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

Four Ways to Improve on the Mediterranean Diet

Improving on the Mediterranean Diet.jpg

The traditional Mediterranean diet can be considered mainly, but not exclusively, as a plant-based diet, and certainly not a whole foods, plant-based diet. Olive oil and wine can be considered essentially fruit juices. Even if one is eating a "vegiterranean diet," an entirely plant-based version, there are a number of problematic nutritional aspects that are rarely talked about. For example, the Mediterranean diet includes lots of white bread, white pasta and not a lot of whole grains.

In an anatomy of the health effects of the Mediterranean diet, the single most important component was the high consumption of plant foods. In contrast, high cereal consumption, meaning high grain consumption, did not appear to help. This may be because most grains that modern Mediterranean dieters eat are refined, like white bread, whereas the traditional Mediterranean diet was characterized by unprocessed cereals--in other words, whole grains. And while whole grains have been associated with lower risk of diabetes, heart disease and cancer, refined grain may increase the risk of diabetes, obesity, heart disease and other chronic diseases. In the PREDIMED study, those who ate the most white bread--but not whole grain bread--gained significant weight.

Alcohol may also be a problem. As a plant-centered diet, adherence to a Mediterranean diet is associated with lower cancer risk, but does not appear to lower breast cancer risk. With all the fruits, veggies, nuts, seeds, beans and low saturated fat content, you'd assume there would be lower breast cancer risk, but alcohol is a known breast carcinogen, even in moderate amounts. When researchers created a special adapted version of the Mediterranean diet score that excluded alcohol, the diet does indeed appear to reduce breast cancer risk.

The wonderful grape phytonutrients in red wine can improve our arterial function such that if you drink nonalcoholic red wine (wine with the alcohol removed), you get a significant boost in endothelial function--the ability of our arteries to relax and dilate normally, increasing blood flow. If you drink the same red wine with alcohol, it abolishes the beneficial effect and counteracts the benefit of the grape phytonutrients. So, it would be better just to eat grapes. You can find more information about this in my video Improving on the Mediterranean Diet.

Similarly, there are components of extra virgin olive oil--the antioxidant phytonutrients, that may help endothelial function, but when consumed as oil, (even extra virgin olive oil), it may impair arterial function. So even if white bread dipped in olive oil is the very symbol of the Mediterranean diet, we can modernize it by removing oils and refined grains.

Another important, albeit frequently ignored issue in the modern Mediterranean diet is sodium intake. Despite evidence linking salt intake to high blood pressure, heart disease and strokes, dietary salt intake in the U.S. is on the rise. Right now, Americans get about seven to ten grams a day, mostly from processed foods. If we were to decrease that just by three grams every year, we could possibly save tens of thousands of people from having a heart attack, prevent tens of thousands of strokes, and tens of thousands of deaths. There is a common misperception that only certain people should reduce their salt intake and that for the vast majority of the population, salt reduction is unnecessary, but in reality, the opposite is true.

There is much we can learn from the traditional Mediterranean diet. A defining characteristic of the Mediterranean diet is an abundance of plant foods, but one thing that seems to have fallen by the wayside. No main Mediterranean meal is replete without lots of greens, a key part of not only a good Mediterranean diet, but of any good diet.

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

I touch more on whole grains in How Many Meet the Simple Seven? and Whole Grains May Work As Well As Drugs.

More on breast cancer and alcohol in Breast Cancer and Alcohol: How Much Is Safe?, Preventing Skin Cancer From the Inside Out, and Breast Cancer Risk: Red Wine v. White Wine.

I've touched on olive oil in the other videos in this Mediterranean diet series, but also have an older video Extra Virgin Olive Oil vs. Nuts and more recently, Olive Oil & Artery Function.

More on sodium in Dietary Guidelines: With a Grain of Big Salt, Big Salt - Getting to the Meat of the Matter, and Can Diet Protect Against Kidney Cancer? But what if without salt everything tastes like cardboard? Not to worry! See Changing Our Taste Buds.

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

Four Ways to Improve on the Mediterranean Diet

Improving on the Mediterranean Diet.jpg

The traditional Mediterranean diet can be considered mainly, but not exclusively, as a plant-based diet, and certainly not a whole foods, plant-based diet. Olive oil and wine can be considered essentially fruit juices. Even if one is eating a "vegiterranean diet," an entirely plant-based version, there are a number of problematic nutritional aspects that are rarely talked about. For example, the Mediterranean diet includes lots of white bread, white pasta and not a lot of whole grains.

