Gene edited 'healthy' bread

January 2022

One elusive, and potentially very lucrative, holy grail long pursued by the biotech industry is GM wheat. Not just any GM wheat of course, but one which is acceptable to consumers and to their food suppliers.

Realising that the ace to play in winning over a biotech-sceptical public could well be the anti-cancer card, the US market is being sounded out using gene-edited potatoes designed not to give you cancer [1] and cancer-busting GM purple tomatoes [2]. In the UK, the government is forging ahead with a field trial of gene-edited wheat which they claim, like the GM spuds, won't give us cancer. 

If you're a bit surprised to hear that two major staple crops, wheat and potatoes, are carcinogens, the actual culprit is the high temperature (above 120 degrees C) at which they're frequently cooked. Fried potatoes and crisp wheat products have been found to contain the chemical 'acrylamide', a by-product arising from the reaction of certain sugars with free asparagine* when heated. Although acrylamide mostly passes through the gut without causing problems, at very large doses a small amount can be absorbed and converted to a highly carcinogenic derivative.

* Asparagine is an amino acid which can exist in free form able to react with other biochemicals, or as a building block of proteins.

Acrylamide has been designated "probably carcinogenic" by the International Agency for Research on Cancer (IARC) on the bases of animal experiments, and, while it has never been demonstrated that acrylamide in food has actually caused cancer in humans, there is an increasing awareness that the disease arises when multiple triggers present together [3]. In light of this uncertainty, food processors are required to apply mitigating procedures to reduce the acrylamide content to as low as reasonably achievable*.

* If this sounds vague, it's because a 'safe level' of a carcinogen can't be defined.

However, what happens to foods in the hands of the end-user can't be regulated, and the GM answer is therefore to edit out a major enzyme involved in asparagine synthesis in the wheat plant. The resulting reduced likelihood of acrylamide contamination in wheat-based foods is good PR: as the media declared "toast could get healthier".

You might, by now, be asking if we've always been plaguing ourselves with cancer by eating our (well-fired) daily bread?

No, we haven't. The risk of acrylamide formation has arisen due to modern agricultural methods.

Historically, our crops got the nutrients they needed from microbial action on the soil, especially on the plant and animal debris there. Our modern, vast areas of intensively grown wheat are only possible because concentrated artificial fertilisers, such as nitrogen, are applied to top up the depleted soil nutrients.

In the case of sulphur, an element needed by the crops for protein building, the Green Revolution was for many years conveniently propped up by the Industrial Revolution: environmental pollution due to industry was so high that there was always a plentiful supply of sulphur kicking around in the system, and never any need to add more to the soil. 

Then, we cleaned up our act, and industrial emissions declined, along with sulphur pollution.

Now, our wheat crops, growing thick and fast on their fix of artificial nitrogen, are clean out of sulphur. What seems to happen in sulphur-deprived wheat is a mobilisation of free amino acids, especially (you guessed it) asparagine.

The project leader of the gene-edited wheat explained "Acrylamide has been a very serious problem for food manufacturers since being discovered in food in 2002." But, is gene editing the only, or the best, solution to this self-created 'very serious problem'?

A 2016 study put forward a more obvious suggestion: "... a key aspect of acrylamide mitigation would be the avoidance of sulphur deficiency during wheat cultivation ... Screening existing varieties for low asparagine accumulation and further improvement by plant breeding could also be part of the solution." (Curtis and Halford). In other words, perhaps it would it serve us better to improve our agronomic practice by making sure the crop is optimally supplied with sulphur, and by doing a little conventional plant breeding. Note that the latter suggestion isn't fanciful: strains of wheat with a naturally low asparagine levels are already known.

OUR COMMENT

In the 20 years since the discovery of the acrylamide risk, there has been ample time to solve the problem by conventional breeding of low-asparagine wheat strains and by working out a practical way to optimise sulphur levels in the soil. Or rather there would have been time, if crop scientists weren't devoting all their resources to chasing GM solutions. GM Freeze has pragmatically suggested teaching people to use a toaster properly.

Public sedation put out by scientists and regulators informs us that gene-editing "only involve(s) changes that could have been made using traditional breeding methods" (George Eustace, DEFRA). This trivialisation is deliberately misleading: gene editing carries all the same risks as any other GM technique. The novel disturbed genome has a real potential to generate harmful qualities in the food. Indeed, there is mounting evidence of damage to the wider genome from 'precise' edits [4,5].

Modern wheat seems increasingly poorly tolerated by the human digestive system: add-on effects from a gene-edited crop with its disturbed physiology risk making a bad situation worse.

Consider asking your MP to point out to our regulators that gene-edited wheat is neither necessary nor desirable.

Background

[1] ACRYLAMIDE IN POTATOES - December 2018

[2] RED NOT PURPLE - March 2014

[3] THE GLYPHOSATE CANCER LAG-PHASE IS OVER - September 2021

[4] THE PRECISION PROBLEM IN GENOME EDITING - August 2021

[5] CRISPR'S EPIGENETIC SCARS - August 2021

SOURCES:

• Tanya Y. Curtis and Nigel G Halford, 2016, Reducing the acrylamide-forming potential of wheat, Food and Energy Security
• About Sulphur, Sulphur Deficiency Sources and Symptoms, The Sulphur Institute
• Bryant Mason, The Importance of Sulfur in Your Soil, Soil Doctor, 5.05.20
• UK gene editing public consultation announcement expected mid-June, GM Watch, 3.06.21
• Lamiat Sabin, Scientists closer to making bread with 'low cancer-causing risk' when toasted, Independent, 2.09.21

Photo: Creative Commons