We have previously covered the group of 29 nasty chemicals collectively called dioxins and dioxin-like PCBs because of their similar mode of action.
In brief, they are toxic chemicals that persist in the environment for years and accumulate at low levels in the food chain, usually in the fatty tissues of animals.
However, different interpretations among scientific organisations of their absolute toxicity have led to some confusion.
In an attempt to develop a better understanding of the risks to human and animal health conferred by dioxins and dioxin-like compounds, the European Food Safety Authority initiated a groundbreaking review of the available scientific literature and exposure information. In an exhaustive opinion published in November 2018, EFSA’s Panel on Contaminants in the Food Chain concluded that such environmental pollutants, although only present at low levels in food and feed, pose a considerable health concern.
Accordingly, the Panel set a new tolerable weekly intake (TWI) for dioxins and dioxin-like PCBs in food of 2 picograms per kilogram of body weight, an incredibly low limit reflecting their severe toxicity.
The new TWI is seven-times lower than the previous EU tolerable intake set by the European Commission’s former Scientific Committee on Food in 2001. The change is based on the availability of new epidemiological human and experimental animal data on the toxicity of these substances and more refined modelling techniques for predicting levels in the human body over time.
Current protection not sufficient
The new TWI is protective against effects on semen quality, the most sensitive adverse health effect, as well as a lower sex ratio of sons to daughters, higher levels of thyroid-stimulating hormone in new-borns and developmental enamel defects on teeth.
Worryingly, data from European countries indicate an exceedance of the new tolerable intake level with the main contributors being fatty fish, cheese and livestock meat.
Average and high exposures were, respectively, up to five and 15 times the new TWI in all age groups.
Should you take action?
As there are little or no acute health effects from consuming single foods containing dioxins and dioxin-like PCBs, it’s more a matter of cumulative chronic effects outside the direct control of individual consumers.
Although the presence of these compounds in food and feed has declined in the last 30 years thanks to the efforts of public authorities and industry, a further concerted effort is needed to bring current exposure to safe levels.
Thus, continued vigilance is important, particularly in light of the new proposed TWI. As this is not always the case and testing of food is expensive, some pressure from consumer groups could be beneficial.