Comparing Pollutant Levels Between Different Diets

Comparing Pollutant Levels Between Different Diets.jpeg

The results of the CHAMACOS (Center for the Health Assessment of Mothers and Children of Salinas) study were published recently. This study of a California birth cohort investigated the relationship between exposure to flame retardant chemical pollutants in pregnancy and childhood, and subsequent neurobehavioral development. Why California? Because California children's exposures to these endocrine disruptors and neurotoxins are among the highest in the world.

What did they find? The researchers concluded that both prenatal and childhood exposures to these chemicals "were associated with poorer attention, fine motor coordination, and cognition" (particularly verbal comprehension) by the time the children reached school age. "This study, the largest to date, contributes to growing evidence suggesting that PBDEs [polybrominated diphenyl ethers, flame retardant chemicals] have adverse impacts on child neurobehavioral development." The effects may extend into adolescence, again affecting motor function as well as thyroid gland function. The effect on our thyroid glands may even extend into adulthood.

These chemicals get into moms, then into the amniotic fluid, and then into the breast milk. The more that's in the milk, the worse the infants' mental development may be. Breast milk is still best, but how did these women get exposed in the first place?

The question has been: Are we exposed mostly from diet or dust? Researchers in Boston collected breast milk samples from 46 first-time moms, vacuumed up samples of dust from their homes, and questioned them about their diets. The researchers found that both were likely to blame. Diet-wise, a number of animal products were implicated. This is consistent with what's been found worldwide. For example, in Europe, these flame retardant chemical pollutants are found mostly in meat, including fish, and other animal products. It's similar to what we see with dioxins--they are mostly found in fish and other fatty foods, with a plant-based diet offering the lowest exposure.

If that's the case, do vegetarians have lower levels of flame retardant chemical pollutants circulating in their bloodstreams? Yes. Vegetarians may have about 25% lower levels. Poultry appears to be the largest contributor of PBDEs. USDA researchers compared the levels in different meats, and the highest levels of these pollutants were found in chicken and turkey, with less in pork and even less in beef. California poultry had the highest, consistent with strict furniture flammability codes. But it's not like chickens are pecking at the sofa. Chickens and turkeys may be exposed indirectly through the application of sewer sludge to fields where feed crops are raised, contamination of water supplies, the use of flame-retarded materials in poultry housing, or the inadvertent incorporation of fire-retardant material into the birds' bedding or feed ingredients.

Fish have been shown to have the highest levels overall, but Americans don't eat a lot of fish so they don't contribute as much to the total body burden in the United States. Researchers have compared the level of PBDEs found in meat-eaters and vegetarians. The amount found in the bloodstream of vegetarians is noticeably lower, as you can see in my video Flame Retardant Pollutants and Child Development. Just to give you a sense of the contribution of chicken, higher than average poultry eaters have higher levels than omnivores as a whole, and lower than average poultry eaters have levels lower than omnivores.

What are the PBDE levels in vegans? We know the intake of many other classes of pollutants is almost exclusively from the ingestion of animal fats in the diet. What if we take them all out of the diet? It works for dioxins. Vegan dioxin levels appear markedly lower than the general population. What about for the flame retardant chemicals? Vegans have levels lower than vegetarians, with those who've been vegan around 20 years having even lower concentrations. This tendency for chemical levels to decline the longer one eats plant-based suggests that food of animal origin contributes substantially. But note that levels never get down to zero, so diet is not the only source.

The USDA researchers note that there are currently no regulatory limits on the amount of flame retardant chemical contamination in U.S. foods, "but reducing the levels of unnecessary, persistent, toxic compounds in our diet is certainly desirable."

I've previously talked about this class of chemicals in Food Sources of Flame Retardant Chemicals. The same foods seem to accumulate a variety of pollutants:

Many of these chemicals have hormone- or endocrine-disrupting effects. See, for example:

In health,

Michael Greger, M.D.

PS: If you haven't yet, you can subscribe to my free videos here and watch my live, year-in-review presentations:

Image Credit: Mitchell Haindfield / Flickr. This image has been modified.

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Comparing Pollutant Levels Between Different Diets

Comparing Pollutant Levels Between Different Diets.jpeg

The results of the CHAMACOS (Center for the Health Assessment of Mothers and Children of Salinas) study were published recently. This study of a California birth cohort investigated the relationship between exposure to flame retardant chemical pollutants in pregnancy and childhood, and subsequent neurobehavioral development. Why California? Because California children's exposures to these endocrine disruptors and neurotoxins are among the highest in the world.

