A synthesis review covering zinc biogeochemistry in soils, plant uptake mechanisms, and human health implications of zinc across the soil-to-food-to-human pathway. The paper includes data from a comprehensive soil survey of India (14,863 samples) and synthesizes human zinc deficiency epidemiology, body distribution, and functional roles.
Key numbers
- Adult human body zinc content: 1.4 to 2.3 g, distributed across skeletal muscle, bone, liver, kidney, skin, and prostate (p. 4).
- Global zinc deficiency: approximately one-third of the global population is zinc-deficient (p. 4).
- India soil survey (14,863 samples): 49% of soils potentially deficient in zinc; 33% deficient in boron; 12% deficient in iron; 11% deficient in molybdenum; 5% deficient in manganese; 3% deficient in copper (p. 4).
- Zinc roles in humans: component of over 300 enzymes including carbonic anhydrase, alkaline phosphatase, alcohol dehydrogenase, superoxide dismutase, and RNA polymerase; structural role in zinc-finger transcription factors; immune function (thymulin production, T-cell differentiation); DNA synthesis and repair (p. 4-5).
- Zinc deficiency manifestations: growth retardation, impaired immune function, delayed wound healing, dermatitis, hypogonadism in males, and cognitive impairment (p. 5).
- Zinc phytoremediation context: zinc can accumulate in hyperaccumulator plants such as Thlaspi caerulescens and Arabidopsis halleri, relevant for soil remediation but not for food concentration data in conventional food crops (p. 7-9).
- LOD/LOQ: not reported for soil survey data (survey-level analysis of existing data, not an independent laboratory measurement with stated LOD).
Methods (brief)
The soil survey data (14,863 samples) was a secondary synthesis of compiled India soil database data, not independent laboratory analysis by these authors. Plant uptake sections describe mechanisms of zinc absorption in root systems (ZIP family transporters, MTP exporters). Human health section is a narrative synthesis without systematic search protocol.
Evidence fitness
This source supports characterization of the soil-to-human zinc pathway and provides the India-wide soil mineral deficiency survey data. It is appropriate as context for understanding how soil zinc deficiency translates to human dietary deficiency through plant-based food systems. The body content figure (1.4 to 2.3 g) is sourced from this paper and is cited on the target page. Plant uptake, phytoremediation, and pot experiment data in this paper are contextual for the uptake pathway; they are not food concentration data for finished conventional foods. These sections are labeled accordingly and are not mixed into finished-food data.
Limitations
The India soil survey data are survey-level estimates; sample collection protocols and analytical quality control for the 14,863 samples are described in cited primary references rather than in this synthesis. The human health section is a narrative review without formal systematic methodology. Food concentration data for conventional food crops are not provided in a format usable as contamination data for finished foods.
Related evidence
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