Plant-Based Diets as the Nutritional Equivalent of Quitting Smoking

The Best Kept Secret in Medicine.jpeg

Despite the most widely accepted and well-established chronic disease practice guidelines uniformly calling for lifestyle change as the first line of therapy, doctors often don't follow these recommendations. As seen in my video, The Best Kept Secret in Medicine, lifestyle interventions are not only safer and cheaper but often more effective in reducing heart disease and failure, hypertension, stroke, cancer, diabetes, and deaths from all causes than nearly any other medical intervention.

"Some useful lessons may come from the war on tobacco," Dr. Neal Barnard wrote in the American Medical Association's ethics journal. When he stopped smoking himself in the 1980s, the lung cancer death rate was peaking in the United States. As the prevalence of smoking dropped, so have lung cancer rates. No longer were doctors telling patients to "[g]ive your throat a vacation" by smoking a fresh cigarette. Doctors realized they were "more effective at counseling patients to quit smoking if they no longer had tobacco stains on their own fingers." "In other words, doctors went from being bystanders--or even enablers--to leading the fight against smoking." And today, says Dr. Barnard, "Plant-based diets are the nutritional equivalent of quitting smoking."

From an editorial in the journal Alternative Therapies in Health and Medicine: "If we were to gather the world's top nutrition scientists and experts (free from food industry influence), there would be very little debate about the essential properties of good nutrition. Unfortunately, most doctors are nutritionally illiterate. And worse, they don't know how to use the most powerful medicine available to them: food."

Physician advice matters. When doctors told patients to improve their diets by cutting down on meat, dairy, and fried foods, patients were more likely to make dietary changes. It may work even better if doctors practice what they preach. Researchers at Emory University randomized patients to watch one of two videos. In one video, a physician briefly mentioned her personal dietary and exercise practices and visible on her desk were both a bike helmet and an apple. In the other video, she did not discuss her personal healthy practices, and the helmet and apple were missing. In both videos, the doctor advised the patients to cut down on meat, not usually have meat for breakfast, and have no meats for lunch or dinner at least half the time. In the disclosure video, the physician related that she herself had successfully cut down on meat. Perhaps not surprisingly, patients rated that physician to be more believable and motivating. Physicians who walk the walk--literally--and have healthier eating habits not only tend to counsel more about exercise and diet, but have been found to seem more credible or motivating when they do so.

It may also make them better doctors. A randomized controlled intervention to clean up doctors' diets, called the Promoting Health by Self Experience (PHASE) trial, found that healthcare providers' personal lifestyles were correlated directly with their clinical performance. Healthcare providers' improved wellbeing and lifestyle cascaded to the patients and clinics, suggesting an additional strategy to achieve successful health promotion.

Are you ready for the best kept secret in medicine? Given the right conditions, the body can heal itself. For example, treating cardiovascular disease with appropriate dietary changes is good medicine, reducing mortality without any adverse effects. We should keep doing research, certainly, but educating physicians and patients alike about the existing knowledge regarding the power of nutrition as medicine may be the best investment we can make.

Of course, to advise patients about nutrition, physicians first have to educate themselves, as it is unlikely they received formal nutrition education during their medical training:

For more on the power of healthy living, see:

In health,

Michael Greger, M.D.

PS: If you haven't yet, you can subscribe to my free videos here and watch my live, year-in-review presentations:

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

Original Link

Plant-Based Diets as the Nutritional Equivalent of Quitting Smoking

The Best Kept Secret in Medicine.jpeg

Despite the most widely accepted and well-established chronic disease practice guidelines uniformly calling for lifestyle change as the first line of therapy, doctors often don't follow these recommendations. As seen in my video, The Best Kept Secret in Medicine, lifestyle interventions are not only safer and cheaper but often more effective in reducing heart disease and failure, hypertension, stroke, cancer, diabetes, and deaths from all causes than nearly any other medical intervention.

"Some useful lessons may come from the war on tobacco," Dr. Neal Barnard wrote in the American Medical Association's ethics journal. When he stopped smoking himself in the 1980s, the lung cancer death rate was peaking in the United States. As the prevalence of smoking dropped, so have lung cancer rates. No longer were doctors telling patients to "[g]ive your throat a vacation" by smoking a fresh cigarette. Doctors realized they were "more effective at counseling patients to quit smoking if they no longer had tobacco stains on their own fingers." "In other words, doctors went from being bystanders--or even enablers--to leading the fight against smoking." And today, says Dr. Barnard, "Plant-based diets are the nutritional equivalent of quitting smoking."

