Why are there so many more celiacs? The answer could be in fertilisers

BarcelonaFertilisers used to increase wheat yields around the world could be one of the factors behind the increase in cases of celiac disease in recent decades, according to a study by an international team of scientists led by ecologist Josep Peñuelas, a researcher at the Centre for Ecological Research and Forestry Applications (CREAF), which has been published in the journal Foods. "We are dedicated to global ecology and we have seen that an important factor of global change is that we fertilise the planet with more and more nitrogen, which has effects on microorganisms, plants and animals, one of which is us," explains Peñuelas.

Indeed, between the 1960s and today, there has been a tenfold increase in the use of nitrogen-containing fertilizers in wheat fields in most parts of the world. These products have increased crop yields 3.5-fold, but they have also caused wheat to incorporate more nitrogen, thereby increasing the content of proteins known as gliadins in the grain. Gliadins, in turn, are part of gluten, the set of wheat proteins that give elasticity, consistency and sponginess to flour-based products such as bread and cakes, and make them palatable. And gluten, as is known from numerous biomedical studies, causes some people to experience an immune system attack on the small intestine that prevents the correct absorption of nutrients. This is celiac disease, which can cause, among other things, abdominal pain, weight loss, growth problems and mood swings.

The study finds that, on the one hand, the intake of wheat products has increased from 55 kilos per person per year to 65 (an increase of 18%) from 1960 to 2010. During the same period, the area devoted to wheat crops has remained constant. What has increased, however, is the use of nitrogen-based fertilisers, and this has meant that the overall consumption of gliadins has increased: between 1960 and 2010 it has risen from 2.4 to 3.8 kilos per person per year (an increase of 58%). In parallel to this increase, researchers have observed that the prevalence of celiac disease has increased during this time. In the United States, the population diagnosed with celiac disease has increased from 0.2 to 1 percent in 25 years. In countries such as Finland or Sweden, the prevalence of the disease is between 2 and 3 percent, while in Europe as a whole this value is close to 1 percent. All this data, together with the fact that in countries where more gluten is consumed there are more cases of celiac disease, have led researchers to conclude that the increasing use of these fertilisers may be a cause of the disease that until now had gone unnoticed.

"This study is a contribution from ecology to medical science," explains Peñuelas, since "nitrogen fertilisation translates into a possible direct global health problem. However, as scientists clarify, the increase in cases of celiac disease may be caused by many factors, such as improved diagnosis, the use of additives in bread or the change in the microorganisms of the digestive tract as a result of changes in eating habits. "If this relationship between nitrogen fertilisation and celiac disease is demonstrated in future experiments, we would have an important tool to control and prevent the extent of the disease," write the authors. According to Peñuelas, a possible solution would be to develop "wheat varieties that accumulate less gliadins despite growing in nitrogen-rich soils".