Plant versus Animal Iron

Plant versus Animal Iron.jpeg

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

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

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

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

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

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

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

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

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

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

In health,

Michael Greger, M.D.

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

Image Credit: Sally Plank

Original Link

Plant versus Animal Iron

Plant versus Animal Iron.jpeg

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

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

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

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

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

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

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

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

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

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

In health,

Michael Greger, M.D.

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

Image Credit: Sally Plank

Original Link

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

Which Dietary Factors Affect Breast Cancer Most?

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One of my favorite cancer-specific charities, the American Institute for Cancer Research, lauds the China Study and the documentary Forks Over Knives, with which they share the same bottom-line message: The healthiest diets are those that revolve around whole plant foods.

They then translate that advice into their Ten Recommendations for Cancer Prevention, featured in my video Which Dietary Factors Affect Breast Cancer Most? We now have evidence that those who follow such advice are actually protected against cancer. Breast cancer risk was reduced by 60% in women who met at least five recommendations compared with those who met none. The most important dietary advice was to be as lean as possible within the normal range of body weight, eat mostly foods of plant origin, and limit alcoholic drinks.

What about other cancers? Greater adherence to the AICR dietary guidelines was also associated with significantly less endometrial, colorectal, lung, kidney, stomach, oral, liver, and esophageal cancer. In other words, adherence to dietary recommendations for cancer prevention may lower the risk of developing most types of cancer. The drop in bladder cancer did not reach statistical significance, but a larger follow-up study following 469,000 people for 11 years (the largest to date) found that just a 3% increase in the consumption of animal protein calories was associated with a 15% higher risk of bladder cancer, whereas just a 2% increase in plant protein was associated with a 23% lower risk.

AICR recommendation number ten is that cancer survivors should follow the recommendations for cancer prevention. The same diet that can help prevent cancer in the first place can be used to help save our life after diagnosis. Adherence to the guidelines for cancer prevention was found to be associated with lower mortality among older female cancer survivors, or breast cancer and other cancers in general.

A cancer diagnosis is considered a teachable moment to get people eating and living healthier. Oncologists revel at the growth in the number of cancer survivors in this country, now ten million strong and growing. It's great that those with cancer are living longer, but even better to prevent it in the first place so we can all live longer. Not only does adherence to the guidelines lower cancer risk, but extends our lifespan because the guidelines are also significantly associated with a lower hazard of dying from heart disease and respiratory disease, suggesting that following the recommendations could "significantly increase longevity."

Just like eating to prevent cancer helps to prevent heart disease, eating to protect our heart helps prevent cancer. It sounds self-evident, but adherence to a healthy lifestyle is therefore associated with a lower risk of mortality overall. And the more healthy behaviors we have, the longer we get to live. Such factors included not smoking, walking every day, or eating green leafy vegetables almost daily.

To help differentiate the effects of diet from other lifestyle behaviors like smoking and drinking on cancer incidence, Adventists were recently compared to Baptists. Both discourage alcohol and tobacco, but the Adventists go further, encouraging a reduction of meat. In general, the Adventists had lower cancer hazard rates than the Baptists, and within Adventist populations, the vegetarians did even better, and those eating the most plants, did the best.

Why do plant-based diets appear to lower the risk of cancer? A number of fascinating mechanisms:

Specific to breast cancer:

Though plant-based beverages may be harmful: Breast Cancer and Alcohol: How Much Is Safe?

In terms of foods associated with breast cancer survival, 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--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.

Image Credit: MesserWoland

Image Credit: [Lev Kropotov] © 123RF.com

Original Link

How Big Food Twists the Science

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Just like mosquitos are the vectors of spread for malaria, a landmark article published last year in one of the most prestigious medical journals, Lancet, described large food corporations as the vectors of spread for chronic disease. Unlike "infectious disease epidemics, however, these corporate disease vectors implement sophisticated campaigns to undermine public health interventions." Most mosquitoes don't have as good PR firms.

A key message was that "alcohol and ultra-processed food and drink industries use similar strategies as the tobacco industry to undermine effective public health policies and programs." What they mean by ultra-processed is things like burgers, frozen meals, chicken nuggets, fish sticks, potato chips, doughnuts and soda pop.

