Editing down cancer risk in our favourite foods

I bumped into this video of Nigel Halford brilliantly explaining what the problem is with acrylamide in our food and how he recruited CRISPR to lower its content in wheat. Acrylamide is a highly undesirable processing contaminant discovered in 2002. “It’s a big issue for the food industry because it’s carcinogenic, at least in rodents, and probably also in humans, and has also effects on development and fertility”, he says when interviewed at the Euroseeds Congress 2022. 

It forms from natural precursors during cooking and high temperature processing over 120 degrees. “A lot of your favourite foods contain some acrylamide, some more than others, so the benchmark levels are set at different levels for different foods”, Halford explains.

We are talking about breakfast cereals, biscuits, crispbread, potato products both fried and roasted, and coffee unfortunately. Acrylamide forms from reducing sugars naturally present in foods and the amminoacid asparagine (only in its free form, not when it’s incorporated into proteins).

“There is nothing being added so you can’t take it away”.  However a solution could be to reduce the asparagine levels, that are particularly high in wheat grain. This is why scientists at Rothamstead Research targeted a gene coding for the enzyme asparagine synthetase.

“We have basically knocked it out using the CRISPR-Cas9 technique. We have plants with every version of that gene knocked out and also plants with only partial knockouts, just in case there was a negative effect on grain development”. They have studied them for a number of years and are in the second year of field testing (please read Rothamsted’s Q&A to learn more).

Results look promising. “We’ve analyzed the grain, it looks really good, free asparagine concentration is just about a half of the unedited controls in the field, which is the real test of whether or not your technology is working. We are really excited about that, we are writing the paper”.

After watching the video I asked Halford for confirmation: the paper was submitted at the beginning of December. I also asked which food contaminant he would be interested in targeting next.

“Not another contaminant, but we would like to use genome editing to increase the concentration of a different amino acid, lysine, in our wheat that is already low in asparagine. Lysine is an essential amino acid (i.e. we need to get it in our diet, as do pigs and chickens), and cereal grains are generally deficient in it”.

Then I inquired if anybody was using CRISPR to develop low acrylamide potatoes. He replied that “there are low acrylamide GM potatoes on the market in the USA (Innate and Innate 2 by Simplot). I know that an Australian group has been trying gene editing to reduce asparagine levels in potato tubers but they have not published anything yet.”

Furthermore “a Swedish group has used a different GE technique, TALENS, to knock out an invertase gene, producing potatoes with lower concentrations of fructose and glucose, the other acrylamide precursors. That has been published but nothing on the market”.

What about coffee? “If anything is happening it is in-house. I don’t know of anything in the public domain”, Halford said.

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