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BBSRC helps put the pea into diabetes prevention

In an age ravenous for ‘exciting biting’, the mature pea has generally been overshadowed by more fashionable foodstuffs. But insights unlocked using the cutting-edge plant genetics expertise and world-leading seed collection at the John Innes Centre – both built up over many years with BBSRC support – have provided a taste of a promising new role for this often-overlooked legume. Could pea varieties containing a particular type of starch become a key ingredient in efforts to subdue the rising, costly tide of diabetes that has hit the UK and many other countries worldwide? 

Key impacts

  • BBSRC-funded research reveals peas’ ability to reduce blood-sugar spikes and so potentially deliver health benefits[1].
  • Demonstrating that research into pea traits, beyond protein content, has the potential to increase the value of pulse crops. 
  • Pivotal role for the John Innes Centre’s long-established Germplasm Resource Unit in reducing the time needed to identify pea varieties for study. Plus the Dorothea de Winton field station in providing the space and resource necessary to grow sufficient amounts of peas for food trials.
  • Worked together with the Quadram Institute, where infrastructure was used to demonstrate how the peas were digested.
  • Huge opportunity for UK plant-breeders to develop commercial pea varieties high in resistant starch, with increased pea production offering environmental benefits such as nitrogen fixation and improved soil health.
  • Given the necessary approvals for mass use as an ingredient in prepared foods or as a snack, there is clear potential for pea to help reduce the rising, multi-billion-£ costs of treating diabetes.
  • The research raises the possibility for the mutation to be bred into other staple crops, such as rice and wheat.

Peas in our time

For thousands of years, peas have been part of our diet. But we have much more than nutrition to thank them for. In the mid-19th century, Gregor Mendel (dubbed ‘the father of genetics’) conducted his groundbreaking experiments which revealed the fundamental laws of inheritance. And the subject of those experiments? Peas. Small beginnings, but Mendel had lit the touchpaper to an age of discovery about genetics that has fundamentally shaped fields as diverse as agriculture and medicine ever since.

At Norwich’s John Innes Centre – a world-renowned centre of excellence in plant and microbial science, mainly funded by BBSRC – Mendel’s legacy is alive and well. Indeed, the first Director, William Bateson, of what was then the John Innes Horticultural Institution[2], coined the term ‘genetics’ over a century ago. Today, a jewel in its crown is the Germplasm Resource Unit (GRU)[3], a public collection of seeds of incalculable value to researchers and plant-breeders, funded by BBSRC via a National Capability grant designed to support science, facilities and infrastructure that help the UK stay at the cutting edge, for national and public benefit. “The GRU is in constant use, helping to frame new questions about plant genetics,” says Professor Claire Domoney, whose team at the Centre focuses on the legume family of vegetables. “It now holds over 3,500 variants of peas alone.”  These were to provide the platform for a welcome breakthrough in one of this century’s big health challenges.   

Resistance movement

Diabetes is a growing health and financial burden; within the UK nearly 5 million people have the disease[4], costing the NHS £14 billion/year[5], while in 2019 diabetes caused an estimated 1.5 million deaths worldwide[6]. Key to preventing and managing the condition is controlling the blood-sugar spikes that occur after eating. One possible ally is starch – a carbohydrate found in many foods – and, most of all, so-called ‘resistant’ starch that resists digestion in the small intestine and acts as a brake on the body’s glucose production.

“The ‘all carbs are bad for you’ mantra needs correcting,” says Dr Jonathan Clarke, Head of Business Development at the John Innes Centre. “Starch definitely has an image problem, among both the food industry and the public. But resistant starch is one of the good guys, offering many long-term health benefits. The trouble is, there’s not enough of it in what we currently eat.” Some pea varieties contain high levels of this beneficial material. Could eating them as a snack or as flour mixed into cooked foods help people maintain healthy glucose levels?  

