) at the European Food Safety Authority (EFSA) that antioxidants don’t work is not what this multi-billion dollar industry wanted to hear.
OK, so EFSA didn’t say “antioxidants don’t work.” But they reached the opinion that a range of antioxidant foods and constituents (relating to about 170 dossiers) do not deliver “antioxidant properties” or protect body cells and molecules such as DNA, proteins and lipids from oxidative damage.
The opinion went on to state that: “…no evidence has been provided to establish that having antioxidant activity/content and/or antioxidant properties is a beneficial physiological effect.”
So where does this leave us? Throwing our berry extracts and grape juices in the bin? Well, no. Let’s seize this as the opportunity to move antioxidants forward.
Start with the basics
I wrote a comment just over two years ago calling for a v2.0 system to break up the catch-all marketing of antioxidants. Many of the points raised in that article ring true today.
When we talk about antioxidants, we’re talking about a “substance (as beta-carotene or vitamin C) that inhibits oxidation or reactions promoted by oxygen, peroxides, or free radicals”, according to the Merriam-Webster dictionary.
But such a definition groups together thousands of compounds, be it vitamin C or tocopherols or anthocyanins or stilbenes or flavanols or superoxide dismutase or coenzyme Q10. One term implies one mechanism of action. In a recent interview on NutraIngredients, Jeffrey Blumberg, professor of antioxidants at Tufts University, said: “It’s simplification that could get us into trouble.”
Proving a benefit
If we want to prove that antioxidant activity is indeed associated with a beneficial physiological effect, then we need to do the clinical trials to show it, and that means EFSA’s 'gold standard' randomised clinical trial (RCT) approach.
But how do we produce a controlled trial for such compounds? We ingest them from a myriad of sources, so controlling for them would be nigh-on impossible. How would you even start looking at this and identifying benefits of individual nutrients, then in combination with other nutrients, and then in whole foods and food products? You can’t. This represents a serious log in the road.
We’ve tried to test antioxidants in clinical trials before, only to be disappointed by the results. These studies do more to question the role of randomised clinical trials for nutrients than question the nutrients themselves, but that is a debate EFSA and its equivalents around the world do not seem to want to have .
It is clear from a vast body of observational/ epidemiological studies that increased dietary intakes of antioxidants from fruits and vegetables, for example, are associated with reduced risks of a range of disease, including cancer, cardiovascular disease and diabetes. These results may not prove causality but they do indicate that we should not turn our backs on these compounds.
So this brings us on to a wider debate of how to test for nutrient benefits: We need to consider the science as a whole, including epidemiology, and in vitro or in vivo mechanistic studies, and not blinker ourselves with results of big clinical trials.
(Interestingly, this is what EFSA has done for many, if not all, of the vitamins and minerals – the totality of the evidence was used. This would suggest that all is not lost.)
We should also take Prof Blumberg’s advice and differentiate: Emphasise the multifunctional benefits of these compounds we now call antioxidants. Use a range of scientific techniques to show that anthocyanins, for example, affect other physiological processes, and build a claim around that, not its antioxidant activity.
The green shoots of revival are there. Let’s ensure we encourage their growth.
Stephen Daniells is the science editor for NutraIngredients, NutraIngredients-USA, FoodNavigator, and FoodNavigator-USA. He has a PhD in chemistry from the Queen’s University of Belfast and has worked in research in The Netherlands and France. He has been writing about nutrition and food science for over four years, and he will be chairing the NutraIngredients Antioxidants 2010 Conference in Brussels.
For more information about the conference and to register, please click here .