How Much Water Should We Drink Every Day?

How Much Water Should We Drink Every Day?.jpeg

More than 2000 years ago Hippocrates (460-377 BCE) said, "If we could give every individual the right amount of nourishment and exercise, not too little and not too much, we would have found the safest way to health." What does that mean when it comes to water? Water has been described as a neglected, unappreciated, and under-researched subject, and further complicating the issue, a lot of the papers extolling the need for proper hydration are funded by the bottled water industry.

It turns out the often quoted "drink at least eight glasses of water a day" dictum has little underpinning scientific evidence . Where did that idea come from? The recommendation was traced to a 1921 paper, in which the author measured his own pee and sweat and determined we lose about 3% of our body weight in water a day, or about 8 cups (see How Many Glasses of Water Should We Drink in a Day?). Consequently, for the longest time, water requirement guidelines for humanity were based on just one person.

There is evidence that not drinking enough may be associated with falls and fractures, heat stroke, heart disease, lung disorders, kidney disease, kidney stones, bladder and colon cancer, urinary tract infections, constipation, dry mouth, cavities, decreased immune function and cataract formation. The problem with many of these studies is that low water intake is associated with several unhealthy behaviors, such as low fruit and vegetable intake, more fast-food, less shopping at farmers markets. And who drinks lots of water? People who exercise a lot. No wonder they tend to have lower disease rates!

Only large and expensive randomized trials could settle these questions definitively. Given that water cannot be patented, such trials seem unlikely; who's going to pay for them? We're left with studies that find an association between disease and low water intake. But are people sick because they drink less, or are they drinking less because they're sick? There have been a few large prospective studies in which fluid intake is measured before disease develops. For example, a Harvard study of 48,000 men found that the risk of bladder cancer decreased by 7% for every extra daily cup of fluid we drink. Therefore, a high intake of water--like 8 cups a day--may reduce the risk of bladder cancer by about 50%, potentially saving thousands of lives.

The accompanying editorial commented that strategies to prevent the most prevalent cancers in the West are remarkably straightforward in principle. To prevent lung cancer, quit smoking; to prevent breast cancer, maintain your ideal body weight and exercise; and to prevent skin cancer, stay out of the sun. Now comes this seemingly simple way to reduce the risk of bladder cancer: drink more fluids.

Probably the best evidence we have for a cut off of water intake comes from the Adventist Health Study, in which 20,000 men and women were studied. About one-half were vegetarian, so they were also getting extra water by eating more fruits and vegetables. Those drinking 5 or more glasses of water a day had about half the risk of dying from heart disease compared to those who drank 2 or fewer glasses a day. Like the Harvard study, this protection was found after controlling for other factors such as diet and exercise. These data suggest that it was the water itself that was decreasing risk, perhaps by lowering blood viscosity (blood thickness).

Based on all the best evidence to date, authorities from Europe, the U.S. Institute of Medicine, and the World Health Organization recommend between 2.0 and 2.7 liters (8 to 11 cups) of water a day for women, and 2.5 to 3.7 liters (10 to 15 cups) a day for men. This includes water from all sources, not just beverages. We get about a liter from food and the water our body makes. So this translates into a recommendation for women to drink 4 to 7 cups of water a day and men 6 to 11 cups, assuming only moderate physical activity at moderate ambient temperatures.

We can also get water from all the other drinks we consume, including caffeinated drinks, with the exception of stronger alcoholic drinks like wines and spirits. Beer can leave you with more water than you started with, but wine actively dehydrates you. However, in the cancer and heart disease studies I mentioned above, the benefits were only found with increased water consumption, not other beverages.

I've previously touched on the cognitive benefits of proper hydration here: Does a Drink Of Water Make Children Smarter?

Surprised tea is hydrating? See my video Is Caffeinated Tea Dehydrating?

Surprised that the 8-a-day rested on such flimsy evidence? Unfortunately, so much of what we do in medicine has shaky underpinnings. That's the impetus behind the idea of evidence-based medicine (what a concept!). Ironically, this new movement may itself undermine some of the most effective treatments. See Evidence-Based Medicine or Evidence-Biased?

How else can we reduce our risk of bladder cancer? See Raw Broccoli and Bladder Cancer Survival.

What kind of water? I recommend tap water, which tends to be preferable from a chemical and microbial contamination standpoint. What about buying one of those fancy alkalizing machines? See Alkaline Water: a Scam?

