Few might know, but the United Nations has declared 2016 the International Year of the Pulse. What of it, you ask. And what is a pulse anyway?
The (food‐related) term ‘pulse’ is used to describe the seeds of legumes. They include lentils, chickpeas, faba beans, broad beans, field peas and lupins. They are a traditional dietary staple in many parts of the world, and the main reason for the UN’s declaration is to highlight this food group’s potential ability to address global health, nutrition, food security and sustainability issues. Increases in production and consumption of pulses could provide a low cost source of nutrient‐ dense food for people in many parts of the world facing food shortages. There are significant potential environmental and health benefits associated with increasing consumption of pulses.
The pluses of pulses
Pulses offer high quality nutrition (protein, carbohydrates, vitamins and minerals) produced with less demand on resources. As demand for dairy and meat products increases, water availability may start to limit their production in some regions. Compared to the production of other protein sources, pulses have much lower resource requirements. To produce a kilogram of beef requires, on average, 13,000 litres of water while a kilogram of lentils uses only about 50 litres. A further benefit of pulses is their potentially low carbon footprint. Producing one kilogram of legumes is estimated to create on average about 0.5 kilogram of CO2, compared to one kilogram of beef which may generate about
9.5 kilograms of CO2.
Growing pulse crops can actually improve the condition and productivity of the soil from which they are grown. Most other crops require fertilisers to provide sufficient soil nitrogen in farmland, especially in soils with depleted nutrients after long‐term farming. Fertilisers can be expensive for poor farmers, and contribute to greenhouse gases both in their manufacture and after their application (via the release of nitrous oxide). Indeed, as the UN’s Food and Agriculture Organisation reported:
Emissions generated during the application of synthetic fertilizers accounted for 13 percent of agricultural emissions (725 Mt CO2 eq.) in 2011, and are the fastest growing emissions source in agriculture, having increased some 37 percent since 2001.
While farming pulses may still require some fertiliser and pest control, pulses have an advantage unique to legumes of being able to benefit soil through ‘nitrogen fixing’. Bacteria in their root systems are able to secure nitrogen gas from the air and convert it into readily usable nitrogen compounds that the plants absorb, allowing rapid growth in soils that are poor in available nitrogen. In the process, some of these nitrogenous compounds remain in the soil after harvesting the crop. This improves soil fertility for future crops (of any sort) and reduces the need for fertiliser.
Pulses can also increase food security, by enabling more food to be produced with fewer resources, as outlined above. Pulses can be distributed with less packaging than most crops and without refrigeration requirements. Pulse seeds have been relied on to provide aid following natural disasters in numerous emergency situations. However, pulses (especially lupins) may contain a range of dangerous toxins and some ‘anti‐nutrients’ (which prevent absorption of beneficial substances), but selective breeding and appropriate preparation and cooking can minimise many of these.
Health benefits
Pulses represent a low‐fat and nutrient‐dense option for increasing plant‐based dietary components. They feature in all five of the nutritional ‘blue zone’ traditional diets, which are believed to be associated with greatest longevity and health. In addition to providing an excellent source of fibre, (which brings many established health benefits), pulses are also a source of complex carbohydrates, protein and important micronutrients. The 2013 Australian Dietary Guidelines and updated Australian Food Pyramid state that Australians should aim for 5 serves of vegetables / legumes food group every day, noting that most Australians currently eat only half that amount. The updated Healthy Eating food pyramid also includes legumes in the lean meat / protein category.
In many parts of the world, crops that form the basis of local diets provide insufficient quantities of protein, vitamins and minerals to support good health. Pulses are rich in B vitamins and provide a good source of iron, zinc, selenium, phosphorus and potassium. They also contain a high concentration of protein (17‐30% of the dry weight, which is about twice that of other cereals).
Admittedly, this is considered ‘lower quality’ protein compared to most animal protein, because not all essential amino acids are present. However, eating pulses with other grains will complement the amino acids that are lacking in the pulses, and therefore can provide high quality protein that is as good as animal protein.
Australia’s pulse industry
Pulse Australia paints a bright picture for ongoing growth in Australia’s production and export of pulses. In 2015 Australia produced 2.2 million tonnes, up from 1.3 million tonnes in 1990, resulting in exports of A$1.2 billion. Pulse Australia estimated there were a record 661,000 hectares of chickpeas sown in 2015 (an increase from the previous 2012 record of 564,000 hectares). There is a large and growing international market for pulses, representing an opportunity for Australian exports.
In an effort to increase Australia’s pulse production, with improved yield and uptake of pulse farming, the Pulse Breeding Australia program is developing pulse varieties with increased resistance to disease, decreased requirements for artificial fertilisers and improved tolerance to stresses such as salt, heat and frost.
“Super‐pulses”
We hear a lot about novel exotic ‘superfoods’ (basically referring to nutrient‐dense foods), but pulses are a good example of an original, albeit low key, class of ‘superfood’. In addition, they are less environmentally damaging than many other crops, and leave behind well‐fertilised soil as an added benefit. The International Year of the Pulse gives a well‐deserved boost to these not‐so‐new superfoods.