From an editorial in the journal Alternative Therapies in Health and Medicine: "If we were to gather the world's top nutrition scientists and experts (free from food industry influence), there would be very little debate about the essential properties of good nutrition. Unfortunately, most doctors are nutritionally illiterate. And worse, they don't know how to use the most powerful medicine available to them: food."

Physician advice matters. When doctors told patients to improve their diets by cutting down on meat, dairy, and fried foods, patients were more likely to make dietary changes. It may work even better if doctors practice what they preach. Researchers at Emory University randomized patients to watch one of two videos. In one video, a physician briefly mentioned her personal dietary and exercise practices and visible on her desk were both a bike helmet and an apple. In the other video, she did not discuss her personal healthy practices, and the helmet and apple were missing. In both videos, the doctor advised the patients to cut down on meat, not usually have meat for breakfast, and have no meats for lunch or dinner at least half the time. In the disclosure video, the physician related that she herself had successfully cut down on meat. Perhaps not surprisingly, patients rated that physician to be more believable and motivating. Physicians who walk the walk--literally--and have healthier eating habits not only tend to counsel more about exercise and diet, but have been found to seem more credible or motivating when they do so.

It may also make them better doctors. A randomized controlled intervention to clean up doctors' diets, called the Promoting Health by Self Experience (PHASE) trial, found that healthcare providers' personal lifestyles were correlated directly with their clinical performance. Healthcare providers' improved wellbeing and lifestyle cascaded to the patients and clinics, suggesting an additional strategy to achieve successful health promotion.

Are you ready for the best kept secret in medicine? Given the right conditions, the body can heal itself. For example, treating cardiovascular disease with appropriate dietary changes is good medicine, reducing mortality without any adverse effects. We should keep doing research, certainly, but educating physicians and patients alike about the existing knowledge regarding the power of nutrition as medicine may be the best investment we can make.

Of course, to advise patients about nutrition, physicians first have to educate themselves, as it is unlikely they received formal nutrition education during their medical training:

For more on the power of healthy living, see:

In health,

Michael Greger, M.D.

PS: If you haven't yet, you can subscribe to my free videos here and watch my live, year-in-review presentations:

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

Original Link

Big Sugar Takes on the World Health Organization

Big Sugar Takes on the World Health Organization.jpeg

The World Health Organization (WHO) recommends we reduce our consumption of salt, trans fats, saturated fats, and added sugars. Why? Because consumption of such foods is the cause of at least 14 million deaths every year from chronic diseases.

"Several decades ago, it was heresy to talk about an impending global pandemic of obesity." Today, we're seeing chronic disease rates skyrocket around the world. The Western diet has been exported to the far reaches of the planet, with white flour, sugar, fat, and animal-based foods replacing beans, peas, lentils, other vegetables, and whole grains.

In order to understand the reasons underlying this trend toward greater consumption of animal products, sugar, and oils, and reduced consumption of whole plant foods, we need to begin by understanding the purposeful economic manipulations that have occurred since World War II relating to agricultural policies around the world. For example, since early in the last century, the U.S. government "has supported food production through subsidies and other policies, resulting in large surpluses of food commodities, meat, and calories. In this artificial market, large food producers and corporations-Big Agriculture and Big Food-became very profitable." Their profitability may be part of the problem.

Dr. Margaret Chan, the Director-General of the World Health Organization, gave the opening address at the 8th Global Conference on Health Promotion. One of the biggest challenges facing health promotion worldwide, she said, is that the efforts to prevent our top killers "go against the business interests of powerful economic operators." It is not just Big Tobacco anymore. "Public health must also contend with Big Food, Big Soda, and Big Alcohol. All of these industries fear regulation and protect themselves by using the same tactics...front groups, lobbies, promises of self-regulation, lawsuits, and industry-funded research that confuses the evidence and keeps the public in doubt."

And the World Health Organization should know. In 2003, the organization released a draft report that outlined a global strategy to address issues of diet. Although many of the WHO's recommendations were rather tame, a remarkable series of events was spurred by six words in the report: "limit the intake of 'free' sugars" (added sugar). Within days, the sugar industry, through the Sugar Association, enlisted the support of officials high in the U.S. government and led a vigorous attack on both the report and the World Health Organization itself, culminating in a threat to get Congress to withdraw U.S. funding to the WHO. The WHO, the organization that "deals with AIDS, malnutrition, infectious disease, bioterrorism, and more, threatened because of its stance on sugar." At the same time, the U.S. went to bat for American tobacco companies and led the charge against the World Health Organization's Framework Convention on Tobacco Control.

