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.

Original Link

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.

Original Link

Using a Smell Test to Diagnose Alzheimer’s Disease

Using a Smell Test to Diagnose Alzheimer's Disease.jpeg

Alzheimer's disease (AD) pathology appears to start in the part of the brain that handles smell before subsequently spreading to additional brain regions and then, ultimately, taking over much of the rest of the brain. This led some to speculate that Alzheimer's disease may begin in the nose. Perhaps there's some environmental agent that might enter the brain through some portal in the nostrils?

This is the so-called olfactory vector hypothesis. The anatomy of the nose is well suited for the transfer of things directly into the brain, since the olfactory nerves that stick out into the nose project directly into the brain, bypassing the blood-brain barrier. The nose was actually a major infection route for the polio virus. Public health officials you started cauterizing the nasal passages of schoolchildren by spraying caustic chemicals up their noses in an effort to prevent the disease.

The concern is if people breathe in some ionized metals like aluminum dust, for example, it could be transported into the brain through these olfactory nerves at a rate of about 2 millimeters an hour, which is practically 2 inches a day. Doubt has been cast on this theory, however, by a case report of a woman born with a birth defect in which she had no smell nerves yet still developed Alzheimer's-like pathology. And so, to date, all the supporting evidence is really just circumstantial. It is clear, though, that changes in the sense of smell is among the first clinical signs of Alzheimer's, occurring during the preclinical phase--that is, before there's any noticeable cognitive decline. Could we use these changes to predict or diagnose the disease?

For years, researchers have been trying to find markers of brain illness hidden in people's ability to smell using all sorts of fancy gadgets. For example, functional MRI scans can detect differences in brain activation in response to an odor. In my video, Peanut Butter Smell Test for Alzheimer's, you can see the responses to lavender. You'll see a representation of a normal brain's responses to the odor versus an Alzheimer's brain. This unequivocally demonstrates that we can pick up changes in smell function due to Alzheimer's. But do we really need a million-dollar machine?

An ingenious group of researchers at the University of Florida discovered all we may need is some peanut butter and a ruler.

Considering that the left side of the brain primarily processes what we smell through our left nostril and the right side of our brain covers the right nostril, and understanding that Alzheimer's strikes the left side more than the right, what if you performed the following experiment: Close your eyes and mouth, breathe normally through the nose, then close one nostril, and hold a foot-long ruler out from the open nostril. Once your eyes, mouth, and one nostril are closed, open a container of peanut butter at the bottom of the ruler (one foot away from your open nostril). Move the peanut butter closer by 1 centimeter upon each exhale until you can detect the odor. Then repeat the whole procedure again using your other nostril.

This is exactly what the University of Florida researchers did with their subjects. What did they find? The normal elderly control subjects in the study smelled the peanut butter as soon as it came within an average of 18 centimeters (about 7 inches) from either nostril. It was about the same, roughly 7 inches, in the right nostrils of Alzheimer's patients. But in their left nostrils, it was a mere 2 inches! The peanut butter had to be only 2 inches away before the Alzheimer's patients could detect it through their left nostrils. This happened every single time. Indeed, the researchers found that a "left nostril impairment of odor detection was present in all the patients with probable AD." There was no left-right difference in the control group; they could smell the peanut butter when it was the same distance away from both their left and right nostrils. In the Alzheimer's group, however, there was a 12-centimeter difference.

The disparity was so great that we may be able to set a cutoff value for the diagnosis of Alzheimer's. The researchers reported that "[c]ompared to patients with other causes of dementia this nostril asymmetry of odor detection...was 100% sensitive and 100% specific for probable AD," meaning no false positives and no false negatives. Compared to healthy people, it was 100% sensitive in picking up cases of probable Alzheimer's and 92% specific. What exactly does that mean? In this study, if you had Alzheimer's, there was a 100% chance of having that wide left-right discrepancy. But, if you did have that discrepancy, the chance of having Alzheimer's was only 92%. This means there were some false positives.

The reason it's only "probable" Alzheimer's is because the only way we can really confirm someone has the disease is on autopsy. The current criteria for diagnosing Alzheimer's require an extensive evaluation, combined with fancy positron emission tomography (PET) scans and spinal taps. All of these tests are expensive and hard to get, can be invasive, and can have potential complications. On top of that, they are neither highly sensitive nor specific. The left-right nostril / peanut butter odor detection test, however, was fast, simple, non-invasive, and inexpensive. They concluded that may make peanut butter an ideal instrument for the early detection of Alzheimer's disease.

