What Animal Protein Does in Your Colon

What Animal Protein Does in Your Colon.jpeg

There's a take-off of the industry slogan, "Beef: It's What's For Dinner" - "Beef: It's What's Rotting in Your Colon." I saw this on a shirt once with some friends and I was such the party pooper--no pun intended--explaining to everyone that meat is fully digested in the small intestine, and never makes it down into the colon. It's no fun hanging out with biology geeks.

But I was wrong!

It's been estimated that with a typical Western diet, up to 12 grams of protein can escape digestion, and when it reaches the colon, it can be turned into toxic substances like ammonia. This degradation of undigested protein in the colon is called putrefaction, so a little meat can actually end up putrefying in our colon. The problem is that some of the by-products of this putrefaction process can be toxic.

It's generally accepted that carbohydrate fermentation--the fiber and resistant starches that reach our colon--results in beneficial effects because of the generation of short-chain fatty acids like butyrate, whereas protein fermentation is considered detrimental. Protein fermentation mainly occurs in the lower end of colon and results in the production of potentially toxic metabolites. That may be why colorectal cancer and ulcerative colitis tends to happen lower down--because that's where the protein is putrefying.

Probably the simplest strategy to reduce the potential harm of protein fermentation is to reduce dietary protein intake. But the accumulation of these toxic byproducts of protein metabolism may be attenuated by the fermentation of undigested plant matter. In my video, Bowel Wars: Hydrogen Sulfide vs. Butyrate, you can see a study out of Australia showed that if you give people foods containing resistant starch you can block the accumulation of potentially harmful byproducts of protein metabolism. Resistant starch is resistant to small intestine digestion and so it makes it down to our colon where it can feed our good bacteria. Resistant starch is found in cooked beans, split peas, chickpeas, lentils, raw oatmeal, and cooled cooked pasta (like macaroni salad). Apparently, the more starch that ends up in the colon, the less ammonia that is produced.

Of course, there's protein in plants too. The difference is that animal proteins tend to have more sulfur-containing amino acids like methionine, which can be turned into hydrogen sulfide in our colon. Hydrogen sulfide is the rotten egg gas that may play a role in the development of the inflammatory bowel disease, ulcerative colitis (see Preventing Ulcerative Colitis with Diet).

The toxic effects of hydrogen sulfide appear to be a result of blocking the ability of the cells lining our colon from utilizing butyrate, which is what our good bacteria make from the fiber and resistant starch we eat. It's like this constant battle in our colon between the bad metabolites of protein, hydrogen sulfide, and the good metabolites of carbohydrates, butyrate. Using human colon samples, researchers were able to show that the adverse effects of sulfide could be reversed by butyrate. So we can either cut down on meat, eat more plants, or both.

There are two ways hydrogen sulfide can be produced, though. It's mainly present in our large intestine as a result of the breakdown of sulfur-containing proteins, but the rotten egg gas can also be generated from inorganic sulfur preservatives like sulfites and sulfur dioxide.

Sulfur dioxide is used as a preservative in dried fruit, and sulfites are added to wines. We can avoid sulfur additives by reading labels or by just choosing organic, since they're forbidden from organic fruits and beverages by law.

More than 35 years ago, studies started implicating sulfur dioxide preservatives in the exacerbation of asthma. This so-called "sulfite-sensitivity" seems to affect only about 1 in 2,000 people, so I recommended those with asthma avoid it, but otherwise I considered the preservative harmless. I am now not so sure, and advise people to avoid it when possible.

Cabbage family vegetables naturally have some sulfur compounds, but thankfully, after following more than a hundred thousand women for over 25 years, researchers concluded cruciferous vegetables were not associated with elevated colitis risk.

Because of animal protein and processed food intake, the standard American diet may contain five or six times more sulfur than a diet centered around unprocessed plant foods. This may help explain the rarity of inflammatory bowel disease among those eating traditional whole food, plant-based diets.

How could companies just add things like sulfur dioxide to foods without adequate safety testing? See Who Determines if Food Additives are Safe? For other additives that may be a problem, see Titanium Dioxide & Inflammatory Bowel Disease and Is Carrageenan Safe?

More on this epic fermentation battle in our gut in Stool pH and Colon Cancer.

Does the sulfur-containing amino acid methionine sound familiar? You may remember it from such hits as Starving Cancer with Methionine Restriction and Methionine Restriction as a Life Extension Strategy.

These short-chain fatty acids released by our good bacteria when we eat fiber and resistant starches are what may be behind the second meal effect: Beans and the Second Meal Effect.

I mentioned ulcerative colitis. What about the other inflammatory bowel disease Crohn's? See Preventing Crohn's Disease With Diet and Dietary Treatment of Crohn's Disease.