What did they find? The researchers concluded that both prenatal and childhood exposures to these chemicals "were associated with poorer attention, fine motor coordination, and cognition" (particularly verbal comprehension) by the time the children reached school age. "This study, the largest to date, contributes to growing evidence suggesting that PBDEs [polybrominated diphenyl ethers, flame retardant chemicals] have adverse impacts on child neurobehavioral development." The effects may extend into adolescence, again affecting motor function as well as thyroid gland function. The effect on our thyroid glands may even extend into adulthood.

These chemicals get into moms, then into the amniotic fluid, and then into the breast milk. The more that's in the milk, the worse the infants' mental development may be. Breast milk is still best, but how did these women get exposed in the first place?

The question has been: Are we exposed mostly from diet or dust? Researchers in Boston collected breast milk samples from 46 first-time moms, vacuumed up samples of dust from their homes, and questioned them about their diets. The researchers found that both were likely to blame. Diet-wise, a number of animal products were implicated. This is consistent with what's been found worldwide. For example, in Europe, these flame retardant chemical pollutants are found mostly in meat, including fish, and other animal products. It's similar to what we see with dioxins--they are mostly found in fish and other fatty foods, with a plant-based diet offering the lowest exposure.

If that's the case, do vegetarians have lower levels of flame retardant chemical pollutants circulating in their bloodstreams? Yes. Vegetarians may have about 25% lower levels. Poultry appears to be the largest contributor of PBDEs. USDA researchers compared the levels in different meats, and the highest levels of these pollutants were found in chicken and turkey, with less in pork and even less in beef. California poultry had the highest, consistent with strict furniture flammability codes. But it's not like chickens are pecking at the sofa. Chickens and turkeys may be exposed indirectly through the application of sewer sludge to fields where feed crops are raised, contamination of water supplies, the use of flame-retarded materials in poultry housing, or the inadvertent incorporation of fire-retardant material into the birds' bedding or feed ingredients.

Fish have been shown to have the highest levels overall, but Americans don't eat a lot of fish so they don't contribute as much to the total body burden in the United States. Researchers have compared the level of PBDEs found in meat-eaters and vegetarians. The amount found in the bloodstream of vegetarians is noticeably lower, as you can see in my video Flame Retardant Pollutants and Child Development. Just to give you a sense of the contribution of chicken, higher than average poultry eaters have higher levels than omnivores as a whole, and lower than average poultry eaters have levels lower than omnivores.

What are the PBDE levels in vegans? We know the intake of many other classes of pollutants is almost exclusively from the ingestion of animal fats in the diet. What if we take them all out of the diet? It works for dioxins. Vegan dioxin levels appear markedly lower than the general population. What about for the flame retardant chemicals? Vegans have levels lower than vegetarians, with those who've been vegan around 20 years having even lower concentrations. This tendency for chemical levels to decline the longer one eats plant-based suggests that food of animal origin contributes substantially. But note that levels never get down to zero, so diet is not the only source.

The USDA researchers note that there are currently no regulatory limits on the amount of flame retardant chemical contamination in U.S. foods, "but reducing the levels of unnecessary, persistent, toxic compounds in our diet is certainly desirable."

I've previously talked about this class of chemicals in Food Sources of Flame Retardant Chemicals. The same foods seem to accumulate a variety of pollutants:

Many of these chemicals have hormone- or endocrine-disrupting effects. See, for example:

In health,

Michael Greger, M.D.

PS: If you haven't yet, you can subscribe to my free videos here and watch my live, year-in-review presentations:

Image Credit: Mitchell Haindfield / Flickr. This image has been modified.

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How a Tick Bite Can Lead to Food Allergies

NF-Aug25 Alpha Gal and the Lone Star Tick.jpg

In the beginning, Aristotle defined two forms of life on planet Earth: plants and animals. Two thousand years later, the light microscope was invented and we discovered tiny, single-celled organisms like amoebas. Then, the electron microscope was invented and we discovered bacteria. Finally, in 1969, biologists recognized fungi as a separate category, and we've had at least five kingdoms of life ever since.