Does all this sound a bit too good to be true? It may be. A University of Pennsylvania research team was unable to replicate the results. Click here to read their paper. So at this point, the data are mixed. I'll do another post once more studies are published and we have a better handle on whether it's useful or not.

Of course, it's better to prevent Alzheimer's in the first place. Check out these videos for more information.

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: Sally Plank

Original Link

Using a Smell Test to Diagnose Alzheimer’s Disease

Using a Smell Test to Diagnose Alzheimer's Disease.jpeg

Alzheimer's disease (AD) pathology appears to start in the part of the brain that handles smell before subsequently spreading to additional brain regions and then, ultimately, taking over much of the rest of the brain. This led some to speculate that Alzheimer's disease may begin in the nose. Perhaps there's some environmental agent that might enter the brain through some portal in the nostrils?

This is the so-called olfactory vector hypothesis. The anatomy of the nose is well suited for the transfer of things directly into the brain, since the olfactory nerves that stick out into the nose project directly into the brain, bypassing the blood-brain barrier. The nose was actually a major infection route for the polio virus. Public health officials you started cauterizing the nasal passages of schoolchildren by spraying caustic chemicals up their noses in an effort to prevent the disease.

The concern is if people breathe in some ionized metals like aluminum dust, for example, it could be transported into the brain through these olfactory nerves at a rate of about 2 millimeters an hour, which is practically 2 inches a day. Doubt has been cast on this theory, however, by a case report of a woman born with a birth defect in which she had no smell nerves yet still developed Alzheimer's-like pathology. And so, to date, all the supporting evidence is really just circumstantial. It is clear, though, that changes in the sense of smell is among the first clinical signs of Alzheimer's, occurring during the preclinical phase--that is, before there's any noticeable cognitive decline. Could we use these changes to predict or diagnose the disease?

For years, researchers have been trying to find markers of brain illness hidden in people's ability to smell using all sorts of fancy gadgets. For example, functional MRI scans can detect differences in brain activation in response to an odor. In my video, Peanut Butter Smell Test for Alzheimer's, you can see the responses to lavender. You'll see a representation of a normal brain's responses to the odor versus an Alzheimer's brain. This unequivocally demonstrates that we can pick up changes in smell function due to Alzheimer's. But do we really need a million-dollar machine?

An ingenious group of researchers at the University of Florida discovered all we may need is some peanut butter and a ruler.

Considering that the left side of the brain primarily processes what we smell through our left nostril and the right side of our brain covers the right nostril, and understanding that Alzheimer's strikes the left side more than the right, what if you performed the following experiment: Close your eyes and mouth, breathe normally through the nose, then close one nostril, and hold a foot-long ruler out from the open nostril. Once your eyes, mouth, and one nostril are closed, open a container of peanut butter at the bottom of the ruler (one foot away from your open nostril). Move the peanut butter closer by 1 centimeter upon each exhale until you can detect the odor. Then repeat the whole procedure again using your other nostril.

This is exactly what the University of Florida researchers did with their subjects. What did they find? The normal elderly control subjects in the study smelled the peanut butter as soon as it came within an average of 18 centimeters (about 7 inches) from either nostril. It was about the same, roughly 7 inches, in the right nostrils of Alzheimer's patients. But in their left nostrils, it was a mere 2 inches! The peanut butter had to be only 2 inches away before the Alzheimer's patients could detect it through their left nostrils. This happened every single time. Indeed, the researchers found that a "left nostril impairment of odor detection was present in all the patients with probable AD." There was no left-right difference in the control group; they could smell the peanut butter when it was the same distance away from both their left and right nostrils. In the Alzheimer's group, however, there was a 12-centimeter difference.

The disparity was so great that we may be able to set a cutoff value for the diagnosis of Alzheimer's. The researchers reported that "[c]ompared to patients with other causes of dementia this nostril asymmetry of odor detection...was 100% sensitive and 100% specific for probable AD," meaning no false positives and no false negatives. Compared to healthy people, it was 100% sensitive in picking up cases of probable Alzheimer's and 92% specific. What exactly does that mean? In this study, if you had Alzheimer's, there was a 100% chance of having that wide left-right discrepancy. But, if you did have that discrepancy, the chance of having Alzheimer's was only 92%. This means there were some false positives.