It's so nice to have data on such a fundamental question. We have much to thank the Adventists for. You will see their studies cropping up frequently. See, for example, Plant-Based Diets and Diabetes, The Okinawa Diet: Living to 100, and Evidence-Based Eating.

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. Image has been modified.

Original Link

How Much Water Should We Drink Every Day?

How Much Water Should We Drink Every Day?.jpeg

More than 2000 years ago Hippocrates (460-377 BCE) said, "If we could give every individual the right amount of nourishment and exercise, not too little and not too much, we would have found the safest way to health." What does that mean when it comes to water? Water has been described as a neglected, unappreciated, and under-researched subject, and further complicating the issue, a lot of the papers extolling the need for proper hydration are funded by the bottled water industry.

It turns out the often quoted "drink at least eight glasses of water a day" dictum has little underpinning scientific evidence . Where did that idea come from? The recommendation was traced to a 1921 paper, in which the author measured his own pee and sweat and determined we lose about 3% of our body weight in water a day, or about 8 cups (see How Many Glasses of Water Should We Drink in a Day?). Consequently, for the longest time, water requirement guidelines for humanity were based on just one person.

There is evidence that not drinking enough may be associated with falls and fractures, heat stroke, heart disease, lung disorders, kidney disease, kidney stones, bladder and colon cancer, urinary tract infections, constipation, dry mouth, cavities, decreased immune function and cataract formation. The problem with many of these studies is that low water intake is associated with several unhealthy behaviors, such as low fruit and vegetable intake, more fast-food, less shopping at farmers markets. And who drinks lots of water? People who exercise a lot. No wonder they tend to have lower disease rates!

Only large and expensive randomized trials could settle these questions definitively. Given that water cannot be patented, such trials seem unlikely; who's going to pay for them? We're left with studies that find an association between disease and low water intake. But are people sick because they drink less, or are they drinking less because they're sick? There have been a few large prospective studies in which fluid intake is measured before disease develops. For example, a Harvard study of 48,000 men found that the risk of bladder cancer decreased by 7% for every extra daily cup of fluid we drink. Therefore, a high intake of water--like 8 cups a day--may reduce the risk of bladder cancer by about 50%, potentially saving thousands of lives.

The accompanying editorial commented that strategies to prevent the most prevalent cancers in the West are remarkably straightforward in principle. To prevent lung cancer, quit smoking; to prevent breast cancer, maintain your ideal body weight and exercise; and to prevent skin cancer, stay out of the sun. Now comes this seemingly simple way to reduce the risk of bladder cancer: drink more fluids.

Probably the best evidence we have for a cut off of water intake comes from the Adventist Health Study, in which 20,000 men and women were studied. About one-half were vegetarian, so they were also getting extra water by eating more fruits and vegetables. Those drinking 5 or more glasses of water a day had about half the risk of dying from heart disease compared to those who drank 2 or fewer glasses a day. Like the Harvard study, this protection was found after controlling for other factors such as diet and exercise. These data suggest that it was the water itself that was decreasing risk, perhaps by lowering blood viscosity (blood thickness).

Based on all the best evidence to date, authorities from Europe, the U.S. Institute of Medicine, and the World Health Organization recommend between 2.0 and 2.7 liters (8 to 11 cups) of water a day for women, and 2.5 to 3.7 liters (10 to 15 cups) a day for men. This includes water from all sources, not just beverages. We get about a liter from food and the water our body makes. So this translates into a recommendation for women to drink 4 to 7 cups of water a day and men 6 to 11 cups, assuming only moderate physical activity at moderate ambient temperatures.

We can also get water from all the other drinks we consume, including caffeinated drinks, with the exception of stronger alcoholic drinks like wines and spirits. Beer can leave you with more water than you started with, but wine actively dehydrates you. However, in the cancer and heart disease studies I mentioned above, the benefits were only found with increased water consumption, not other beverages.

I've previously touched on the cognitive benefits of proper hydration here: Does a Drink Of Water Make Children Smarter?

Surprised tea is hydrating? See my video Is Caffeinated Tea Dehydrating?

Surprised that the 8-a-day rested on such flimsy evidence? Unfortunately, so much of what we do in medicine has shaky underpinnings. That's the impetus behind the idea of evidence-based medicine (what a concept!). Ironically, this new movement may itself undermine some of the most effective treatments. See Evidence-Based Medicine or Evidence-Biased?