In my video, Higher Quality May Mean Higher Risk, I talk about the potential downsides of consuming proteins from within our own kingdom, such as the impact our fellow animal proteins can have on boosting our liver's production of a cancer-promoting hormone called IGF-1.

In Eating Outside Our Kingdom, I talked about other potential advantages of preferably dipping into the plant and mushroom kingdoms for dinner, not only from a food safety perspective (we're more likely to get infected by animal pathogens than Dutch Elm Disease), but because of the potential for cross-reactivity between animal and human proteins. Our immune system is more likely to get confused between a chicken leg and our own legs than it is with a banana, so there may be less potential to trigger an autoimmune reaction, like degenerative brain diseases or inflammatory arthritis (See Diet & Rheumatoid Arthritis). In attacking some foreign animal meat protein, some of our own similarly composed tissues may get caught in the crossfire.

It's not just proteins. If you remember the Neu5Gc story (see Inflammatory Meat Molecule Neu5GC), sialic acid in other animals may cause inflammation in our arteries (see Nonhuman Molecules Lining Our Arteries) and help breast tumors and other human cancers to grow (see How Tumors Use Meat to Grow: Xeno-Autoantibodies). Now a new twist has been added to the story.

The reason Neu5Gc triggers inflammation is because humans lost the ability to make it two million years ago, and so when our body is exposed to it through animal products, it's treated as a foreign molecule, causing inflammation. But there's also another oligosaccharide called alpha-gal that humans, chimps, and apes lost the ability to make 20 million years ago, but is still made by a variety of animals, including many animals we eat.

Anti-gal antibodies may be involved in a number of detrimental processes that may result in allergic, autoimmune, and autoimmune-like diseases, such as auto-immune thyroid disorders. We see higher levels of anti-gal antibodies in Crohn's disease victims. These antibodies even react against about half of human breast tumors, and we can find them in atherosclerotic plaques in people's necks. However, those are all mostly speculative risks. We do know that alpha-gal is a major obstacle to transplanting pig organs into people, like kidneys, because our bodies reject alpha-gal as foreign. In fact, alpha-gal is thought to be the major target for human anti-pig antibodies.

It's interesting that if we look at those that abstain from pork for whatever reason, they have fewer swine-specific immune cells in their bloodstream. Researchers speculate that oral intake of pork could ferry swine molecules into the bloodstream via gut-infiltrating lymphocytes to prime the immune response. So we can have an allergic reaction to eating pig kidneys too, but such severe meat allergies were considered rare, until an unusual report surfaced. First described in 2009, the report included details on 24 cases of meat allergies triggered by tick bites.

Within a year, it was obvious that the cases should be counted in hundreds rather than dozens. By 2012, there were thousands of cases across a large area of the southern and eastern U.S., and new cases are now popping up in several countries around the world.

The culprit, the lone star tick, so-called because females have a white spot on their back, are famous for causing Masters' disease, a disease similar to Lyme syndrome, also known as STARI (southern tick associated rash illness). But thanks to the lone star tick steadily expanding its range (even as far as Long Island, NY), it's not necessarily just so Southern any more.

What is the relevance of tick bites to the production of allergy-causing anti-meat antibodies to alpha-gal? Good question. What we know is that if you get bitten by one of these ticks, you can develop an allergy to meat (See Alpha Gal and the Lone Star Tick). This appears to be the first example of a response to an external parasite giving rise to an important form of food allergy. We don't know the exact mechanism, but it may be because there's something in the tick saliva that's cross-reacting with alpha-gal, or because the tick is injecting you with animal allergens from its last meal.

What role may these tick-bite induced allergies play in the development of chronic hives and other allergic skin reactions in children? See Tick Bites, Meat Allergies, and Chronic Urticaria.

Here's some videos unearthing the IGF-1 story:

Neu5Gc is what opened up this whole can of worms:

I wonder if alpha gal is playing a role in the improvements in arthritis and Crohn's on plant-based diets: Dietary Treatment of Crohn's Disease and Diet & Rheumatoid Arthritis.

In health,
Michael Greger, M.D.

PS: If you haven't yet, you can subscribe to my videos for free by clicking here and watch my full 2012 - 2015 presentations Uprooting the Leading Causes of Death, More than an Apple a Day, From Table to Able, and Food as Medicine.

