The quest for a radical new world for antioxidants
‘Antioxidants’ is a term beloved of marketers the world over and, as a result, consumer awareness has never been higher. But negative opinions from the European Food Safety Authority (EFSA) now have many asking: What next for antioxidants?
When we talk about antioxidants, we’re talking about a “substance (such as beta-carotene or vitamin C) that inhibits oxidation or reactions promoted by oxygen, peroxides, or free radicals”, according to the Merriam-Webster dictionary.
Last week, I chaired the NutraIngredients Antioxidants 2010 conference in Brussels, with presenters ranging from market researchers to scientists at the cutting edge of antioxidant research. I learnt a lot and it is clear that much of the science is moving in a different direction to the marketers.
An analyst from Euromonitor International expects growth to continue for a range of antioxidant-rich foods, from green tea to pomegranate juice. Euromonitor stats show a global supplements market worth $9.18bn (€6.7bn) in 2009, with vitamin C accounting for $3.4bn (€2.49bn), coenzyme Q10 at $897m (€657m) and vitamin E at $1.39bn (€1.02bn).
But hold off on the tickertape – the regulations are raining on this victory parade: Mary Gilsenan from Leatherhead noted that simply putting ‘antioxidant’ on the label is a health claim.
And with EFSA’s panel stating: “…no evidence has been provided to establish that having antioxidant activity/content and/or antioxidant properties is a beneficial physiological effect”, it would seem the days of “rich in antioxidants” may be coming to an end, in Europe at least. (It is noteworthy, however, that EFSA has said that vitamin C may offer cell and DNA protection in a generic article 13.1 opinion from last year. A selenium claim for similar benefits has also been approved.)
Is EFSA correct? Some say yes: Scientists including Dr Peter Hollman (RIKILT - Institute of Food Safety and Wageningen University), Dr David Vauzour (The University of Reading), and Dr Christina Khoo (Ocean Spray Cranberries) presented on how various antioxidant compounds have clear benefits for a range of health conditions, but the mechanisms are not related to antioxidant activity.
These compounds may quench free radicals in a test tube, but in the body they may produce benefits via anti-inflammatory pathways, or changing gene expression, or boosting the levels of compounds to relax blood vessels, or indirectly promoting antioxidant defences by stimulating the body’s own antioxidant enzymes like superoxide dismutase (SOD).
It will take a little while for this science to filter down to consumers, and marketers will continue to push antioxidants. Indeed, we are already seeing more sophisticated marketing: In the US, for example, Hershey’s already has a dark chocolate bar with “natural source of flavanol antioxidants” on the label (not just antioxidants, but flavanol antioxidants!), and ORAC values are being used to beef up the increasingly tame ‘antioxidant’ label.
Karen Schaich from Rutgers University taught us that many antioxidant assays are over-used (especially ORAC) and the limitations may outweigh the benefits. However, Schaich has high hopes for combining results from the various assays, as well as for emerging tests such as Cuprac, which uses the copper(II)−neocuproine [Cu(II)-Nc] reagent as the chromogenic oxidizing agent (J. Agric. Food Chem., 2004, Vol. 52, pp. 7970-7981).
ORAC values alone are already being used to differentiate antioxidant products, and this is not a good thing for consumers: Antioxidant activity in a test tube may not translate to antioxidant activity in the body. In this case we need to look at biomarkers. In May in the US, the Institute of Medicine (IoM) issued a report and a call for the use of biomarkers for evaluating the claims associated with dietary supplements and functional food ingredients, as well as pharmaceuticals.
Prof Wilhelm Stahl from Heinrich-Heine-University, Düsseldorf shared his extensive knowledge with attendees on the biomarker concept. There are well established biomarkers out there, he said, and obtaining an antioxidant claim based on sound science monitoring changes in these compounds may still keep antioxidants alive.
So, where now for antioxidants? There is clearly significant potential for these compounds, both in the maintenance of optimal health and in reducing the risk of chronic disease, but they may not be working directly as antioxidants.
Back in February I interviewed Jeff Blumberg, professor of antioxidants at Tufts University, and he said: “Stopping use of the term ‘antioxidant’ provides a terrific opportunity to differentiate yourself and promote the multifunctional benefits of these compounds we now call antioxidants.”
Antioxidants beyond antioxidants – now that is a radical concept.
Stephen Daniells is the senior editor for NutraIngredients-USA and FoodNavigator-USA. He has a PhD in chemistry from Queen’s University, Belfast and help post-doctoral research positions at the Technical University of Delft (Netherlands) and the University of Montpellier (France).
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