In an anatomy of the health effects of the Mediterranean diet, the single most important component was the high consumption of plant foods. In contrast, high cereal consumption, meaning high grain consumption, did not appear to help. This may be because most grains that modern Mediterranean dieters eat are refined, like white bread, whereas the traditional Mediterranean diet was characterized by unprocessed cereals--in other words, whole grains. And while whole grains have been associated with lower risk of diabetes, heart disease and cancer, refined grain may increase the risk of diabetes, obesity, heart disease and other chronic diseases. In the PREDIMED study, those who ate the most white bread--but not whole grain bread--gained significant weight.

Alcohol may also be a problem. As a plant-centered diet, adherence to a Mediterranean diet is associated with lower cancer risk, but does not appear to lower breast cancer risk. With all the fruits, veggies, nuts, seeds, beans and low saturated fat content, you'd assume there would be lower breast cancer risk, but alcohol is a known breast carcinogen, even in moderate amounts. When researchers created a special adapted version of the Mediterranean diet score that excluded alcohol, the diet does indeed appear to reduce breast cancer risk.

The wonderful grape phytonutrients in red wine can improve our arterial function such that if you drink nonalcoholic red wine (wine with the alcohol removed), you get a significant boost in endothelial function--the ability of our arteries to relax and dilate normally, increasing blood flow. If you drink the same red wine with alcohol, it abolishes the beneficial effect and counteracts the benefit of the grape phytonutrients. So, it would be better just to eat grapes. You can find more information about this in my video Improving on the Mediterranean Diet.

Similarly, there are components of extra virgin olive oil--the antioxidant phytonutrients, that may help endothelial function, but when consumed as oil, (even extra virgin olive oil), it may impair arterial function. So even if white bread dipped in olive oil is the very symbol of the Mediterranean diet, we can modernize it by removing oils and refined grains.

Another important, albeit frequently ignored issue in the modern Mediterranean diet is sodium intake. Despite evidence linking salt intake to high blood pressure, heart disease and strokes, dietary salt intake in the U.S. is on the rise. Right now, Americans get about seven to ten grams a day, mostly from processed foods. If we were to decrease that just by three grams every year, we could possibly save tens of thousands of people from having a heart attack, prevent tens of thousands of strokes, and tens of thousands of deaths. There is a common misperception that only certain people should reduce their salt intake and that for the vast majority of the population, salt reduction is unnecessary, but in reality, the opposite is true.

There is much we can learn from the traditional Mediterranean diet. A defining characteristic of the Mediterranean diet is an abundance of plant foods, but one thing that seems to have fallen by the wayside. No main Mediterranean meal is replete without lots of greens, a key part of not only a good Mediterranean diet, but of any good diet.

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

I touch more on whole grains in How Many Meet the Simple Seven? and Whole Grains May Work As Well As Drugs.

More on breast cancer and alcohol in Breast Cancer and Alcohol: How Much Is Safe?, Preventing Skin Cancer From the Inside Out, and Breast Cancer Risk: Red Wine v. White Wine.

I've touched on olive oil in the other videos in this Mediterranean diet series, but also have an older video Extra Virgin Olive Oil vs. Nuts and more recently, Olive Oil & Artery Function.

More on sodium in Dietary Guidelines: With a Grain of Big Salt, Big Salt - Getting to the Meat of the Matter, and Can Diet Protect Against Kidney Cancer? But what if without salt everything tastes like cardboard? Not to worry! See Changing Our Taste Buds.

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 Two Most Active Ingredients of the Mediterranean Diet

Which Parts of the Mediterranean Diet Extended Life.jpg

Olives and nuts are plant foods, and as such, are packed with antioxidants, raising the antioxidant level of our bloodstream resulting in lower fat oxidation and free radical DNA damage, but what's happening inside people's arteries?

