A Fishy Tale About POPs: The Chemicals That May Kill

There are almost 6 million Google entries and more than 5,000 articles in the National Library of Medicine regarding persistent organic pollutants (POPs) — and yet it’s infrequent that my patients are aware of the health risks of this group of chemicals.

More than 50 years ago, Rachel Carson wrote about the harmful effects of one POP, dichlorodiphenyltrichloroethane (DDT), in her classic book Silent Spring.

Since then the health concerns about POPs in humans are growing. In fact, this topic is of special concern to my practice of cardiology because exposure to POPs has been linked to higher levels of cholesterol, blood pressure, atherosclerosis, and cardiac deaths. And now new data raise the possibility that exposure to POPs during life may shorten life itself. But first, more about POPs.


You should know that they …

· Are highly toxic to humans and the environment

· Persist in the environment, resisting degradation, and can be stored easily in human and animal fat

· Are able to accumulate in terrestrial and aquatic (fish) systems we may eat.

POPs are used in agriculture, manufacturing, and industry and include such well-known names as dioxin and PCBs. The list of the 12 most serious chemicals is called the “Dirty Dozen.”

In 2001, the United States joined 90 other countries in signing a treaty agreeing to reduce or eliminate the Dirty Dozen. Unfortunately, POPs are still being produced by countries not in the treaty and can easily be spread through contaminated waters worldwide.


These chemicals can cause reproductive problems, birth defects, hypertension, behavioral changes, and even death. They are suspected human carcinogens and disrupt the immune and endocrine systems.

Plus, a link between the level of POPs and developing diabetes has been identified. Scientists studied more than 1,000 nurses over the long term and concluded that their findings supported “an association between POP exposure and the risk of type 2 diabetes.”


In a 2010 study by the University of Texas School of Public Health, the highest levels of POPs in food purchased in supermarkets in Dallas were found in milk, catfish fillets, and salmon. Other sources were eggs, meat and dairy. They are low in foods of plant origin.

The amount of POPs in the fatty tissue of animals — particularly farmed salmon — may explain why eating oily fish has been linked to diabetes in humans.


These harmful chemicals can be found in more than 96 percent of obese individuals. It’s feared that these stores can release POPs into the bloodstream and cause continual exposure and harm, even if measures are made to reduce intake of POP-contaminated foods.


Researchers in Uppsala, Sweden investigated whether POPs levels in the blood were associated with premature death. The cohort study used data from the population-based Prospective Investigation of the Vasculature in Uppsala Seniors (PIVUS) study, collected between May 2001 and June 2004 when participants reached age 70 years. Participants were followed up for 5 years after the first examination. Mortality was tracked from age 70 to 80 years. Eighteen POPs identified by the Stockholm Convention, including polychlorinated biphenyls (PCBs), organochlorine pesticides, and a brominated flame retardant, were measured in plasma levels by gas chromatography-mass spectrometry. The study sample included 992 individuals of whom half were men. During a follow-up period of 10 years, 158 deaths occurred. A significant association was found between hexa-chloro- through octa-chloro-substituted (highly chlorinated) PCBs and all-cause mortality. The most significant association was observed for PCB 206. Following adjustment for hypertension, diabetes, smoking, body mass index, and cardiovascular disease at baseline, levels of PCBs 206, 189, 170, and 209 were still significantly associated with all-cause mortality. These associations were mainly because of death from cardiovascular diseases.


  1. You can have your concentration of POPs measured by a health professional, usually by environmental or functional medicine practitioner, and elevated levels can be treated. Assisting liver detoxification support with supplements that boost glutathione production such as N-acetyl cysteine and enhancing excertion with infrared sauna therapy may be useful.
  2. Taking organic chlorella and eating organic cilantro may aid excretion of POPs and is recommended for all as a protective measure.
  3. Reducing or eliminating animal foods from your diet, where POPs are found in highest concentrations, is wise. Avoiding farmed fish — particularly salmon and catfish — is recommended.
  4. Switching from conventional to organic food sources can quickly lower the burden of POPs when studied in children.
  5. Switching to a plant based diet of whole fruits and vegetables has been recommended.

I suggest staying up to date on efforts to educate and eliminate POPs and other chemicals in our food and home from reliable sources like the Environmental Working Group.

Professor of Cardiology, Summa cum Laude grad, Kahn Center for Longevity and GreenSpace Cafe. www.drjoelkahn.com @drjkahn. Author The Plant Based Solution NEW

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