How else can we reduce our risk of bladder cancer? See Raw Broccoli and Bladder Cancer Survival.

What kind of water? I recommend tap water, which tends to be preferable from a chemical and microbial contamination standpoint. What about buying one of those fancy alkalizing machines? See Alkaline Water: a Scam?

It's so nice to have data on such a fundamental question. We have much to thank the Adventists for. You will see their studies cropping up frequently. See, for example, Plant-Based Diets and Diabetes, The Okinawa Diet: Living to 100, and Evidence-Based Eating.

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. Image has been modified.

Original Link

Organic versus Conventional: Which has More Nutrients?

Organic versus Conventional - Which has More Nutrients?.jpeg

Are organic foods safer and healthier than conventional alternatives? Those are two separate questions. Some consumers are interested in getting more nutrients; others are more concerned about getting fewer pesticides. Let's do nutrition first.

As seen in my video, Are Organic Foods More Nutritious?, hundreds of studies have been reviewed and researchers didn't find significant differences for most of the traditional nutrients like vitamins and minerals. They concluded that despite the widespread perception that organically produced foods are more nutritious, they didn't find robust evidence to support that perception. They did, however, find higher levels of phenolic phytonutrients in organic.

These so-called "secondary metabolites" of plants are thought to be behind many of the benefits ascribed to eating fruits and vegetables. Organic fruits and vegetables had between 19 and 69% more of a variety of these antioxidant compounds. The theory was that these phytonutrients are created by the plant for its own protection. For example, broccoli releases the bitter compounds like sulforaphane when the plant is chewed to ward off those who might eat it. Bugs take one bite and say, "Ew, this tastes like broccoli!" But pesticide-laden plants are bitten less by bugs and so may be churning out fewer of these compounds. Plants raised organically, on the other hand, are in a fight for their lives and may necessarily have to produce more protection. That was the theory anyway, but we don't have good evidence to back it up. The more likely reason has to do with the fertilizer; plants given high dose synthetic nitrogen fertilizers may divert more resources to growth rather than defense.

These antioxidants may protect the plant, but what about us? More antioxidant phytonutrients are found in organic vegetables and so yes, they displayed more antioxidant activity, but also more antimutagenic activity. Researchers exposed bacteria to a variety of mutagenic chemicals like benzopyrene, the polycyclic aromatic hydrocarbon found in barbecued meat, or IQ, the heterocyclic amine found in grilled/broiled/fried meats (as well as cigarette smoke), and there were fewer DNA mutations in the petri dishes where they added organic vegetables compared to the petri dishes where they added conventional vegetables.

Preventing DNA damage in bacteria is one thing, but what about effects on actual human cells? Organic strawberries may taste better, and have higher antioxidant activity and more phenolic phytonutrients, but what happens when you stack them up head-to-head against human cancer cells? Extracts from organically grown strawberries suppressed the growth of colon cancer cells and breast cancer cells significantly better than extracts from conventional strawberries. Now this was dripping strawberries onto cancer cells growing in a petri dish, but as I showed in Strawberries versus Esophageal Cancer, there are real life circumstances in which strawberries come into direct contact with cancerous and precancerous lesions, and so presumably organic strawberries would work even better, but they haven't yet been tested in clinical trials.

Although in vitro studies show higher antioxidant and antimutagenic activity as well as better inhibition of cancer cell proliferation, clinical studies on the impact of eating organic on human disease simply haven't been done. Based on antioxidant phytonutrient levels, organic produce may be considered 20 to 40% healthier, the equivalent of adding one or two serving's worth to a five-a-day regimen. But organic produce may be 40% more expensive, so for the same money you could just buy the extra servings worth of conventional produce. From a purely nutrients-per-dollar standpoint, it's not clear that organic foods are any better. But people often buy organic foods to avoid chemicals, not because they are more nutritious. For more on the best available science comparing the nutritional content, pesticide risk, heavy metal toxicity, and food poisoning risk of organic versus conventionally raised foods )including practical tips for making your own DIY fruit and veggie wash), see:

I imagine that the reaction to this series will be similar to that for the one I did on GMO foods, riling up critics on both sides of the debate:

More on the nutritional implications of stressed-out plants here:

Production method aside, in vitro, Which Fruit Fights Cancer Better?