Researchers measured the amount of atherosclerotic plaque in the neck arteries going to the brain in folks who for years were eating added nuts, added extra virgin olive oil or neither to their daily diets. In the control group, the plaque got worse, which is what happens when one continues to eat an artery-clogging diet, but there were no significant changes in the added extra virgin olive oil group, and the plaque in the added nut group appeared to get better. The nuts appeared to induce a regression of the disease, or at least a significant delay in the progression. The nut group was still suffering strokes, but only half as many, perhaps because the reduction in plaque height within the arteries on extra nuts was indicating a stabilization of the plaque, rendering them less likely to rupture. You can see these results in my video Which Parts of the Mediterranean Diet Extended Life?

Adding nuts to our diet may also improve endothelial function, boosting the ability of our arteries to dilate naturally by about 30 percent. If you look at the baseline adherence to Mediterranean diet principles and control for things like smoking and exercise, there were only two factors significantly associated with reduced heart attack and stroke risk: more vegetables and more nuts. No significant association with the olive oil, wine, fish or cutting back on soda and cookies. Among the individual components, only increased consumption of vegetables and nuts were related to reduced cardiovascular events.

On the one hand, cutting stroke risk in half just by eating a handful of nuts a day is pretty amazing, but those in the added nut group didn't appear to live any longer overall. This is in contrast to other studies that suggested that frequent nut consumption may extend life. For example, the Harvard health professionals studies, involving a whopping three million person-years of follow-up over decades, found nut consumption associated with fewer deaths from cancer, heart disease, respiratory disease and most importantly fewer deaths overall. This was confirmed by all the other big major prospective studies in a recent review.

So what's going on here with the study showing no longevity benefit from nuts? Did they just not wait long enough? Just because people were randomized to the nut group didn't mean they actually ate more nuts, and those randomized to the other groups didn't necessarily stay away.

If you re-analyze the data comparing the death rates of those who actually ate more nuts to those who actually didn't, nut consumption was indeed associated with significantly reduced risk of death. If you do the same kind of post hoc analysis with olive oil, even with the extra virgin, there is no benefit in terms of living longer. This is consistent with how Ancel Keys, the so-called Father of the Mediterranean diet, viewed olive oil. He thought of its benefit more as a way of just replacing animal fats; anything to get people to eat less lard and butter.

What is the best kind of nut? The greatest benefits were attributed to walnuts, particularly for preventing cancer deaths. Those eating more than three servings of walnuts a week appeared to cut their risk of dying from cancer in half.

Now it's just a matter of communicating the research to the public. All the major cancer groups emphasize a more plant-based diet, remarkably consistent with the World Health Organization guidelines for healthy eating. The far-reaching positive effects of a plant-based diet--including walnuts--may be the most critical message for the public.

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

Think the effects of adding a few nuts to one's daily diet are too good to believe? Check out my video Four Nuts Once a Month. For more on Walnuts and Artery Function check out the video, and for more on nuts and cancer prevention, see Which Nut Fights Cancer Better?

Nuts May Help Prevent Death and so may beans; see Increased Lifespan from Beans. What about Fruits and Longevity: How Many Minutes per Mouthful?

More on protecting ourselves from "brain attacks" in Preventing Strokes with Diet.

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: garlandcannon / Flickr. This image has been modified.

Original Link

The Two Most Active Ingredients of the Mediterranean Diet

Which Parts of the Mediterranean Diet Extended Life.jpg

Olives and nuts are plant foods, and as such, are packed with antioxidants, raising the antioxidant level of our bloodstream resulting in lower fat oxidation and free radical DNA damage, but what's happening inside people's arteries?

Researchers measured the amount of atherosclerotic plaque in the neck arteries going to the brain in folks who for years were eating added nuts, added extra virgin olive oil or neither to their daily diets. In the control group, the plaque got worse, which is what happens when one continues to eat an artery-clogging diet, but there were no significant changes in the added extra virgin olive oil group, and the plaque in the added nut group appeared to get better. The nuts appeared to induce a regression of the disease, or at least a significant delay in the progression. The nut group was still suffering strokes, but only half as many, perhaps because the reduction in plaque height within the arteries on extra nuts was indicating a stabilization of the plaque, rendering them less likely to rupture. You can see these results in my video Which Parts of the Mediterranean Diet Extended Life?

