Dioxin

Persistent pollutant that bio-accumulates in the food chain

Dioxins are widely common environmental pollutants. They belong to the so-called “dirty dozen”, a group of dangerous chemicals known as persistent organic pollutants (POPs).

 

Dioxins are byproducts in the manufacturing process of certain chlorinated intermediates and products, like chlorine bleaching processes and manufacture of herbicides and bactericides. Uncontrolled waste incinerators (solid waste and hospital waste) are often the worst contributes of dioxins, due to incomplete burning. 

 

Dioxins are highly toxic and can cause reproductive and developmental problems, damage the immune system, interfere with hormones and also cause cancer.

The chemical name for dioxin is: 2,3,7,8- tetrachlorodibenzo para dioxin (TCDD). The name "dioxins" is often used for the family of structurally and chemically related polychlorinated dibenzo para dioxins (PCDDs) and polychlorinated dibenzofurans (PCDFs). Certain dioxin-like polychlorinated biphenyls (PCBs) and furans with similar toxic properties are also included under the term “dioxins”. Some 419 types of dioxin-related compounds have been identified but only about 30 of these are considered to have significant toxicity, with TCDD being the most toxic.

Routes of exposure

Although levels have decreased in the last 30 years, dioxins are extremely persistent compounds and break down very slowly. In fact, a large part of the current exposures to dioxins in the US is due to releases that occurred decades ago.

 

Dioxins bio-accumulate in the food chain, mainly in fatty tissue of animals. More than 90% of human exposure is through meat and dairy products, fish and shellfish.The higher an animal is in the food chain, the higher the concentration of dioxins. That explains why big predatory fish such as tuna are a greater source for dioxin in our diet. Once dioxins enter the body, they last a long time because of their chemical stability and their ability to be absorbed by fat tissue, where they are then stored in the body. Their half-life in the body is estimated to be 7 to 11 years. 

Health effects

Due to its persistency and its multiple adverse health effects, dioxins are a serious world-wide public health concern. Long-term exposure is linked with impairment of the immune system, the developing nervous system, the endocrine system and reproductive functions. 

Dioxins where shown to promote oxidative damage and DNA fractures, initiating and supporting cancerous processes. On top of that, dioxins alter the metabolism of estradiol and estrogen in breast cells tissue, which may further increase the risk for breast cancer.

Dioxins affect thyroid-stimulating hormone production. In pregnant women with poor dioxin-metabolizing enzyme activity, chances for impaired fetal brain development and hypothyroidism in the fetus increase.

How to reduce the risk from exposure to dioxin

Dioxin accumulates in fatty tissue. Individuals with a genetic sensitivity to dioxin are advised to take the following measures:

  • Choose leaner cuts of beef, pork, and poultry.

  • Trim the fat and remove skin from chicken before cooking.

  • Choose non-fat and low-fat milk and milk products.

​Large, predatory fish accumulate more dioxin since they are on top of their food chain. Fatty fish store more dioxin than lean fish.

  • Trim away fatty areas such as the belly, top of the back and dark meat along the sides.

  • Remove or puncture the skin before cooking to allow the fat to drain off.

  • Broil, grill, roast or steam the fish on a rack to allow the fat to drain away.

  • Do not fry large fatty types of fish such as salmon or bluefish.

A balanced diet, including adequate amounts of fruits, vegetables and cereals will help to avoid excessive exposure from a single source. This is a long-term strategy to reduce body burdens, and will boost your body's anti-oxidation capacities.