Diet and Hiatal Hernia

Diet and Hiatal Hernia.jpeg

In terms of preventing acid reflux heartburn, high-fat meals cause dramatically more acid exposure in the esophagus in the hours after a meal. I talked about this in Diet and GERD Acid Reflux Heartburn. High fiber intake decreases the risk, but why? One typically thinks of fiber as helping out much lower in the digestive tract.

A systematic review and meta-analysis published in 2013 found a highly significant protective association between esophageal adenocarcinoma and dietary fiber intake, suggesting that individuals with the highest fiber intakes have an approximately 30% lower risk of cancer. This could be because of the phytates in high-fiber foods slowing cancer growth, fiber's anti-inflammatory effects, or even fiber removing carcinogens. But those are all generic anti-cancer effects of whole plant foods. Specific to this type of acid irritation-induced esophageal cancer, fiber may reduce the risk of reflux in the first place. But how?

As you can see in my video, Diet and Hiatal Hernia, hiatus hernia occurs when part of the stomach is pushed up through the diaphragm into the chest cavity, which makes it easy for acid to reflux into the esophagus and throat. Hiatus hernia affects more than 1 in 5 American adults. In contrast, in rural African communities eating their traditional plant-based diets, the risk wasn't 1 in 5; it was closer to 1 in 1,000--almost unheard of. Hiatus hernia is almost peculiar to those who consume western-type diets. Why are plant-based populations protected? Perhaps because they pass such large, soft stools, three or four times the volume as Westerners.

What does the size and consistency of one's bowel movement have to do with hiatal hernia? A simple model may be helpful in illustrating the mechanism that produces upward herniation of the stomach through the hole (called the esophageal hiatus) in the diaphragm, which separates the abdomen from the chest. If a ball with a hole in its wall is filled with water and then squeezed, the water is pushed out through the hole. If we liken the abdominal cavity to the ball, the esophageal hiatus in the diaphragm corresponds with the hole in the ball. Abdominal straining during movement of firm feces corresponds to squeezing the ball and may result in the gradual expulsion of the upper end of the stomach from the abdominal cavity up into the chest. It's like when we squeeze a stress ball. Straining at stool raises pressures inside our abdominal cavity more than almost any other factor.

In effect, straining at stool puts the squeeze on our abdomen and may herniate part of our stomach up. "Consistent with this concept is the observation that in Africans the lower esophageal sphincter is entirely subdiaphragmatic, whereas it usually straddles the diaphragm in Westerners and is above the diaphragm in the presence of hiatus hernia."

This same abdominal pressure from straining may cause a number of other problems, too. Straining can cause herniations in the wall of the colon itself, known as diverticulosis. That same pressure can backup blood flow in the veins around the anus, causing hemorrhoids, and also push blood flow back into the legs, resulting in varicose veins.

Hiatal hernia is not the only condition that high-fiber diets may protect against. See:

I also have a load of other bowel movement videos:

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

Diet and Hiatal Hernia

Diet and Hiatal Hernia.jpeg

In terms of preventing acid reflux heartburn, high-fat meals cause dramatically more acid exposure in the esophagus in the hours after a meal. I talked about this in Diet and GERD Acid Reflux Heartburn. High fiber intake decreases the risk, but why? One typically thinks of fiber as helping out much lower in the digestive tract.

A systematic review and meta-analysis published in 2013 found a highly significant protective association between esophageal adenocarcinoma and dietary fiber intake, suggesting that individuals with the highest fiber intakes have an approximately 30% lower risk of cancer. This could be because of the phytates in high-fiber foods slowing cancer growth, fiber's anti-inflammatory effects, or even fiber removing carcinogens. But those are all generic anti-cancer effects of whole plant foods. Specific to this type of acid irritation-induced esophageal cancer, fiber may reduce the risk of reflux in the first place. But how?