As discussed in my video, Big Sugar Takes on the World Health Organization, the threat from the sugar industry was described by WHO insiders as worse than any pressure they ever got from the tobacco lobby. As revealed in an internal memo, the U.S. government apparently had a list of demands. These included deletion of all references to the science that WHO experts had compiled on the matter and the removal of all references to fat, oils, sugar, and salt.

The threats failed to make the WHO withdraw their report. Entitled "Diet, Nutrition and the Prevention of Chronic Disease," it "concluded that a diet low in saturated fat, sugar and salt and high in fruit and vegetables was required to tackle the epidemic rise in chronic diseases worldwide." They did end up watering it down, though. Gone was reference to the comprehensive scientific report, and gone was its call for its recommendations to be actually translated into national guidelines.

History has since repeated. At the last high-level United Nations meeting to address chronic diseases, representatives from some Western countries, including the United States, helped block a consensus on action after lobbying from the alcohol, food, tobacco, and drug industries. When asked why Michelle Obama's successful childhood obesity programs in the U.S. should not be modeled around the world, a U.S. official responded that they might harm American exports.

See also: How Much Added Sugar Is Too Much?

If sugar is bad, then what about all the sugar in fruit? See If Fructose Is Bad, What About Fruit? and How Much Fruit Is Too Much?.

For more on the corrupting political and economic influences in nutrition, see videos such as:

And because of that, check out a couple of my introductory videos: Why You Should Care about Nutrition and Taking Personal Responsibility for Your Health.

In health,

Michael Greger, M.D.

PS: If you haven't yet, you can subscribe to my free videos here and watch my live, year-in-review presentations:

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

Original Link

Big Sugar Takes on the World Health Organization

Big Sugar Takes on the World Health Organization.jpeg

The World Health Organization (WHO) recommends we reduce our consumption of salt, trans fats, saturated fats, and added sugars. Why? Because consumption of such foods is the cause of at least 14 million deaths every year from chronic diseases.

"Several decades ago, it was heresy to talk about an impending global pandemic of obesity." Today, we're seeing chronic disease rates skyrocket around the world. The Western diet has been exported to the far reaches of the planet, with white flour, sugar, fat, and animal-based foods replacing beans, peas, lentils, other vegetables, and whole grains.

In order to understand the reasons underlying this trend toward greater consumption of animal products, sugar, and oils, and reduced consumption of whole plant foods, we need to begin by understanding the purposeful economic manipulations that have occurred since World War II relating to agricultural policies around the world. For example, since early in the last century, the U.S. government "has supported food production through subsidies and other policies, resulting in large surpluses of food commodities, meat, and calories. In this artificial market, large food producers and corporations-Big Agriculture and Big Food-became very profitable." Their profitability may be part of the problem.

Dr. Margaret Chan, the Director-General of the World Health Organization, gave the opening address at the 8th Global Conference on Health Promotion. One of the biggest challenges facing health promotion worldwide, she said, is that the efforts to prevent our top killers "go against the business interests of powerful economic operators." It is not just Big Tobacco anymore. "Public health must also contend with Big Food, Big Soda, and Big Alcohol. All of these industries fear regulation and protect themselves by using the same tactics...front groups, lobbies, promises of self-regulation, lawsuits, and industry-funded research that confuses the evidence and keeps the public in doubt."

And the World Health Organization should know. In 2003, the organization released a draft report that outlined a global strategy to address issues of diet. Although many of the WHO's recommendations were rather tame, a remarkable series of events was spurred by six words in the report: "limit the intake of 'free' sugars" (added sugar). Within days, the sugar industry, through the Sugar Association, enlisted the support of officials high in the U.S. government and led a vigorous attack on both the report and the World Health Organization itself, culminating in a threat to get Congress to withdraw U.S. funding to the WHO. The WHO, the organization that "deals with AIDS, malnutrition, infectious disease, bioterrorism, and more, threatened because of its stance on sugar." At the same time, the U.S. went to bat for American tobacco companies and led the charge against the World Health Organization's Framework Convention on Tobacco Control.

As discussed in my video, Big Sugar Takes on the World Health Organization, the threat from the sugar industry was described by WHO insiders as worse than any pressure they ever got from the tobacco lobby. As revealed in an internal memo, the U.S. government apparently had a list of demands. These included deletion of all references to the science that WHO experts had compiled on the matter and the removal of all references to fat, oils, sugar, and salt.

The threats failed to make the WHO withdraw their report. Entitled "Diet, Nutrition and the Prevention of Chronic Disease," it "concluded that a diet low in saturated fat, sugar and salt and high in fruit and vegetables was required to tackle the epidemic rise in chronic diseases worldwide." They did end up watering it down, though. Gone was reference to the comprehensive scientific report, and gone was its call for its recommendations to be actually translated into national guidelines.

