Dr. Ismail Cakmak

Overcoming zinc deficiencies in human populations through agronomic biofortification



Dr. Ismail Cakmak, winner of the 2016 IPNI Science Award and the 2005 IFA International Crop Nutrition Award, explains how the agronomic biofortification of food crops with zinc can help overcome zinc deficiency in human populations living in developing countries.

IFA: Congratulations for winning the 2016 IPNI Science Award! Can you explain the work that was recognized by this Award?
Dr. I. Cakmak
: Thank you. We received this Prize for our long-term efforts in agronomic biofortification, or enrichment, of cereals with zinc. We work towards the objective of reducing zinc deficiencies in developing countries: our ProgramHarverstZinc HarverstZinc, which IFA and other fertilizer institutions support, develops agronomic and fertilizer strategies to counter micronutrient malnutrition. HarvestZinc project has been developed under International HarvestPlus Program and coordinated by Sabanci University in Istanbul.

We’ve demonstrated that foliar zinc fertilizer application is highly effective to improve grain zinc concentration, to reach levels that meet human demand. We used high throughput analytical techniques (using ICP-Laser Ablation Spectometry and X-Ray fluorescence microscopy) to demonstrate that the late-season foliar spray of zinc to wheat results in increased zinc concentration in the endosperm fraction of wheat grain (i.e. the most consumed part of wheat grain). This finding has very important implications for the improvement of dietary intake of zinc in the developing world.

This fertilizer strategy works for a large number of countries, with diverse soil and climate conditions and also different cultivars of wheat and rice. We’ve found that soil zinc applications are very important to improve the grain yield of cereals on zinc-deficient soils. Soil zinc applications also contribute to grain zinc concentration; but not at adequate level for human nutrition. By contrast, foliar zinc application is highly effective in improving cereal grains with zinc at sufficient levels for human nutrition.

IFA: How does Zinc contribute to plant health?
Dr. I. Cakmak
: Zinc has critical functions in plant growth; about 10% of proteins in biological systems need zinc for their stability and function. Zinc is also required for the biosynthesis of proteins, and for better pollen viability. Plants that are deficient in zinc are highly sensitive to high light or radiation intensity, heat, drought and pathogenic infections. Plants having a good Zn status show better tolerance to pathogenic attack. In most cases, zinc deficiency in crop plants is “hidden”; it means plants show significant decreases in their yield capacity without showing visual zinc deficiency symptoms. Therefore, it is important to ensure and maintain a good zinc nutritional status in crop plants.

IFA: What are the health benefits of biofortification? In which countries have you tested them?
Dr. I. Cakmak
:Today, 2 billion people suffer from zinc deficiencies. This is due to the reduction in daily dietary zinc intake: cereals are inherently low in zinc; so populations whose consumption is cereal-based, namely in developing countries, receive far below the required daily zinc intake (e.g., 15 mg Zn per day). Zinc deficiency can lead to diverse health complications, especially for young children: it can lead to impairments in brain function, mental health, weakened immune systems and also poor physical development.

We’ve conducted field trials in 13 developing and transition countries, including China, India, Pakistan, Thailand, Laos, Zambia, Zimbabwe, Mozambique, South Africa, Brazil, Kazakhstan, Mexico and Turkey. In these countries, we’ve also organized “zinc days”, to inform and educate growers, agronomists and students on the problems linked to soil and human zinc deficiencies. To our knowledge, several national research programs were started in these countries following these interventions, focusing on agronomic biofortification of food crops with zinc. We also stress the importance of zinc-enriched seeds for better seed quality and vitality, besides the human health benefits. Seeds with higher zinc concentration germinate better, have better seedling vigor and tolerate better environmental stresses.

IFA: Are countries picking up on these biofortification efforts?
Dr. I. Cakmak
:I think so, yes. We know of several on-going national research activities and MSc or PhD thesis projects that focus on agronomic and genetic biofortification. In some countries, governments are directly involved in HarvestZinc activities, and in plant breeding efforts of the HarvestPlus Program.

IFA: What is next for your project, HarvestZinc?
Dr. I. Cakmak
:Today, we’re also looking at iodine biofortification. It’s part of the third phase of HarvestZinc, which will last three years. Iodine deficiency is another common micronutrient deficiency in human populations, that also has severe health consequences and merits attention. Iodine deficiency is a particular micronutrient deficiency problem, because it occurs both in developing and well-developed countries. Our recent results show that foliar iodine spray is also very effective in increasing grain iodine concentrations of various cereal species. A very new paper on iodine biofortification of cereal crops is ready to submit to an international journal around these days.


About Dr. I. Cakmak:

Dr. Cakmak received his B.Sc. from Cukurova University in 1980; his M.Sc. from Cukurova University in 1981; and his Ph.D. from Hohenheim University-Stuttgart, Germany in 1988. Since 2000, he has worked as a Professor of Plant Physiology at Sabanci University in Istanbul, Turkey. Dr. Cakmak is well known for his research on cereal crops and zinc nutrition. He directed a multi-institutional project, funded by the North Atlantic Treaty Organization (NATO), on the issue of zinc deficiency in Turkey (1993 to 1998).

The “HarvestZinc” project was developed by Dr. Cakmak under the HarvestPlus Program to improve grain concentration of zinc and iodine in nine different countries (e.g. Asia, Africa, and South America). The focus was on using innovative application methods and novel micronutrient fertilizer combinations.

Dr. Cakmak has authored over 160 peer-reviewed publications, received over 18,600 citations (Google Scholar), and authored/co-authored seven book chapters. He has a Hirsch Index of 71 (Google Scholar), which is a very high value within his field. He has been recognized with several awards including the Alexander von Humboldt Foundation Georg Forster Research Prize, 2007 Australian Academy of Technological Sciences and Engineering Crawford Fund “Derek Tribe Award Medal”, the 2005 IFA International Crop Nutrition Award and the Scientific and Technical Research Council of Turkey Science Prize. Since 2012, he has been an elected member for “The Academy of Europe” and “The Science Academy” in Turkey. Very recently, he has received the World Academy of Sciences Prize, 2016 in Agricultural Sciences.


About the IPNI Science Award:

The IPNI Science Award is intended to recognize outstanding achievements in research, extension, or education; with focus on efficient management of plant nutrients and their positive interaction in fully integrated cropping systems that enhance yield potential.