Going on a gene hunt

Supported by a BBSRC Diet and Health Research Industry Club (DRINC) grant[7], and working with Imperial College London and the Quadram Institute (an institute strategically funded by BBSRC, alongside the John Innes Centre on the Norwich Research Park), Claire Domoney set out to investigate the peas’ potential. The first step was to select pea varieties to investigate. “Using the GRU, we chose two near-identical pea lines with a major difference in a single gene,” she explains. “One has a genetic mutation that means it contains a large amount of resistant starch – a mutation first studied by Mendel and whose genetic basis was determined here at the Centre 30 years ago. We could then multiply seeds from these variants to obtain sufficient amounts to support food manufacture and assess impact on blood-sugar levels. This really shows how decisions about what to breed and what to store in the GRU can deliver important benefits to research many years later.”

Importantly, the selected varieties were used to produce mature peas (much less starch is present in immature peas) in sufficient bulk for the trials. It was important, too, for the purpose of these experiments, to know how processing the peas for consumption impacted on the amount of resistant starch.

“This study has shown us that by preparing these peas in certain ways we can further reduce these blood sugar spikes, opening up new possibilities for making healthier foods using controlled food processing techniques.” Professor Pete Wilde, Quadram Institute

Trials return a positive verdict

Video credit: John Innes Centre
On-screen captions and an autogenerated transcript is available on YouTube.

Four trials took place at Imperial College London, each involving between 10 and 25 adult volunteers with no existing health conditions. The results were hugely encouraging. “A major advantage of our trials was that we had two near-identical pea products to compare,” Professor Domoney reports. “The pea which is high in resistant starch suppressed blood sugar spikes when compared with the control, while whole peas performed better than pea flour. The striking clarity of the results was a pleasant surprise. They could be very good news in terms of helping to prevent diabetes and to ensure people with pre-diabetes don’t progress to the next stage of this nasty disease.”

Now thoughts are turning to translating this promising research into real-world impact and to what extent the results are replicable with other crops such as wheat, rice, and potatoes.

“Despite national campaigns to promote healthy eating, type 2 diabetes diagnosis rates continue to rise. An alternative dietary strategy to maintain normal blood glucose rates among the population is to improve the composition of commonly consumed foods. There is much evidence that diets rich in a type of carbohydrate called resistant starch have a positive impact on controlling blood glucose levels, and hence reduce susceptibility to type 2 diabetes.” Dr Katerina Petropoulou, Imperial College London

Plenty of challenges lie ahead, including the need to breed high-resistant-starch pea varieties suitable for full-scale agricultural growing to maturity, not to mention eventual issues surrounding target markets, health claims, food labelling and price points. But with early signs of interest secured via the Centre’s strong links with plant-breeders and the food industry, fostered through BBSRC-funded networks, it could be that the pea has a new market and is on track to be part of a successful recipe for tackling diabetes – and finally achieve undeniable ‘superfood’ status.

In Numbers

3.8 million The number of people living with a diagnosis of diabetes in the UK[8]
£14 billion The annual cost to the NHS of treating diabetes and related conditions
3,500 The number of pea varieties currently stored in the GRU
£775,014

BBSRC direct grant funding for this research project[9]

Final Say…

"There’s huge scope for the UK to turn these findings into widespread health benefits, as well as a big opportunity for our agri-food sector. BBSRC’s long-term, strategic funding for the John Innes Centre is the key reason these prospects are now in our sights.”

Dr Jonathan Clarke, the John Innes Centre

References

    [7] Joint grant to the John Innes Centre, Imperial College London, Quadram Institute, and Scottish Universities Environmental Research Centre totalling £775k titled ‘Using crop genetics to understand the importance of dietary resistant starches for maintaining healthy glucose homeostasis’ (BB/L025531/1BB/L025582/1, BB/L025566/1  and BB/L025418/1).

    [9] Joint grant to the John Innes Centre, Imperial College London, Quadram Institute, and Scottish Universities Environmental Research Centre totalling £775k titled ‘Using crop genetics to understand the importance of dietary resistant starches for maintaining healthy glucose homeostasis’ (BB/L025531/1BB/L025582/1, BB/L025566/1  and BB/L025418/1).

    Contact

    Emma Cook

    Email: emma.cook@bbsrc.ukri.org