Virtual food

Nutritional information as provided on food labels tell us little about the effects various food components actually have on our body. But that could change, thanks to a novel concept described by New Zealand researcher Dr John Monro in 'Journal of the Science of Food and Agriculture' - the use of virtual food components (VFCs) to evaluate the really physiological effects of what we eat.

VFCs are nutrient-like values that allow food data to say not only what a food is, but also what it does, and how well it does it.

Like traditional nutritional information, VFCs are presented as weights. They provide information about the functional efficiency of a food, by comparing the effect of that food with a suitable reference material of known activity.

For example, Monro's first VFC - glycaemic glucose equivalent (GGE) - is a measure of the glucose-raising potential of a food, compared to glucose. The activity of the test food is deduced as a percentage of the activity of an equal amount of the reference food. Thus a food with GGE of 15 would impose the same blood glucose level as 15 g of glucose. It is like saying how much of the reference is in 100 g of the food.

In JSFA, Monro and colleague Eva Martinet describe a second VFC - wheat bran equivalents for faecal bulk (WBEfb) - and show how an effective food product for bowel regularity could be designed from knowledge of the VFC content of its ingredients, but not from its dietary fibre content.

Whereas WBEfb expresses bulking efficiency, dietary fibre is a completely unreliable guide to the effect of fibre on the body, given that some fibres are actually destroyed by fermentation in the colon, and thus do not contribute bulk.

Despite their virtual nature, VFCs could show up the real performers amongst the hundreds of so-called functional foods that flood supermarket shelves these days.