Super peas

Maria Burke

A type of ‘super pea’ may help control blood sugar levels and could reduce the risk of Type 2 diabetes, according to a new UK study which suggests incorporating pea flour into foods.

‘Wrinkled’ peas contain a natural genetic mutation that produces higher amounts of resistant starch than ordinary smooth peas. The body takes longer to break down resistant starch so sugar is released more slowly into the bloodstream, resulting in more stable increases rather than in the spikes often seen after a meal. Frequent, large sugar spikes are thought to increase the risk of diabetes. Evidence shows that diets rich in resistant starch can help control blood glucose levels, and reduce susceptibility to Type 2 diabetes.

‘These starches are not completely digested in the upper parts of the digestive tract and are available for fermentation by bacteria in the colon,’ explains lead author Gary Frost of Imperial College, London. Previous research at Imperial has suggested that, as these bacteria ferment the starch, they produce short-chain fatty acids (SCFA), which boost insulin-producing cells that help control blood sugar.

The researchers found that wrinkled peas appeared to prevent spikes in blood sugar levels when eaten as part of a meal or as added flour (Nature Food, doi: 10.1038/s43016-020-00159-8). Tracer molecules added to the peas allowed the researchers to track how they were absorbed and digested.

Tests using a human gut model, carried out by Peter Wilde’s team at Quadram Institute Bioscience, showed that the way that the peas were prepared and cooked affected how quickly they were digested. ‘We found that cooking the whole peas gave the slowest digestion, compared to flour and biscuits [made from peas], mainly because a significant proportion of the starch was encapsulated within the pea cells, which further slowed release of the starch,’ explains Wilde.

The Quadram team also showed there were significant benefits to gut microbiota because of the fermentation process taking place there. ‘Both the peas and pea flour resulted in higher production of propionate and butyrate [SCFA] by the microbiota,’ says Wilde. ‘There was no difference between the whole pea and flour groups. So it would appear processing is less important for the microbiota.’

Further research is focusing on breeding the mutation into staple crops, such as rice and wheat, and discovering whether similar genetic variations occur in other pulses.