Adding nuts to our diet may also improve endothelial function, boosting the ability of our arteries to dilate naturally by about 30 percent. If you look at the baseline adherence to Mediterranean diet principles and control for things like smoking and exercise, there were only two factors significantly associated with reduced heart attack and stroke risk: more vegetables and more nuts. No significant association with the olive oil, wine, fish or cutting back on soda and cookies. Among the individual components, only increased consumption of vegetables and nuts were related to reduced cardiovascular events.

On the one hand, cutting stroke risk in half just by eating a handful of nuts a day is pretty amazing, but those in the added nut group didn't appear to live any longer overall. This is in contrast to other studies that suggested that frequent nut consumption may extend life. For example, the Harvard health professionals studies, involving a whopping three million person-years of follow-up over decades, found nut consumption associated with fewer deaths from cancer, heart disease, respiratory disease and most importantly fewer deaths overall. This was confirmed by all the other big major prospective studies in a recent review.

So what's going on here with the study showing no longevity benefit from nuts? Did they just not wait long enough? Just because people were randomized to the nut group didn't mean they actually ate more nuts, and those randomized to the other groups didn't necessarily stay away.

If you re-analyze the data comparing the death rates of those who actually ate more nuts to those who actually didn't, nut consumption was indeed associated with significantly reduced risk of death. If you do the same kind of post hoc analysis with olive oil, even with the extra virgin, there is no benefit in terms of living longer. This is consistent with how Ancel Keys, the so-called Father of the Mediterranean diet, viewed olive oil. He thought of its benefit more as a way of just replacing animal fats; anything to get people to eat less lard and butter.

What is the best kind of nut? The greatest benefits were attributed to walnuts, particularly for preventing cancer deaths. Those eating more than three servings of walnuts a week appeared to cut their risk of dying from cancer in half.

Now it's just a matter of communicating the research to the public. All the major cancer groups emphasize a more plant-based diet, remarkably consistent with the World Health Organization guidelines for healthy eating. The far-reaching positive effects of a plant-based diet--including walnuts--may be the most critical message for the public.

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

Think the effects of adding a few nuts to one's daily diet are too good to believe? Check out my video Four Nuts Once a Month. For more on Walnuts and Artery Function check out the video, and for more on nuts and cancer prevention, see Which Nut Fights Cancer Better?

Nuts May Help Prevent Death and so may beans; see Increased Lifespan from Beans. What about Fruits and Longevity: How Many Minutes per Mouthful?

More on protecting ourselves from "brain attacks" in Preventing Strokes with Diet.

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: garlandcannon / Flickr. This image has been modified.

Original Link

The Mediterranean Diet or a Whole Food Plant-Based Diet?

The Mediterranean Diet or a Whole Food Plant-Based Diet.jpg

Recent studies have shown that higher Mediterranean diet adherence scores are associated with a significant reduction of the risk of death, heart disease, cancer, and brain disease. The problem with population studies like these is that people who eat healthier may also live healthier, and so how do we know it's their diet? I examine this in The Mediterranean Diet or a Whole Food Plant-Based Diet?.

As the American Heart Association position states, "Before advising people to follow a Mediterranean diet, we need more studies to find out whether the diet itself or other lifestyle factors account for the lower deaths from heart disease." How do you do that? There are ways you can control for obvious things like smoking and exercise--which many of the studies did--but ideally you'd do an interventional trial, the gold standard of nutritional science. You change people's diets while trying to keep everything else the same and see what happens.

We got that kind of trial 20 years ago with the famous Lyon Diet Heart Study where about 600 folks who had just had their first heart attack were randomized into two groups. The control group received no dietary advice, apart whatever their doctors were telling them, while the experimental group was told to eat more of a Mediterranean-type diet, supplemented with a canola-oil based spread to give them the plant-based omega-3's they'd normally be getting from weeds and walnuts if they actually lived on a Greek isle in the 1950's.

The Mediterranean diet group did end up taking some of the dietary advice to heart. They ate more bread, more fruit, less deli meat, less meat in general, and less butter and cream; other than that, no significant changes in diet were reported in terms of wine, olive oil, or fish consumption. So, they ate less saturated fat and cholesterol, more plant-based omega 3's, but didn't have huge dietary changes. Even so, at the end of about four years, 44 individuals from the control group had a second heart attack, either fatal or nonfatal, but only 14 suffered another attack in the group that changed their diet. So they went from having a 4% chance of having a heart attack every year down to 1%.