The reason it's only "probable" Alzheimer's is because the only way we can really confirm someone has the disease is on autopsy. The current criteria for diagnosing Alzheimer's require an extensive evaluation, combined with fancy positron emission tomography (PET) scans and spinal taps. All of these tests are expensive and hard to get, can be invasive, and can have potential complications. On top of that, they are neither highly sensitive nor specific. The left-right nostril / peanut butter odor detection test, however, was fast, simple, non-invasive, and inexpensive. They concluded that may make peanut butter an ideal instrument for the early detection of Alzheimer's disease.

Does all this sound a bit too good to be true? It may be. A University of Pennsylvania research team was unable to replicate the results. Click here to read their paper. So at this point, the data are mixed. I'll do another post once more studies are published and we have a better handle on whether it's useful or not.

Of course, it's better to prevent Alzheimer's in the first place. Check out these videos for more information.

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: Sally Plank

Original Link

What’s the Mediterranean Diet’s Secret?

Why Was Heart Disease Rare in the Mediterranean?.jpg

The Mediterranean Diet is an "in" topic nowadays in both the medical literature and the lay media. As one researcher put it, "Uncritical laudatory coverage is common, but specifics are hard to come by: What is it? Where did it come from? Why is it good? Merits are rarely detailed; possible downsides are never mentioned." So, let's dig in....

After World War II, the government of Greece asked the Rockefeller foundation to come in and assess the situation. Impressed by the low rates of heart disease in the region, nutrition scientist Ancel Keys--after which "K" rations were named--initiated his famous seven countries study. In this study, he found the rate of fatal heart disease on the Greek isle of Crete was 20 times lower than in the United States. They also had the lowest cancer rates and fewest deaths overall. What were they eating? Their diets were more than 90% plant-based, which may explain why coronary heart disease was such a rarity. A rarity, that is, except for a small class of rich people whose diet differed from that of the general population--they ate meat every day instead of every week or two.

So, the heart of the Mediterranean diet is mainly plant-based, and low in meat and dairy, which Keys considered the "major villains in the diet" because of their saturated fat content. Unfortunately, no one is really eating the traditional Mediterranean diet anymore, even in the Mediterranean. The prevalence of coronary heart disease skyrocketed by an order of magnitude within a few decades in Crete, blamed on the increased consumption of meat and cheese at the expense of plant foods.

Everyone is talking about the Mediterranean diet, but few do it properly. People think of pizza or spaghetti with meat sauce, but while "Italian restaurants brag about the healthy measuring in diet, they serve a travesty of it." If no one's really eating this way anymore, how do you study it?

Researchers came up with a variety of Mediterranean diet adherence scoring systems to see if people who are eating more Mediterranean-ish do better. You get maximum points the more plant foods you eat, and effectively you get points deducted by eating just a single serving of meat or dairy a day. So it's no surprise those that eat relatively higher on the scale have a lower risk of heart disease, cancer, and death overall. After all, the Mediterranean diet can be considered to be a "near vegetarian" diet. "As such, it should be expected to produce the well-established health benefits of vegetarian diets." That is, less heart disease, cancer, death, and inflammation; improved arterial function; a lower risk of developing type 2 diabetes; a reduced risk for stroke, depression, and cognitive impairment.

How might it work? I've talked about the elegant studies showing that those who eat plant-based diets have more plant-based compounds, like aspirin, circulating within their systems. Polyphenol phytonutrients in plant foods are associated with a significantly lower risk of dying. Magnesium consumption is also associated with a significantly lower risk of dying, and is found in dark green leafy vegetables, as well as fruits, beans, nuts, soy, and whole grains.

Heme iron, on the other hand--the iron found in blood and muscle--acts as a pro-oxidant and appears to increase the risk of diabetes, whereas plant-based, non-heme iron appears safe. Similarly, with heart disease, animal-based iron was found to significantly increase the risk of coronary heart disease, our number one killer, but not plant-based iron. The Mediterranean diet is protective compared to the Standard American Diet--no question--but any diet rich in whole plant foods and low in animal-fat consumption could be expected to confer protection against many of our leading killers.

Here are some more videos on the Mediterranean Diet:

For more information on heme iron, see Risk Associated With Iron Supplements.

More on magnesium is found in How Do Nuts Prevent Sudden Cardiac Death? and Mineral of the Year--Magnesium.

