The 3 Vitamins that Prevent Brain Loss

The 3 Vitamins that Prevent Brain Loss.jpeg

By our seventies, one in five of us will suffer from cognitive impairment. Within five years, half of those cognitively impaired will progress to dementia and death. The earlier we can slow or stop this process, the better.

Although an effective treatment for Alzheimer's disease is unavailable, interventions just to control risk factors could prevent millions of cases. An immense effort has been spent on identifying such risk factors for Alzheimer's and developing treatments to reduce them.

In 1990, a small study of 22 Alzheimer's patients reported high concentrations of homocysteine in their blood. The homocysteine story goes back to 1969 when a Harvard pathologist reported two cases of children, one dating back to 1933, whose brains had turned to mush. They both suffered from extremely rare genetic mutations that led to abnormally high levels of homocysteine in their bodies. Is it possible, he asked, that homocysteine could cause brain damage even in people without genetic defects?

Here we are in the 21st century, and homocysteine is considered "a strong, independent risk factor for the development of dementia and Alzheimer's disease." Having a blood level over 14 (µmol/L) may double our risk. In the Framingham Study, researchers estimate that as many as one in six Alzheimer's cases may be attributable to elevated homocysteine in the blood, which is now thought to play a role in brain damage and cognitive and memory decline. Our body can detoxify homocysteine, though, using three vitamins: folate, vitamin B12, and vitamin B6. So why don't we put them to the test? No matter how many studies find an association between high homocysteinea and cognitive decline, dementia, or Alzheimer's disease, a cause-and-effect role can only be confirmed by interventional studies.

Initially, the results were disappointing. Vitamin supplementation did not seem to work, but the studies were tracking neuropsychological assessments, which are more subjective compared to structural neuroimaging--that is, actually seeing what's happening to the brain. A double-blind randomized controlled trial found that homocysteine-lowering by B vitamins can slow the rate of accelerated brain atrophy in people with mild cognitive impairment. As we age, our brains slowly atrophy, but the shrinking is much accelerated in patients suffering from Alzheimer's disease. An intermediate rate of shrinkage is found in people with mild cognitive impairment. The thinking is if we could slow the rate of brain loss, we may be able to slow the conversion to Alzheimer's disease. Researchers tried giving people B vitamins for two years and found it markedly slowed the rate of brain shrinkage. The rate of atrophy in those with high homocysteine levels was cut in half. A simple, safe treatment can slow the accelerated rate of brain loss.

A follow-up study went further by demonstrating that B-vitamin treatment reduces, by as much as seven-fold, the brain atrophy in the regions specifically vulnerable to the Alzheimer's disease process. You can see the amount of brain atrophy over a two-year period in the placebo group versus the B-vitamin group in my Preventing Brain Loss with B Vitamins? video.

The beneficial effect of B vitamins was confined to those with high homocysteine, indicating a relative deficiency in one of those three vitamins. Wouldn't it be better to not become deficient in the first place? Most people get enough B12 and B6. The reason these folks were stuck at a homocysteine of 11 µmoles per liter is that they probably weren't getting enough folate, which is found concentrated in beans and greens. Ninety-six percent of Americans don't even make the minimum recommended amount of dark green leafy vegetables, which is the same pitiful number who don't eat the minimum recommendation for beans.

If we put people on a healthy diet--a plant-based diet--we can drop their homocysteine levels by 20% in just one week, from around 11 mmoles per liter down to 9 mmoles per liter. The fact that they showed rapid and significant homocysteine lowering without any pills or supplements implies that multiple mechanisms may have been at work. The researchers suggest it may be because of the fiber. Every gram of daily fiber consumption may increase folate levels in the blood nearly 2%, perhaps by boosting vitamin production in the colon by all our friendly gut bacteria. It also could be from the decreased methionine intake.

Methionine is where homocysteine comes from. Homocysteine is a breakdown product of methionine, which comes mostly from animal protein. If we give someone bacon and eggs for breakfast and a steak for dinner, we can get spikes of homocysteine levels in the blood. Thus, decreased methionine intake on a plant-based diet may be another factor contributing to lower, safer homocysteine levels.

The irony is that those who eat plant-based diets long-term, not just at a health spa for a week, have terrible homocysteine levels. Meat-eaters are up at 11 µmoles per liter, but vegetarians at nearly 14 µmoles per liter and vegans at 16 µmoles per liter. Why? The vegetarians and vegans were getting more fiber and folate, but not enough vitamin B12. Most vegans were at risk for suffering from hyperhomocysteinaemia (too much homocysteine in the blood) because most vegans in the study were not supplementing with vitamin B12 or eating vitamin B12-fortified foods, which is critical for anyone eating a plant-based diet. If you take vegans and give them B12, their homocysteine levels can drop down below 5. Why not down to just 11? The reason meat-eaters were stuck up at 11 is presumably because they weren't getting enough folate. Once vegans got enough B12, they could finally fully exploit the benefits of their plant-based diets and come out with the lowest levels of all.

This is very similar to the findings in my video Vitamin B12 Necessary for Arterial Health.