Image Credit: USGS Bee Inventory and Monitoring Lab / Flickr

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Red Dye No. 3 and Thyroid Cancer

NF-Apr30 Seeing Red No. 3 Coloring to Dye for.jpg

Fifteen million pounds of food dyes are sold every year in the U.S. Why? Foods "are artificially colored to make unattractive mixtures of basic ingredients and food additives acceptable to consumers." Food colorings are added to countless processed food products to "conceal the absence of fruits, vegetables, or other ingredients and to make the food appear better or of greater value than it is." Otherwise cherry popsicles might actually look as if they had no cherries in them!

I've talked about the role of food dyes in causing ADHD symptoms in kids (See Food Dyes and ADHD), but what about their role in cancer?

Due to cancer concerns, Red dye #1 was banned in 1961. Red #2 was banned in 1976, and Red #4 was banned soon after. But what about Red No. 3, used today in everything from sausage to maraschino cherries? It was found to cause DNA damage in human liver cells in vitro, comparable to the damage caused by a chemotherapy drug whose whole purpose is to break down DNA, but Red No. 3 was also found to influence children's behavior over 30 years ago and to interfere with thyroid function over 40 years ago. Why is it still legal?

By 1985, the FDA had already postponed action on banning the Red No. 3 twenty-six times, even though the Acting Commissioner of the FDA said Red No. 3 was "of greatest public health concern," imploring his agency to not knowingly allow continued exposure (at high levels in the case of Red No. 3) of the public to "a provisionally listed color additive that has clearly been shown to induce cancer while questions of mechanism are explored. The credibility of the Department of Health and Human Services would suffer if decisions are not made soon on each of these color additives." That was over 30 years ago. (To see the 1985 article published in the New York Times, check out my video, Red no. 3, Coloring to Dye for).

At the end of the day, industry pressure won out. While FDA scientists and FDA commissioners have recommended that the additive be banned, there has been tremendous pressure to delay the recommendations from being implemented.

In 1990, concerned about cancer risk, the FDA banned the use of Red No. 3 in anything going on our skin, but it remained legal to continue to put it in anything going in our mouths. The FDA also said they planned to end all other remaining uses of Red No. 3, lamenting that the cherries in 21st century fruit cocktail "could well be light brown."

But over 20 years later it's still in our food supply. After all, the agency estimated that the lifetime risk of thyroid tumors in humans from Red No. 3 in food was at most one in a hundred thousand. Based on the current U.S. population that's 3,000.

This whole fiasco might become clearer once you watch my video Who Determines if Food Additives Are Safe?

I've touched on food coloring additives before:

Some other videos on popular food additives include:

-Michael Greger, M.D.

PS: If you haven't yet, you can subscribe to my free videos here and watch my live year-in-review presentations Uprooting the Leading Causes of Death, More Than an Apple a Day, and From Table to Able.

Image Credit: Kathleen Franklin / Flickr

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Alkylphenol Endocrine Disruptors and Allergies

NF-Apr23 Alkylphenol Endocrine Disruptors and Allergies.jpg

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 three times the odds of both suspected and physician-diagnosed eczema. The researchers suggest that certain components of meat may affect the fetal immune system. But what about the moms, themselves? A plant-based diet may also help alleviate allergies in adults. See Say No to Drugs by Saying Yes to More Plants and Preventing Allergies in Adulthood.

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.

Some have suggested that 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."

Saturated fat wasn't associated with increased prevalence either, so what other constituents in meat may be to blame? The researchers considered the cooked meat carcinogens, the heterocyclic amines, the polycyclic aromatic hydrocarbons, and the nitrosamines.

A new review, highlighted in my video, Alkylphenol Endocrine Disruptors and Allergies, 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 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, in our body fat, in our urine, in our bloodstream, and even in the umbilical cord blood going to our babies. How did it get there? 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 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 fertility (such as dropping normal sperm counts), 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.

To find out which foods may contain these alkylphenol endocrine disruptors, check out my video Dietary Sources of Alkylphenol Endocrine Disruptors.

More on endocrine disruptors in:

A different class of chemicals has been found to be associated with smaller penis size in humans. See Chicken Consumption and the Feminization of Male Genitalia.

-Michael Greger, M.D.

PS: If you haven't yet, you can subscribe to my free videoshere and watch my live year-in-review presentations Uprooting the Leading Causes of Death, More Than an Apple a Day, and From Table to Able.