A cynic might say that while there was less death and disease, the Mediterranean diet continued to feed their heart disease, so much so that 14 of them suffered new heart attacks while on the diet. Yes, their disease progressed a lot less than the regular diet group (about four times less), but what if there was a diet that could stop or reverse heart disease?

Dr. Caldwell Esselstyn and colleagues at the Cleveland Clinic recently published a case series of 198 consecutive patients with cardiovascular disease counseled to switch to a diet composed entirely of whole plant foods. Of the 198, 177 stuck to the diet, whereas the other 21 fell off the wagon, setting up kind of a natural experiment. What happened to the 21? This was such a sick group of patients that more than half suffered from either a fatal heart attack or needed angioplasty or a heart transplant. In that same time period of about four years, of the 177 that stuck to the plant-based diet, only one had a major event as a result of worsening disease. As Dean Ornish noted in his response to the latest trial, "a Mediterranean diet is better than what most people are consuming"...but even better may be a diet based on whole plant foods.

Dr. Esselstyn's was not a randomized trial, so it can't be directly compared to the Lyon study, and it included very determined patients. Not everyone is willing to dramatically change their diets, even if it may literally be a matter of life or death. In which case, rather than doing nothing, eating a more Mediterranean-type diet may cut risk for heart attack survivors by about two-thirds. Cutting 99% of risk would be better if Esselstyn's results were replicated in a controlled trial, but even a 70% drop in risk could save tens of thousands of lives every year.

For more on the Mediterranean diet, check out:

For more on Dr. Esselstyn's amazing work:

If the short-chain plant-based omega-3s in flax seeds and walnuts appear so beneficial, what about the long-chain omega-3's found in fish and fish oil? There are pros and cons. See, for example, Mercury vs. Omega-3s for Brain Development, Is Fish Oil Just Snake Oil?, and Omega-3's and the Eskimo Fish Tale.

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: wildpixel / Thinkstock. This image has been modified.

Original Link

The Mediterranean Diet or a Whole Food Plant-Based Diet?

The Mediterranean Diet or a Whole Food Plant-Based Diet.jpg

Recent studies have shown that higher Mediterranean diet adherence scores are associated with a significant reduction of the risk of death, heart disease, cancer, and brain disease. The problem with population studies like these is that people who eat healthier may also live healthier, and so how do we know it's their diet? I examine this in The Mediterranean Diet or a Whole Food Plant-Based Diet?.

As the American Heart Association position states, "Before advising people to follow a Mediterranean diet, we need more studies to find out whether the diet itself or other lifestyle factors account for the lower deaths from heart disease." How do you do that? There are ways you can control for obvious things like smoking and exercise--which many of the studies did--but ideally you'd do an interventional trial, the gold standard of nutritional science. You change people's diets while trying to keep everything else the same and see what happens.

We got that kind of trial 20 years ago with the famous Lyon Diet Heart Study where about 600 folks who had just had their first heart attack were randomized into two groups. The control group received no dietary advice, apart whatever their doctors were telling them, while the experimental group was told to eat more of a Mediterranean-type diet, supplemented with a canola-oil based spread to give them the plant-based omega-3's they'd normally be getting from weeds and walnuts if they actually lived on a Greek isle in the 1950's.

The Mediterranean diet group did end up taking some of the dietary advice to heart. They ate more bread, more fruit, less deli meat, less meat in general, and less butter and cream; other than that, no significant changes in diet were reported in terms of wine, olive oil, or fish consumption. So, they ate less saturated fat and cholesterol, more plant-based omega 3's, but didn't have huge dietary changes. Even so, at the end of about four years, 44 individuals from the control group had a second heart attack, either fatal or nonfatal, but only 14 suffered another attack in the group that changed their diet. So they went from having a 4% chance of having a heart attack every year down to 1%.

A cynic might say that while there was less death and disease, the Mediterranean diet continued to feed their heart disease, so much so that 14 of them suffered new heart attacks while on the diet. Yes, their disease progressed a lot less than the regular diet group (about four times less), but what if there was a diet that could stop or reverse heart disease?