For more details on ensuring a regular reliable source of vitamin B12:

There are more benefits to lowering your methionine intake. Check out Methionine Restriction as a Life Extension Strategy and Starving Cancer with Methionine Restriction.

For more on brain health in general, see these 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:

Image Credit: Thomas Hawk / Flickr. This image has been modified.

Original Link

Optimal Bowel Movement Position

Optimal Bowel Movement Position.jpeg

Compared to rural African populations eating traditional plant-based diets, white South Africans and black and white Americans have more than 50 times more heart disease, 10 times more colon cancer, more than 50 times more gallstones and appendicitis, and more than 25 times the rates of "pressure diseases"--diverticulitis, hemorrhoids, varicose veins, and hiatal hernia.

As I discussed in my Should You Sit, Squat, or Lean During a Bowel Movement?, bowel movements should be effortless. When we have to strain at stool, the pressure may balloon out-pouchings from our colon, causing diverticulosis; inflate hemorrhoids around the anus; cause the valves in the veins of our legs to fail, causing varicose veins; and even force part of the stomach up through the diaphragm into our chest cavity, causing a hiatal hernia (as I covered previously). When this was first proposed by Dr. Denis Burkitt, he blamed these conditions on the straining caused by a lack of fiber in the diet. He did, however, acknowledge there were alternative explanations. For example, in rural Africa, they used a traditional squatting position when they defecated, which may have taken off some of the pressure.

For hundreds of thousands of years, everyone used the squatting position, which may help by straightening the "anorectal angle." There's actually a kink at almost a 90-degree angle right at the end of the rectum that helps keep us from pooping our pants when we're just out walking around. That angle only slightly straightens out in a common sitting posture on the toilet. Maximal straightening out of this angle occurs in a squatting posture, potentially permitting smoother defecation. (I remember sitting in geometry class wondering when I'd ever use the stuff I was learning. Little did I know I would one day be calculating anorectal angles with it! Stay in school, kids :)

How did they figure this out? Researchers filled latex tubes with a radiopaque fluid, stuck them up some volunteers, and took X-rays with the hips flexed at various angles. They concluded that flexing the knees towards the chest like one does when squatting may straighten that angle and reduce the amount of pressure needed to empty the rectum. This idea wasn't directly put to the test until 2002, when researchers used defecography (which are X-rays taken while the person is defecating) on subjects in sitting and squatting positions. Indeed, squatting increased the anorectal angle from around 90 degrees all the way up to about 140.

So should we all get one of those little stools for our stools, like the Squatty Potty that you put in front of your toilet to step on? No, they don't seem to work. Researchers tried adding a footstool to decrease sitting height, but it didn't seem to significantly affect the time it took to empty one's bowels or decrease the difficulty of defecating. They tried even higher footstools, but people complained of extreme discomfort using them. Nothing seemed to compare with actual squatting, which may give the maximum advantage. However, in developed nations, it may not be convenient. But, we can achieve a similar effect by leaning forward as we sit, with our hands on or near the floor. The researchers advise all sufferers from constipation to adopt this forward-leaning position when defecating, as the weight of our torso pressing against the thighs may put an extra squeeze on our colons.

Instead of finding ways to add more pressure, why not get to the root of the problem? "The fundamental cause of straining is the effort required to pass unnaturally firm stools." By manipulating the anorectal angle through squatting or leaning, we can more easily pass unnaturally firm stools. But why not just treat the cause and eat enough fiber-containing whole plant foods to create stools so large and soft that you could pass them effortlessly at any angle?

Famed cardiologist Dr. Joel Kahn once said that you know you know you're eating a plant-based diet when "you take longer to pee than to poop."

In all seriousness, even squatting does not significantly decrease the pressure gradient that may cause a hiatal hernia. It does not prevent the pressure transmission down into the legs that may cause varicose veins. And this is not just a cosmetic issue. Protracted straining can cause heart rhythm disturbances and reduction in blood flow to the heart and brain, resulting in defecation-related fainting and death. Just 15 seconds of straining can temporarily cut blood flow to the brain by 21% and blood flow to the heart by nearly one-half, thereby providing a mechanism for the well-known "bed pan death" syndrome. If you think you have to strain a lot while sitting, try having a bowel movement on your back. Bearing down for just a few seconds can send our blood pressure up to nearly 170 over 110, which may help account for the notorious frequency of sudden and unexpected deaths of patients while using bed pans in hospitals. Hopefully, if we eat healthy enough, we won't end up in the hospital to begin with.

Wondering How Many Bowel Movements Should You Have Every Day? Watch the video to find out!

The "forcing part of your stomach up through the diaphragm into our chest cavity" phenomenon is covered in my video Diet and Hiatal Hernia. The "ballooning of out-pouchings from our colon" is called diverticulosis. There's a video I did about 6 years ago (Diverticulosis & Nuts), but I have some new and improved ones available: Diverticulosis: When Our Most Common Gut Disorder Hardly Existed and Does Fiber Really Prevent Diverticulosis?

More on that extraordinary African data here:

So excited to be able to slip in a plug for Dr. Kahn's work. His brand of "interpreventional cardiology" can be found at www.drjoelkahn.com.

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. This image has been modified.