As you can see in my video, Diet and Hiatal Hernia, hiatus hernia occurs when part of the stomach is pushed up through the diaphragm into the chest cavity, which makes it easy for acid to reflux into the esophagus and throat. Hiatus hernia affects more than 1 in 5 American adults. In contrast, in rural African communities eating their traditional plant-based diets, the risk wasn't 1 in 5; it was closer to 1 in 1,000--almost unheard of. Hiatus hernia is almost peculiar to those who consume western-type diets. Why are plant-based populations protected? Perhaps because they pass such large, soft stools, three or four times the volume as Westerners.

What does the size and consistency of one's bowel movement have to do with hiatal hernia? A simple model may be helpful in illustrating the mechanism that produces upward herniation of the stomach through the hole (called the esophageal hiatus) in the diaphragm, which separates the abdomen from the chest. If a ball with a hole in its wall is filled with water and then squeezed, the water is pushed out through the hole. If we liken the abdominal cavity to the ball, the esophageal hiatus in the diaphragm corresponds with the hole in the ball. Abdominal straining during movement of firm feces corresponds to squeezing the ball and may result in the gradual expulsion of the upper end of the stomach from the abdominal cavity up into the chest. It's like when we squeeze a stress ball. Straining at stool raises pressures inside our abdominal cavity more than almost any other factor.

In effect, straining at stool puts the squeeze on our abdomen and may herniate part of our stomach up. "Consistent with this concept is the observation that in Africans the lower esophageal sphincter is entirely subdiaphragmatic, whereas it usually straddles the diaphragm in Westerners and is above the diaphragm in the presence of hiatus hernia."

This same abdominal pressure from straining may cause a number of other problems, too. Straining can cause herniations in the wall of the colon itself, known as diverticulosis. That same pressure can backup blood flow in the veins around the anus, causing hemorrhoids, and also push blood flow back into the legs, resulting in varicose veins.

Hiatal hernia is not the only condition that high-fiber diets may protect against. See:

I also have a load of other bowel movement videos:

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

Are the Benefits of Organic Food Underrated or Overrated?

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Pesticides have been classified as probable carcinogens for 25 years. Different pesticides have been associated with different cancers through a variety of mechanisms, including genetic damage--direct hits to our DNA or chromosomes--and epigenetic modification, changes in the way our genes are expressed. These effects have been documented in workers who are spraying the pesticides, but exposure to pesticide residues that remain on food is much smaller.

More recently, higher cancer rates have also been noted in people who live in areas where pesticides are heavily sprayed, but what about the food we buy at the store? Organic fruits and vegetables have fewer pesticides, but even the levels on conventional produce are generally well below acceptable limits. There is still scientific controversy about the safety of some pesticides even under the regulatory limits, however, given the possible additive effects of the mixture of pesticides to which we're exposed. The pesticide approval process also doesn't take into account toxic breakdown products such as dioxins that can form once pesticides are released into the environment.

Cadmium is another issue. In the largest review to date, involving hundreds of studies, not only did organic foods have more antioxidant phytonutrients, but lower concentrations of cadmium. Cadmium is one of three highly toxic heavy metals (along with lead and mercury) found in the food supply. Cadmium accumulates in the body, so we should try to keep intake as low as possible. Organic crops only have about half the cadmium, which is thought to come from the phosphate fertilizers that are added to conventional crops.

Of course, not all organic foods are healthy. The organic food industry is now worth tens of billions of dollars, and they didn't get that way just selling carrots. We can now buy pesticide-free potato chips and organic jelly beans. Organic foods can be even worse because, for example, people falsely judge organic Oreo cookies to have fewer calories than conventional Oreos, and so may eat more. Forgoing exercise was deemed more acceptable when the person had just chosen an organic dessert rather than a conventional one. In fact, leniency toward forgoing exercise was slightly greater after choosing an organic dessert than after eating no dessert at all--organic cookies were effectively viewed as having negative calories! Organic junk food is still junk food.

