Fibre, we are told, is having a moment. About time. Many of us in the nutrition communication space have been banging on about the benefits of fibre for decades, with little impact on how much people actually consume. Although that’s probably because we refer to things like the ‘nutrition communication space’, without really affecting what normal people have for their tea.
But now, it seems consumer sands are shifting. Fibre is joining protein as a must-have front-of-pack nutrition claim on hundreds of health-targeted food products. Across the industry, everyone is looking to enrich products with fibre and wholegrains, and many consumers are attempting to up their intake.
In terms of public health, this is a near unqualified good. Increasing UK fibre consumption could have a positive impact on many of the most pressing food system issues, including cardiovascular disease, colorectal cancers, type 2 diabetes and obesity.
However, with increased focus comes increased scrutiny. As we attempt to get more fibre into diets, and growing numbers of fibre-related claims start to appear on-pack, it is likely that scientific testing for fibre will become a focus. And the harder people look, the messier a picture they will find.
The reality of fibre testing
It is surprisingly tricky to test for fibre in a lab, partly because it is by far the most complex and diverse major nutrient. In essence, fibre is whatever is left over after digestion in the stomach and small intestine, and so most testing involves attempting to replicate that digestion with enzymes, then drying and weighing the leftovers.
This is a complex and multi-staged process, with plenty of potential for error. Anyone who has ever worked with enzymes will know how sensitive and fickle they can be. Small variations in time, temperature, pH or (seemingly) luck can derail the process entirely. Inaccuracy is almost built in.
There are also different types of tests. The standard EGF method has been widely used since the 1990s but does not pick up resistant starch or resistant oligosaccharides, two types of fibre that are known to be important for health. A modified test, m-EGF, does pick these up, but is more expensive, more complex and has more steps, increasing the potential for inaccuracy.
EGF is around 15%-20% inaccurate, which is not ideal, but m-EGF is thought to be 25%-40% inaccurate, which can make a huge difference to on-pack claims, and to consumer health. Unsurprisingly, with either test, the same product can be sent for testing on different days and a completely different result will come back.
What we know about the fibre content of foods comes largely from these tests, including the reported levels in widely-used nutrition tables. It’s a messy picture, unhelpful for anyone charged with increasing fibre in a range of different food products.
This uncertainty has the potential to hand an advantage to unscrupulous companies and brands willing to push the limits. There is a desperate need for better testing and industry standardised methodologies surrounding the amount of evidence required to make a claim. Fibre is suddenly the sexy must-have nutrient, but if we really want to harness the current consumer interest for public good, the seemingly boring issue of testing is perhaps the most important place to start.
Anthony Warner is a development chef at New Food Innovation
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