Original Link

Optimal Bowel Movement Position

Optimal Bowel Movement Position.jpeg

Compared to rural African populations eating traditional plant-based diets, white South Africans and black and white Americans have more than 50 times more heart disease, 10 times more colon cancer, more than 50 times more gallstones and appendicitis, and more than 25 times the rates of "pressure diseases"--diverticulitis, hemorrhoids, varicose veins, and hiatal hernia.

As I discussed in my Should You Sit, Squat, or Lean During a Bowel Movement?, bowel movements should be effortless. When we have to strain at stool, the pressure may balloon out-pouchings from our colon, causing diverticulosis; inflate hemorrhoids around the anus; cause the valves in the veins of our legs to fail, causing varicose veins; and even force part of the stomach up through the diaphragm into our chest cavity, causing a hiatal hernia (as I covered previously). When this was first proposed by Dr. Denis Burkitt, he blamed these conditions on the straining caused by a lack of fiber in the diet. He did, however, acknowledge there were alternative explanations. For example, in rural Africa, they used a traditional squatting position when they defecated, which may have taken off some of the pressure.

For hundreds of thousands of years, everyone used the squatting position, which may help by straightening the "anorectal angle." There's actually a kink at almost a 90-degree angle right at the end of the rectum that helps keep us from pooping our pants when we're just out walking around. That angle only slightly straightens out in a common sitting posture on the toilet. Maximal straightening out of this angle occurs in a squatting posture, potentially permitting smoother defecation. (I remember sitting in geometry class wondering when I'd ever use the stuff I was learning. Little did I know I would one day be calculating anorectal angles with it! Stay in school, kids :)

How did they figure this out? Researchers filled latex tubes with a radiopaque fluid, stuck them up some volunteers, and took X-rays with the hips flexed at various angles. They concluded that flexing the knees towards the chest like one does when squatting may straighten that angle and reduce the amount of pressure needed to empty the rectum. This idea wasn't directly put to the test until 2002, when researchers used defecography (which are X-rays taken while the person is defecating) on subjects in sitting and squatting positions. Indeed, squatting increased the anorectal angle from around 90 degrees all the way up to about 140.

So should we all get one of those little stools for our stools, like the Squatty Potty that you put in front of your toilet to step on? No, they don't seem to work. Researchers tried adding a footstool to decrease sitting height, but it didn't seem to significantly affect the time it took to empty one's bowels or decrease the difficulty of defecating. They tried even higher footstools, but people complained of extreme discomfort using them. Nothing seemed to compare with actual squatting, which may give the maximum advantage. However, in developed nations, it may not be convenient. But, we can achieve a similar effect by leaning forward as we sit, with our hands on or near the floor. The researchers advise all sufferers from constipation to adopt this forward-leaning position when defecating, as the weight of our torso pressing against the thighs may put an extra squeeze on our colons.

Instead of finding ways to add more pressure, why not get to the root of the problem? "The fundamental cause of straining is the effort required to pass unnaturally firm stools." By manipulating the anorectal angle through squatting or leaning, we can more easily pass unnaturally firm stools. But why not just treat the cause and eat enough fiber-containing whole plant foods to create stools so large and soft that you could pass them effortlessly at any angle?

Famed cardiologist Dr. Joel Kahn once said that you know you know you're eating a plant-based diet when "you take longer to pee than to poop."

In all seriousness, even squatting does not significantly decrease the pressure gradient that may cause a hiatal hernia. It does not prevent the pressure transmission down into the legs that may cause varicose veins. And this is not just a cosmetic issue. Protracted straining can cause heart rhythm disturbances and reduction in blood flow to the heart and brain, resulting in defecation-related fainting and death. Just 15 seconds of straining can temporarily cut blood flow to the brain by 21% and blood flow to the heart by nearly one-half, thereby providing a mechanism for the well-known "bed pan death" syndrome. If you think you have to strain a lot while sitting, try having a bowel movement on your back. Bearing down for just a few seconds can send our blood pressure up to nearly 170 over 110, which may help account for the notorious frequency of sudden and unexpected deaths of patients while using bed pans in hospitals. Hopefully, if we eat healthy enough, we won't end up in the hospital to begin with.

Wondering How Many Bowel Movements Should You Have Every Day? Watch the video to find out!

The "forcing part of your stomach up through the diaphragm into our chest cavity" phenomenon is covered in my video Diet and Hiatal Hernia. The "ballooning of out-pouchings from our colon" is called diverticulosis. There's a video I did about 6 years ago (Diverticulosis & Nuts), but I have some new and improved ones available: Diverticulosis: When Our Most Common Gut Disorder Hardly Existed and Does Fiber Really Prevent Diverticulosis?

More on that extraordinary African data here:

So excited to be able to slip in a plug for Dr. Kahn's work. His brand of "interpreventional cardiology" can be found at www.drjoelkahn.com.

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. This image has been modified.

Original Link

Optimal Bowel Movement Frequency

Optimal Bowel Movement Frequency.jpeg

Lasting for 3,000 years, ancient Egypt was one of the greatest ancient civilizations--with a vastly underestimated knowledge of medicine. They even had medical subspecialties. The pharaohs, for example, had access to dedicated physicians to be "guardian[s] of the royal bowel movement," a title alternately translated from the hieroglyphics to mean "Shepherd of the Anus." How's that for a resume builder?