Not only do people tend to overestimate the nutritional benefits of organic foods, they also overestimate the risks of pesticides. People think that as many people die from pesticide residues on conventional food as die in motor vehicle accidents in the United States. Surveys have found organic food buyers may think eating conventional produce is almost as bad as smoking a pack of cigarettes. That kind of thinking is dangerous because it could potentially lead to a decrease in overall fruit and vegetable consumption.

If just half of the U.S. population were to increase fruit and vegetable consumption by a single serving a day, an estimated 20,000 cancer cases might be avoided each year. That's how powerful produce may be. But, because the model was using conventional fruits and veggies, the pesticide burden from those extra fruits and vegetables might result in 10 additional cancer cases. So overall, if half of us ate one more serving, we'd just prevent 19,990 cases of cancer a year.

Now that was a paper written by scientists-for-hire paid for by the Alliance for Food and Farming, which is a bunch of conventional produce growers, so they probably exaggerated the benefits and minimized the risks, but I think the bottom line is sound. We get a tremendous benefit from eating conventional fruits and vegetables that far outweighs whatever tiny bump in risk we may get from the pesticides. Why not reap the benefits without the risk and choose organic? Great! But we should never let concern about pesticides stop us from stuffing our face with as many fruits and vegetables as possible.

My video, Are the Benefits of Organic Food Underrated or Overrated?, was the final installment of a 5-part series on organics. The first four videos are:

I've covered the issue of cadmium in our diet before in Cadmium and Cancer: Plant vs. Animal Foods and Male Fertility and Diet. Heavy metals are found concentrated in seafood and organ meats, but can also be found in certain supplements and protein powders.

In health,

Michael Greger, M.D.

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

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

Original Link

Are the Benefits of Organic Food Underrated or Overrated?

Vegsource.jpeg

Pesticides have been classified as probable carcinogens for 25 years. Different pesticides have been associated with different cancers through a variety of mechanisms, including genetic damage--direct hits to our DNA or chromosomes--and epigenetic modification, changes in the way our genes are expressed. These effects have been documented in workers who are spraying the pesticides, but exposure to pesticide residues that remain on food is much smaller.

More recently, higher cancer rates have also been noted in people who live in areas where pesticides are heavily sprayed, but what about the food we buy at the store? Organic fruits and vegetables have fewer pesticides, but even the levels on conventional produce are generally well below acceptable limits. There is still scientific controversy about the safety of some pesticides even under the regulatory limits, however, given the possible additive effects of the mixture of pesticides to which we're exposed. The pesticide approval process also doesn't take into account toxic breakdown products such as dioxins that can form once pesticides are released into the environment.

Cadmium is another issue. In the largest review to date, involving hundreds of studies, not only did organic foods have more antioxidant phytonutrients, but lower concentrations of cadmium. Cadmium is one of three highly toxic heavy metals (along with lead and mercury) found in the food supply. Cadmium accumulates in the body, so we should try to keep intake as low as possible. Organic crops only have about half the cadmium, which is thought to come from the phosphate fertilizers that are added to conventional crops.

Of course, not all organic foods are healthy. The organic food industry is now worth tens of billions of dollars, and they didn't get that way just selling carrots. We can now buy pesticide-free potato chips and organic jelly beans. Organic foods can be even worse because, for example, people falsely judge organic Oreo cookies to have fewer calories than conventional Oreos, and so may eat more. Forgoing exercise was deemed more acceptable when the person had just chosen an organic dessert rather than a conventional one. In fact, leniency toward forgoing exercise was slightly greater after choosing an organic dessert than after eating no dessert at all--organic cookies were effectively viewed as having negative calories! Organic junk food is still junk food.

Not only do people tend to overestimate the nutritional benefits of organic foods, they also overestimate the risks of pesticides. People think that as many people die from pesticide residues on conventional food as die in motor vehicle accidents in the United States. Surveys have found organic food buyers may think eating conventional produce is almost as bad as smoking a pack of cigarettes. That kind of thinking is dangerous because it could potentially lead to a decrease in overall fruit and vegetable consumption.