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 / Flickr. This image has been modified.

Original Link

What Animal Protein Does in Your Colon

What Animal Protein Does in Your Colon.jpeg

There's a take-off of the industry slogan, "Beef: It's What's For Dinner" - "Beef: It's What's Rotting in Your Colon." I saw this on a shirt once with some friends and I was such the party pooper--no pun intended--explaining to everyone that meat is fully digested in the small intestine, and never makes it down into the colon. It's no fun hanging out with biology geeks.

But I was wrong!

It's been estimated that with a typical Western diet, up to 12 grams of protein can escape digestion, and when it reaches the colon, it can be turned into toxic substances like ammonia. This degradation of undigested protein in the colon is called putrefaction, so a little meat can actually end up putrefying in our colon. The problem is that some of the by-products of this putrefaction process can be toxic.

It's generally accepted that carbohydrate fermentation--the fiber and resistant starches that reach our colon--results in beneficial effects because of the generation of short-chain fatty acids like butyrate, whereas protein fermentation is considered detrimental. Protein fermentation mainly occurs in the lower end of colon and results in the production of potentially toxic metabolites. That may be why colorectal cancer and ulcerative colitis tends to happen lower down--because that's where the protein is putrefying.

Probably the simplest strategy to reduce the potential harm of protein fermentation is to reduce dietary protein intake. But the accumulation of these toxic byproducts of protein metabolism may be attenuated by the fermentation of undigested plant matter. In my video, Bowel Wars: Hydrogen Sulfide vs. Butyrate, you can see a study out of Australia showed that if you give people foods containing resistant starch you can block the accumulation of potentially harmful byproducts of protein metabolism. Resistant starch is resistant to small intestine digestion and so it makes it down to our colon where it can feed our good bacteria. Resistant starch is found in cooked beans, split peas, chickpeas, lentils, raw oatmeal, and cooled cooked pasta (like macaroni salad). Apparently, the more starch that ends up in the colon, the less ammonia that is produced.

Of course, there's protein in plants too. The difference is that animal proteins tend to have more sulfur-containing amino acids like methionine, which can be turned into hydrogen sulfide in our colon. Hydrogen sulfide is the rotten egg gas that may play a role in the development of the inflammatory bowel disease, ulcerative colitis (see Preventing Ulcerative Colitis with Diet).

The toxic effects of hydrogen sulfide appear to be a result of blocking the ability of the cells lining our colon from utilizing butyrate, which is what our good bacteria make from the fiber and resistant starch we eat. It's like this constant battle in our colon between the bad metabolites of protein, hydrogen sulfide, and the good metabolites of carbohydrates, butyrate. Using human colon samples, researchers were able to show that the adverse effects of sulfide could be reversed by butyrate. So we can either cut down on meat, eat more plants, or both.

There are two ways hydrogen sulfide can be produced, though. It's mainly present in our large intestine as a result of the breakdown of sulfur-containing proteins, but the rotten egg gas can also be generated from inorganic sulfur preservatives like sulfites and sulfur dioxide.

Sulfur dioxide is used as a preservative in dried fruit, and sulfites are added to wines. We can avoid sulfur additives by reading labels or by just choosing organic, since they're forbidden from organic fruits and beverages by law.

More than 35 years ago, studies started implicating sulfur dioxide preservatives in the exacerbation of asthma. This so-called "sulfite-sensitivity" seems to affect only about 1 in 2,000 people, so I recommended those with asthma avoid it, but otherwise I considered the preservative harmless. I am now not so sure, and advise people to avoid it when possible.

Cabbage family vegetables naturally have some sulfur compounds, but thankfully, after following more than a hundred thousand women for over 25 years, researchers concluded cruciferous vegetables were not associated with elevated colitis risk.

Because of animal protein and processed food intake, the standard American diet may contain five or six times more sulfur than a diet centered around unprocessed plant foods. This may help explain the rarity of inflammatory bowel disease among those eating traditional whole food, plant-based diets.

How could companies just add things like sulfur dioxide to foods without adequate safety testing? See Who Determines if Food Additives are Safe? For other additives that may be a problem, see Titanium Dioxide & Inflammatory Bowel Disease and Is Carrageenan Safe?

More on this epic fermentation battle in our gut in Stool pH and Colon Cancer.

Does the sulfur-containing amino acid methionine sound familiar? You may remember it from such hits as Starving Cancer with Methionine Restriction and Methionine Restriction as a Life Extension Strategy.

These short-chain fatty acids released by our good bacteria when we eat fiber and resistant starches are what may be behind the second meal effect: Beans and the Second Meal Effect.

I mentioned ulcerative colitis. What about the other inflammatory bowel disease Crohn's? See Preventing Crohn's Disease With Diet and Dietary Treatment of Crohn's Disease.