And more on polyphenols can be seen in videos like How to Slow Brain Aging by Two Years and Juicing Removes More Than Just Fiber.

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: Couleur / Pixabay. This image has been modified.

Original Link

What’s the Mediterranean Diet’s Secret?

Why Was Heart Disease Rare in the Mediterranean?.jpg

The Mediterranean Diet is an "in" topic nowadays in both the medical literature and the lay media. As one researcher put it, "Uncritical laudatory coverage is common, but specifics are hard to come by: What is it? Where did it come from? Why is it good? Merits are rarely detailed; possible downsides are never mentioned." So, let's dig in....

After World War II, the government of Greece asked the Rockefeller foundation to come in and assess the situation. Impressed by the low rates of heart disease in the region, nutrition scientist Ancel Keys--after which "K" rations were named--initiated his famous seven countries study. In this study, he found the rate of fatal heart disease on the Greek isle of Crete was 20 times lower than in the United States. They also had the lowest cancer rates and fewest deaths overall. What were they eating? Their diets were more than 90% plant-based, which may explain why coronary heart disease was such a rarity. A rarity, that is, except for a small class of rich people whose diet differed from that of the general population--they ate meat every day instead of every week or two.

So, the heart of the Mediterranean diet is mainly plant-based, and low in meat and dairy, which Keys considered the "major villains in the diet" because of their saturated fat content. Unfortunately, no one is really eating the traditional Mediterranean diet anymore, even in the Mediterranean. The prevalence of coronary heart disease skyrocketed by an order of magnitude within a few decades in Crete, blamed on the increased consumption of meat and cheese at the expense of plant foods.

Everyone is talking about the Mediterranean diet, but few do it properly. People think of pizza or spaghetti with meat sauce, but while "Italian restaurants brag about the healthy measuring in diet, they serve a travesty of it." If no one's really eating this way anymore, how do you study it?

Researchers came up with a variety of Mediterranean diet adherence scoring systems to see if people who are eating more Mediterranean-ish do better. You get maximum points the more plant foods you eat, and effectively you get points deducted by eating just a single serving of meat or dairy a day. So it's no surprise those that eat relatively higher on the scale have a lower risk of heart disease, cancer, and death overall. After all, the Mediterranean diet can be considered to be a "near vegetarian" diet. "As such, it should be expected to produce the well-established health benefits of vegetarian diets." That is, less heart disease, cancer, death, and inflammation; improved arterial function; a lower risk of developing type 2 diabetes; a reduced risk for stroke, depression, and cognitive impairment.

How might it work? I've talked about the elegant studies showing that those who eat plant-based diets have more plant-based compounds, like aspirin, circulating within their systems. Polyphenol phytonutrients in plant foods are associated with a significantly lower risk of dying. Magnesium consumption is also associated with a significantly lower risk of dying, and is found in dark green leafy vegetables, as well as fruits, beans, nuts, soy, and whole grains.

Heme iron, on the other hand--the iron found in blood and muscle--acts as a pro-oxidant and appears to increase the risk of diabetes, whereas plant-based, non-heme iron appears safe. Similarly, with heart disease, animal-based iron was found to significantly increase the risk of coronary heart disease, our number one killer, but not plant-based iron. The Mediterranean diet is protective compared to the Standard American Diet--no question--but any diet rich in whole plant foods and low in animal-fat consumption could be expected to confer protection against many of our leading killers.

Here are some more videos on the Mediterranean Diet:

For more information on heme iron, see Risk Associated With Iron Supplements.

More on magnesium is found in How Do Nuts Prevent Sudden Cardiac Death? and Mineral of the Year--Magnesium.

And more on polyphenols can be seen in videos like How to Slow Brain Aging by Two Years and Juicing Removes More Than Just Fiber.

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: Couleur / Pixabay. This image has been modified.

Original Link

Reducing Glycotoxin Intake to Help Reduce Brain Loss

Reducing Glycotoxin Intake to Prevent Alzheimer's.jpg

Each of us has about six billion miles of DNA. How does our body keep it from getting all tangled up? There are special proteins called histones, which act like spools with DNA as the thread. Enzymes called sirtuins wrap the DNA around the histones and by doing so, silence whatever genes were in that stretch of DNA, hence their name SIRtuins, which stands for silencing information regulator.

