As part of its longstanding mission to support food security and sustainable agriculture, Safer Phosphates aims at bringing forward strong scientific arguments to highlight how heavy metals may enter and threaten the human food chain – and consequently – human health. According to the World Health Organization, around 200,000 people die every year from chemical poisoning, including poisoning by heavy metals, with the major part being from preventable chemical exposure.
Cadmium is a heavy metal found as an environmental contaminant, both through natural occurrence and from industrial and agricultural sources. Foodstuffs are the main source of cadmium exposure for the non-smoking general population, leading to an accumulation of cadmium and more generally heavy metals in the body through contaminated soil and/or drinking water. Extensive scientific literature has found that prolonged exposure to Cadmium can affect the skin, bones, organ and nervous system functionality, and contribute to the development of cancer.
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The food groups that contribute most to dietary cadmium exposure are cereals, vegetables, nuts and pulses, starchy roots or potatoes and meat products.
In light of the above, Safer Phosphates would like to put forward two recent scientific conclusions which illustrate the importance of understanding the impact of dietary cadmium intake on human health and more specifically of health issues amongst children and adults caused by plant-based dietary sources.
Risk factor for decreased kidney function in the adult population
In the first study undertaken by the University of Illinois, based on data from 12,577 adult participants, it was found that the association between blood cadmium concentration and low levels of kidney function was significant based on diet as the primary route of exposure to cadmium (i.e. by excluding smokers).
More specifically, the study confirmed that “cadmium exposure is associated with decreased glomerular filtration and increased urine protein excretion and provide evidence that the magnitude of these associations differ by sex and may vary based on preexisting diabetes and hypertension. Future prospective sex-specific investigations are necessary to address concerns of reverse causality and efforts should be made to reduce smoking and environmental contamination from cadmium to protect human health”.
As such, the above conclusions highlight once again the importance of creating policies which regulate and prevent cadmium from entering the environment, through water and ecosystems where food is grown (Agency for Toxic Substances and Disease Registry (ATSDR), 2012; He et al., 2005).
Children’s neurodevelopmental disorders
Exposure to hazardous chemicals during growth and development can result in acute long-term effects on the health of children. The strict regulations and measures applied in European countries mean that food is generally safe, but ingestion of contaminated food may still present a significant route of exposure to chemical hazards. As children’s bodies are developing and they generally consume more food on a body weight basis than adults, children are at particular risk of illness from exposure to chemical contaminants in food.
As such, growing concerns have been put forward by the scientific community with regards to environmental pollutants playing a role in the increasing global prevalence of neurodevelopmental disorders. In the last decade, observational studies have indeed suggested that prenatal and childhood exposure to cadmium may impair cognitive function.
In this context, the second study was conducted by the Institute of Environmental Medicine (Sweden) and the International Centre for Diarrheal Disease Research (Bangladesh) over a 10 year period among 1 489 children at age 1.5, 5 and 10 years old. The aim was to clarify whether the impact of a child's prenatal exposure to cadmium remained and if continued exposure through childhood was further detrimental to their cognitive abilities and behaviour.
In the original study conducted by Kippler et al. in 2012, among 1305 mother-child pairs in Bangladesh, associations of both maternal and early childhood urinary cadmium concentrations with child development was assessed. The present study was a follow-up of these children at 10 years of age, when they have had a longer period of childhood cadmium exposure through a rice-based diet.
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Based on both studies, the findings provided strong evidence of adverse effects of cadmium on brain development. While the previous study (Kippler et al., 2012) indicated that both girls and boys were affected by cadmium, the second evaluation at 10 years of age indicated that:
inverse associations mainly occurred in boys, in whom all the cognitive outcomes were affected;
the cadmium exposure originated primarily from consumption of rice which when sampled was found to contain elevated concentrations of the heavy metal;
findings are of concern as similar exposure levels are common worldwide.
Based on the above examples, it is clear that the reduction of dietary exposure to cadmium is of the upmost importance for all age categories.
In view of reducing these clearly negative effects and the related severe risks to human health, Safer Phosphates would therefore like to emphasise the necessity to focus on a progressive reduction of cadmium in the environment notably through human activities such as the manufacturing of phosphate-based fertilisers containing high levels of heavy metals.
With that objective in mind, the Members of Safer Phosphates will continue to supply countries with mineral fertilisers that do not contain concentrations of toxic impurities, which are harmful not only to soil but also to human health, in line with the ambitions laid down by the Farm-to-Fork Strategy and the overall approach of the European Union towards ensuring food security for consumers.
Sources:
EFSA (2012). Scientific Report of EFSA: Cadmium dietary exposure in the European population. Parma: European Food Safety Authority (EFSA), 10(1) pp 1-37. B.
WHO (2010). Exposure to Cadmium: A Major Public Health Concern.
Geneva: World Health Organization (WHO). C. Wolf J., Prüss-Ustün, A. and Vickers C. (2016).
Associations between blood cadmium concentration and kidney function in the U.S. population: Impact of sex, diabetes and hypertension. Jessica M. Madrigal, Ana C. Ricardo, Victoria Persky, Mary Turyk (Environmental Research, February 2019, https://doi.org/10.1016/j.envres.2018.11.009)
Cadmium Exposure and Cognitive Abilities and Behaviour at 10 Years of Age: A Prospective Cohort Study. Klara Gustin, Fahmida Tofail, Marie Vahter, Maria Kippler (Environment International, April 2018 https://doi.org/10.1016/j.envint.2018.02.020)