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 / Flickr. This image has been modified.

Original Link

High Blood Pressure: Normal but Not Natural

High Blood Pressure - Normal but Not Natural.jpeg

The most comprehensive and systematic analysis of causes of death ever undertaken allows us to answer questions like, how many lives could we save if people cut back on soda? The answer is 299,521. Soft drinks aren't just bad because they're empty calories. More than just not being a health-promoting item, soda appears to be an actively death-promoting item. Of course, it's not as deadly as processed meats such as bacon, bologna, ham, or hot dogs, which account for about 800,000 deaths every year--killing twice as many women as domestic violence and five times more people than all illegal drugs combined.

On the other hand, eating more whole grains could save 1.7 million lives. And more vegetables could save 1.8 million lives every year. If only we ate more nuts and seeds, we'd save 2 and a half million lives. But fruit is apparently what the world needs most (they didn't look at beans) with 4.9 million lives hanging in the balance every year. The cure is not drugs or vaccines; the cure is fruit. The #1 dietary risk factor for death in the world may be not eating enough fruit.

One reason why plant-based diets can save so many millions is because the #1 killer risk factor in the world is high blood pressure, laying to waste nine million people year after year. In the United States, high blood pressure affects nearly 78 million--that's one in three of us. As we age our pressures get higher and higher, such that by age 60, it strikes more than half of that population. If it affects most of us when we get older, maybe it's less a disease and more just a natural, inevitable consequence of getting older?

No.

We've known for nearly a century that high blood pressure need never occur. Researchers measured the blood pressure of a thousand people in rural Kenya. Up until age 40, the blood pressures of rural Africans were about the same as Europeans and Americans, down around 120's over 80's, but as Westerners age, our pressures creep up such that by age 60 the average person is hypertensive, exceeding 140 over 90. But the pressures of those in rural Africa improved with age; not only did they not develop hypertension, their blood pressures actually got better.

The 140/90 cut-off is arbitrary. Just like studies that show the lower our cholesterol the better--there's really no safe level above about 150--blood pressure studies also support a "lower the better" approach. Even people who start out with blood pressure under 120/80 appear to benefit from blood pressure reduction. The ideal blood pressure, the no-benefit-from-reducing-it-further blood pressure, appears to be 110/70. Is it possible to get blood pressures under 110 over 70? It's not just possible, it can be normal for those eating healthy enough diets (see How Not to Die from High Blood Pressure).

Over two years at a rural Kenyan hospital, 1,800 patients were admitted. How many cases of high blood pressure were found? Zero. Wow. They must have had low rates of heart disease. Actually, they had no rates of heart disease. Not low risk--no risk. Not a single case of arteriosclerosis was found.

Having a "normal" blood pressure may set you up for dying from "normal" causes such as heart attacks and strokes. For more on this concept, see When Low Risk Means High Risk. It's like having a normal cholesterol level (see Optimal Cholesterol Level).

It seems high blood pressure is a choice. Like cavities: Cavities and Coronaries: Our Choice.

Even end-stage malignant hypertension can be reversed with diet (thereby demonstrating it was the diet and not other lifestyle factors that protected traditional plant-based populations). See Kempner Rice Diet: Whipping Us Into Shape.

Flax seeds, hibiscus tea, whole grains, and nitrate-rich vegetables may offer additional protection:

Why not just take the drugs? See The Actual Benefit of Diet vs. Drugs and Why Prevention is Worth a Ton of Cure. And be sure to check out my summary video, How Not to Die from High Blood Pressure, as well as The Evidence that Salt Raises Blood Pressure.

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 / Flickr. This image has been modified.

Original Link

High Blood Pressure: Normal but Not Natural

High Blood Pressure - Normal but Not Natural.jpeg

The most comprehensive and systematic analysis of causes of death ever undertaken allows us to answer questions like, how many lives could we save if people cut back on soda? The answer is 299,521. Soft drinks aren't just bad because they're empty calories. More than just not being a health-promoting item, soda appears to be an actively death-promoting item. Of course, it's not as deadly as processed meats such as bacon, bologna, ham, or hot dogs, which account for about 800,000 deaths every year--killing twice as many women as domestic violence and five times more people than all illegal drugs combined.

On the other hand, eating more whole grains could save 1.7 million lives. And more vegetables could save 1.8 million lives every year. If only we ate more nuts and seeds, we'd save 2 and a half million lives. But fruit is apparently what the world needs most (they didn't look at beans) with 4.9 million lives hanging in the balance every year. The cure is not drugs or vaccines; the cure is fruit. The #1 dietary risk factor for death in the world may be not eating enough fruit.