Although they were discovered only about a decade ago, the study of sirtuins "has become one of the most promising areas of biomedicine," since they appear to be involved in promoting healthy aging and longevity. Suppression of this key host defense is considered a central feature of Alzheimer's disease, as shown in Reducing Glycotoxin Intake to Prevent Alzheimer's.

Autopsies of Alzheimer's victims reveal that loss of sirtuin activity is closely associated with the accumulation of the plaques and tangles in the brain that are characteristic of Alzheimer's disease. Sirtuin appears to activate pathways that steer the brain away from the formation of plaque and tangle proteins. "Because a decrease in sirtuin activity can clearly have deleterious effects" on nerve health, researchers are trying to come up with drugs to increase sirtuin activity, but why not just prevent its suppression in the first place?

Glycotoxins in our food suppress sirtuin activity, also known as advanced glycation end products, or AGE's. Our modern diet includes excessive AGE's, which can be neurotoxic. High levels in the blood may predict cognitive decline over time. If you measure the urine levels of glycotoxins flowing through the bodies of older adults, those with the highest levels went on to suffer the greatest cognitive decline over the subsequent nine years.

As we age, our brain literally shrinks. In our 60's and 70's, we lose an average of five cubic centimeters of total brain tissue volume every year, but some people lose more than others. Brain atrophy may be reduced in very healthy individuals, and a few people don't lose any brain at all. Normally we lose about 2% of brain volume every year, but that's just the average. Although the average brain loss for folks in their 70's and 80's was 2.1%, some lost more, some lost less, and some men and women lost none at all over a period of four years.

Researchers in Australia provided the first evidence linking AGEs with this kind of cerebral brain loss. So, limiting one's consumption of these compounds may end up having significant public health benefits. Because sirtuin deficiency is both preventable and reversible by dietary AGE reduction, a therapeutic strategy that includes eating less AGE's may offer a new strategy to combat the epidemic of Alzheimer's.

Some glycotoxins are produced internally, particularly in diabetics, but anyone can get them from smoking and eating, particularly foods high in fat and protein cooked at high temperatures. In my video, Avoiding a Sugary Grave, I listed the 15 foods most contaminated with glycotoxins; mostly chicken, but also pork, beef, and fish, which may help explain why those that eat the most meat may have triple the risk of getting dementia compared to long-time vegetarians. Note there are some relatively high fat and protein plant foods such as nuts and soy products, so I no longer recommend toasting nuts and would steer clear from roasted tofu.

I've covered advanced glycation end-products in Glycotoxins, Bacon, Eggs, and Gestational Diabetes During Pregnancy, and Why is Meat a Risk Factor for Diabetes?.

More on slowing brain aging in How to Slow Brain Aging By Two Years.

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: lightwise © 123RF.com. This image has been modified.

Original Link

Reducing Glycotoxin Intake to Help Reduce Brain Loss

Reducing Glycotoxin Intake to Prevent Alzheimer's.jpg

Each of us has about six billion miles of DNA. How does our body keep it from getting all tangled up? There are special proteins called histones, which act like spools with DNA as the thread. Enzymes called sirtuins wrap the DNA around the histones and by doing so, silence whatever genes were in that stretch of DNA, hence their name SIRtuins, which stands for silencing information regulator.

Although they were discovered only about a decade ago, the study of sirtuins "has become one of the most promising areas of biomedicine," since they appear to be involved in promoting healthy aging and longevity. Suppression of this key host defense is considered a central feature of Alzheimer's disease, as shown in Reducing Glycotoxin Intake to Prevent Alzheimer's.

Autopsies of Alzheimer's victims reveal that loss of sirtuin activity is closely associated with the accumulation of the plaques and tangles in the brain that are characteristic of Alzheimer's disease. Sirtuin appears to activate pathways that steer the brain away from the formation of plaque and tangle proteins. "Because a decrease in sirtuin activity can clearly have deleterious effects" on nerve health, researchers are trying to come up with drugs to increase sirtuin activity, but why not just prevent its suppression in the first place?

Glycotoxins in our food suppress sirtuin activity, also known as advanced glycation end products, or AGE's. Our modern diet includes excessive AGE's, which can be neurotoxic. High levels in the blood may predict cognitive decline over time. If you measure the urine levels of glycotoxins flowing through the bodies of older adults, those with the highest levels went on to suffer the greatest cognitive decline over the subsequent nine years.

