What are micronutrients and why are they so crucial for soil, plant and human health?
Farmers have largely relied on NPK fertilizers to replenish these primary macronutrients in the soil, which have been taken up by crops, and to promote agricultural productivity. Yet, additional secondary macronutrients and micronutrients are also crucial for ensuring healthy soils and healthy crops, as already spelled out by Justus von Liebig’s Law of The Minimum (1840), which states that plant growth and health is not controlled by the total amount of nutrients available in the soil, but that plant growth and health is controlled by the scarcest of the nutrients available in the soil.
My area of expertise lies in human nutrition, however. We know that inadequate intakes of essential vitamins and minerals compromise cognitive development, lower disease resistance, increase mortality, stunt growth, and lower work productivity. Preschool children and mothers of reproductive age are most vulnerable due to their higher requirements.
An estimated 2 billion people in the developing world suffer from the effects of micronutrient malnutrition (mainly related to deficiencies of iron, zinc, vitamin A, iodine, and folates), caused primarily by poor quality diets which are characterized by adequate food staple intakes, but low intakes of higher cost vegetable, fruit, pulses, and animal products which are relatively dense in minerals and vitamins.
For example, 10 billion vitamin A capsules (at an approximate cost of $10-15 billion) have been distributed over the past twenty years for preschool children – with the effect of (for those who receive capsules) reducing preschool mortality by an estimated 23 percent. The Global Disease Burden 2015 estimates that 1.24 billion people are affected by iron deficiency anemia which leads to permanent impairment of cognitive function in pre-school children. 1.2 billion people are at risk for zinc deficiency. 450,000 deaths among pre-school children are attributed to zinc deficiency due to weakened immune systems. In addition, despite worldwide efforts, including implementation of universal salt iodization over the past 30 years, iodine deficiency still represents a global public health problem in the world.
Stunting, suggested to be associated with zinc deficiency, affects around 1 out of 4 children under five years of age in low- and middle-income countries (LMICs). Progress in achieving the global targets for a 40% reduction of child stunting and a 50% reduction of anemia in 2025 is still too slow. Stunting is strongly associated with poor brain development and cognitive function. Global losses in economic productivity due to macronutrient and micronutrient deficiencies reach more than 2 to 3 percent at a global cost of US$1.4-$2.1 trillion per year.
Interestingly, there is no consensus in the international nutrition community that low protein intakes are a serious public health problem.
What are the most promising ways to address micronutrient deficiencies in human populations? Do we also need to be concerned about adequate protein content in grains?
The fundamental underlying cause of mineral and vitamin deficiencies in developing countries is that non-staple foods – vegetables, fruits, pulses, and especially animal products which are rich in bioavailable minerals and vitamins – are not affordable by the poor. Moreover, prices for these non-staple foods have risen significantly relative to staple foods (mostly cereals, roots and tubers) over the past several decades. The poor eat high amounts of food staples to keep from going hungry and are severely constrained by low incomes and high non-staple food prices to improve their dietary quality.
Strategies to increase intakes of minerals and vitamins through food systems include (but are not limited to):
Biofortification, which is the process of breeding for high-yielding staple food crops which are more mineral and vitamin dense. Because biofortified staple foods (grain and root crops) sell for the same price as non-biofortified staple foods, biofortified foods may be substituted one-for-one in diets, providing more minerals and vitamins at no extra cost to family food budgets.
Increasing the productivity of key, nutritious non-staple foods in particular countries, rapidly increasing local supply, and thereby lowering national prices significantly. For example, Operation Food in India lowered milk prices by 50% for a certain period of time. Eggs and specific vegetables, which are not widely traded internationally, are other examples of possible focus commodities.
Importantly, and in addition to the above, research under the HarvestZinc program, led by Ismail Cakmak of Sabanci University, has revealed that fertilizer policy in principle can increase iron, zinc and iodine intakes in several ways:
It is already well known that fertilizers have increased agricultural productivity significantly. Global food prices are much lower than they otherwise would have been without widespread use of NPK, ceteris paribus improving dietary quality in LMICs, although apparently this has never been modelled, well quantified, and documented.
Application of fertilizers, especially nitrogen and sulphur containing fertilizers, increases the concentration of protein, iron, and zinc in the grains of staple foods (more so wheat, than rice, than maize). Protein is a sink for deposition of iron and zinc in grains.
Zinc may be added to commonly applied compound fertilizers and foliar sprays to significantly increase grain zinc content:
Under certain soil conditions, zinc in compound fertilizers will increase crop yields
Grain with higher seed zinc content, replanted as seeds, will give higher yields in the following season
Some evidence suggests that there is a synergistic effect between use of fertilizers (and additions of zinc in fertilizers and foliar sprays) and HarvestPlus-biofortified crop varieties in increasing grain concentration of iron and zinc.
What’s required to scale up the use of biofertilization?
Better nutrition and economic growth happen most rapidly and resources are invested most efficiently when government and the private sector work together in coordination. Each have an important role to play.
In the area of mineral fertilization, or what is often called agronomic biofortification, the first requirement is information dissemination and advocacy. People, agencies, institutions – public, private, and non-governmental -- need to better understand the current effects and potential effects of fertilizer policy on mineral and vitamin deficiencies in LMICs. Some of this information is already available to make a start. Some of it needs to be better quantified, documented, and published because many questions will be raised.
I know this from my own experience in promoting biofortification. There is a tremendous inertia in wanting to continue doing things in the same way as they have always been done. But we know that under the current status quo, much misery is being suffered due to mineral and vitamin malnutrition.
Informational materials need to be developed and disseminated, some research is required to develop more complete and precise numbers. Then the next step is start somewhere, to convince governments and fertilizer companies in particular countries to take actions (based on data provided by research), and to monitor and measure nutrition outcomes. See what works and what does not work. Document what has happened. That feeds into additional and more powerful advocacy. Essentially, that is the course we have taken at HarvestPlus with biofortification, working in collaboration with so many partners.
How can a multi stakeholder forum such as this one help support agronomic biofortification scaling up?
Many people around the world make a good living working in agriculture, certainly many people at this conference, and that is great. We all want to see the opportunities that we have expand to as many small-holder farmers in LMICs as possible. But at the same time, we also have to be very cognizant of why we produce food – to be healthy. We can’t ignore this primary role of the agriculture sector in the many decades ahead that it will take to eliminate poverty. Literally billions of people, especially women and children, are unhealthy under the current agriculture and food systems.
So we take this message forward from here – that agriculture is not all about increasing productivity and reducing poverty. It also about securing national health. And then of course from there we have to get into the particular policies and scientific details, and how are we going to invest our resources, with a particular focus on fertilizers.
I myself have not interacted a great deal with the fertilizer industry – and I am very happy to have this opportunity – but for me the key question coming out of this meeting is how will the fertilizer industry react – as a highly impactful sector in global agriculture and food systems, and as responsible stewards of public welfare?
Let me end with this quote which has inspired me over the years:
“Such intimately related subjects as agriculture, food, nutrition and health have become split up into innumerable rigid and self-contained little units, each in the hands of some group of specialists. The experts, …soon find themselves…learning more and more about less and less…The remedy is to look at the whole field covered by crop production, animal husbandry, food, nutrition, and health as one related subject and…to realize…that the birthright of every crop, every animal, and every human being is health.”
The quote sounds very timely, but it was written 1948 in a book entitled “The Soil and Health,” authored by Sir Albert Howard.