One reason why plant-based diets can save so many millions is because the #1 killer risk factor in the world is high blood pressure, laying to waste nine million people year after year. In the United States, high blood pressure affects nearly 78 million--that's one in three of us. As we age our pressures get higher and higher, such that by age 60, it strikes more than half of that population. If it affects most of us when we get older, maybe it's less a disease and more just a natural, inevitable consequence of getting older?

No.

We've known for nearly a century that high blood pressure need never occur. Researchers measured the blood pressure of a thousand people in rural Kenya. Up until age 40, the blood pressures of rural Africans were about the same as Europeans and Americans, down around 120's over 80's, but as Westerners age, our pressures creep up such that by age 60 the average person is hypertensive, exceeding 140 over 90. But the pressures of those in rural Africa improved with age; not only did they not develop hypertension, their blood pressures actually got better.

The 140/90 cut-off is arbitrary. Just like studies that show the lower our cholesterol the better--there's really no safe level above about 150--blood pressure studies also support a "lower the better" approach. Even people who start out with blood pressure under 120/80 appear to benefit from blood pressure reduction. The ideal blood pressure, the no-benefit-from-reducing-it-further blood pressure, appears to be 110/70. Is it possible to get blood pressures under 110 over 70? It's not just possible, it can be normal for those eating healthy enough diets (see How Not to Die from High Blood Pressure).

Over two years at a rural Kenyan hospital, 1,800 patients were admitted. How many cases of high blood pressure were found? Zero. Wow. They must have had low rates of heart disease. Actually, they had no rates of heart disease. Not low risk--no risk. Not a single case of arteriosclerosis was found.

Having a "normal" blood pressure may set you up for dying from "normal" causes such as heart attacks and strokes. For more on this concept, see When Low Risk Means High Risk. It's like having a normal cholesterol level (see Optimal Cholesterol Level).

It seems high blood pressure is a choice. Like cavities: Cavities and Coronaries: Our Choice.

Even end-stage malignant hypertension can be reversed with diet (thereby demonstrating it was the diet and not other lifestyle factors that protected traditional plant-based populations). See Kempner Rice Diet: Whipping Us Into Shape.

Flax seeds, hibiscus tea, whole grains, and nitrate-rich vegetables may offer additional protection:

Why not just take the drugs? See The Actual Benefit of Diet vs. Drugs and Why Prevention is Worth a Ton of Cure. And be sure to check out my summary video, How Not to Die from High Blood Pressure, as well as The Evidence that Salt Raises Blood Pressure.

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 / Flickr. This image has been modified.

Original Link

How to Prevent a Heart Attack

How to Prevent a Heart Attack.jpeg

In my video Arterial Acne, I described atherosclerotic plaques as inflamed pockets of pus. Our coronary arteries start out healthy, but then the saturated fat, trans fat, and cholesterol in the standard American diet increases the cholesterol in our blood, which accumulates in the artery wall. This triggers an inflammatory response. This so-called fatty streak can then grow into an atherosclerotic plaque, which has the potential to rupture into our artery. If that happens, a blood clot forms, shutting off blood flow to a part of our heart, which can then die off and ultimately kill us.

What causes that final step, the rupture of the plaque? Ten years ago, researchers at Michigan State proposed a mechanism. They noted that when you look at ruptured plaques from autopsies of people who died from heart attacks, they were filled with cholesterol crystals protruding out from the plaque. So, the researchers wondered if maybe all that cholesterol in the plaque gets so supersaturated that it reaches a point where it crystallizes like sugar water forming rock candy. The growing crystals may then burst the plaque open.

To test out this theory they first made a supersaturated solution of cholesterol in a test tube to see if it expanded when it crystallized, and indeed it did-just like how water expands when it crystallizes into ice. In my video Cholesterol Crystals May Tear Through Our Artery Lining, you can see a massive cholesterol crystal shooting out the top of a test tube. Under a microscope, the tips of the cholesterol crystals were sharp jagged needles.

The researchers tried placing a thin membrane over the top of the test tube to see if the cholesterol needles would poke through, and indeed the sharp tips of the cholesterol crystals cut through the membrane. This suggested that the crystallization of supersaturated cholesterol in atherosclerotic plaques could indeed induce the rupture that kills us.

A test tube is one thing, but can you actually see crystals poking out in autopsy specimens? Yes, cholesterol crystals piercing the arterial plaque were found in patients who died with heart attacks, with extensive protrusions of cholesterol crystals into the middle of the artery.

What makes us think it was the crystals that actually burst the plaque? All those studied who died of acute heart attacks had perforating cholesterol crystals sticking out of their plaques, but no crystals were found perforating the arteries of people who had severe atherosclerosis, but died first of other, non-cardiac causes.