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

Organic versus Conventional: Which has More Nutrients?

Organic versus Conventional - Which has More Nutrients?.jpeg

Are organic foods safer and healthier than conventional alternatives? Those are two separate questions. Some consumers are interested in getting more nutrients; others are more concerned about getting fewer pesticides. Let's do nutrition first.

As seen in my video, Are Organic Foods More Nutritious?, hundreds of studies have been reviewed and researchers didn't find significant differences for most of the traditional nutrients like vitamins and minerals. They concluded that despite the widespread perception that organically produced foods are more nutritious, they didn't find robust evidence to support that perception. They did, however, find higher levels of phenolic phytonutrients in organic.

These so-called "secondary metabolites" of plants are thought to be behind many of the benefits ascribed to eating fruits and vegetables. Organic fruits and vegetables had between 19 and 69% more of a variety of these antioxidant compounds. The theory was that these phytonutrients are created by the plant for its own protection. For example, broccoli releases the bitter compounds like sulforaphane when the plant is chewed to ward off those who might eat it. Bugs take one bite and say, "Ew, this tastes like broccoli!" But pesticide-laden plants are bitten less by bugs and so may be churning out fewer of these compounds. Plants raised organically, on the other hand, are in a fight for their lives and may necessarily have to produce more protection. That was the theory anyway, but we don't have good evidence to back it up. The more likely reason has to do with the fertilizer; plants given high dose synthetic nitrogen fertilizers may divert more resources to growth rather than defense.

These antioxidants may protect the plant, but what about us? More antioxidant phytonutrients are found in organic vegetables and so yes, they displayed more antioxidant activity, but also more antimutagenic activity. Researchers exposed bacteria to a variety of mutagenic chemicals like benzopyrene, the polycyclic aromatic hydrocarbon found in barbecued meat, or IQ, the heterocyclic amine found in grilled/broiled/fried meats (as well as cigarette smoke), and there were fewer DNA mutations in the petri dishes where they added organic vegetables compared to the petri dishes where they added conventional vegetables.

Preventing DNA damage in bacteria is one thing, but what about effects on actual human cells? Organic strawberries may taste better, and have higher antioxidant activity and more phenolic phytonutrients, but what happens when you stack them up head-to-head against human cancer cells? Extracts from organically grown strawberries suppressed the growth of colon cancer cells and breast cancer cells significantly better than extracts from conventional strawberries. Now this was dripping strawberries onto cancer cells growing in a petri dish, but as I showed in Strawberries versus Esophageal Cancer, there are real life circumstances in which strawberries come into direct contact with cancerous and precancerous lesions, and so presumably organic strawberries would work even better, but they haven't yet been tested in clinical trials.

Although in vitro studies show higher antioxidant and antimutagenic activity as well as better inhibition of cancer cell proliferation, clinical studies on the impact of eating organic on human disease simply haven't been done. Based on antioxidant phytonutrient levels, organic produce may be considered 20 to 40% healthier, the equivalent of adding one or two serving's worth to a five-a-day regimen. But organic produce may be 40% more expensive, so for the same money you could just buy the extra servings worth of conventional produce. From a purely nutrients-per-dollar standpoint, it's not clear that organic foods are any better. But people often buy organic foods to avoid chemicals, not because they are more nutritious. For more on the best available science comparing the nutritional content, pesticide risk, heavy metal toxicity, and food poisoning risk of organic versus conventionally raised foods )including practical tips for making your own DIY fruit and veggie wash), see:

I imagine that the reaction to this series will be similar to that for the one I did on GMO foods, riling up critics on both sides of the debate:

More on the nutritional implications of stressed-out plants here:

Production method aside, in vitro, Which Fruit Fights Cancer Better?

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

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

Striving for Alkaline Pee and Acidic Poo

Stool pH and Colon Cancer.jpg

More than 30 years ago, an idea was put forward that high colonic pH promoted colorectal cancer. A high colonic pH may promote the creation of carcinogens from bile acids, a process that is inhibited once you get below a pH of about 6.5. This is supported by data which shows those at higher risk for colon cancer may have a higher stool pH, and those at lower risk have a low pH. There was a dramatic difference between the two groups, with most of the high risk group over pH 8, and most of the low risk group under pH 6 (see Stool pH and Colon Cancer).

