The ORAC of organic and the promise of phyto-alexins

Mark Tallon, PhD | May 31, 2009

What was once considered a rock-solid category, organic is now feeling the pressure as consumers become ever more price sensitive. High-priced organics are being down-traded in a category often defined by its disciples' loyalty to the organic mantra of good for you and good for the environment. Despite sales of $21 billion in 2008 and 12 per cent growth, the category began showing signs of a slowdown in the order of five per cent over 2007-08, with some suggesting a 10 per cent fall.¹

A cloudy issue for organic is that the category has limited science behind its health benefits beyond those achieved with foods produced through conventional farming methods (ie, using pesticides). In this case, health benefit means a specific health impact not possible when comparing organic and nonorganic foods or beverages head-to-head in a randomised, controlled clinical trial — meaning a benefit by commission, not omission.

This lack of data implies the organic message has to be based on the brand platform, 'Does not contain.' This was highlighted in a Whole Foods Market survey, with 70 per cent of consumers indicating that purchasing triggers are based on the avoidance of pesticides.² Though, toward the end of March 2009, the trade media picked up on a so-called new class of phytochemicals called 'phyto-alexins.' However, until now few details on their merits in organic foods have been discussed.

Phyto-alexins and organic farming

Phyto-alexins are low molecular-weight compounds that accumulate in plants in response to infection, wounding, freezing, UV light and micro-organisms.³ These processes, also known as Induced Systemic Resistance (ISR) of plants against pathogens, are a widespread phenomenon, but only recently have the potential health benefits been recognised. Even less characterised is the impact of farming methods, and more specifically organic farming methods, resulting in altered levels of phyto-alexins.

Flavonoids, stilbenes (ie, resveratrol), ally sulphides, carotanoids, and saponins are just some of the phytonutrients that could be classified as phyto-alexins. However, there is an important distinction in relation to what is a phyto-alexin-containing product and what is not. The nutrients mentioned above should be defined as phyto-anticipins, and they are already present in the plant prior to injury or chemical/microbial challenge.⁴

Although there may be some difficulty in defining plants based solely on their phyto-alexin or phyto-anticipin concentration, other nutrients such as glyceollins found in soy can only be present if the plant has been microbially challenged.⁵ Glyceollins have now been shown to demonstrate anti-oestrogenic and anticancer activities.^6,7,8 It is the identification of these health-promoting, phyto-alexin-specific compounds — not present in the plant/food pre challenge — that may provide the key to a new science behind defining the innate goodness of organic at a nutrient level.

So now that the science lesson is over, why would organic farming lead to an increased concentration of these classes of phyto-alexins? In conventional agricultural practices, the use of fertilisers, herbicides and insecticides protects the plant from damage. The downside is that the synthesis of secondary phytochemicals (phyto-alexins such as glyceollins) to protect the plant does not occur or occurs at relatively lower levels.⁹ With organic farming, many of these protective chemicals (such as synthetic pesticides) are not utilised, leaving plants more susceptible to attack by insects and plant pathogens. The result is that organic plants may have a much higher, and natural, secondary phytochemical profile as evidenced by the in vivo synthesis of specific phyto-alexins.

This is exciting, and represents a potential point of nutritional differentiation between organically and traditionally grown foods. To date, many of the comparative studies between organic and nonorganic foods show contradictory results in relation to their level of vitamins, minerals and phytonutrients (some show organics better, others worse). This is of no surprise, as many of the phytochemicals and nutrients present in plants are not there as a consequence of cellular protection but as a function of growth.

Leveraging the asset

The future of phyto-alexins should be as a means to push the 'healthy and better-for-you' message of organic foods for what they contain vs what chemicals they do not. Identifying specific phyto-alexins that develop as a result of organic farming is step one of this new approach.

Superfruits have utilised the broad-based ORAC test to characterise the theoretical benefits of high antioxidant levels in fruits and, as such, a similar testing protocol could be developed to promote the concept of organic-plant goodness. Additional challenges will be to not only identify phyto-alexins that are synthesised as a product of organic farming, but also to strip out those that can be produced using methods not conducive with the consumer view of 'natural.' These methods (often called elicitors) include UV light exposure,¹⁰ electrical currents (hydroponics),¹¹ or other microbials that would normally not be present.

The main benefits of this novel research should not be to use science to sell the product, but rather to use the science to back up consumer-friendly health claims. This will involve some well-designed and implemented branding. The area of phyto-alexins and organic farming is in its early stages of development, but is an area of great promise for highlighting organic as a healthier food option.

Mark J Tallon, PhD, is chief science officer of NutriSciences, a London-based consultancy firm specialising in health-claim substantiation, product development and technical writing. www.NutriSciences.com

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