If just half of the U.S. population were to increase fruit and vegetable consumption by a single serving a day, an estimated 20,000 cancer cases might be avoided each year. That's how powerful produce may be. But, because the model was using conventional fruits and veggies, the pesticide burden from those extra fruits and vegetables might result in 10 additional cancer cases. So overall, if half of us ate one more serving, we'd just prevent 19,990 cases of cancer a year.

Now that was a paper written by scientists-for-hire paid for by the Alliance for Food and Farming, which is a bunch of conventional produce growers, so they probably exaggerated the benefits and minimized the risks, but I think the bottom line is sound. We get a tremendous benefit from eating conventional fruits and vegetables that far outweighs whatever tiny bump in risk we may get from the pesticides. Why not reap the benefits without the risk and choose organic? Great! But we should never let concern about pesticides stop us from stuffing our face with as many fruits and vegetables as possible.

My video, Are the Benefits of Organic Food Underrated or Overrated?, was the final installment of a 5-part series on organics. The first four videos are:

I've covered the issue of cadmium in our diet before in Cadmium and Cancer: Plant vs. Animal Foods and Male Fertility and Diet. Heavy metals are found concentrated in seafood and organ meats, but can also be found in certain supplements and protein powders.

In health,

Michael Greger, M.D.

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

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

Original Link

Estrogen in Meat, Dairy, and Eggs

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Estrogen hormones can be thousands of times more estrogenic than typical endocrine-disrupting chemicals. Dietary exposure to natural sex steroids (in meat, dairy, and eggs) is "therefore highly relevant in the discussion of the impact of estrogens on human development and health." And chicken estrogen is identical to human estrogen--they're identical molecules. So it doesn't matter if it ends up in our drinking supply from women taking birth control pills excreting it in their urine, or cows excreting it into their milk. The source doesn't matter; the quantity does.

If you check out my video Estrogen in Meat, Dairy, and Eggs, you can see that a child's exposure to estrogens in drinking water is about 150 times lower than exposure from cow's milk, so our day-to-day estrogen exposure levels are more likely determined by whether or not we happen to eat dairy products that day.

Human urine is "often cited as the main source of natural and synthetic estrogens in the aquatic environment," but the level of estrogen even in the urine of heavy meat-eaters, who have significantly higher levels, pales in comparison to the estrogen excreted by the farm animals themselves. Pig, sheep, cattle, and chickens produce literally tons of estrogen every year.

Women may excrete 16 mg every day, but farm animals may release ten times more, or in the case of pregnant cows, thousands of times more. Animal waste may contribute an estimated 90% of total estrogens in the environment. Five gallons of runoff water contaminated with chicken manure may contain a birth control pill's worth of estrogen.

Estrogen levels in poultry litter are so high that when farmers feed chicken manure to their animals to save on feed costs, it may trigger premature development. Poultry manure has among the highest hormone content, quadruple the total estrogens, and nine times more 17-beta estradiol, the most potent estrogen and a "complete" carcinogen, as it exerts both tumor initiating and tumor promoting effects.

From a human health standpoint, do we really care about feminized fish, or the appearance of "intersex roaches"? The problem is that the hormones get into the food supply. Endogenous steroid hormones in food of animal origin are unavoidable as they occur naturally in these products. It's not a matter of injected hormones, which are banned in places like Europe in order to protect consumers' health. Sex steroid hormones are part of animal metabolism, and so all foodstuffs of animal origin contain these hormones, which have been connected with several human health problems. (See Why Do Vegan Women Have 5x Fewer Twins?)

What effects might these female hormones have on men? See Dairy Estrogen and Male Fertility.

The implications of this relatively new practice of milking cows even when they're pregnant is further explored in:

More on xenoestrogens in:

In health,
Michael Greger, M.D.

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

Image Credit: [Nakhorn Yuangkratoke] © 123RF.com

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What to Eat to Protect Against Kidney Cancer

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58,000 Americans are diagnosed with kidney cancer every year, and 13,000 die. And the numbers have been going up. Approximately 4 percent of cases are hereditary, but what about the other 96 percent? The only accepted risk factor has been tobacco use, but cigarette smoking has been declining.