Today, the primacy of the bowel movement's importance continues. Some have called for bowel habits to be considered a vital sign on how the body is functioning, along with heart rate, blood pressure, and breathing rate. Medical professionals may not particularly relish hearing all about their patients' bowel movements, but it is a vital function that nurses and doctors need to assess.

Surprisingly, the colon has remained relatively unexplored territory, one of the body's final frontiers. For example, current concepts of what "normal" stools are emanated primarily from the records of 12 consecutive bowel movements in 27 healthy subjects from the United Kingdom, who boldly went where no one had gone before. Those must have been some really detailed records.

It's important to define what's normal. When it comes to frequency, for example, we can't define concepts like constipation or diarrhea unless we know what's normal. Standard physiology textbooks may not be helpful in this regard. One text implies that anything from one bowel movement every few weeks or months to 24 in just one day can be regarded as normal. Once every few months is normal?

Out of all of our bodily functions, we may know the least about defecation. Can't we just ask people? It turns out people tend to exaggerate. There's a discrepancy between what people report and what researchers find when they record bowel habits directly. It wasn't until 2010 when we got the first serious look. In my video, How Many Bowel Movement's Should You Have Everyday? you'll see the study that found that normal stool frequency was between three per week and three per day, based on the fact that that's where 98% of people tended to fall. But normal doesn't necessarily mean optimal.

Having a "normal" salt intake can lead to a "normal" blood pressure, which can help us to die from all the "normal" causes like heart attacks and strokes. Having a normal cholesterol level in a society where it's normal to drop dead of heart disease--our number-one killer--is not necessarily a good thing. Indeed, significant proportions of people with "normal bowel function" reported urgency, straining, and incomplete defecation, leading the researchers of the 2010 study to conclude that these kinds of things must be normal. Normal, maybe, if we're eating a fiber-deficient diet, but not normal for our species. Defecation should not be a painful exercise. This is readily demonstrable. For example, the majority of rural Africans eating their traditional fiber-rich, plant-based diets can usually pass without straining a stool specimen on demand. The rectum may need to accumulate 4 or 5 ounces of fecal matter before the defecation reflex is fully initiated, so if we don't even build up that much over the day, we'd have to strain to prime the rectal pump.

Hippocrates thought bowel movements should ideally be two or three times a day, which is what we see in populations on traditional plant-based diets. These traditional diets have the kind of fiber intakes we see in our fellow Great Apes and may be more representative of the type of diets we evolved eating for millions of years. It seems somewhat optimistic, though, to expect the average American to adopt a rural African diet. We can, however, eat more plant-based and bulk up enough to take the Hippocratic oath to go two or three times a day.

There's no need to obsess about it. In fact, there's actually a "bowel obsession syndrome" characterized in part by "ideational rambling over bowel habits." But three times a day makes sense. We have what's called a gastrocolic reflex, which consists of a prompt activation of muscular waves in our colon within 1 to 3 minutes of the ingestion of the first mouthfuls of food to make room for the meal. Even just talking about food can cause our brains to increase colon activity. This suggests the body figured that one meal should be about enough to fill us up down there. So maybe we should eat enough unprocessed plant foods to get up to three a day--a movement for every meal.

I know people are suckers for poop videos--I'm so excited to finally be getting these up! There actually is a recent one--Diet and Hiatal Hernia--that talks about the consequences of straining on stool. Hernias are better than Bed Pan Death Syndrome, though, which is what I talk about in in my video, Should You Sit, Squat, or Lean During a Bowel Movement?

Here are some older videos on bowel health:

For more on this concept of how having "normal" health parameters in a society where it's normal to drop dead of heart attacks and other such preventable fates, see my video When Low Risk Means High Risk.

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. This image has been modified.

Original Link

Optimal Bowel Movement Frequency

Optimal Bowel Movement Frequency.jpeg

Lasting for 3,000 years, ancient Egypt was one of the greatest ancient civilizations--with a vastly underestimated knowledge of medicine. They even had medical subspecialties. The pharaohs, for example, had access to dedicated physicians to be "guardian[s] of the royal bowel movement," a title alternately translated from the hieroglyphics to mean "Shepherd of the Anus." How's that for a resume builder?

Today, the primacy of the bowel movement's importance continues. Some have called for bowel habits to be considered a vital sign on how the body is functioning, along with heart rate, blood pressure, and breathing rate. Medical professionals may not particularly relish hearing all about their patients' bowel movements, but it is a vital function that nurses and doctors need to assess.

Surprisingly, the colon has remained relatively unexplored territory, one of the body's final frontiers. For example, current concepts of what "normal" stools are emanated primarily from the records of 12 consecutive bowel movements in 27 healthy subjects from the United Kingdom, who boldly went where no one had gone before. Those must have been some really detailed records.

It's important to define what's normal. When it comes to frequency, for example, we can't define concepts like constipation or diarrhea unless we know what's normal. Standard physiology textbooks may not be helpful in this regard. One text implies that anything from one bowel movement every few weeks or months to 24 in just one day can be regarded as normal. Once every few months is normal?