History has since repeated. At the last high-level United Nations meeting to address chronic diseases, representatives from some Western countries, including the United States, helped block a consensus on action after lobbying from the alcohol, food, tobacco, and drug industries. When asked why Michelle Obama's successful childhood obesity programs in the U.S. should not be modeled around the world, a U.S. official responded that they might harm American exports.

See also: How Much Added Sugar Is Too Much?

If sugar is bad, then what about all the sugar in fruit? See If Fructose Is Bad, What About Fruit? and How Much Fruit Is Too Much?.

For more on the corrupting political and economic influences in nutrition, see videos such as:

And because of that, check out a couple of my introductory videos: Why You Should Care about Nutrition and Taking Personal Responsibility for Your Health.

In health,

Michael Greger, M.D.

PS: If you haven't yet, you can subscribe to my free videos here and watch my live, year-in-review presentations:

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

Original Link

What Causes Diabetes?

What Causes Diabetes?.jpeg

After about age 20, we may have all the insulin-producing beta cells we're ever going to get. So if we lose them, we may lose them for good. Autopsy studies show that by the time type 2 diabetes is diagnosed, we may have already killed off half of our beta cells.

You can kill pancreatic cells right in a petri dish. If you expose the insulin-producing beta cells in our pancreas to fat, they suck it up and then start dying off. Fat breakdown products can interfere with the function of these cells and ultimately lead to their death. A chronic increase in blood fat levels can be harmful to our pancreas.

It's not just any fat; it's saturated fat. As you can see in my video, What Causes Diabetes?, predominant fat in olives, nuts, and avocados gives a tiny bump in death protein 5, but saturated fat really elevates this contributor to beta cell death. Therefore, saturated fats are harmful to beta cells. Cholesterol is, too. The uptake of bad cholesterol (LDL) can cause beta cell death as a result of free radical formation.

Diets rich in saturated fats not only cause obesity and insulin resistance, but the increased levels of circulating free fats in the blood (non-esterified fatty acids, or NEFAs) may also cause beta cell death and may thus contribute to the progressive beta cell loss we see in type 2 diabetes. These findings aren't just based on test tube studies. If researchers have infused fat into people's blood streams, they can show it directly impairing pancreatic beta cell function. The same occurs when we ingest it.

Type 2 diabetes is characterized by "defects in both insulin secretion and insulin action," and saturated fat appears to impair both. Researchers showed saturated fat ingestion reduces insulin sensitivity within hours. The subjects were non-diabetics, so their pancreases should have been able to boost insulin secretion to match the drop in sensitivity. But no, "insulin secretion failed to compensate for insulin resistance in subjects who ingested [the saturated fat]." This implies saturated fat impaired beta cell function as well, again just within hours after going into our mouth. "[I]ncreased consumption of [saturated fats] has a powerful short- and long-term effect on insulin action," contributing to the dysfunction and death of pancreatic beta cells in diabetes.

Saturated fat isn't just toxic to the pancreas. The fats found predominantly in meat and dairy--chicken and cheese are the two main sources in the American diet--are considered nearly "universally toxic." In contrast, the fats found in olives, nuts, and avocados are not. Saturated fat has been found to be particularly toxic to liver cells, contributing to the formation of fatty liver disease. If you expose human liver cells to plant fat, though, nothing happens. If you expose our liver cells to animal fat, a third of them die. This may explain why higher intake of saturated fat and cholesterol are associated with non-alcoholic fatty liver disease.

By cutting down on saturated fat consumption, we may be able to help interrupt these processes. Decreasing saturated fat intake can help bring down the need for all that excess insulin. So either being fat or eating saturated fat can both cause excess insulin in the blood. The effect of reducing dietary saturated fat intake on insulin levels is substantial, regardless of how much belly fat we have. It's not just that by eating fat we may be more likely to store it as fat. Saturated fats, independently of any role they have in making us fat, "may contribute to the development of insulin resistance and its clinical consequences." After controlling for weight, alcohol, smoking, exercise, and family history, diabetes incidence was significantly associated with the proportion of saturated fat in our blood.

So what causes diabetes? The consumption of too many calories rich in saturated fats. Just like everyone who smokes doesn't develop lung cancer, everyone who eats a lot of saturated fat doesn't develop diabetes--there is a genetic component. But just like smoking can be said to cause lung cancer, high-calorie diets rich in saturated fats are currently considered the cause of type 2 diabetes.