This can explain why dramatically lowering cholesterol levels with diet (and drugs, if necessary) can reduce the risk of fatal heart attack, by pulling cholesterol out of the artery wall, and decreasing the risk of crystallizing these cholesterol needles that may pop your plaque.

Given the powerful visuals, my Cholesterol Crystals May Tear Through Our Artery Lining video might be a good one to share with those in your life with heart disease, in hopes that they might reconsider eating artery-clogging diets.

Blocking the First Step of Heart Disease involves keeping our LDL cholesterol low by decreasing our intake of Trans Fat, Saturated Fat, and Cholesterol: Tolerable Upper Intake of Zero. Swapping red meat for white won't do it: Switching From Beef to Chicken and Fish May Not Lower Cholesterol

Does it matter if LDL cholesterol in our blood is small and dense or large and fluffy? See my video Does Cholesterol Size Matter?

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 / Flickr. This image has been modified.

Original Link

The Five Most Important Dietary Tweaks

The Five Most Important Dietary Tweaks.jpeg

Generally, adherence to healthy lifestyle patterns has decreased during the last 18 years. Obesity is up, exercise is down, and the number of people eating just five servings of fruits and veggies a day dropped like a rock. And we didn't start out that great to begin with.

Only 3% of Americans at the turn of the 21st century had the following four healthy lifestyle characteristics: not smoking, not overweight, five daily servings of fruits and vegetables, and exercising a half hour a day at least five days a week. Whether people were wealthy or college-educated didn't matter; no sub-group even remotely met clinical or public health recommendations.

Where are people falling down the most? You can see in my video What Percent of Americans Lead Healthy Lifestyles?. If you look at heart disease risk factors, for example, most people don't smoke and about half are exercising. But if we look at the healthy diet score-which is based on things like drinking less than four cups of soda a week-a scale of zero to five, only about 1% of Americans score a four or five. The American Heart Association's aggressive 2020 target to improve that by 20% would bring us up to 1.2%.

Since we've known for decades that advanced coronary artery disease may be present by age 20--with atherosclerosis often even present in young children--it is particularly disturbing that healthy lifestyle choices are declining rather than improving in the U.S.

In terms of life expectancy, the U.S. is down around 27 or 28 out of the 34 OECD free-market democracies. The people of Slovenia live a year longer than citizens of the United States. Why? According to the most rigorous analysis of risk factors ever published, the number one cause of death and disability in the United States is our diet.

It's the food.

According to the Global Burden of Disease study, the worst five things about our diet are: we don't eat enough fruit, we don't eat enough nuts and seeds, we eat too much salt, too much processed meat, and not enough vegetables.

Studies that have looked at diet quality and chronic disease mortality risk found that those scoring higher (e.g. more whole plant foods), reduced the risk of dying prematurely from heart disease, cancer, and all causes of death combined. There is now an overwhelming body of clinical and epidemiological evidence illustrating the dramatic impact of a healthy lifestyle on reducing all-cause mortality and preventing chronic diseases such as coronary heart disease, stroke, diabetes, and cancer.

Why do we eat so poorly? Aren't we scared of dying from these horrible chronic diseases? It's almost as if we're eating as though our future didn't matter. And there's actually data to back that up, from a study entitled Death Row Nutrition.

The growing macabre fascination with speculating about one's ''last meal'' offers a window into one's true consumption desires when one's value of the future is discounted close to zero. In contrast to pop culture anecdotes, a group of Cornell researchers created a catalog of actual last meals-the final food requests of 247 individuals executed in the United States during a recent five-year period. Meat was the most common request. The researchers go out of their way to note that tofu never made the list, and no one asked for a vegetarian meal. In fact, if you compare the last meals to what Americans normally eat, there's not much difference.

If we continue to eat as though they were our last meals, eventually, they will be.


A few years ago I did a video called Nation's Diet in Crisis. It's sad that it doesn't seem like much has changed. How Many Meet the Simple Seven? is another video in which you can see how your own habits stack up.

For more on fruits and veggies and living longer, see Fruits and Longevity: How Many Minutes per Mouthful? Surprised that nuts made the longevity list? See Nuts May Help Prevent Death. What about legumes? See Increased Lifespan from Beans.

The reason public health professionals are so keen on measuring lifestyle characteristics is because modest improvements may have extraordinary effects. See, for example:

Didn't know the beginnings of heart disease may already be present in children? See my video Heart Disease Starts in Childhood. Think that's tragic? Check out Heart Disease May Start in the Womb. Is it too late if we've been eating poorly most of our lives? It's Never Too Late to Start Eating Healthier.

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 / Flickr. This image has been modified.