Image Credit: Mark Freeth / Flickr

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Which Seaweed to Help Prevent Breast Cancer?

 

 

 

 

 

 

 

 

Which Seaweed is Protective Against Cancer?

Sushi lovers, rejoice. Nori seaweed may favorably alter estrogen metabolism by modulating women’s gut flora, resulting in decreased breast cancer risk.

As traditional East Asian diets have westernized, breast cancer rates have risen. Some researchers have linked this to a quadrupling of animal product consumption. In my video Which Seaweed Is Most Protective Against Breast Cancer, you can see the breast cancer rate of Japanese women living in Japan. Within 10 years of immigrating to the United States, their risk increases, and if they hang around long enough, their risk goes up even more, although it is still somewhat lower than the U.S. national average. This may be because of some of the dietary habits they carry with them—soy and green tea consumption, perhaps eating more mushrooms and seaweed.

We’ve known for over a decade that in vitro (in a Petri dish) seaweed broth is effective at clearing cancer cells. In the video, you can see three different types of human breast cancer exposed to either a widely used chemotherapy drug or a sea vegetable. The seaweed worked better. And unlike the chemo, it didn’t hurt normal, non-cancerous breast cells. What about outside of the test tube, in people?

Well, a population study comparing women with breast cancer to women without found that consuming a single sheet of nori a day may cut a woman’s odds of breast cancer in half. We think it’s because seaweed favorably alters estrogen metabolism, likely due to modulating women’s gut bacteria. The more seaweed we eat, the less estrogen we have in our system, which may lower breast cancer risk.

The breast cancer protection may be because of all the fiber in sea vegetables, or because seaweed may block the enzyme that undermines our body’s attempt to flush out excess hormones. Or seaweed may somehow interfere with estrogen binding to estrogen receptors. Whatever the cause, to effectively lower their estrogen levels, Asian women may be able to get away with about one sheet of nori a day, but American women are physically so much larger that it may take closer to two. There are lots of yummy seaweed snacks out there to make it a tasty experience—just try to get some low-fat, low-sodium ones. They’re just like kale chips, munchies made out of dark green leafy vegetables—can’t beat that!

For more on lowering breast cancer through diet:

The seaweed used fresh in seaweed salads, wakame, unfortunately did not appear to reduce breast cancer risk. Wakame consumption has, however, been found to lower blood pressure in hypertensives (people with high blood pressure). Just two teaspoons of seaweed salad a day for a month dropped people’s blood pressure 14 points, and two months of wakame was associated with up to a two inch skinnier waistline.

As I’ve mentioned before, I’d recommend avoiding hijike, which tends to have too much arsenic (see Avoiding Iodine Deficiency), and kelp, which tends to have too much iodine (see Too Much Iodine Can Be as Bad as Too Little). In fact, too much seaweed of any type may actually increase our risk for thyroid cancer because of the amount of iodine we’d be taking in, but there does not appear to be any increased risk at the levels of consumption I’m talking about, like a sheet of nori every day. And a study of seaweed eaters in California actually found decreased risk, but, again, we’re talking a modest level of intake.

I’ve frequently talked about the benefits of dietary diversity, eating different families of fruits and vegetables, eating different parts of individual plants—such as beets and beet greens. If we just stick to land plants, though, we’re missing out on all the plants from the other 70% of planet earth. Sea vegetables have phytonutrients found nowhere else, special types of fiber, and unique carotenoids and polysaccharides, and various polyphenol defense compounds, each of which may have anti-cancer properties. I encourage everyone to try experimenting until you find a sea vegetable you like, even if that means just sprinkling some powdered dulse on your food. More on the importance of dietary diversity in Garden Variety Anti-Inflammation, Apples and Oranges: Dietary Diversity, and Constructing a Cognitive Portfolio.

For more on some of the other protective dietary components in the diets of Japanese women, check out Why Do Asian Women Have Less Breast Cancer? and Breast Cancer Survival and Soy.

And if you enjoy anti-cancer comparison videos, make sure to also check out Which Fruit Fights Cancer Better? and #1 Anticancer Vegetable.

-Michael Greger, M.D.

PS: If you haven’t yet, you can subscribe to my free videos here and watch my live year-in-review presentations Uprooting the Leading Causes of Death and More Than an Apple a Day.

Image Credit: srsldy / Flickr

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