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

How to Prevent Ulcerative Colitis with Diet

Preventing Ulcerative Colitis with Diet.jpg

What has driven the dramatic increase in prevalence of the inflammatory bowel disease Crohn's disease in societies that rapidly westernized--a disease practically unknown just a century ago? What has changed in our internal and external environment that has led to the appearance of this horrible disease?

Japan suffered one of the most dramatic increases, and out of all the changing dietary components, animal protein appeared to be the strongest factor. There was an exponential increase in newly diagnosed Crohn's patients and daily animal protein intake, whereas the greater the vegetable protein, the fewer the cases of Crohn's, which is consistent with data showing a more plant-based diet may be successful in both preventing and treating Crohn's disease (See Preventing Crohn's Disease With Diet and Dietary Treatment of Crohn's Disease). But what about other inflammatory bowel diseases?

In the largest study of its kind, shown in my video Preventing Ulcerative Colitis with Diet, 60,000 people were followed for more than a decade. Researchers found that high total protein intake--specifically animal protein--was associated with a significantly increased risk of the other big inflammatory bowel disease, ulcerative colitis. It wasn't just protein in general, but the "association between high protein intake and inflammatory bowel disease risk was restricted to animal protein."Since World War II, animal protein intake has increased not only in Japan but also in all developed countries. This increase in animal protein consumption is thought to explain some of the increased incidence of inflammatory bowel disease in the second half of the 20th century.

Other studies found this as well, but why? What's the difference between animal protein and plant protein? Animal proteins tend to have more sulfur containing amino acids like methionine, which bacteria in our gut can turn into the toxic rotten egg smell gas, hydrogen sulfide. Emerging evidence suggests that sulfur compounds may play a role in the development of ulcerative colitis, a chronic inflammatory disease of the colon and rectum characterized by bloody diarrhea.

The first hint as to the importance of our gut flora was in the 1970's when "analysis of stools showed that their bulk was made up of mostly bacteria, not undigested material." We're pushing out trillions of bacteria a day and they just keep multiplying and multiplying. They do wonderful things for us like create the protective compound, butyrate, from the fiber we eat, but unfortunately, the bacteria may also elaborate toxic products from food residues such as hydrogen sulfide "in response to a high-meat diet."

Hydrogen sulfide is a bacterially derived cell poison that has been implicated in ulcerative colitis. We had always assumed that sulfide generation in the colon is driven by dietary components such as sulfur-containing amino acids, but we didn't know for sure until a study from Cambridge was published. Researchers had folks eat five different diets each with escalating meat contents from vegetarian all the way up to a steak each day. They found that the more meat one ate, the more sulfide; ten times more meat meant ten times more sulfide. They concluded that "dietary protein from meat is an important substrate for sulfide generation by bacteria in the human large intestine."

Hydrogen sulfide can then act as a free radical and damage our DNA at concentrations way below what our poor colon lining is exposed to on a routine basis, which may help explain why diets higher in meat and lower in fiber may produce so-called "fecal water" that causes about twice as much DNA damage. Fecal water is like when researchers make a tea from someone's stool.

The biology of sulfur in the human gut has escaped serious attention until recently. Previously it was just thought of as the rotten egg smell in malodorous gas, but the increase in sulfur compounds in response to a supplement of animal protein is not only of interest in the field of flatology--that is, the formal study of farts--but may also be of importance in the development of ulcerative colitis.

I have several videos on our microbiome, including:

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

Original Link

How to Prevent Ulcerative Colitis with Diet

Preventing Ulcerative Colitis with Diet.jpg

What has driven the dramatic increase in prevalence of the inflammatory bowel disease Crohn's disease in societies that rapidly westernized--a disease practically unknown just a century ago? What has changed in our internal and external environment that has led to the appearance of this horrible disease?

Japan suffered one of the most dramatic increases, and out of all the changing dietary components, animal protein appeared to be the strongest factor. There was an exponential increase in newly diagnosed Crohn's patients and daily animal protein intake, whereas the greater the vegetable protein, the fewer the cases of Crohn's, which is consistent with data showing a more plant-based diet may be successful in both preventing and treating Crohn's disease (See Preventing Crohn's Disease With Diet and Dietary Treatment of Crohn's Disease). But what about other inflammatory bowel diseases?

In the largest study of its kind, shown in my video Preventing Ulcerative Colitis with Diet, 60,000 people were followed for more than a decade. Researchers found that high total protein intake--specifically animal protein--was associated with a significantly increased risk of the other big inflammatory bowel disease, ulcerative colitis. It wasn't just protein in general, but the "association between high protein intake and inflammatory bowel disease risk was restricted to animal protein."Since World War II, animal protein intake has increased not only in Japan but also in all developed countries. This increase in animal protein consumption is thought to explain some of the increased incidence of inflammatory bowel disease in the second half of the 20th century.