This may help explain the 50-fold lower rates of colon cancer in Africa compared to America. The bacteria we have in our gut depends on what we eat. If we eat lots of fiber, then we preferentially feed the fiber eating bacteria, which give us back all sorts of health promoting substances like short-chain fatty acids that have anti-inflammatory and anti-cancer properties. More of these organic acids were found in the stools of native Africans than African Americans. More acids, so lower pH. Whereas putrefactive bacteria, eating animal protein, are able to increase stool pH by producing alkaline metabolites like ammonia.

The pH of the stools of white versus black children in Africa was compared. Children were chosen because you can more readily sample their stools, particularly the rural black schoolchildren who were eating such high fiber diets--whole grains, legumes, nuts, vegetables, fruits, and wild greens--that 90% of them could produce a stool on demand. Stuffed from head to tail with plants, they could give you a stool sample at any time, just as easy as getting a urine sample. It was hard to even get access to the white kids, though, who were reluctant to participate in such investigations, even though they were given waxed cartons fitted with lids while all the black kids got was a plate and a square of paper towel.

The researchers found significantly lower fecal pH in those eating the traditional, rural plant-based diets compared to those eating the traditional Western diet, who were eating far fewer whole plant foods than the black children. But, remove some of those whole plant foods, like switch their corn for white bread for just a few days and their stool pH goes up, and add whole plant foods like an extra five to seven servings of fruit every day, and their stool pH goes down even further and gets more acidic. It makes sense because when you ferment fruits, veggies, and grains, they turn sour, like vinegar, sauerkraut, or sourdough, because good bacteria like lactobacillus produce organic acids like lactic acid. Those who eat a lot of plants have more of those good bugs. So, using the purple cabbage test highlighted in my video, Testing Your Diet with Pee & Purple Cabbage, we want blue pee, but pink poo.

If you compare the fecal samples of those eating vegetarian or vegan to those eating standard diets, plant-based diets appear to shift the makeup of the bacteria in our gut, resulting in a significantly lower stool pH, and the more plant-based, the lower the pH dropped. It's like a positive feedback loop: fiber-eating bacteria produce the acids to create the pH at which fiber-eating bacteria thrive while suppressing the group of less beneficial bugs.

It might taken even as little as two weeks to bring stool pH down on a plant-based diet. In a study published in the British Journal of Cancer, a dozen volunteers carefully selected for their trustworthiness and randomized to sequentially go on regular, vegetarian, or vegan diets and two weeks in, a significant drop in fecal pH was achieved eating completely plant-based.

But there are differing qualities of plant-based diets. For example, the two groups followed in the study I mentioned earlier had dramatically different stool pH, yet both groups were vegetarian. The high risk group was eating mostly refined grains, very little fiber, whereas the low risk group was eating whole grains and beans, packed with fiber for our fiber-friendly flora to munch on.

Just as a "reduction of high serum cholesterol contributes to the avoidance of coronary heart disease," a fall in the fecal pH value may contribute to the avoidance of bowel cancer and through the same means, eating more whole plant foods.

More on colon cancer prevention in:

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: Kitti Sukhonthanit © 123RF.com. This image has been modified.

Original Link

Striving for Alkaline Pee and Acidic Poo

Stool pH and Colon Cancer.jpg

More than 30 years ago, an idea was put forward that high colonic pH promoted colorectal cancer. A high colonic pH may promote the creation of carcinogens from bile acids, a process that is inhibited once you get below a pH of about 6.5. This is supported by data which shows those at higher risk for colon cancer may have a higher stool pH, and those at lower risk have a low pH. There was a dramatic difference between the two groups, with most of the high risk group over pH 8, and most of the low risk group under pH 6 (see Stool pH and Colon Cancer).

This may help explain the 50-fold lower rates of colon cancer in Africa compared to America. The bacteria we have in our gut depends on what we eat. If we eat lots of fiber, then we preferentially feed the fiber eating bacteria, which give us back all sorts of health promoting substances like short-chain fatty acids that have anti-inflammatory and anti-cancer properties. More of these organic acids were found in the stools of native Africans than African Americans. More acids, so lower pH. Whereas putrefactive bacteria, eating animal protein, are able to increase stool pH by producing alkaline metabolites like ammonia.

