Getting the most out of wheat

October 28, 2014

The impact of wheat on diet and health is frequently overlooked. In particular, in developed countries its consumption in processed products has led to the perception that it is little more than a high-calorie food. This, in fact, is a misconception which can have serious consequences for public health.

Wheat contributes significantly to the daily intake of essential dietary components, including B vitamins, minerals such as iron and zinc and dietary fiber. The health benefits of these are established¬ – iron transports oxygen around the body, zinc is important for maintaining a healthy immune system and dietary fiber is essential for bowel health and reduces the risk of heart disease, diabetes, obesity and colo-rectal cancer. Cereal fiber is one of the few plant-derived food components that is accepted by both the U.S. Government and the European Commission for health claims on food labels.

In addition, wheat contains numerous phytochemicals that may benefit human health. Phenolic antioxidants, for example, could improve vascular function and provide resistance to a range of illnesses.

How can wheat production and processing maximize these benefits in products attractive to consumers in both the developing and developed worlds?

I think a two-pronged approach is required.

First, processing systems need to be optimized to increase the bioactive components in flours and foods. Although almost all bioactive components are concentrated in the bran and germ of the wheat grain, the vast majority of wheat products are manufactured from highly-refined white flours and these parts of the grain have been removed by milling. The obvious solution is to use whole meal rather than white flour, but this is not always possible, due to adverse effects on processing and low consumer acceptability. There is no point in producing nutritious products that are not appealing!

However, even moderate increases in the amount of flour recovered from the grain (the extraction rate) can have significant effects on the nutritional value of wheat-based products. For example, increasing the extraction rate from 70 percent to more than 80 percent can double the contents of components such as phenolic acids, minerals and fiber. Traditional high-extraction flours, such as those used to make flat breads in South Asia (chapatti, poorie, parontha) and the Middle East (Tanoor in Iran, Lavash and Baladi in Egypt), should therefore continue to be used and should also be promoted more widely for other wheat products, rather than replaced with Western-style breads made from highly-refined white flour.

A longer-term approach is to genetically improve the wheat crop to accumulate more bioactive components. Progress in this area will be slower due to the strong effects of the climate and soil type on grain composition. Positive progress, however, is already being made in increasing the contents of minerals and dietary fiber, which will be assisted by developing new methods to improve the efficiency of wheat breeding. It is also important to exploit the full range of wheat diversity in breeding – including land races and historical varieties – rather than focus solely on modern varieties.

Improving the nutritional and health benefits of wheat will clearly have the greatest impact on public health in less developed countries with less diversity in diets. However, it will also reduce the incidence of “Western diseases” associated with over-consumption of over-refined products (such as Type 2 diabetes, cardiovascular disease and obesity). These diseases are also increasing at an alarming rate in the rapidly urbanizing populations of countries such as India and China, where they may exist alongside malnutrition. Dietary interventions are therefore urgently required to prevent their increase to epidemic levels.

Against this background, improving the quality of wheat products is a clear priority for national and international agencies.

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