Shifting to a more plant based diet
Dietary Guidelines around the globe recommend the inclusion of grain foods and legumes as part of a healthy diet. Despite this, there is a common belief that a diet including larger amounts of plant-based foods may not provide adequate nutrients. New Australian research has demonstrated that it is possible to achieve adequate nutrient intake on a diet that is dominated by whole grains, legumes, nuts, seeds, fruit and vegetables.
According to Dr Rosemary Stanton OAM, “Diets dominated by whole grains, legumes, nuts, seeds, fruits and vegetables are almost certainly the way of the future.” Dr Stanton is the editor of a supplement of peer-reviewed articles dedicated to plant-based nutrition was published this week with the Medical Journal of Australia (MJA). The Grains & Legumes Nutrition Council is pleased to be associated with this extensive review of the science demonstrating the contribution of plant-based foods to the Australian diet.
Comparisons of population intakes with dietary recommendations indicate that to meet dietary intakes people need to shift toward a more plant-based eating pattern. The recently published draft Australian Dietary Guidelines indicates that to satisfy recommended dietary intakes, adults need to increase grain foods in the diet by 30%, and in particular high-fibre and wholegrain products by 160%. In addition Australians would need to consume 40% more fish, poultry, seafood and eggs, or legumes / beans, nuts or seeds.
International recommendations also indicate a similar shift. At the recent Wholegrain Summit in the USA, Dr Eric Rimm from Harvard University and a member of the advisory committee for the US Dietary Guidelines, explained that one of the key principles of the 2010 Dietary Guidelines was to encourage a diet that includes more plant foods such as whole grains, legumes, nuts and fruit and vegetables.
The MJA supplement includes articles on the adequacy of a diet dominated by plant foods and highlights the contribution of plant foods such as grains and legumes to key nutrients in a healthy diet. Plant-based foods such as grains and legumes, along with nuts and seeds, are a source of a range of nutrients including protein, iron and zinc.
Plant foods contribute significantly to the protein intake in the Australian diet. While most grain and legume foods have limited amounts of some amino acids, the review found that a varied plant-based diet can easily meet protein requirements as long the diet meets energy needs.
A diet rich in whole grains, legumes, nuts, seeds, dried fruits, iron-fortified cereals and green leafy vegetables provides an adequate intake of iron. The paper in the MJA Supplement on iron requirements explains that this is because a person eating a more plant-based diet will adjust to absorb iron more readily. In fact, most of the iron in the Australian diet comes from plant foods.
Phytate is a known inhibitor of zinc absorption. However, the inhibition can be reduced by processes used to make or prepare most grain foods legumes such as soaking, heating, fermenting and leavening. Plant foods high in zinc include cooked brown rice (1.9mg in 1 cup), tofu (1.7mg/100g), and cashews (1.7g/30g handful).
This research demonstrates that it is possible to achieve adequate nutrient intake on a diet that is dominated by whole grains, legumes, nuts, seeds, fruits and vegetables. The Grains & Legumes Nutrition Council recommends Australians follow the Australian Dietary Guidelines and eat a variety of foods including high fibre and whole grain foods as well as legumes.
The 40 page supplement is available online via the MJAOPEN website www.mja.com.au/open.
National Health and Medical Research Council. Revised Draft for Public Consultation:
Australian Dietary Guidelines & Australian Guide to Healthy Eating. 2011, Commonwealth of Australia: Canberra