Dioxin is a rather simple molecule, consisting of two benzene molecules connected by two oxygen atoms, and each benzene has two attached chlorine atoms. It is similar to polychlorinated biphenyls (PCBs) in composition and damaging health effects, only dioxins are worse.
Dioxin is aknown human carcinogen (i.e., causing cancer); it also causes a wide range of adverse non-cancer effects to reproduction, development, the immune system and the hormone (endocrine) systems. According to a just released EPA report, dioxin is associated with depression of the immune system, leading to increased infections; it interferes with thyroid levels (a metabolism hormone); alters glucose tolerance; and has been linked to diabetes. A 2003 report by the Institute of Medicine cited a high-priority risk management intervention to reduce exposure to dioxins in girls and young women before they become pregnant.
How potent are dioxins? EPA’s 2010 report states that people should consume less than one-trillionth of a gram of dioxin per kilogram of body weight per day. (For a 100 pound person, the recommendation amounts to less than 50 trillionths of a gram per day.) This quantity is so extremely small that you can consider it to be zero, i.e., a person should avoid any and all exposures to dioxins. (This quantity of table salt would be a single crystal about the size of a typical bacterium.)
What is the source of dioxins and how are you exposed to them? The major sources are copper smelters, waste incinerators, and paper pulp manufacturing. If you live downwind from one of these, you are likely getting a dose higher than people in other areas of the country. Nevertheless, everyone is exposed to low levels of dioxins because they are carried long distances on the wind, ultimately ending up on the soil and plants; from there they are taken up by any animals that eat forage, i.e., cattle, hogs, and chickens. Hence dioxins show up in your home in milk, cheese, beef, port, chicken, and some fish. Because dioxins accumulate in the fatty tissue of animals, to minimize your exposure, minimize your consumption of fats. Purchase meats and eggs that come from animal that have been grain or grass fed.