Transcript: Alkylphenol Endocrine Disruptors and Allergies
In my video, Preventing Childhood Allergies, I noted a study in Japan that found higher maternal intake of meat during pregnancy was significantly associated with about 3 times the odds of both suspected and physician-diagnosed eczema. They suggest that certain components of meat may affect the fetal immune system. But what about the moms themselves?
Seasonal allergies have exploded in Japan in the past few decades, starting with the first reported case in 1964 and now affecting millions every year. We've seen a rising prevalence of allergic diseases around the industrialized world in past decades, but perhaps nothing quite this dramatic.
Researchers suggested profound changes in the Japanese diet may have played a role. Over the latter half of the century total meat, fish, and milk intake rose hundreds of percent in Japan, so researchers decided to look into dietary meat and fat intake and the prevalence of these seasonal pollen allergies. No association with overall fat, but higher meat intake was significantly associated with an increased prevalence.
So maybe it was the saturated fat? No, that didn't seem to be it, so what other constituents in meat may be to blame? Well, there are the cooked meat carcinogens, the heterocyclic amines, polycyclic aromatic hydrocarbons, and nitrosamines, but who knows.
This new review, however, raised an intriguing possibility. There's a class of industrial pollutants called alkylphenols, recognized as common toxic endocrine disrupting chemicals that tend to accumulate in the human body and may be associated with the adverse effects of allergic diseases. A variety of studies have shown how they may exacerbate allergen-induced inflammation, suggesting that alkylphenol exposure may influence the onset, progression, and severity of allergic diseases. These toxic xenoestrogens can be found in human breast milk, stored up in our body fat, coursing through our urine, our bloodstream, and even in the umbilical cord blood going to our babies. How do did it get there? How do people get exposed? Through contaminated food.
It all goes back to a famous study about the reduction of penis size and testosterone levels in alligators living in a contaminated environment. I don't know what you all do for a day job, but these researchers observed that a population of juvenile alligators living on one lake in Florida exhibited a significantly smaller penis size and lower blood concentrations of testosterone compared to animals on some different lake. The most important difference between the two lakes was that lake stubby was fed by relatively polluted waters. They attributed the "short penis phenomenon" to estrogen-mimicking (xenoestrogenic) environmental metabolites of DDT that still pollute our Earth. This seminal work introduced the concept of endocrine disruptors. Environmental xenoestrogens might result in feminization of exposed male animals. And that's just the shriveled tip of the iceberg.
Since then endocrine-disrupting chemicals have been implicated in the dramatic rise over the last 50 years of diseases like breast cancer, prostate cancer, testicular cancer, diabetes, obesity, and decreased fertility, such as dropping normal sperm counts.
Not to mention genital birth defects such as penile malformations, preterm birth, neurobehavioral disorders in children linked to thyroid disruption and earlier breast development in young girls. Because genes do not change fast enough to explain these increases, environmental causes must be involved. Since our greatest exposure to the environment is through our gut, it's no surprise that our greatest exposure to these endocrine-disrupting chemicals is through diet.
Which foods? I'll cover that next.
To see any graphs, charts, graphics, images, and quotes to which Dr. Greger may be referring, watch the above video. This is just an approximation of the audio contributed by Ariel Levitsky.
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