Susan Featherstone wrote an article, 'All you need to know about dioxins', for the April issue of Food Review. For the basics on what dioxins are and how they occur in our food, look no further.
The term dioxin usually refers to a group of persistent organic pollutants that share a similar chemical structure (polychlorinated dibenzodioxins (PCDDs). The word dioxin formally refers to the central dioxygenated ring, which is stabilised by the two flanking benzene rings. Polychlorinated dibenzofurans (PCDFs) and polychlorinated biphenyls (PCBs) are often called ‘dioxin-like’ as they behave in a similar way and are often included in the same set of safety limits.
Dioxins are not manufactured or found in food intentionally, but are formed as by-products of ordinary human activities, such as metal smelting, the manufacture of herbicides and pesticides and in the bleaching of paper , and also in combustion processes such as commercial or municipal waste incineration, burning of chlorine-containing substances such as polyvinyl chloride (PVC) and fuels such as wood, coal, diesel or oil, and even household fires. Dioxins can also be formed as a result of natural processes such as forest fires and volcanic eruptions. Cigarette smoke contains small amounts of dioxins.
The main concern with dioxins is that they accumulate in fatty tissue in the body and are very persistent. Exposure to relatively low levels of dioxins over long periods may contribute to reproductive and developmental problems and damage the immune system of humans and animals. They are thought to interfere with hormones and also cause cancer. Exposure to high levels of dioxins could result in a skin disease called chloracne; a condition where acne-like lesions occur mainly on the face and upper body. Other effects of exposure to large amounts of dioxins may include skin rashes, skin discoloration, excessive body hair, and mild liver damage.
Foods high in animal fat, such as milk, meat, fish and eggs (and foods that use these as ingredients) are the main source of dioxins for humans where are stored in fatty tissues and are neither metabolised nor excreted.
