A group of toxins, known as persistent organic pollutants (POPs), are present throughout the environment. They come mainly from pesticides, industrial chemicals, pharmaceuticals and industrial waste.
Avoiding them completely is impossible. They are even found in remote areas like the arctic. The best we can do is reduce our exposure to them.
Our main exposure is through food. Fortunately, wise food selection can make a huge difference.
These toxins bioaccumulate, which means increasingly greater levels are found as we move up the food chain. Plants have the lowest concentrations and some fish and fish oils the highest. Once ingested by animals these toxins are off loaded into their fat and milk, so these products are the most contaminated. Fish and animal livers have high concentrations too.
A further complication is animal feed. For example, in Sweden, fish from polluted areas of the Baltic sea must be sold with a health warning. However no warning is required to sell fish that have been fed these polluted fish. This problem has spread as far as Australia. Unfortunately, what an animal was feed is not shown on food labels.
The World Health Organisation tested foods for polychlorinated biphenyls (PCBs), a subgroup of POPs. The wide range of toxin levels can be seen in this list:
• Animal fat: 20 to 240 μg/kg
• Cow’s milk: 5 to 200 μg/kg
• Butter: 30 to 80 μg/kg
• Fish: 10 to 500 μg/kg, on a fat basis. Certain fish species (eel) and fish products (fish liver and fish oils) may contain much higher levels, up to 10,000 μg/kg
• Vegetables, cereals, fruits, and a number of other products: <10 μg/kg
Much of the meat and dairy sold will have pollutant concentrations within tolerable limits. However, given the limits of food labelling it is impossible to know which ones.
POP exposure can cause developmental defects and chronic illnesses. Some are carcinogens and some endocrine disruptors affecting the reproductive system, central nervous system, and immune system. According to the World Health Organisation, 90% of human exposure, to dioxins, a subgroup of POPs, is through food, mainly meat and dairy products, fish and shellfish.
Avoiding these toxins is particularly important for pregnant women and children. Low-level exposures have been linked to low birth weights and neuro-developmental effects in children.
Be careful if you’re buying fish oil. If you are looking for an alternative, one option is algae-based omega 3 oil. This contains the longer chain DHA and EPA omega 3 oils contained in fish oil as opposed to the shorter chain ALA omega 3 oil found in plants.