Original Link

How to Prevent a Heart Attack

How to Prevent a Heart Attack.jpeg

In my video Arterial Acne, I described atherosclerotic plaques as inflamed pockets of pus. Our coronary arteries start out healthy, but then the saturated fat, trans fat, and cholesterol in the standard American diet increases the cholesterol in our blood, which accumulates in the artery wall. This triggers an inflammatory response. This so-called fatty streak can then grow into an atherosclerotic plaque, which has the potential to rupture into our artery. If that happens, a blood clot forms, shutting off blood flow to a part of our heart, which can then die off and ultimately kill us.

What causes that final step, the rupture of the plaque? Ten years ago, researchers at Michigan State proposed a mechanism. They noted that when you look at ruptured plaques from autopsies of people who died from heart attacks, they were filled with cholesterol crystals protruding out from the plaque. So, the researchers wondered if maybe all that cholesterol in the plaque gets so supersaturated that it reaches a point where it crystallizes like sugar water forming rock candy. The growing crystals may then burst the plaque open.

To test out this theory they first made a supersaturated solution of cholesterol in a test tube to see if it expanded when it crystallized, and indeed it did-just like how water expands when it crystallizes into ice. In my video Cholesterol Crystals May Tear Through Our Artery Lining, you can see a massive cholesterol crystal shooting out the top of a test tube. Under a microscope, the tips of the cholesterol crystals were sharp jagged needles.

The researchers tried placing a thin membrane over the top of the test tube to see if the cholesterol needles would poke through, and indeed the sharp tips of the cholesterol crystals cut through the membrane. This suggested that the crystallization of supersaturated cholesterol in atherosclerotic plaques could indeed induce the rupture that kills us.

A test tube is one thing, but can you actually see crystals poking out in autopsy specimens? Yes, cholesterol crystals piercing the arterial plaque were found in patients who died with heart attacks, with extensive protrusions of cholesterol crystals into the middle of the artery.

What makes us think it was the crystals that actually burst the plaque? All those studied who died of acute heart attacks had perforating cholesterol crystals sticking out of their plaques, but no crystals were found perforating the arteries of people who had severe atherosclerosis, but died first of other, non-cardiac causes.

This can explain why dramatically lowering cholesterol levels with diet (and drugs, if necessary) can reduce the risk of fatal heart attack, by pulling cholesterol out of the artery wall, and decreasing the risk of crystallizing these cholesterol needles that may pop your plaque.

Given the powerful visuals, my Cholesterol Crystals May Tear Through Our Artery Lining video might be a good one to share with those in your life with heart disease, in hopes that they might reconsider eating artery-clogging diets.

Blocking the First Step of Heart Disease involves keeping our LDL cholesterol low by decreasing our intake of Trans Fat, Saturated Fat, and Cholesterol: Tolerable Upper Intake of Zero. Swapping red meat for white won't do it: Switching From Beef to Chicken and Fish May Not Lower Cholesterol

Does it matter if LDL cholesterol in our blood is small and dense or large and fluffy? See my video Does Cholesterol Size Matter?

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 / Flickr. This image has been modified.

Original Link

The Five Most Important Dietary Tweaks

The Five Most Important Dietary Tweaks.jpeg

Generally, adherence to healthy lifestyle patterns has decreased during the last 18 years. Obesity is up, exercise is down, and the number of people eating just five servings of fruits and veggies a day dropped like a rock. And we didn't start out that great to begin with.

Only 3% of Americans at the turn of the 21st century had the following four healthy lifestyle characteristics: not smoking, not overweight, five daily servings of fruits and vegetables, and exercising a half hour a day at least five days a week. Whether people were wealthy or college-educated didn't matter; no sub-group even remotely met clinical or public health recommendations.

Where are people falling down the most? You can see in my video What Percent of Americans Lead Healthy Lifestyles?. If you look at heart disease risk factors, for example, most people don't smoke and about half are exercising. But if we look at the healthy diet score-which is based on things like drinking less than four cups of soda a week-a scale of zero to five, only about 1% of Americans score a four or five. The American Heart Association's aggressive 2020 target to improve that by 20% would bring us up to 1.2%.

Since we've known for decades that advanced coronary artery disease may be present by age 20--with atherosclerosis often even present in young children--it is particularly disturbing that healthy lifestyle choices are declining rather than improving in the U.S.

In terms of life expectancy, the U.S. is down around 27 or 28 out of the 34 OECD free-market democracies. The people of Slovenia live a year longer than citizens of the United States. Why? According to the most rigorous analysis of risk factors ever published, the number one cause of death and disability in the United States is our diet.

It's the food.

According to the Global Burden of Disease study, the worst five things about our diet are: we don't eat enough fruit, we don't eat enough nuts and seeds, we eat too much salt, too much processed meat, and not enough vegetables.

