The study, led by Professor Peter Shewry for the EU-funded Healthgrain project, isolated the components known to play a role in prevention of cardiovascular disease and type-2 diabetes and compared them across grain varieties, in order to find out which have the best nutritional profiles.
The researchers wrote: “Detailed comparisons of the bread wheat lines show that it is possible to identify lines in which high levels of phytochemicals and dietary fiber components are combined with good yield and processing quality. This means that commercially competitive lines with high levels of bioactive components are a realistic goal for plant breeders.”
The research is due to be published in the November 26 issue of the American Chemical Society’s Journal of Agriculture and Food Chemistry.
Lack of understanding
Evidence of whole grains’ role in disease prevention has been mounting over the past decade, forming a strong enough basis for health claims to be made in the United States, Sweden and the United Kingdom. According to the researchers, however: “The component(s) in wholegrain that are responsible for these effects on the protection of health and homeostasis and their mechanism(s) of action are still not fully understood.”
In particular, they examined fibre content and phytochemicals known to have an antioxidant effect, including sterols, phenolic acids and folates.
Scope and limitations
As nutrient levels vary between grain varieties, they grew, harvested and milled 150 wheat varieties used for bread making and 50 other grain varieties – oats, barley and rye – over a one-year period in Hungary. The grains originated worldwide, but the researchers acknowledged that there were limitations to the single-site study.
They wrote: “The Healthgrain diversity screen has generated the most extensive database currently available on bioactive components in wheat and other smallgrain cereals...Nevertheless, it must be borne in mind that the data originate from a single series of samples grown on one site in one year…Hence, environment interactions are not known.”
However, they also noted that while previous studies have shown varying amounts of several components from site to site and year by year, “the ranking order of the lines remains fairly constant.”
Healthgrain was set up in 2005 to promote consumption of whole grains in Europe as a way to reduce the incidence of heart disease and diabetes. It says that one of its main aims is to “generate new sources of nutritionally enhanced grain and to provide a ‘biotechnology toolkit’ for plant breeding programmes.”