But how is the food industry like the tobacco industry? The "first strategy is to bias research findings." For example, Philip Morris implemented the Whitecoat project to hire doctors to publish ghost-written studies purporting to negate links between secondhand smoke and harm, publishing biased cherry-picked scientific reports to deny harm and suppress health information. In my video Food Industry-Funded Research Bias, you can see the actual industry memo describing the Whitecoat Project, designed to reverse the scientific "misconception" that secondhand smoke is harmful.

Similarly, funding from these large food corporations biases research. Studies show systematic bias from industry funding, so we get the same kind of tactics--supplying misinformation, use of supposedly conflicting evidence and hiding negative data.

The same scientists-for-hire that downplayed the risks of secondhand smoke are the same hired by the likes of the National Confectioner's Association to say candy cigarettes are A-OK as well. Of course, they declared "no conflict of interest."

The similarities between strategies used by the tobacco, alcohol, and food and drink corporations are unsurprising in view of the flow of people, funds and activities across these industries, which also have histories of joint ownership--like Philip Morris owned both Kraft and Miller Brewing.

So what's their strategy? As a former FDA commissioner described:

"The tobacco industry's strategy was embodied in a script written by the lawyers. Every tobacco company executive in the public eye was told to learn the script backwards and forwards, no deviation was allowed. The basic premise was simple-- smoking had not been proven to cause cancer. Not proven, not proven, not proven--this would be stated insistently and repeatedly. Inject a thin wedge of doubt, create controversy, never deviate from the prepared line. It was a simple plan and it worked."

Internal industry memos make this explicit, stating "doubt is our product, since it is the best means of competing with the body of fact that exists in the mind of the general public." The internal industry memos list objective number one as "to set aside in the minds of millions the false conviction that cigarette smoking causes lung cancer and other diseases; a conviction based on fanatical assumptions, fallacious rumors, unsupported claims and the unscientific statements and conjectures of publicity-seeking opportunists... [We need] to lift the cigarette from the cancer identification as quickly as possible, and to establish--once and for all--that no scientific evidence has ever been produced, presented or submitted to prove conclusively that cigarette smoking causes cancer," similar to what's now coming out from the food industry, from the same folks that brought us smoke and candy.

This is part of a series of "political" blogs which includes my video, Collaboration with the New Vectors of Disease. Why don't I just "stick to the science"? When there are billions of dollars at stake, the body of evidence can be skewed and manipulated. Funders can determine which studies are performed, how they're performed and whether or not they get published at all. That's why I think it's important to take a broader view to account for the ways the scientific method can be perverted for profit.

Here are some examples:

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.

Original Link

Virus in Chicken Could Be Linked to Obesity

NF-May31 Infectobesity Adenovirus 36 and Childhood Obesity.jpeg

Recently, there has been research examining the connection between poultry consumption and weight gain. One study out of the Netherlands examining about 4,000 people, correlated chicken consumption with weight gain. Another study followed 89,000 people in four other countries and found that animal protein intake was associated with long-term weight gain, and poultry was the worst, with 40 percent more weight gain than red meat or processed meat.

What makes poultry so bad? Yes, chickens are fatty these days because of the way we've genetically manipulated them--up to ten times more fat and calories than they used to have--but one bizarre theory postulated that it might be due to an obesity-causing chicken virus. In one study, one in five obese humans tested positive to the chicken virus SMAM-1, with those exposed to the chicken virus averaging 33 pounds heavier than those testing negative.

SMAM-1 was the first chicken virus to be associated with human obesity, but not the last. The original obesity-causing chicken virus SMAM-1 was able to effectively transmit obesity from one chicken to another when caged together, similar to a human adenovirus Ad-36, a human obesity-associated virus first associated with obesity in chickens and mice. Ad-36 spreads quickly from one chicken to another via nasal, oral or fecal excretion and contamination, causing obesity in each chicken. This of course raises serious concerns about Ad-36-induced adiposity in humans.