Nitrosamines are one of the most potent carcinogens in cigarette smoke. One hot dog has as many nitrosamines and nitrosamides as five cigarettes. And these carcinogens are also found in fresh meat as well: beef, chicken and pork. So even though smoking rates have dropped, perhaps the rise in kidney cancer over the last few decades may have something to do with meat consumption. But would kidney cancer just be related to the processed meats like bacon, sausage, hot dogs and cold cuts that have nitrate and nitrite additives, or fresh meat as well?

The NIH-AARP study featured in my video Can Diet Protect Against Kidney Cancer? is the largest prospective study on diet and health ever performed--about 500,000 followed for nine years. In addition to examining nitrate and nitrite intake from processed meat, they also looked at intake from other sources such as fresh meat, eggs and dairy. Nitrite from animal sources, not just processed meats, was associated with an increased risk of kidney cancer, and total intake of nitrate and nitrite from processed meat sources was also associated with kidney cancer risk. The researchers found no associations with nitrate or nitrite intake from plant sources, but nitrates from processed meat was associated with cancer.

When meat producers advertise their bacon or lunch meat as "uncured," this means no nitrites or nitrates added. But if you look at the small print you'll see something like, "except for celery juice." That's just a sneaky way to add nitrites. Processed meat producers ferment the nitrates in celery to create nitrites, then add it to the meat; a practice even the industry admits "may be viewed as incorrect at best or deceptive at worst."

But that same fermentation of nitrates to nitrites can happen thanks to bacteria on our tongue when we eat vegetables. So why are nitrates and nitrites from vegetables on our tongue harmless, but nitrates and nitrites from vegetables in meat linked to cancer? The actual carcinogens are not nitrites, but nitrosamines and nitrosamides. In our stomach, to turn nitrites into nitros-amines, and nitros-amides we need amines and amides, which are concentrated in animal products. And vitamin C and other antioxidants in plant foods block the formation of these carcinogens in our stomach. That's why we can safely benefit from the nitrates in vegetables without the cancer risk. In fact some of the highest nitrate vegetables like arugula, kale, and collards are associated with decreased risk of kidney cancer. The more plants, it appears, the better.

Plant-based diets and fiber-rich diets are recommended to prevent cancer directly, as well as chronic conditions associated with kidney cancer, such as obesity, high blood pressure and diabetes. It's similar to sodium intake and kidney cancer. Sodium intake increases kidney disease risk, but that's not just because sodium intake increases blood pressure. It appears the salt is associated with increased cancer risk even independently of hypertension. What about plant-based diets? Turns out the protective association remains even in people who are not obese and have normal blood pressure. So overall, plant-based and fiber-rich diets appear to do both: decrease cancer risk directly and indirectly.

I briefly address kidney health in Preventing Kidney Failure Through Diet and Treating Kidney Failure Through Diet, but have a whole series of more in-depth videos dealing with various kidney issues.

More on the fascinating nitrate/nitrite story in my 17-part series about improving athletic performance with nitrate-rich vegetables such as beets and arugula. Here are a few short highlights:

More on carcinogens caused by cooking meat in videos like:

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: RDSVS / Flickr

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Treating Pancreatic Cancer with Turmeric Curcumin

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Pancreatic cancer is among the most aggressive forms of human cancer, characterized by a very high mortality rate. It represents the fourth leading cause of cancer death in United States, killing 32,000 people annually. With a five-year survival rate of only three percent and a median survival rate of less than six months, pancreatic cancer carries one of the poorest prognoses. The diagnosis of pancreatic cancer is one of the worst things a doctor ever has to tell a patient. The only FDA-approved therapies for it, Gemcitabine and Erlotinib, produce objective responses in less than ten percent of patients, while causing severe side-effects in the majority. There is a desperate need for new options.

Clinical research to test new treatments is split into phases. Phase I trials are just to make sure the treatment is safe, to see how much you can give before it becomes toxic. Curcumin, the natural yellow pigment in the spice turmeric has passed a number of those. In fact, there was so little toxicity, the dosing appeared limited only by the number of pills patients were willing to swallow.