As we age, our brain literally shrinks. In our 60's and 70's, we lose an average of five cubic centimeters of total brain tissue volume every year, but some people lose more than others. Brain atrophy may be reduced in very healthy individuals, and a few people don't lose any brain at all. Normally we lose about 2% of brain volume every year, but that's just the average. Although the average brain loss for folks in their 70's and 80's was 2.1%, some lost more, some lost less, and some men and women lost none at all over a period of four years.

Researchers in Australia provided the first evidence linking AGEs with this kind of cerebral brain loss. So, limiting one's consumption of these compounds may end up having significant public health benefits. Because sirtuin deficiency is both preventable and reversible by dietary AGE reduction, a therapeutic strategy that includes eating less AGE's may offer a new strategy to combat the epidemic of Alzheimer's.

Some glycotoxins are produced internally, particularly in diabetics, but anyone can get them from smoking and eating, particularly foods high in fat and protein cooked at high temperatures. In my video, Avoiding a Sugary Grave, I listed the 15 foods most contaminated with glycotoxins; mostly chicken, but also pork, beef, and fish, which may help explain why those that eat the most meat may have triple the risk of getting dementia compared to long-time vegetarians. Note there are some relatively high fat and protein plant foods such as nuts and soy products, so I no longer recommend toasting nuts and would steer clear from roasted tofu.

I've covered advanced glycation end-products in Glycotoxins, Bacon, Eggs, and Gestational Diabetes During Pregnancy, and Why is Meat a Risk Factor for Diabetes?.

More on slowing brain aging in How to Slow Brain Aging By Two Years.

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: lightwise © 123RF.com. This image has been modified.

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How May Eating Plants Help Prevent Alzheimer’s Disease?

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Intake of saturated fats and added sugars, two of the primary components of a modern Western diet, is linked with the development of Alzheimer's disease. There has been a global shift in dietary composition, from traditional diets high in starches and fiber, to what has been termed the Western diet, high in fat and sugar, low in whole, plant foods. What's so great about fruits and vegetables?

Plant-derived foods contain thousands of compounds with antioxidant properties, some of which can traverse the blood-brain barrier and may have neuroprotective effects by assisting with antioxidant defense. There's this concept of "brain rust," that neurodegenerative diseases arise from excess oxidative stress. But Nature has gifted humankind with a plethora of plants--fruits, vegetables, and nuts, and the diverse array of bioactive nutrients present in these natural products may play a pivotal role in prevention and one day, perhaps, even the cure of various neurodegenerative diseases, such as Alzheimer's disease.

Accumulated evidence suggests that naturally occurring plant compounds may potentially hinder neurodegeneration, and even improve memory and cognitive function, as I've shared in my videos Preventing Alzheimer's Disease with Plants and How to Slow Brain Aging By Two Years) and treating Alzheimer's with spices such as saffron or turmeric (See Saffron for the Treatment of Alzheimer's and Treating Alzheimer's with Turmeric).

Vegetables may be particularly protective, in part because of certain compounds we eat that concentrate in the brain, found in dark green leafy vegetables, the consumption of which are associated with lower rates of age-related cognitive decline.

Yet when you look at systemic reviews on what we can do to prevent cognitive decline, you'll see conclusions like this: "The current literature does not provide adequate evidence to make recommendations for interventions." The same is said for Alzheimer's, "Currently, insufficient evidence exists to draw firm conclusions on the association of any modifiable factors with risk of Alzheimer's disease." Doctors cite the lack of randomized controlled trials (RCTs) as the basis for their conclusions. RCTs are the gold standard used to test new medicines. This is where researchers randomize people into two groups, half get the drug and half don't, to control for confounding factors. The highest level of evidence is necessary because drugs may kill a hundred thousand Americans every year - not medication errors or illicit drugs, just regular, FDA-approved prescription drugs, making medication alone the sixth leading cause of death in the United States. So, you better make absolutely sure the benefits of new drugs outweigh the often life-threatening risks.

But we're talking about diet and exercise--the side effects are all good, so we don't need the same level of rigorous evidence to prescribe them.