The easiest way to test this hypothesis is to experimentally infect humans with the virus. However, ethical reasons preclude experimental infection of humans, and so the evidence will have to remain indirect. In the absence of direct experimental data, we must rely on population studies, similar to how researchers nailed smoking and lung cancer. About 15 percent of Americans are already infected with Ad-36, so we can follow them and see what happens. That's exactly what a research team out of Taiwan did (highlighted in my video Infectobesity: Adenovirus 36 and Childhood Obesity). They followed 1,400 Hispanic men and women for a decade and found that not only were those exposed to the virus fatter than those who were not, but also over the ten years, those with a history of infection had a greater percentage of body fat over time.

Most studies done to date on adults have found a connection between exposure to Ad-36 and obesity, and all studies done so far on childhood obesity show an increase in prevalence of infection in obese children compared to non-obese children. We're now up to more than a thousand children studied with similar findings. Obese children who tested positive for the virus weighed 35 pounds more than children who tested negative.

The virus appears to both increase the number of fat cells by mobilizing precursor stem cells and increase the accumulation of fat within the cells. If we take liposuction samples of fat from people, the fat cell precursors turn into fat cells at about five times the rate in people who came to the liposuction clinic already infected. Fat taken from non-infected people that was then exposed to the virus start sucking up fat at a faster rate, potentially inducing obesity without increasing food intake.

Just as Ad-36 can be transmitted horizontally from one infected chicken to another in the same cage, subsequently causing obesity in each chicken, this same virus is also easily transmitted among humans, raising the question as to whether at least some cases of childhood obesity can be considered an infectious disease. Researchers publishing in the International Journal of Pediatric Obesity speculate that this animal adenovirus may have mutated to become a human adenovirus capable of infecting humans and causing obesity.

In health,
Michael Greger, M.D.

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

Image Credit: Glasseyes view / Flickr

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Do Dietary Toxins Contribute to Hand Tremors?

NF-Nov26 Essential Tremor and Diet.jpg

Essential tremor, affecting 1 in 25 adults over 40 and up to 1 in 5 of those in their 90s, is one of the most common neurological diseases. In addition to the potentially debilitating hand tremor, there can be other neuropsychiatric manifestations, including difficulty walking and various levels of cognitive impairment.

Might beta-carboline neurotoxins play a role in essential tremor? Harmane is one of the most potent of the tremor-producing neurotoxins. Expose people to harmane, and they develop tremors; take it away, and the tremors disappear. What if we're exposed long-term? A recent study at Columbia University, highlighted in my video, Essential Tremor and Diet, found that those with essential tremor have much higher levels of this toxin in their bloodstream compared to those without tremor. Furthermore, the higher the harmane levels, the worse the tremor. The highest levels are found in those who have both essential tremor and cancer, suggesting harmane may be playing a role in both diseases.

How did folks get exposed to these chemicals? Primarily through meat: beef, pork, fish, and especially chicken. So if this potent, tremor-producing neurotoxin is concentrated in cooked muscle foods, is meat consumption associated with a higher risk of essential tremor? Another Columbia University study found that men who ate the most meat had 21 times the odds of essential tremor. To put that in context, if we go back to the original studies on smoking and lung cancer, we see that smoking was only linked to about 14 times the odds, not 21.

Blood levels of this neurotoxin may shoot up within five minutes of eating meat. Five minutes? It's not even digested by then. This rapid uptake is indicative of significant absorption directly through the mouth straight into the bloodstream, bypassing the stomach and, most importantly, bypassing the detoxifying enzymes of the liver. This may lead to higher exposure levels in peripheral organs, like the brain.

Due to its high fat solubility, harmane accumulates in brain tissue, and, using a fancy brain scan called "proton magnetic resonance spectroscopic imaging," higher harmane levels have been linked to greater metabolic dysfunction in the brains of essential tremor sufferers.

Harmane is also found in certain heated plants, like tobacco. A broiled chicken breast has about 13 micrograms of harmane, and cigarettes average about one microgram, so a half pack of cigarettes could expose us to almost as much of this neurotoxin as a serving of chicken. Harman is created when tobacco is burned, and also when coffee beans are roasted. However, coffee intake has not been tied to increased risk (and neither has tobacco for that matter), so it may be something else in meat that's to blame for the 2,000 percent increase in odds for this disabling brain disease.