Studies that have looked at diet quality and chronic disease mortality risk found that those scoring higher (e.g. more whole plant foods), reduced the risk of dying prematurely from heart disease, cancer, and all causes of death combined. There is now an overwhelming body of clinical and epidemiological evidence illustrating the dramatic impact of a healthy lifestyle on reducing all-cause mortality and preventing chronic diseases such as coronary heart disease, stroke, diabetes, and cancer.

Why do we eat so poorly? Aren't we scared of dying from these horrible chronic diseases? It's almost as if we're eating as though our future didn't matter. And there's actually data to back that up, from a study entitled Death Row Nutrition.

The growing macabre fascination with speculating about one's ''last meal'' offers a window into one's true consumption desires when one's value of the future is discounted close to zero. In contrast to pop culture anecdotes, a group of Cornell researchers created a catalog of actual last meals-the final food requests of 247 individuals executed in the United States during a recent five-year period. Meat was the most common request. The researchers go out of their way to note that tofu never made the list, and no one asked for a vegetarian meal. In fact, if you compare the last meals to what Americans normally eat, there's not much difference.

If we continue to eat as though they were our last meals, eventually, they will be.


A few years ago I did a video called Nation's Diet in Crisis. It's sad that it doesn't seem like much has changed. How Many Meet the Simple Seven? is another video in which you can see how your own habits stack up.

For more on fruits and veggies and living longer, see Fruits and Longevity: How Many Minutes per Mouthful? Surprised that nuts made the longevity list? See Nuts May Help Prevent Death. What about legumes? See Increased Lifespan from Beans.

The reason public health professionals are so keen on measuring lifestyle characteristics is because modest improvements may have extraordinary effects. See, for example:

Didn't know the beginnings of heart disease may already be present in children? See my video Heart Disease Starts in Childhood. Think that's tragic? Check out Heart Disease May Start in the Womb. Is it too late if we've been eating poorly most of our lives? It's Never Too Late to Start Eating Healthier.

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 / Flickr. This image has been modified.

Original Link

Benefits of Nuts for Stroke Prevention

PREDIMED - Does Eating Nuts Prevent Strokes.jpg

In the PREDIMED study, from the Spanish "PREvencio ́n con DIeta MEDiterranea," a whopping 7,447 patients were randomized into three groups. These were folks at high risk for a heart attack, about half were obese, diabetic and most had high blood pressure and high cholesterol, but they had not yet had their first heart attack or stroke. A third were told to eat a Mediterranean diet and given a free quart of extra virgin olive oil every week. The second group were told to eat a Mediterranean diet and given a half pound of free nuts every week, and the last third were told to follow the American Heart Association guidelines and reduce their fat intake. No portion control or exercise advice was given, and they were followed for about five years. The results were published in the New England Journal of Medicine.

The first thing you do when you look at a diet intervention trial is see what the groups actually ended up eating, which can be very different from what they were told to eat. For example, the so-called low-fat group started out at 39 percent of calories from fat, and ended up getting 37 percent of calories from fat, which is high fat even compared to the Standard American Diet which comes in at 33 percent, something the researchers plainly acknowledged. In fact, the control group didn't change much at all over the years, so can be thought of as the what-if-you-don't-do-anything group, which is still an important control group to have. Though the two Mediterranean diet groups didn't get much more Mediterranean. You can see the charts in my video PREDIMED: Does Eating Nuts Prevent Strokes?

The two Mediterranean groups were told to eat more fruits and vegetables, for example, and less meat and dairy, but didn't accomplish any of those compared to control. The biggest changes recorded were, not surprisingly, in the consumption of the freebies. The group that got a free jug of extra-virgin olive oil delivered to their home every week really did start increasing their consumption, in part by replacing some of the refined olive oil they had been using. And those that got a half pound of free nuts sent to them every week for four years straight did start eating more nuts.

Basically the researchers designed a study to test two different Mediterranean diets versus a low fat diet, but ended up studying something very different. In essence, they studied what happens when thousands of people switch from consuming about three tablespoons of olive oil a day (half virgin) to four tablespoons of all virgin, compared to thousands of people who all the sudden go from eating about a half an ounce of nuts a day to a whole ounce, compared to thousands of people who don't make much of a change at all. It may not have been what they were hoping for, but these are important research questions in and of themselves.