Phase II trials are conducted to see if the drug actually has an effect. Curcumin did, in 2 of the 21 patients that were evaluated. One patient had a 73 percent tumor reduction, but the effect was short-lived. One lesion remained small, but a curcumin-resistant tumor clone emerged. The other patient, who had a stable disease for over 18 months, showed slow improvement over a year. The only time that patient's cancer markers bumped up was during a brief three-week stint where the curcumin was stopped.

So curcumin does seem to help some patients with pancreatic cancer, and most importantly, there appears to be little downside. No curcumin-related toxic effects were observed in up to doses of eight grams per day. What happens after eight grams? We don't know because no one was willing to take that many pills. The patients were willing to go on one of the nastiest chemotherapy regimens on the planet, but didn't want to be inconvenienced with swallowing a lot of capsules.

The only surefire way to beat pancreatic cancer is to prevent it in the first place. In 2010 I profiled a study conducted by the National Institutes of Health, the largest such study in history, which found that dietary fat of animal origin was associated with increased pancreatic cancer risk.

Which animal fat is the worst? The second largest study (highlighted in my video: Turmeric Curcumin and Pancreatic Cancer) has since chimed in to help answer that question. Researchers found that poultry was the worst, with 72 percent increased risk of pancreatic cancer associated with every 50 grams of daily poultry consumption. Fifty grams is just about a quarter of a chicken breast. The reason white meat came out worse than red may be because of the cooked meat carcinogens in chicken, the heterocyclic amines that build up in grilled and baked chicken. These mutagenic chemicals have been associated with a doubling of pancreatic cancer risk (See Estrogenic Cooked Meat Carcinogens).

Meat has been associated with significantly increased risk, whereas fake meat is associated with significantly less risk. Those who eat plant-based meats like veggie burgers or veggie dogs three or more times a week had less than half the risk of fatal pancreatic cancer. Legumes and dried fruit appear to be similarly protective.

My grandfather died of pancreatic cancer. By the time the first symptom arose, a dull ache in his gut, it was too late. That's why we need to work on preventing it.

I previously touched on pancreatic cancer prevention in Poultry Exposure Tied to Liver and Pancreatic Cancer and attempts at pancreatic cancer treatment in Gerson Therapy for Cancer and Gerson-style Therapy vs. Chemotherapy.

For more on the heterocyclic amine cooked meat carcinogens:

I've done a bunch of videos on turmeric and various cancers:

And more on this amazing spice (and more to come):

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: Sara Marlowe / Flickr

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Why are Chickens Fed Prozac?

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Between 1940 and 1971, the synthetic estrogen DES was prescribed to several million pregnant women with the promise that it would "help prevent miscarriages." Problems were first highlighted in 1953 when it became clear that DES was not only ineffective but potentially harmful. However, a powerful and emotive advertising campaign ensured that its use continued until 1971, when it was found to cause cancer of the vagina in the daughters of the mothers who took it. DES was also used to stunt the growth of girls who were predicted to grow "abnormally tall." As one pediatric textbook put it in 1968, "excessive tallness in girls can be a handicap ... it provides difficulty in the purchase of smart clothes; the victim is ineligible for certain sought-after professional positions such as air line hostess; and poses problems in selecting suitable dancing partners."

What most people don't know is that the greatest usage of DES was by the livestock industry, used to improve "feed conversion" in cattle and chickens. Within a year of approval, DES was fed to millions of farm animals. Although it was shown to be a human carcinogen in 1971, DES used in meat production was not completely banned until 1979. (Now, the meat industry just uses different synthetic estrogen implants.) Even decades after DES was banned, we're still seeing its effects--an elevation of birth defects even down to the third generation.