I also have a few videos about the other major tremor condition, Parkinson's Disease: Preventing Parkinson's Disease with Diet and Treating Parkinson's Disease with Diet

Other compounds created in cooked meats may also have implications for cancer risk:

-Michael Greger, M.D.

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

Image Credit: Gennaro D'Orio / Flickr

Original Link

Why Some Dietary Cholesterol Studies Fail to Show Harm

NF-Oct29 when low risks means high risk  .jpg

How else can we make decisions for ourselves and our families but by the best available balance of evidence? The latest meta-analysis, pooling data from more than a dozen studies involving more than 300,000 people, indicates that there is a dose dependent association between egg consumption and the risk of cardiovascular disease and diabetes. But that doesn't mean every individual study showed evidence of harm. Even though the totality of evidence points to harm, the egg industry can cherry-pick studies that show no apparent effects.

If eggs are harmful, why don't all of the studies on heart disease and egg consumption show significant harm? It may have to do with Geoffrey Rose's "sick population" concept. If an entire population is sick, then the range of "health" may not be sufficiently broad to establish a significant association. Rose's paper is one of the most famous papers ever written in preventive medicine and should be required reading for all medical students.

Imagine if everyone smoked 20 cigarettes a day. If everybody smoked, then clinical studies, case-control studies, and cohort studies would all lead us to conclude that lung cancer was a genetic disease; and in one sense that would be true. Some smokers get cancer; others lifelong smokers never do. But if everybody smoked, we'd never know that smoking was a risk factor. Thankfully, in the case of cigarettes and lung cancer, it so happened that the original study populations contained about equal numbers of smokers and non-smokers. In such a situation, studies are able to identify smoking as the main risk factor.

But take cholesterol. In the video, When Low Risk Means High Risk, you can see the cholesterol levels of the people with and without heart disease in the famous Framingham Heart Study. There's hardly any difference because practically everybody's cholesterol was too high; it's like everyone was a smoker. The painful truth is that even someone at "low risk" for heart disease is likely to die of heart disease. Everyone who eats the standard Western diet is, in fact, a high-risk individual when it comes to heart disease.

In a sick population like ours where nearly everyone is eating lots of saturated fat and cholesterol, adding some more saturated fat and cholesterol in the form of eggs may just take us from one sorry state--probably dying from heart disease--to another sorry state--still probably dying from heart disease.

So when the current federal guidelines say we need to particularly restrict dietary cholesterol if we're at high risk for heart disease, we need to realize that nearly all Americans that live past middle age are at high risk of dying from heart disease--it's our #1 cause of death. As stroke specialist David Spence and colleagues put it, "A 20-year old man might feel safe smoking and eating egg yolks because his heart attack is 45 years or so in the future. But why would he want to accelerate the progression of his atherosclerotic plaque and bring it on sooner? Stopping egg yolks after the heart attack would be like quitting smoking after lung cancer is diagnosed."

There may in fact be a plateau of risk for smoking, too. Whether we smoke for 25 years or 35 years, our risk for lung cancer may be the same--really high, but about the same. The tobacco industry could truthfully tell someone who's smoked for most of their lives that, don't worry, you can keep smoking and your risk of lung cancer won't go up (conveniently failing to mention that if you're already at high risk and you quit completely, your risk would drop dramatically). It's like if you took a raging drunk and had them take a shot of whiskey. In someone who's hammered, it might not make much difference, but to a teetotaler, a couple shots could have quite an effect. So it's like the alcohol industry with a group of drunks saying, see, couple shots, no big deal. But that doesn't mean it's not better to be sober.

Instead of going from high risk to high risk, better to go to low risk or no risk.

This reminds me of what the beef industry tried to pull. See BOLD Indeed: Beef Lowers Cholesterol?

Is our diet really that bad? See Nation's Diet in Crisis.

Here are a few other important egg industry videos:

-Michael Greger, M.D.

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

Image Credit: Keoni Cabral / Flickr

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

Food as Medicine

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

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

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

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

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

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

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

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

-Michael Greger

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