With no significant differences in meat and dairy intake, there were no significant differences in saturated fat or cholesterol intake, so no surprise there was no significant differences in their blood cholesterol levels, and so no difference in their subsequent number of heart attacks. In the five or so years the study ran, there were 37 heart attacks in the olive oil group, 31 in the nut group and 38 in the neither group. No significant difference. Same with dying from a heart attack or stroke or from any cause--but, those in the olive oil and especially the nut group had significantly fewer strokes. All three groups were eating stroke-promoting diets; some people in all three groups had strokes after eating these diets for years, and so ideally we'd choose diets that can stop or reverse the disease process, but the diet with added extra virgin olive oil caused about a third fewer strokes, and adding nuts seemed to cut their stroke risk nearly in half. If this worked as well in the general population, in the U.S. alone that would mean preventing 89,000 strokes a year. That's would be like ten strokes an hour around the clock prevented simply by adding half an ounce of nuts to one's daily diet.

Here are some of my previous videos on the Mediterranean diet:

The PREDIMED study got a bad rap because of how it was reported, but it's an extraordinary trial that continues to churn out useful results.

More on nuts in:

But what about nuts and weight gain? See Nuts and Obesity: The Weight of Evidence .

For videos on olive oil, see Extra Virgin Olive Oil vs. Nuts and Olive Oil & Artery Function.

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 / Flickr. This image has been modified.

Original Link

Benefits of Nuts for Stroke Prevention

PREDIMED - Does Eating Nuts Prevent Strokes.jpg

In the PREDIMED study, from the Spanish "PREvencio ́n con DIeta MEDiterranea," a whopping 7,447 patients were randomized into three groups. These were folks at high risk for a heart attack, about half were obese, diabetic and most had high blood pressure and high cholesterol, but they had not yet had their first heart attack or stroke. A third were told to eat a Mediterranean diet and given a free quart of extra virgin olive oil every week. The second group were told to eat a Mediterranean diet and given a half pound of free nuts every week, and the last third were told to follow the American Heart Association guidelines and reduce their fat intake. No portion control or exercise advice was given, and they were followed for about five years. The results were published in the New England Journal of Medicine.

The first thing you do when you look at a diet intervention trial is see what the groups actually ended up eating, which can be very different from what they were told to eat. For example, the so-called low-fat group started out at 39 percent of calories from fat, and ended up getting 37 percent of calories from fat, which is high fat even compared to the Standard American Diet which comes in at 33 percent, something the researchers plainly acknowledged. In fact, the control group didn't change much at all over the years, so can be thought of as the what-if-you-don't-do-anything group, which is still an important control group to have. Though the two Mediterranean diet groups didn't get much more Mediterranean. You can see the charts in my video PREDIMED: Does Eating Nuts Prevent Strokes?

The two Mediterranean groups were told to eat more fruits and vegetables, for example, and less meat and dairy, but didn't accomplish any of those compared to control. The biggest changes recorded were, not surprisingly, in the consumption of the freebies. The group that got a free jug of extra-virgin olive oil delivered to their home every week really did start increasing their consumption, in part by replacing some of the refined olive oil they had been using. And those that got a half pound of free nuts sent to them every week for four years straight did start eating more nuts.

Basically the researchers designed a study to test two different Mediterranean diets versus a low fat diet, but ended up studying something very different. In essence, they studied what happens when thousands of people switch from consuming about three tablespoons of olive oil a day (half virgin) to four tablespoons of all virgin, compared to thousands of people who all the sudden go from eating about a half an ounce of nuts a day to a whole ounce, compared to thousands of people who don't make much of a change at all. It may not have been what they were hoping for, but these are important research questions in and of themselves.

With no significant differences in meat and dairy intake, there were no significant differences in saturated fat or cholesterol intake, so no surprise there was no significant differences in their blood cholesterol levels, and so no difference in their subsequent number of heart attacks. In the five or so years the study ran, there were 37 heart attacks in the olive oil group, 31 in the nut group and 38 in the neither group. No significant difference. Same with dying from a heart attack or stroke or from any cause--but, those in the olive oil and especially the nut group had significantly fewer strokes. All three groups were eating stroke-promoting diets; some people in all three groups had strokes after eating these diets for years, and so ideally we'd choose diets that can stop or reverse the disease process, but the diet with added extra virgin olive oil caused about a third fewer strokes, and adding nuts seemed to cut their stroke risk nearly in half. If this worked as well in the general population, in the U.S. alone that would mean preventing 89,000 strokes a year. That's would be like ten strokes an hour around the clock prevented simply by adding half an ounce of nuts to one's daily diet.

Here are some of my previous videos on the Mediterranean diet:

The PREDIMED study got a bad rap because of how it was reported, but it's an extraordinary trial that continues to churn out useful results.

More on nuts in:

But what about nuts and weight gain? See Nuts and Obesity: The Weight of Evidence .

For videos on olive oil, see Extra Virgin Olive Oil vs. Nuts and Olive Oil & Artery Function.

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 / Flickr. This image has been modified.

Original Link