Could Global Intensification of Nitrogen Fertilisation Increase Immunogenic Proteins and Favour the Spread of Coeliac Pathology?

Abstract

Fertilisation of cereal crops with nitrogen (N) has increased in the last five decades. In particular, the fertilisation of wheat crops increased by nearly one order of magnitude from 1961 to 2010, from 9.84 to 93.8 kg N ha−1 y−1. We hypothesized that this intensification of N fertilisation would increase the content of allergenic proteins in wheat which could likely be associated with the increased pathology of coeliac disease in human populations. An increase in the per capita intake of gliadin proteins, the group of gluten proteins principally responsible for the development of coeliac disease, would be the responsible factor. We conducted a global meta-analysis of available reports that supported our hypothesis: wheat plants growing in soils receiving higher doses of N fertilizer have higher total gluten, total gliadin, α/β-gliadin, γ-gliadin and ω-gliadin contents and higher gliadin transcription in their grain. We thereafter calculated the per capita annual average intake of gliadins from wheat and derived foods and found that it increased from 1961 to 2010 from approximately 2.4 to 3.8 kg y−1 per capita (+1.4 ± 0.18 kg y−1 per capita, mean ± SE), i.e., increased by 58 ± 7.5%. Finally, we found that this increase was positively correlated with the increase in the rates of coeliac disease in all the available studies with temporal series of coeliac disease. The impacts and damage of over-fertilisation have been observed at an environmental scale (e.g., eutrophication and acid rain), but a potential direct effect of over-fertilisation is thus also possible on human health (coeliac disease).

The α-Gliadins in Bread Wheat: Effect of Nitrogen Treatment on the Expression of the Major Celiac Disease Immunogenic Complex in Two RNAi Low-Gliadin Lines

“…It was hypothesized that the increase in N fertilization could be related to a potential increase of gluten in wheat grains and flours and thus to the spread of CD ( Penuelas et al, 2020 ). They carried out a meta-analysis (1961–2016) and found that the increase in N fertilization rates was associated with increased content of total gluten, including all gliadin fractions, and gliadin transcripts in wheat grains, which provided a strong potential increase in the average human intake of gliadins.…”

Drought is a stronger driver of soil respiration and microbial communities than nitrogen or phosphorus addition in two Mediterranean tree species

“…The availability of soil nutrients can affect soil respiration, but these effects can vary depending on the dose and duration (Cascio et al, 2017). Some ecosystems will be more limited by nitrogen (N), and others will be more limited by phosphorus (P) (Penuelas et al, 2020;Peñuelas et al, 2013), and N and P contents can have interactive effects. These differences depend primarily on the soil, especially its age, and can vary greatly between geographical locations and biome types.…”

Wheat/Gluten-Related Disorders and Gluten-Free Diet Misconceptions: A Review

“…Intensified fertilization with N may increase the allergenic proteins content of wheat, which may be related to the increase in CD pathology. The study that put forward this hypothesis concluded, after a literature meta-analysis, that wheat grown under higher N availability in the soil produces not only higher yield but also grains and flour with higher concentrations of gliadin in all genotypes [225]. However, further experimental studies need to be done, and if this hypothesis stands, we will have an important lead to follow to prevent and control the spread of CD.…”