Out of all of our bodily functions, we may know the least about defecation. Can't we just ask people? It turns out people tend to exaggerate. There's a discrepancy between what people report and what researchers find when they record bowel habits directly. It wasn't until 2010 when we got the first serious look. In my video, How Many Bowel Movement's Should You Have Everyday? you'll see the study that found that normal stool frequency was between three per week and three per day, based on the fact that that's where 98% of people tended to fall. But normal doesn't necessarily mean optimal.

Having a "normal" salt intake can lead to a "normal" blood pressure, which can help us to die from all the "normal" causes like heart attacks and strokes. Having a normal cholesterol level in a society where it's normal to drop dead of heart disease--our number-one killer--is not necessarily a good thing. Indeed, significant proportions of people with "normal bowel function" reported urgency, straining, and incomplete defecation, leading the researchers of the 2010 study to conclude that these kinds of things must be normal. Normal, maybe, if we're eating a fiber-deficient diet, but not normal for our species. Defecation should not be a painful exercise. This is readily demonstrable. For example, the majority of rural Africans eating their traditional fiber-rich, plant-based diets can usually pass without straining a stool specimen on demand. The rectum may need to accumulate 4 or 5 ounces of fecal matter before the defecation reflex is fully initiated, so if we don't even build up that much over the day, we'd have to strain to prime the rectal pump.

Hippocrates thought bowel movements should ideally be two or three times a day, which is what we see in populations on traditional plant-based diets. These traditional diets have the kind of fiber intakes we see in our fellow Great Apes and may be more representative of the type of diets we evolved eating for millions of years. It seems somewhat optimistic, though, to expect the average American to adopt a rural African diet. We can, however, eat more plant-based and bulk up enough to take the Hippocratic oath to go two or three times a day.

There's no need to obsess about it. In fact, there's actually a "bowel obsession syndrome" characterized in part by "ideational rambling over bowel habits." But three times a day makes sense. We have what's called a gastrocolic reflex, which consists of a prompt activation of muscular waves in our colon within 1 to 3 minutes of the ingestion of the first mouthfuls of food to make room for the meal. Even just talking about food can cause our brains to increase colon activity. This suggests the body figured that one meal should be about enough to fill us up down there. So maybe we should eat enough unprocessed plant foods to get up to three a day--a movement for every meal.

I know people are suckers for poop videos--I'm so excited to finally be getting these up! There actually is a recent one--Diet and Hiatal Hernia--that talks about the consequences of straining on stool. Hernias are better than Bed Pan Death Syndrome, though, which is what I talk about in in my video, Should You Sit, Squat, or Lean During a Bowel Movement?

Here are some older videos on bowel health:

For more on this concept of how having "normal" health parameters in a society where it's normal to drop dead of heart attacks and other such preventable fates, see my video When Low Risk Means High Risk.

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. This image has been modified.

Original Link

Diet and Hiatal Hernia

Diet and Hiatal Hernia.jpeg

In terms of preventing acid reflux heartburn, high-fat meals cause dramatically more acid exposure in the esophagus in the hours after a meal. I talked about this in Diet and GERD Acid Reflux Heartburn. High fiber intake decreases the risk, but why? One typically thinks of fiber as helping out much lower in the digestive tract.

A systematic review and meta-analysis published in 2013 found a highly significant protective association between esophageal adenocarcinoma and dietary fiber intake, suggesting that individuals with the highest fiber intakes have an approximately 30% lower risk of cancer. This could be because of the phytates in high-fiber foods slowing cancer growth, fiber's anti-inflammatory effects, or even fiber removing carcinogens. But those are all generic anti-cancer effects of whole plant foods. Specific to this type of acid irritation-induced esophageal cancer, fiber may reduce the risk of reflux in the first place. But how?

As you can see in my video, Diet and Hiatal Hernia, hiatus hernia occurs when part of the stomach is pushed up through the diaphragm into the chest cavity, which makes it easy for acid to reflux into the esophagus and throat. Hiatus hernia affects more than 1 in 5 American adults. In contrast, in rural African communities eating their traditional plant-based diets, the risk wasn't 1 in 5; it was closer to 1 in 1,000--almost unheard of. Hiatus hernia is almost peculiar to those who consume western-type diets. Why are plant-based populations protected? Perhaps because they pass such large, soft stools, three or four times the volume as Westerners.

What does the size and consistency of one's bowel movement have to do with hiatal hernia? A simple model may be helpful in illustrating the mechanism that produces upward herniation of the stomach through the hole (called the esophageal hiatus) in the diaphragm, which separates the abdomen from the chest. If a ball with a hole in its wall is filled with water and then squeezed, the water is pushed out through the hole. If we liken the abdominal cavity to the ball, the esophageal hiatus in the diaphragm corresponds with the hole in the ball. Abdominal straining during movement of firm feces corresponds to squeezing the ball and may result in the gradual expulsion of the upper end of the stomach from the abdominal cavity up into the chest. It's like when we squeeze a stress ball. Straining at stool raises pressures inside our abdominal cavity more than almost any other factor.

