Secret to better health might lie with better broccoli

The answer to future food security concerns might not be, “Grow more food,” but “Grow better, more nutritious food,” according to researchers at the University of Nottigham.

Martin Broadley, an associate professor of plant nutrition, is leading a team that’s looking for ways to grow “super” versions of cabbages and broccoli (Brassica) without a high-tech fix like genetic engineering. Rather, the researchers hope to “biofortify” such green leafy vegetables using a combination of conventional breeding techniques and new, nutrient-enhancing fertiliser.

While cabbages and broccoli are a well-known part of a healthy diet, they don’t contain as large an amount of key minerals as they might, according to Broadley, who’s secured funding to carry out new research into boosting such vegetables’ calcium and magnesium content.

The research, funded by the Biotechnology and Biological Sciences Research Council (BBSRC) and a fertiliser company, could make a real difference to human health worldwide, Broadley said.

“This project is an exciting opportunity which could ultimately deliver real dietary benefits for the UK and globally,” he said. “Recent studies have shown that leafy Brassica crops are excellent targets for biofortification with calcium and magnesium, even where vegetable consumption is relatively low, such as in the UK. By combining fertiliser-use with the development of more ‘blue-skies’ conventional breeding tools, we hope that this project will bring benefits in both the short and longer-terms, as well as improve our understanding of plants.”

All humans require 22 essential minerals to live. Yet billions of people worldwide consume insufficient minerals, including calcium and magnesium. Since most calcium is stored in bones, calcium-deficient diets can reduce bone strength and increase fracture-risks and osteoporosis. In developing countries, calcium deficiency can also cause rickets. Magnesium deficiency is linked to hypertension, cardiovascular disease, and pre-eclampsia in pregnancy.

In the UK, vegetables — excluding potatoes — provide less than one-tenth of dietary calcium and magnesium intakes. A relatively modest increase in the concentration of these minerals in green leafy vegetables could have a significant beneficial effect on health.

“Although it seems an obvious solution, we do not yet know how much calcium or magnesium fertiliser to apply to soil to optimise dietary intakes,” Broadley said. “This is because fertiliser studies tend to focus on crop yield. The ‘blue-skies’ breeding approaches rely on the fact that each different variety of Brassica represents a unique collection of variants of genes (alleles). However, just like different dog breeds, Brassica varieties are — in theory — interfertile. By crossing different varieties, and finding combinations of alleles which alter the calcium and magnesium content of plant leaves, we can inform conventional breeding programmes. The most exciting part of this project is that it builds directly on recent investment in Brassica research in the UK and elsewhere, which means we will soon have a fully-sequenced genome to work with, alongside other important resources.”

“Taking social and economic issues aside, the challenge we face is to produce enough nutrition for a growing global population using limited resources and without significant negative impact to the environment,” said Douglas Kell, chief executive of the BBSRC. “There are a number of ways to approach this through bioscience research, one of which is to actually aim to increase the nutritional value of the food we are producing. Dr Broadley’s project is a good example of where UK bioscience research is taking on this challenge and his success in enriching essential minerals in cabbages, broccoli, Chinese cabbage and pak choi will be an important step in insuring against a future food security crisis.”

The four-year project is part of a long-standing collaboration between scientists at The University of Nottingham, The University of Warwick, Rothamsted Research and the Scottish Crop Research Institute (SCRI).