Zinc in soil-crop-animal-human health continuum

Abstract
Globally, zinc (Zn) deficiency in soils, and subsequently crops, has emerged as one
of the most prevalent among micronutrients, resulting in a severe decline in crop
yields and nutritional quality and in adversely affecting animal and human health.
Worldwide, more than half of the agricultural soils are inherently deficient in Zn,
and the health of about one-third of the global human population is impacted by
Zn deficiency. Zinc is an essential micronutrient for animal and human health, and,
in the developing world, Zn deficiency has been identified as the fifth cause of disease
and death for humans. The World Health Organization (WHO) reports that annually
more than 800,000 people, including around 450,000 children under the age of 5,
die due to Zn deficiency. Zinc supplementation was frequently associated with
boosting immunity against COVID-19 in recent years. Because most of the Zn in
animals and humans is derived from soil-grown crops, their source of Zn is highly
dependent on plant Zn, especially in crops or fodder; in turn, crop Zn is dependent
on available soil Zn levels. This integrated review describes Zn distribution, behavior,
and fate in soils and its uptake and role in plants and crop production, as well as in
the well-being of animals and humans. It discusses recent findings concerning Zn
deficiency in all steps of the human food chain (from soil, to crop, animal, and human),
and how it can be addressed through novel Zn fertilizers, soil amendments, and
biofortification of Zn.