In effect, straining at stool puts the squeeze on our abdomen and may herniate part of our stomach up. "Consistent with this concept is the observation that in Africans the lower esophageal sphincter is entirely subdiaphragmatic, whereas it usually straddles the diaphragm in Westerners and is above the diaphragm in the presence of hiatus hernia."

This same abdominal pressure from straining may cause a number of other problems, too. Straining can cause herniations in the wall of the colon itself, known as diverticulosis. That same pressure can backup blood flow in the veins around the anus, causing hemorrhoids, and also push blood flow back into the legs, resulting in varicose veins.

Hiatal hernia is not the only condition that high-fiber diets may protect against. See:

I also have a load of other bowel movement 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:

Image Credit: Sally Plank. This image has been modified.

Original Link

Diet and Hiatal Hernia

Diet and Hiatal Hernia.jpeg

In terms of preventing acid reflux heartburn, high-fat meals cause dramatically more acid exposure in the esophagus in the hours after a meal. I talked about this in Diet and GERD Acid Reflux Heartburn. High fiber intake decreases the risk, but why? One typically thinks of fiber as helping out much lower in the digestive tract.

A systematic review and meta-analysis published in 2013 found a highly significant protective association between esophageal adenocarcinoma and dietary fiber intake, suggesting that individuals with the highest fiber intakes have an approximately 30% lower risk of cancer. This could be because of the phytates in high-fiber foods slowing cancer growth, fiber's anti-inflammatory effects, or even fiber removing carcinogens. But those are all generic anti-cancer effects of whole plant foods. Specific to this type of acid irritation-induced esophageal cancer, fiber may reduce the risk of reflux in the first place. But how?

As you can see in my video, Diet and Hiatal Hernia, hiatus hernia occurs when part of the stomach is pushed up through the diaphragm into the chest cavity, which makes it easy for acid to reflux into the esophagus and throat. Hiatus hernia affects more than 1 in 5 American adults. In contrast, in rural African communities eating their traditional plant-based diets, the risk wasn't 1 in 5; it was closer to 1 in 1,000--almost unheard of. Hiatus hernia is almost peculiar to those who consume western-type diets. Why are plant-based populations protected? Perhaps because they pass such large, soft stools, three or four times the volume as Westerners.

What does the size and consistency of one's bowel movement have to do with hiatal hernia? A simple model may be helpful in illustrating the mechanism that produces upward herniation of the stomach through the hole (called the esophageal hiatus) in the diaphragm, which separates the abdomen from the chest. If a ball with a hole in its wall is filled with water and then squeezed, the water is pushed out through the hole. If we liken the abdominal cavity to the ball, the esophageal hiatus in the diaphragm corresponds with the hole in the ball. Abdominal straining during movement of firm feces corresponds to squeezing the ball and may result in the gradual expulsion of the upper end of the stomach from the abdominal cavity up into the chest. It's like when we squeeze a stress ball. Straining at stool raises pressures inside our abdominal cavity more than almost any other factor.

In effect, straining at stool puts the squeeze on our abdomen and may herniate part of our stomach up. "Consistent with this concept is the observation that in Africans the lower esophageal sphincter is entirely subdiaphragmatic, whereas it usually straddles the diaphragm in Westerners and is above the diaphragm in the presence of hiatus hernia."

This same abdominal pressure from straining may cause a number of other problems, too. Straining can cause herniations in the wall of the colon itself, known as diverticulosis. That same pressure can backup blood flow in the veins around the anus, causing hemorrhoids, and also push blood flow back into the legs, resulting in varicose veins.

Hiatal hernia is not the only condition that high-fiber diets may protect against. See:

I also have a load of other bowel movement 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:

Image Credit: Sally Plank. This image has been modified.

Original Link

Solving a Colon Cancer Mystery

Solving-a-Colon-Cancer-Mystery.jpeg

Colorectal cancer is the second leading cause of cancer death in the United States, after lung cancer. The rates of lung cancer around the world vary by a factor of 10. If there was nothing we could do to prevent lung cancer--if it just happened at random--we'd assume that the rates everywhere would be about the same. But since there's such a huge variation in rates, it seems like there's probably some external cause. Indeed, we now know smoking is responsible for 90% of lung cancer cases. If we don't want to die of the number-one cancer killer, we can throw 90% of our risk out the window just by not smoking.

There's an even bigger variation around the world for colon cancer. As discussed in Solving a Colon Cancer Mystery, it appears colon cancer doesn't just happen, something makes it happen. If our lungs can get filled with carcinogens from smoke, maybe our colons are getting filled with carcinogens from food. Researchers from the University of Pittsburgh and the University of Limpopo sought to answer the question, "Why do African Americans get more colon cancer than native Africans?" Why study Africans? Because colon cancer is extremely rare in native African populations, more than 50 times lower than rates of Americans, white or black.

It's the fiber, right? The first to describe the low rates of colon cancer in native Africans, Dr. Denis Burkitt ascribed it to their staple diet traditionally high in whole grains and, consequently, high in fiber content. We seem to get a 10% reduction in risk for every 10 grams of fiber we eat a day. If it's a 1% drop for each gram, and native Africans are eating upwards of 100 grams a day, it could explain why colon cancer is so rare in sub-Saharan Africa.