Other studies found this as well, but why? What's the difference between animal protein and plant protein? Animal proteins tend to have more sulfur containing amino acids like methionine, which bacteria in our gut can turn into the toxic rotten egg smell gas, hydrogen sulfide. Emerging evidence suggests that sulfur compounds may play a role in the development of ulcerative colitis, a chronic inflammatory disease of the colon and rectum characterized by bloody diarrhea.

The first hint as to the importance of our gut flora was in the 1970's when "analysis of stools showed that their bulk was made up of mostly bacteria, not undigested material." We're pushing out trillions of bacteria a day and they just keep multiplying and multiplying. They do wonderful things for us like create the protective compound, butyrate, from the fiber we eat, but unfortunately, the bacteria may also elaborate toxic products from food residues such as hydrogen sulfide "in response to a high-meat diet."

Hydrogen sulfide is a bacterially derived cell poison that has been implicated in ulcerative colitis. We had always assumed that sulfide generation in the colon is driven by dietary components such as sulfur-containing amino acids, but we didn't know for sure until a study from Cambridge was published. Researchers had folks eat five different diets each with escalating meat contents from vegetarian all the way up to a steak each day. They found that the more meat one ate, the more sulfide; ten times more meat meant ten times more sulfide. They concluded that "dietary protein from meat is an important substrate for sulfide generation by bacteria in the human large intestine."

Hydrogen sulfide can then act as a free radical and damage our DNA at concentrations way below what our poor colon lining is exposed to on a routine basis, which may help explain why diets higher in meat and lower in fiber may produce so-called "fecal water" that causes about twice as much DNA damage. Fecal water is like when researchers make a tea from someone's stool.

The biology of sulfur in the human gut has escaped serious attention until recently. Previously it was just thought of as the rotten egg smell in malodorous gas, but the increase in sulfur compounds in response to a supplement of animal protein is not only of interest in the field of flatology--that is, the formal study of farts--but may also be of importance in the development of ulcerative colitis.

I have several videos on our microbiome, including:

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

Original Link

Why Smoothies are Better Than Juicing

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Studies such as a recent Harvard School of Public Health investigation found that the consumption of whole fruits is associated with a significantly lower risk of type 2 diabetes, whereas fruit juice consumption is associated with a higher risk, highlighting the dramatic difference between eating whole fruits and drinking fruit juice. Cholesterol serves as another example. If we eat apples, our cholesterol drops. On the other hand, if we drink apple juice, our cholesterol may actually go up a little. Leaving just a little of the fiber behind--as in cloudy apple juice--was found to add back in some of the benefit.

We used to think of fiber as just a bulking agent that helps with bowel regularity. We now know fiber is digestible by our gut bacteria, which make short chain fatty acids (SCFAs) out of it. SCFAs have a number of health promoting effects, such as inhibiting the growth of bad bacteria and increasing mineral absorption. For example, experimentally infused into the rectum of the human body, SCFAs can stimulate calcium absorption, so much so that we can improve the bone mineral density of teenagers just by giving them the fiber naturally found in foods like onions, asparagus, and bananas.

Our good bacteria also uses fiber to maintain normal bowel structure and function, preventing or alleviating diarrhea, stimulating colonic blood flow up to five-fold, and increasing fluid and electrolyte uptake. The major fuel for the cells that line our colon is butyrate, which our good bacteria make from fiber. We feed them, and they feed us right back.

If the only difference between fruit and fruit juice is fiber, why can't the juice industry just add some fiber back to the juice? The reason is because we remove a lot more than fiber when we juice fruits and vegetables. We also lose all the nutrients that are bound to the fiber.

In the 1980's, a study (highlighted in my video, Juicing Removes More Than Just Fiber) found a discrepancy in the amount of fiber in carob using two different methods. A gap of 21.5 percent was identified not as fiber but as nonextractable polyphenols, a class of phytonutrients thought to have an array of health-promoting effects. Some of the effects associated with the intake of dietary fiber in plants may actually be due to the presence of these polyphenols.

Nonextractable polyphenols, usually ignored, are the major part of dietary polyphenols. Most polyphenol phytonutrients in plants are stuck to the fiber. These so-called missing polyphenols make it down to our colon, are liberated by our friendly flora and can then get absorbed into our system. The phytonutrients in fruit and vegetable juice may just be the tip of the iceberg.

For those that like drinking their fruits and vegetables, these findings suggest that smoothies may be preferable. I can imagine people who eat really healthy thinking they get so much fiber from their regular diet that they need not concern themselves with the loss from juicing. But we may be losing more than we think.

For those that like drinking their fruits and vegetables, this suggests smoothies are preferable. I can imagine people who eat really healthy thinking they get so much fiber from their regular diet that they need not concern themselves with the loss from juicing, but they may be losing more than they think.

Why are polyphenol phytonutrients important? See, for example, my video How to Slow Brain Aging by Two Years

Not that fiber isn't important in its own right. Check out:

For more on smoothies, check out:

In health,
Michael Greger, M.D.

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

Image Credit: Craig Sunter / Flickr

Original Link