Dr. Caldwell Esselstyn and colleagues at the Cleveland Clinic recently published a case series of 198 consecutive patients with cardiovascular disease counseled to switch to a diet composed entirely of whole plant foods. Of the 198, 177 stuck to the diet, whereas the other 21 fell off the wagon, setting up kind of a natural experiment. What happened to the 21? This was such a sick group of patients that more than half suffered from either a fatal heart attack or needed angioplasty or a heart transplant. In that same time period of about four years, of the 177 that stuck to the plant-based diet, only one had a major event as a result of worsening disease. As Dean Ornish noted in his response to the latest trial, "a Mediterranean diet is better than what most people are consuming"...but even better may be a diet based on whole plant foods.

Dr. Esselstyn's was not a randomized trial, so it can't be directly compared to the Lyon study, and it included very determined patients. Not everyone is willing to dramatically change their diets, even if it may literally be a matter of life or death. In which case, rather than doing nothing, eating a more Mediterranean-type diet may cut risk for heart attack survivors by about two-thirds. Cutting 99% of risk would be better if Esselstyn's results were replicated in a controlled trial, but even a 70% drop in risk could save tens of thousands of lives every year.

For more on the Mediterranean diet, check out:

For more on Dr. Esselstyn's amazing work:

If the short-chain plant-based omega-3s in flax seeds and walnuts appear so beneficial, what about the long-chain omega-3's found in fish and fish oil? There are pros and cons. See, for example, Mercury vs. Omega-3s for Brain Development, Is Fish Oil Just Snake Oil?, and Omega-3's and the Eskimo Fish Tale.

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: wildpixel / Thinkstock. This image has been modified.

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The Role of Caffeine in Artery Function

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There are dietary guidelines for food, but what about for beverages? A Beverage Guidance Panel was "assembled to provide guidance on the relative health and nutritional benefits and risks of various beverage categories." They ranked them from one to six, and water was ranked number one.

Soda ranked last at number six. Whole milk was grouped with beer, with a recommendation for zero ounces a day, in part out of concern for links between milk and prostate cancer, as well as aggressive ovarian cancer due to IGF-1. Number two on the list, though, after water, was tea and coffee, preferably without creamer or sweetener.

Even without creamer, though, lots of unfiltered coffee can raise cholesterol, but the cholesterol-raising compounds are trapped by the paper filter in brewed coffee, so filtered coffee is probably better.

But about ten years ago, a study was published on the effects of coffee on endothelial function, the function of our arteries. I profile this study in my video Coffee and Artery Function, showing that within 30 minutes of drinking a cup of coffee there was a significant drop in the ability of our arteries to dilate, whereas decaf did not seem to have a significant effect. This was the first study to demonstrate an acute unfavorable effect on arterial function of caffeinated coffee, but one cup of decaf didn't seem to affect performance. And two cups of decaf appeared to have a beneficial effect. So maybe it's a "battle between caffeine and antioxidants." Something in caffeinated coffee appears to be hurting arterial function, whereas something in decaf appears to be helping.

It's similar to red wine. De-alcoholized red wine significantly improves arterial function, as there are grape components trying to help, but the presence of alcohol counteracts and erases the benefit.

Drinking really high antioxidant coffee, by preparing it Greek style for example (where we actually drink the grounds), coffee drinkers may actually be at an advantage

It might not be the caffeine in caffeinated coffee that appears to be harmful, though. In a randomized, double-blind, placebo-controlled, cross-over study, researchers found that caffeine alone--about two and a half cups of coffee worth--significantly improved arterial function in both people with and without heart disease.

Coffee contains more than a thousand different compounds other than caffeine, many of which are also removed by the decaffeination process, so there must be something else in the coffee bean that's causing the problem. In fact, caffeine may even enhance the repair of the fragile inner lining of our arteries by enhancing the migration of our endothelial progenitor cells, the stem cells that patch up potholes in our artery walls.

But how might we get the potential benefit of caffeine without the risky compounds in caffeinated coffee? Tea consumption enhances artery function, and there are substantial beneficial effects of both green tea and black tea. Instead of other components in tea leaves undermining caffeine's potential benefits, they appear to boost the benefit in healthy individuals, as well as heart disease patients, reversing some of their arterial dysfunction, both immediately and long-term.

All the measurements in the studies I've talked about so far were done on the brachial artery, the main artery in the arm (just because it's easier to get to). What we care about, though, is blood flow to the heart. And caffeine appears to impair blood flow to our heart muscle during exercise even in healthy folks, but especially in those with heart disease. Thankfully caffeine in tea form appears to have the opposite effect, significantly improving coronary blood flow, suggesting that tea consumption has a beneficial effect on coronary circulation, though the addition of milk may undermine the protective effects.

