Exploring the health promoting components of whole grains
Eating more whole grains helps to reduce the risk of developing type 2 diabetes, heart disease, hypertension, bowel cancer and inflammation; yet many Australian’s may not be getting enough. One of the key hurdles to convince Australians to eat more whole grains is demonstrating exactly how whole grains reduce the risk of so many diseases. It has long been thought that fibre was the key component in whole grains responsible for disease prevention, however Australian researchers now suggest that components other than fibre which are found in whole grains may be more powerful at promoting health.1
Higher intake of bran (the fibre rich outer layer of whole grains) has been shown to result in many of the same health benefits as eating whole grains themselves. Emerging evidence indicates that when we eat whole grains and bran in particular we are not only eating fibre but we are also eating some highly specialised cells known as the aleurone. The aleurone is unique to whole grains, and is not found in other plant foods like fruit and vegetables. It is nutrient rich, containing a range of vitamins, mineral and antioxidants. In fact thanks to the antioxidant levels found in the aleurone, whole grains antioxidant capacity is equal to that of fruit and vegetables, which seems to be a well kept secret.1,2
Interestingly, whereas most of the grain cells are dead, these aleurone cells remain ‘alive’ and metabolically active even after being dried and prepared to be eaten as food. It has been suggested that these cells and the nutrients they contain contribute to the health benefits of whole grains.1
Researchers have highlighted magnesium, zinc and ferulic acid (an antioxidant) as key health promoting components of the aleurone. Each of these is found in rich supply within the aleurone and each has been observed to have positive effects on and blood glucose control, blood pressure and/or protecting the blood vessels of the body. In the case of whole grains, these three key nutrients are consumed together along with many other nutrients and fibre. This means that any positive effects they have are summed together, which is a likely explanation for the significant health benefits associated with eating whole grains.
Given the years and years it takes to develop chronic disease it is suggested that the combined effects of magnesium, zinc, antioxidants, fibres and the range of other nutrients found in whole grains is the reason why they have been shown to significantly reduce risk of chronic disease.
This recent evidence reinforces that whole grains are just as important as fruits and vegetables in protecting the body against chronic disease. The Grains & Legumes Nutrition CouncilTM recommends that Australians aim to eat at least 48g of whole grains each day for disease prevention.3,4 This is equal to around 3 serves of whole grain foods, with 1 serve being equal to a slice of whole grain bread. The great news is that increasing whole grain intake isn’t difficult since whole grains and whole grain foods are cheap, easily stored and readily available.
1. Lillioja S, et al. Whole grains, type 2 diabetes, coronary heart disease and hypertension: Links to the aleurone preferred over digestible fibre. BioFactors, 2012. Published early online.
2. Fardet A. New hypotheses for the health protective mechanisms of whole-grain cereals: what is beyond fibre? Nutr Res Rev. 2010 23(1):65-134
3. Griffiths T and Nestel P. Developing a target for daily wholegrain intake for Australians. Food Australia. 2006;58(9):431-433.
4. Griffiths T. Towards an Australian ‘daily target intake’ for whole grains. Food Australia. 2007;59(12):600-601.