The pH of the stools of white versus black children in Africa was compared. Children were chosen because you can more readily sample their stools, particularly the rural black schoolchildren who were eating such high fiber diets--whole grains, legumes, nuts, vegetables, fruits, and wild greens--that 90% of them could produce a stool on demand. Stuffed from head to tail with plants, they could give you a stool sample at any time, just as easy as getting a urine sample. It was hard to even get access to the white kids, though, who were reluctant to participate in such investigations, even though they were given waxed cartons fitted with lids while all the black kids got was a plate and a square of paper towel.

The researchers found significantly lower fecal pH in those eating the traditional, rural plant-based diets compared to those eating the traditional Western diet, who were eating far fewer whole plant foods than the black children. But, remove some of those whole plant foods, like switch their corn for white bread for just a few days and their stool pH goes up, and add whole plant foods like an extra five to seven servings of fruit every day, and their stool pH goes down even further and gets more acidic. It makes sense because when you ferment fruits, veggies, and grains, they turn sour, like vinegar, sauerkraut, or sourdough, because good bacteria like lactobacillus produce organic acids like lactic acid. Those who eat a lot of plants have more of those good bugs. So, using the purple cabbage test highlighted in my video, Testing Your Diet with Pee & Purple Cabbage, we want blue pee, but pink poo.

If you compare the fecal samples of those eating vegetarian or vegan to those eating standard diets, plant-based diets appear to shift the makeup of the bacteria in our gut, resulting in a significantly lower stool pH, and the more plant-based, the lower the pH dropped. It's like a positive feedback loop: fiber-eating bacteria produce the acids to create the pH at which fiber-eating bacteria thrive while suppressing the group of less beneficial bugs.

It might taken even as little as two weeks to bring stool pH down on a plant-based diet. In a study published in the British Journal of Cancer, a dozen volunteers carefully selected for their trustworthiness and randomized to sequentially go on regular, vegetarian, or vegan diets and two weeks in, a significant drop in fecal pH was achieved eating completely plant-based.

But there are differing qualities of plant-based diets. For example, the two groups followed in the study I mentioned earlier had dramatically different stool pH, yet both groups were vegetarian. The high risk group was eating mostly refined grains, very little fiber, whereas the low risk group was eating whole grains and beans, packed with fiber for our fiber-friendly flora to munch on.

Just as a "reduction of high serum cholesterol contributes to the avoidance of coronary heart disease," a fall in the fecal pH value may contribute to the avoidance of bowel cancer and through the same means, eating more whole plant foods.

More on colon cancer prevention in:

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:

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How Well Do Cholesterol-Lowering Drugs Actually Work?

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One of the reasons people may undervalue diet and lifestyle changes is an overconfidence in the ability of pills and procedures to prevent disease. For example, people tend to wildly overestimate the power of things like mammograms and colonoscopies to prevent deaths from breast and bowel cancer, or the power of drugs like Fosamax to prevent hip fractures, or the power of cholesterol drugs to prevent fatal heart attacks. Patients believe statin drugs like Lipitor are about 100 times more effective than they actually are in preventing heart attacks. Studies show most people wouldn't take multiple blood pressure medications if they knew the truth.

For most people, the chance of benefit is normally less than 5 percent over five years for cholesterol, blood pressure, and blood thinning drugs. Patients don't want to take drugs unless they have at least a one in five chance--even those who just had a heart attack. It's no wonder, then, that doctors seldom share these figures. Informing patients of the percentage chance of benefit from preventive drug strategies would likely substantially reduce the likelihood that patients would agree to take the drugs every day for the rest of their lives.

For the individual, this is unlikely to be detrimental; after all, there's a 95 percent chance it won't do anything for them. But for the population at large, it would make a difference, so doctors and drug companies oversell the benefits by conveniently not mentioning how tiny they actually are, knowing most patients wouldn't take them if doctors divulged the truth. To practice non-lifestyle medicine is to practice deceptive medicine.

The best that cholesterol-lowering statin drugs appear to do is an absolute risk reduction of 3.1 percent over six years. If Dr. Esselstyn's work can be replicated in a randomized, controlled trial, then a whole foods plant-based diet will have been shown to work twenty times better, an absolute risk reduction of 60 percent after less than four years. In Esselstyn's study, 99.4 percent of high-risk patients that stuck with the diet avoided major cardiac events, such as death from heart attack.