A "modest proposal" was published recently in the Journal of Alzheimer's Disease, an editorial calling for a longitudinal study of dementia prevention. They agreed that definitive evidence for the effectiveness of dementia prevention methods was lacking, so we need large-scaled randomized trials. They suggested we start with 10,000 healthy volunteers in their 20's and split them into five groups. There's evidence, for example, that traumatic brain injury is a risk factor for Alzheimer's, because people with head injuries appear more likely to get the disease, but it's never been put to the test. So, they say, let's take two thousand people and beat half of them in the head with baseball bats, and the other half we'll use Styrofoam bats as a control. Afterall, until we have randomized controls, how can't physicians recommend patients not get hit in the head? They go further saying we should probably chain a thousand people to a treadmill for 40 years, and a thousand people to a couch before recommending exercise. A thousand will be forced to do crossword puzzles; another thousand forced to watch Jerry Springer reruns, lots of meat and dairy or not prescribed for another group for the next 40 years, and we can hook a thousand folks on four packs a day just to be sure.

We help our patients to quit smoking despite the fact that there's not a single randomized controlled trial where they held people down and piped smoke into their lungs for a few decades. It is time to realize that the ultimate study in regard to lifestyle and cognitive health cannot be done. Yet the absence of definitive evidence should not restrict physicians from making reasonable recommendations based on the evidence that is available.

I've discussed how drug-centric approaches to evidence-based medicine may neglect some of the most convincing data: Evidence-Based Medicine or Evidence-Biased?

To see how and why I built NutritionFacts.org on evidence-based principles, see my recent introductory videos:

A sampling of some of my Alzheimer's videos:

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--2013: Uprooting the Leading Causes of Death, More Than an Apple a Day, 2014: From Table to Able: Combating Disabling Diseases with Food, 2015: Food as Medicine: Preventing and Treating the Most Dreaded Diseases with Diet, and my latest, 2016: How Not To Die: The Role of Diet in Preventing, Arresting, and Reversing Our Top 15 Killers.

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Preventing Alzheimer’s Disease with Diet

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Up to half of Alzheimer's cases may be attributable to just seven risk factors shown in my video, Preventing Alzheimer's with Lifestyle Changes, which include diabetes, high blood pressure, obesity, exercise, smoking, depression, and mental exercise; and that's not including diet because there are so many dietary factors that researchers couldn't fit them into their model. But, they acknowledged that diet might be another important modifiable risk factor for Alzheimer's disease. In particular, there is growing evidence that dietary patterns, such as the Mediterranean diet, are associated with lower Alzheimer's risk, as well as slower cognitive decline, but which constituents of the Mediterranean diet are responsible?

The traditional Mediterranean diet is a diet high in intake of vegetables, beans, fruit, and nuts, and low in meat and dairy. When researchers tried to tease out the protective components, fish consumption showed no benefit, neither did moderate alcohol consumption. The two critical pieces appeared to be vegetable consumption, and the ratio between unsaturated fats and saturated fats, essentially plant fats to animal fats.

In studies across 11 countries, fat consumption appeared to be most closely correlated with the prevalence of Alzheimer's disease, with the lowest fat intake and Alzheimer's rates in China to the highest fat intake and Alzheimer's rates in the United States. But this is grouping all fats together.

Harvard researchers examined the relationships of the major fat types to cognitive change over four years among 6,000 healthy older women, and found that higher saturated fat intake was associated with a poorer trajectory of cognition and memory. Women with the highest saturated fat intake had 60 to 70% greater odds of worse change on brain function. The magnitude of cognitive change associated with saturated fat consumption was equivalent to about six years of aging, meaning women with the lowest saturated fat intake had the brain function of women six years younger.

What if one already has Alzheimer's, though? Previously, a group of Columbia University researchers reported that eating a Mediterranean-style diet was related to lower risk for Alzheimer's disease, but whether a Mediterranean diet--or any diet for that matter--is associated with the subsequent course of the disease and outcomes had not been investigated, until now.

In a study highlighted in my video, Preventing Alzheimer's Disease with Diet, researchers found that adherence to the Mediterranean diet may affect not only risk for Alzheimer's disease, but also subsequent disease course, as higher adherence to the Mediterranean diet was associated with lower mortality. And the more they adhered to the healthier diet, the longer they lived. Within five years, only 20% of those with high adherence died, with twice as many deaths in the intermediate adherence group. In the low adherence group, within five years, more than half were dead, and by ten years, 90% were gone. By the end of the study, the only people still alive were those with higher adherence to the healthier diet.

For more on the Mediterranean diet, check out:

I do have a bunch on dietary factors in cognitive decline, though:

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 Uprooting the Leading Causes of Death, More Than an Apple a Day, From Table to Able, and Food as Medicine.

Image Credit: Shawn Allen / Flickr

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