I have a lot of videos on diabetes, including:

Preventing the disease:

And treating it:

In health,

Michael Greger, M.D.

PS: If you haven't yet, you can subscribe to my free videos here and watch my live, year-in-review presentations:

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

Original Link

What Causes Diabetes?

What Causes Diabetes?.jpeg

After about age 20, we may have all the insulin-producing beta cells we're ever going to get. So if we lose them, we may lose them for good. Autopsy studies show that by the time type 2 diabetes is diagnosed, we may have already killed off half of our beta cells.

You can kill pancreatic cells right in a petri dish. If you expose the insulin-producing beta cells in our pancreas to fat, they suck it up and then start dying off. Fat breakdown products can interfere with the function of these cells and ultimately lead to their death. A chronic increase in blood fat levels can be harmful to our pancreas.

It's not just any fat; it's saturated fat. As you can see in my video, What Causes Diabetes?, predominant fat in olives, nuts, and avocados gives a tiny bump in death protein 5, but saturated fat really elevates this contributor to beta cell death. Therefore, saturated fats are harmful to beta cells. Cholesterol is, too. The uptake of bad cholesterol (LDL) can cause beta cell death as a result of free radical formation.

Diets rich in saturated fats not only cause obesity and insulin resistance, but the increased levels of circulating free fats in the blood (non-esterified fatty acids, or NEFAs) may also cause beta cell death and may thus contribute to the progressive beta cell loss we see in type 2 diabetes. These findings aren't just based on test tube studies. If researchers have infused fat into people's blood streams, they can show it directly impairing pancreatic beta cell function. The same occurs when we ingest it.

Type 2 diabetes is characterized by "defects in both insulin secretion and insulin action," and saturated fat appears to impair both. Researchers showed saturated fat ingestion reduces insulin sensitivity within hours. The subjects were non-diabetics, so their pancreases should have been able to boost insulin secretion to match the drop in sensitivity. But no, "insulin secretion failed to compensate for insulin resistance in subjects who ingested [the saturated fat]." This implies saturated fat impaired beta cell function as well, again just within hours after going into our mouth. "[I]ncreased consumption of [saturated fats] has a powerful short- and long-term effect on insulin action," contributing to the dysfunction and death of pancreatic beta cells in diabetes.

Saturated fat isn't just toxic to the pancreas. The fats found predominantly in meat and dairy--chicken and cheese are the two main sources in the American diet--are considered nearly "universally toxic." In contrast, the fats found in olives, nuts, and avocados are not. Saturated fat has been found to be particularly toxic to liver cells, contributing to the formation of fatty liver disease. If you expose human liver cells to plant fat, though, nothing happens. If you expose our liver cells to animal fat, a third of them die. This may explain why higher intake of saturated fat and cholesterol are associated with non-alcoholic fatty liver disease.

By cutting down on saturated fat consumption, we may be able to help interrupt these processes. Decreasing saturated fat intake can help bring down the need for all that excess insulin. So either being fat or eating saturated fat can both cause excess insulin in the blood. The effect of reducing dietary saturated fat intake on insulin levels is substantial, regardless of how much belly fat we have. It's not just that by eating fat we may be more likely to store it as fat. Saturated fats, independently of any role they have in making us fat, "may contribute to the development of insulin resistance and its clinical consequences." After controlling for weight, alcohol, smoking, exercise, and family history, diabetes incidence was significantly associated with the proportion of saturated fat in our blood.

So what causes diabetes? The consumption of too many calories rich in saturated fats. Just like everyone who smokes doesn't develop lung cancer, everyone who eats a lot of saturated fat doesn't develop diabetes--there is a genetic component. But just like smoking can be said to cause lung cancer, high-calorie diets rich in saturated fats are currently considered the cause of type 2 diabetes.

I have a lot of videos on diabetes, including:

Preventing the disease:

And treating it:

In health,

Michael Greger, M.D.

PS: If you haven't yet, you can subscribe to my free videos here and watch my live, year-in-review presentations:

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

Original Link

Solving a Colon Cancer Mystery

Solving-a-Colon-Cancer-Mystery.jpeg

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

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

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

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

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

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

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

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

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

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

In health,

Michael Greger, M.D.

PS: If you haven't yet, you can subscribe to my free videos here and watch my live, year-in-review presentations:

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

Original Link

Solving a Colon Cancer Mystery

Solving-a-Colon-Cancer-Mystery.jpeg

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

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

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

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

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

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

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

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

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

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

In health,

Michael Greger, M.D.

PS: If you haven't yet, you can subscribe to my free videos here and watch my live, year-in-review presentations:

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

Original Link

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