When we have to decide whether we want to go diet versus drugs, we're not making a choice between eating healthy to prevent a heart attack or taking a pill to prevent a heart attack. Because in 97 percent of cases in the near-term, pills don't do anything. We're risking side effects for nothing, whereas if we treat the underlying root cause of the disease by eating a healthy, cholesterol-free diet, we may even reverse the progression of the disease, as seen in my video The Actual Benefit of Diet vs. Drugs.

If we stop eating an artery-clogging diet, our bodies can start dissolving that plaque away, opening up arteries in some cases without drugs or surgery. A healthy whole food plant-based diet by itself may work 20 times better than drugs to combat our #1 killer.

Now that's something doctors may want to tell their patients.

Yes, an ounce of prevention is worth a pound of cure, but a pound isn't that heavy--why change our diet and lifestyle when we can just wait and let modern medicine fix us up? Turns out we overestimate the efficacy of treatment as well, the subject of my video Why Prevention is Worth a Ton of Cure.

Sometimes preventive medicine procedures can even be harmful. See Cancer Risk From CT Scan Radiation and Do Dental X-Rays Cause Brain Tumors?

I've previously noted how an honest physician-patient interaction might go in Fully Consensual Heart Disease Treatment, Optimal Diet: Just Give it To Me Straight, Doc and Disclosing Conflicts of Interest in Medical Research. What should we be saying? See: What Diet Should Physician's Recommend?

So why don't more doctors do it? See Barriers to Heart Disease Prevention and Find Out If Your Doctor Takes Drug Company Money.

More on Dr. Esselstyn's heart disease reversal study in: Evidence-Based Medicine or Evidence-Biased?

Of course then there's just the brute force method: Kempner Rice Diet: Whipping Us Into Shape.

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:

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Reversal of Chronic Disease Risk Even Late in Life

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A hundred years ago, the New York Times reported on a rather sophisticated study for the time: 4,600 cases of cancer appearing over a seven year period, suggesting that the increased consumption of animal foods was to blame. A century later, the latest review on the subjects concluded that mortality from all causes put together, ischemic heart disease, circulatory, and cerebrovascular diseases was significantly lower in those eating meat-free diets, in addition to less cancer and diabetes.

I'm surprised they found such significant results given that people in these studies typically didn't stop eating meat until late in life. For example, in the largest study done up until recently, up to a third of subjects ate vegetarian for less than five years, yet they still ended up with lower rates of heart disease whether they were under 60 or over 60, normal weight or overweight, used to smoke or never smoked; those that had stopped eating meat had lower risk, suggesting that decades of higher risk dietary behavior could be reversed within just years of eating healthier.

If you look at countries that switched from eating traditional, more plant-based diets to more Westernized diets, it may take 20 years for cancer rates to shoot up. It takes decades for most tumors to grow. For example, if you look at Asia, their dietary shift was accompanied by a remarkable increase in mortality rates of breast, colon, and prostate cancers. The same thing can be shown with migration studies. Men moving from rural China to the U.S. experience a dramatic increase in cancer risk, but tumors take time to grow.

So it's remarkable to me that after most of a lifetime eating the standard Western diet, one can turn it around and reverse chronic disease risk with a healthier diet, even late in the game... as discussed in my video, Never Too Late to Start Eating Healthier.

So, "should we all start eating vegetarian?" asked an editorial that accompanied the results from the largest study ever published on Americans eating plant-based diets, which found vegetarian diets to be associated with lower all-cause mortality, meaning those who started eating vegetarian live, on average, longer lives. This analysis included so-called semi-vegetarians, who ate meat at least once a month (but no more than once a week), so it's not yet clear how harmful eating meat a few times a month is. What we can all agree on, though, is that we should limit our intake of junk food and animal fat, and eat more fruits and vegetables. Most authorities will also agree that diets should include whole grains, beans, and nuts. Instead of fighting over whose diet is the best, it's time to acknowledge these common features of diets associated with less disease, and instead focus our attention on helping patients avoid the intense commercial pressures to eat otherwise.

How amazing the human body is if we just treat it right! For more on lifestyle medicine, see:

So please don't allow the perfect to become the enemy of the good. Any movement we can make towards improving our diet can help. Though the earlier the better: See Heart Disease Starts in Childhood and Back in Circulation: Sciatica and Cholesterol.

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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