I'm fascinated by how complicated such a simple question can get. The take-home is that water is the healthiest beverage, followed by tea.

The effects of coffee on cancer risk are more salutary:

I've previously covered Walnuts and Artery Function and Dark Chocolate and Artery Function. Stay tuned for a few more coming up further exploring the effects of tea, olive oil, and plant-based diets on our lovely endothelium.

Low Carb Diets and Coronary Blood Flow is one of the few other studies I've done that measured blood flow within the coronary arteries themselves. For more background on the brachial artery test, see my video The Power of NO.

In health,
Michael Greger, M.D.

PS: If you haven't yet, you can subscribe to my free videos here and watch my live, year-in-review presentations--2013: Uprooting the Leading Causes of Death, More Than an Apple a Day, 2014: From Table to Able: Combating Disabling Diseases with Food, 2015: Food as Medicine: Preventing and Treating the Most Dreaded Diseases with Diet, and my latest, 2016: How Not To Die: The Role of Diet in Preventing, Arresting, and Reversing Our Top 15 Killers.

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Dr. Greger’s 2015 Live Year-in-Review Presentation

Food as Medicine

View my new live presentation here: Food as Medicine: Preventing and Treating the Most Dreaded Diseases with Diet

Every year I scour the world's scholarly literature on clinical nutrition, pulling together what I find to be the most interesting, practical, and groundbreaking science on how to best feed ourselves and our families. I start with the thousands of papers published annually on nutrition (27,000 this year--a new record!) and, thanks to a crack team of volunteers (and now staff!), I'm able to whittle those down (to a mere 8,000 this year). They are then downloaded, categorized, read, analyzed, and churned into the few hundred short videos. This allows me to post new videos and articles every day, year-round, to NutritionFacts.org. This certainly makes the site unique. There's no other science-based source for free daily updates on the latest discoveries in nutrition. The problem is that the amount of information can be overwhelming.

Currently I have more than a thousand videos covering 1,931 nutrition topics. Where do you even begin? Many have expressed their appreciation for the breadth of material, but asked that I try to distill it into a coherent summary of how best to use diet to prevent and treat chronic disease. I took this feedback to heart and in 2012 developed Uprooting the Leading Causes of Death, which explored the role diet may play in preventing, arresting, and even reversing our top 15 killers. Not only did it rise to become one of the Top 10 Most Popular Videos of 2012, it remains my single most viewed video to date, watched over a million times (NutritionFacts.org is now up to more than 1.5 million hits a month!).

In 2013 I developed the sequel, More Than an Apple a Day, in which I explored the role diet could play in treating some of our most common conditions. I presented it around the country and it ended up #1 on our Top 10 Most Popular Videos of 2013. Then in 2014 I premiered the sequel-sequel, From Table to Able, in which I explored the role diet could play in treating some of our most disabling diseases, landing #1 on our Top 10 Most Popular Videos of 2014.

Every year I wonder how I'm going to top the year before. Knowing how popular these live presentations can be and hearing all the stories from folks about what a powerful impact they can have on people's lives, I put my all into this new 2015 one. I spent more time putting together this presentation than any other in my life. It took me an entire month, and when you see it I think you'll appreciate why.

This year, I'm honored to bring you Food as Medicine, in which I go through our most dreaded diseases--but that's not even the best part! I'm really proud of what I put together for the ending. I spend the last 20 minutes or so (starting at 56:22) going through a thought experiment that I'm hoping everyone will find compelling. I think it may be my best presentation ever. You be the judge.

You can watch it at no cost online, but it is also available on DVD through my website or on Amazon. If you want to share copies with others, I have a five for $40 special (enter coupon code 5FOR40FAM). All proceeds from the sales of all my books, DVDs, downloads, and presentations go to the 501c3 nonprofit charity that keeps NutritionFacts.org free for all, for all time. If you want to support this initiative to educate millions about eradicating dietary diseases, please consider making a donation.

After you've watched the new presentation, make sure you're subscribed to get my video updates daily, weekly, or monthly to stay on top of all the latest.

-Michael Greger

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