SCIENTISTS DEMONSTRATE THAT WHITE FLOUR IS THE HEALTHIEST IT’S BEEN IN 200 YEARS
Despite concerns over a lack of genetic diversity, modern wheat has more health benefits
A study comparing historic and modern wheat varieties grown side by side has shown an increase in dietary fibre and other features beneficial to human health.
This is contrary to concerns that the push for higher yields has made today’s wheat less “healthy” than older types.
The 39 wheats varieties, spanning a period of 230 years, were grown three years running at Rothamsted Research in Hertfordshire – which is also the site of the famous Broadbalk wheat trial, which was established in 1843 and is the world’s longest running experiment.
Lead author Dr Alison Lovegrove said: “Despite concerns over the declining genetic variation found across modern wheat types, there is no evidence that the health benefits of white flour from wheat grown in the UK have declined significantly over the past 200 years.
“In fact, we found increasing trends in several components, notably the major form of dietary fibre. This is despite great increases in the yields of wheat grown over this period.”
The team also found the concentration of betaine, which is beneficial for cardio-vascular health, has increased, whilst levels of asparagine - which can be converted to the potentially cancer-causing chemical acrylamide when bread is baked - have decreased.
The amount of certain sugars, including sucrose, maltose and fructose, have also increased over this period.
The stimulus for the study, according to Dr Lovegrove, was that the great increase in wheat yields brought about by the introduction of dwarf wheat varieties in the 1960s also led to a decline in zinc and iron concentrations.
“What was less clear was the impact on other components of nutrition. In addition, many studies look only at wholemeal flour but by far and away white flour products are the ones most people eat.”
For the purposes of the analysis, the 39 wheats were split into three groups – nine which were bred in the years 1790-1916, before an understanding of genetics had been developed; 13 varieties came from 1935-1972, recognised as a period of increasing scientific understanding; and 17 cultivars that were bred using modern breeding techniques between the years 1980 and 2012.
After milling the grain to white flour, the researchers found that the content of dietary fibre has increased steadily over the past two centuries, with modern varieties containing, on average, about a third higher concentration of the major fibre component, the cell wall polysaccharide, arabinoxylan.
This may be significant for consumers, because fibre is deficient in UK diets with about 10% of the intake coming from white bread.
The increase in betaine may also be beneficial to health. The modified amino acid is key in several metabolic pathways and has been found to help protect internal organs and improve heart health.
Similar good news is that acrylamide content has shown a decline. Acrylamide, which is classified as a probable carcinogen, is produced from asparagine and sugars when certain foods, including bread, are cooked above 120o C.
Writing in the journal Scientific Reports, the team report a great deal of variation between years – suggesting that environmental conditions such as rain or drought also affect nutritional quality, but that this is small when compared to the effect of the variety.
Dr Lovegrove said: “There is a strong environmental effect on grain composition which must therefore be taken into account when comparing crops grown at different times or at different places. This is a limitation of many studies that have previously looked at the change in nutritional quality of our food through time.”
The project was funded by UKRI BBSRC and also involved staff from the University of Bristol.
About Rothamsted Research
Rothamsted Research is the longest-running agricultural research institute in the world. We work from gene to field with a proud history of ground-breaking discoveries, from crop treatment to crop protection, from statistical interpretation to soils management. Our founders, in 1843, were the pioneers of modern agriculture, and we are known for our imaginative science and our collaborative influence on fresh thinking and farming practices.
Through independent science and innovation, we make significant contributions to improving agri-food systems in the UK and internationally. In terms of the institute’s economic contribution, the cumulative impact of our work in the UK was calculated to exceed £3000 million a year in 20151. Our strength lies in our systems approach, which combines science and strategic research, interdisciplinary teams and partnerships.
Rothamsted is also home to three unique resources. These National Capabilities are open to researchers from all over the world: The Long-Term Experiments, Rothamsted Insect Survey and the North Wyke Farm Platform.
We are strategically funded by the Biotechnology and Biological Sciences Research Council (BBSRC), with additional support from other national and international funding streams, and from industry. We are also supported by the Lawes Agricultural Trust (LAT).
For more information, visit https://www.rothamsted.ac.uk/; Twitter @Rothamsted
1Rothamsted Research and the Value of Excellence: A synthesis of the available evidence, by Séan Rickard (Oct 2015)
The Biotechnology and Biological Sciences Research Council is part of UK Research and Innovation, a non-departmental public body funded by a grant-in-aid from the UK government.
BBSRC invests in world-class bioscience research and training on behalf of the UK public. Our aim is to further scientific knowledge, to promote economic growth, wealth and job creation and to improve quality of life in the UK and beyond.
Funded by government, BBSRC invested £469 million in world-class bioscience in 2016-17. We support research and training in universities and strategically funded institutes. BBSRC research and the people we fund are helping society to meet major challenges, including food security, green energy and healthier, longer lives. Our investments underpin important UK economic sectors, such as farming, food, industrial biotechnology and pharmaceuticals.
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The Lawes Agricultural Trust, established in 1889 by Sir John Bennet Lawes, supports Rothamsted Research’s national and international agricultural science through the provision of land, facilities and funding. LAT, a charitable trust, owns the estates at Harpenden and Broom's Barn, including many of the buildings used by Rothamsted Research. LAT provides an annual research grant to the Director, accommodation for nearly 200 people, and support for fellowships for young scientists from developing countries. LAT also makes capital grants to help modernise facilities at Rothamsted, or invests in new buildings.