Wait a second. The modern African diet is highly processed and low in fiber, yet there has been no dramatic increase in colon cancer incidence. Their diet today has such a low fiber content because most populations now depend on commercially produced refined cornmeal. We're not just talking low fiber intake, we're talking United States of America low, down around half the recommended daily allowance. Yet colon disease in Africa is still about 50 times less common than in the United States.

Maybe it's because native Africans are thinner and exercise more? No, they're not, and no, they don't. If anything, their physical activity levels may now be even lower than Americans'. So if they're sedentary like us and eating mostly refined carbs, few whole plant foods, and little fiber like us, why do they have 50 times less colon cancer than we do? There is one difference. The diet of both African Americans and Caucasian Americans is rich in meat, whereas the native Africans' diet is so low in meat and saturated fat they have total cholesterol levels averaging 139 mg/dL, compared to over 200 mg/dL in the United States.

They may not get a lot of fiber anymore, but they continue to minimize meat and animal fat consumption, which supports other evidence indicating the most powerful determinants of colon cancer risk may be meat and animal fat intake levels. So why do Americans get more colon cancer than Africans? Maybe the rarity of colon cancer in Africans is not the fiber, but their low animal product consumption.

Although opinions diverge as to whether cholesterol, animal fat, or animal protein is most responsible for the increased colon cancer risk, given that all three have been proven to have carcinogenic properties, it may not really matter which component is worse, as a diet laden in one is usually laden in the others.

I've previously suggested phytates may play a critical role as well (Phytates for the Prevention of Cancer). Resistant starch may be another player. Since native Africans cool down their corn porridge, some of the starch can crystallize and effectively turn into fiber. (This is the same reason pasta salad and potato salad better feed our gut bacteria than starchy dishes served hot.) I touch on it briefly in Bowel Wars: Hydrogen Sulfide vs. Butyrate. Resistant starch may also help explain Beans and the Second Meal Effect. And for even more, see Resistant Starch & Colon Cancer and Getting Starch to Take the Path of Most Resistance.

Fiber may just be a marker for healthier eating since it's only found concentrated in unprocessed plant foods. So the apparent protection afforded by high fiber diets may derive from whole food plant-based nutrition rather than the fiber itself (so fiber supplements would not be expected to provide the same protection). Here are some videos that found protective associations with higher fiber diets:

What might be in animal products that can raise cancer risk? Here's a smattering:

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: Department of Foreign Affairs and Trade / Flickr. This image has been modified.

Original Link

Solving a Colon Cancer Mystery

Solving-a-Colon-Cancer-Mystery.jpeg

Colorectal cancer is the second leading cause of cancer death in the United States, after lung cancer. The rates of lung cancer around the world vary by a factor of 10. If there was nothing we could do to prevent lung cancer--if it just happened at random--we'd assume that the rates everywhere would be about the same. But since there's such a huge variation in rates, it seems like there's probably some external cause. Indeed, we now know smoking is responsible for 90% of lung cancer cases. If we don't want to die of the number-one cancer killer, we can throw 90% of our risk out the window just by not smoking.

There's an even bigger variation around the world for colon cancer. As discussed in Solving a Colon Cancer Mystery, it appears colon cancer doesn't just happen, something makes it happen. If our lungs can get filled with carcinogens from smoke, maybe our colons are getting filled with carcinogens from food. Researchers from the University of Pittsburgh and the University of Limpopo sought to answer the question, "Why do African Americans get more colon cancer than native Africans?" Why study Africans? Because colon cancer is extremely rare in native African populations, more than 50 times lower than rates of Americans, white or black.

It's the fiber, right? The first to describe the low rates of colon cancer in native Africans, Dr. Denis Burkitt ascribed it to their staple diet traditionally high in whole grains and, consequently, high in fiber content. We seem to get a 10% reduction in risk for every 10 grams of fiber we eat a day. If it's a 1% drop for each gram, and native Africans are eating upwards of 100 grams a day, it could explain why colon cancer is so rare in sub-Saharan Africa.

Wait a second. The modern African diet is highly processed and low in fiber, yet there has been no dramatic increase in colon cancer incidence. Their diet today has such a low fiber content because most populations now depend on commercially produced refined cornmeal. We're not just talking low fiber intake, we're talking United States of America low, down around half the recommended daily allowance. Yet colon disease in Africa is still about 50 times less common than in the United States.

Maybe it's because native Africans are thinner and exercise more? No, they're not, and no, they don't. If anything, their physical activity levels may now be even lower than Americans'. So if they're sedentary like us and eating mostly refined carbs, few whole plant foods, and little fiber like us, why do they have 50 times less colon cancer than we do? There is one difference. The diet of both African Americans and Caucasian Americans is rich in meat, whereas the native Africans' diet is so low in meat and saturated fat they have total cholesterol levels averaging 139 mg/dL, compared to over 200 mg/dL in the United States.

