Mineral Nutrition through the Food Chain
Soil to Crop to human nutrition, health and wellbeing
Human healthcare and food
Healthcare in Australia costs over $100billion (9% of GDP). The contribution of food composition to human health, well-being and chronic conditions is increasingly appreciated, but poorly understood. Relatively little research effort has been focused on the relationships between primary inputs into the food chain, from soil to crop plants and the long-term health of human populations.
Mineral nutrition – from soil to chronic disease
A report from the U.S. Nutrition Security Institute (Marler & Wallin, 2006) outlines the rapid increase in rates of chronic diseases between 1980-1994 of between 19% (heart conditions) and 87% (asthma) and indicates the specific mineral deficiencies known to be associated with these diseases. These plant-delivered minerals include macro- and micro-elements magnesium, calcium, potassium, chromium, copper, selenium and zinc. The same report also outlines an outstanding decline in average mineral content of selected vegetables between 1914 and 1997 (from USDA and other sources).
As one example, crop plants supply 90-95% of human calcium and magnesium intake, either directly or via animal feed-chains. However, in many developed countries the intake of these essential minerals is below established requirements to maintain a healthy diet. Globally, billions are likely to be at risk of calcium and magnesium deficiency.
There is scope for intervention in the spread of chronic human disease through innovative agronomic practice, soil management and crop breeding.
In addition, there has been increasing interest in the role that protective phytochemicals, delivered via food crops, may play in delivering the benefits of a healthy diet to combat chronic human diseases and conditions. These include anti-oxidants, tumour-protective agents, vitamins, and a wide range of secondary metabolites. However, relatively little research has focused on the ‘genotype x environment’ interactions affecting these phytochemicals during crop cultivation, and more specifically the relationship between soil micronutrient supply and levels of active phytochemicals that act as anti-oxidants or cancer protectants. Some studies have shown a relationship between levels of zinc and cancer-protecting glucosinolates in brassicas, for which there is also a known relationship with soil sulphur levels.
Soil management and organic production
The contribution that different soil management and cultivation practices can make to the delivery of minerals and phytochemicals to enhance human health has been poorly studied. A UK study commissioned by Dept Environment Food & Rural Affairs (2008) quoted Stolze et al (2000) ‘No clear conclusions about the quality of organic food can be reached using the results of present literature’. In general, conventional organic production systems require more land to achieve equivalent yields of non-organic systems. This contributes to current high food prices, with food security of local and global concern given threats to available land for cultivation. For example, food constitutes 17% of NSW family budgets, with high prices driven by the costs of primary production.
There is an urgent need to address the interaction between soil health and ability of crop plants to take up and utilise mineral nutrients. This will not only reduce the cost and environmental impact of fertiliser use, but is likely to contribute to enhanced human health. The cost of fertilisers (organic or mineral) is prohibitive to many farmers in poorer nations, so breeding has been advocated as the most cost-effective solution to optimise uptake efficiency from the soil. However, within the context of food security and land availability, there is a need to understand the contribution that management of soil health can make to enhancing nutritional composition of crop produce.
Converte is dedicated to work with farmers and other partners interested in ensuring access to healhier produce for our next generation.