They may not get a lot of fiber anymore, but they continue to minimize meat and animal fat consumption, which supports other evidence indicating the most powerful determinants of colon cancer risk may be meat and animal fat intake levels. So why do Americans get more colon cancer than Africans? Maybe the rarity of colon cancer in Africans is not the fiber, but their low animal product consumption.

Although opinions diverge as to whether cholesterol, animal fat, or animal protein is most responsible for the increased colon cancer risk, given that all three have been proven to have carcinogenic properties, it may not really matter which component is worse, as a diet laden in one is usually laden in the others.

I've previously suggested phytates may play a critical role as well (Phytates for the Prevention of Cancer). Resistant starch may be another player. Since native Africans cool down their corn porridge, some of the starch can crystallize and effectively turn into fiber. (This is the same reason pasta salad and potato salad better feed our gut bacteria than starchy dishes served hot.) I touch on it briefly in Bowel Wars: Hydrogen Sulfide vs. Butyrate. Resistant starch may also help explain Beans and the Second Meal Effect. And for even more, see Resistant Starch & Colon Cancer and Getting Starch to Take the Path of Most Resistance.

Fiber may just be a marker for healthier eating since it's only found concentrated in unprocessed plant foods. So the apparent protection afforded by high fiber diets may derive from whole food plant-based nutrition rather than the fiber itself (so fiber supplements would not be expected to provide the same protection). Here are some videos that found protective associations with higher fiber diets:

What might be in animal products that can raise cancer risk? Here's a smattering:

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: Department of Foreign Affairs and Trade / Flickr. This image has been modified.

Original Link

Plant versus Animal Iron

Plant versus Animal Iron.jpeg

It is commonly thought that those who eat plant-based diets may be more prone to iron deficiency, but it turns out that they're no more likely to suffer from iron deficiency anemia than anybody else. This may be because not only do those eating meat-free diets tend to get more fiber, magnesium, and vitamins like A, C, and E, but they also get more iron.

The iron found predominantly in plants is non-heme iron, which isn't absorbed as well as the heme iron found in blood and muscle, but this may be a good thing. As seen in my video, The Safety of Heme vs. Non-Heme Iron, avoidance of heme iron may be one of the key elements of plant-based protection against metabolic syndrome, and may also be beneficial in lowering the risk from other chronic diseases such as heart disease.

The data linking coronary heart disease and the intake of iron, in general, has been mixed. This inconsistency of evidence may be because of where the iron comes from. The majority of total dietary iron is non-heme iron, coming mostly from plants. So, total iron intake is associated with lower heart disease risk, but iron intake from meat is associated with significantly higher risk for heart disease. This is thought to be because iron can act as a pro-oxidant, contributing to the development of atherosclerosis by oxidizing cholesterol with free radicals. The risk has been quantified as a 27% increase in coronary heart disease risk for every 1 milligram of heme iron consumed daily.

The same has been found for stroke risk. The studies on iron intake and stroke have had conflicting results, but that may be because they had never separated out heme iron from non-heme iron... until now. Researchers found that the intake of meat (heme) iron, but not plant (non-heme) iron, was associated with an increased risk of stroke.

The researchers also found that higher intake of heme iron--but not total or plant (non-heme) iron--was significantly associated with greater risk for type 2 diabetes. There may be a 16% increase in risk for type 2 diabetes for every 1 milligram of heme iron consumed daily.

The same has also been found for cancer, with up to 12% increased risk for every milligram of daily heme iron exposure. In fact, we can actually tell how much meat someone is eating by looking at their tumors. To characterize the mechanisms underlying meat-related lung cancer development, researchers asked lung cancer patients how much meat they ate and examined the gene expression patterns in their tumors. They identified a signature pattern of heme-related gene expression. Although they looked specifically at lung cancer, they expect these meat-related gene expression changes may occur in other cancers as well.

We do need to get enough iron, but only about 3% of premenopausal white women have iron deficiency anemia these days. However, the rates are worse in African and Mexican Americans. Taking into account our leading killers--heart disease, cancer, and diabetes--the healthiest source of iron appears to be non-heme iron, found naturally in abundance in whole grains, beans, split peas, chickpeas, lentils, dark green leafy vegetables, dried fruits, nuts, and seeds.

But how much money can be made on beans, though? The processed food industry came up with a blood-based crisp bread, made out of rye flour and blood from cattle and pigs, which is one of the most concentrated sources of heme iron, about two-thirds more than blood from chickens. If blood-based crackers don't sound particularly appetizing, you can always snack on cow blood cookies. And there are always blood-filled biscuits, whose filling has been described as "a dark-colored, chocolate flavored paste with a very pleasant taste." (It's dark-colored because spray-dried pig blood can have a darkening effect on the food product's color.) The worry is not the color or taste, it's the heme iron, which, because of its potential cancer risk, is not considered safe to add to foods intended for the general population.

Previously, I've touched on the double-edged iron sword in Risk Associated With Iron Supplements and Phytates for the Prevention of Cancer. It may also help answer Why Was Heart Disease Rare in the Mediterranean?

Those eating plant-based diets get more of most nutrients since whole plant foods are so nutrient dense. See Nutrient-Dense Approach to Weight Management.

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