Arsenic is another human carcinogen that was fed to chickens. This time by the billions. The arsenic not only ends up in the meat (as I've talked about previously in Arsenic in Chicken and How Many Cancers Caused by Arsenic Laced Chicken?), but also in the feathers, which are fed back to the animals. Because a third of the bird is inedible, the industry takes billions of pounds of heads, bones, guts, and feathers and uses them as fertilizer and animal feed. This feather meal is fed back to chickens, pigs, cows, sheep, and fish. Straight feathers are not particularly nutritious; so guts, heads, and feet may be added for a little extra protein, and manure added for minerals. The problem is that feather meal used as animal feed could contribute to additional arsenic exposure in persons who consume meat. This gave researchers at John Hopkins University and Arizona State an idea. By testing feather meal, they might be able to find out what else chickens are fed. In their study, "Feather Meal: A Previously Unrecognized Route for Reentry into the Food Supply of Multiple Pharmaceuticals and Personal Care Products," (highlighted in my video, Illegal Drugs in Chicken Feathers) they found that all feather samples tested positive for antibiotic type drugs (between two and ten different kinds in each sample), including fluoroquinolones, which have been banned for years. Either the poultry industry is illegally still using the stuff, or it's being used in other animals fed to the chicken. Regardless, when feather meal is fed back to chickens, they are getting exposed to this drug that is against the law to feed to chickens, creating a cycle of re-exposure to banned drugs.

Then it just gets weirder. The feathers contained a half dozen other drugs: Prozac, an antihistamine, a fungicide, a sex hormone, and caffeine. Why doesn't the poultry industry just say no? Evidently, the antihistamines are to combat the respiratory problems from packing so many tens of thousands into the confinement sheds, and the caffeine helps keeps the chickens stay awake so they eat more and grow faster.

The drugs fed to chickens are one reason used to explain why poultry has been tied to increased cancer risk. See Chicken Dioxins, Viruses, or Antibiotics?.

The most concerning drugs currently in the U.S. poultry supply are the antibiotics, though. See, for example:

Ironically, not only may antibiotics in chicken contribute to antibiotic resistant infections, but to the infections in the first place. Check out my video Avoiding Chicken to Avoid Bladder Infections.

Then as if adding potentially harmful chemicals to the chickens themselves wasn't bad enough, more are added in the processing plant: Phosphate Additives in Chicken.

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: U.S. Department of Agriculture / Flickr

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Bile Acids and Breast Cancer

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Why do constipated women appear to be at higher risk for breast cancer? The results of a 1989 study out of the American Journal of Public Health suggested a slight increased risk of breast cancer for both decreased frequency of bowel movements and firm stool consistency. Women who had three or more bowel movements a day appeared to cut their risk of breast cancer in half. This could be because constipation means a greater contact time between our waste and our intestinal wall, which may increase the formation and absorption of fecal mutagens--substances that cause DNA mutations and cancer--into our circulation, eventually ending up in breast tissue.

The concept that more frequent bowl movements decrease breast cancer risk dates back more than a century, where severe constipation, so-called "chronic intestinal stasis," was sometimes dealt with surgically. Figuring that the colon was an inessential part of the human anatomy, why not cure constipation by just cutting it out? After the surgery, they noticed that potentially precancerous changes in the breasts of constipated women seemed to disappear.

It would take another 70 years before researchers followed up on the clues by those distinguished surgeons who claimed breast pathology cleared when constipation was corrected. A 1981 study published in The Lancet investigated the relation between potentially precancerous changes in the breast and the frequency of bowl movements in nearly 1,500 women (See Breast Cancer and Constipation). The researchers found that the risk of precancerous changes was four times greater in women reporting two or fewer bowel movements a week compared to more than once daily.

We know that even the non-lactating breast actively takes up chemical substances from the blood. We also know that there are mutagens in feces. It is not unreasonable to suggest that potentially toxic substances derived from the colon have damaging or even carcinogenic effects upon the lining of the breast. Toxic substances like bile acids. Bile acids were first shown to promote tumors in mice in 1940, but subsequent experiments on rats led to the mistaken belief that bile acids just promoted existing cancers and couldn't initiate tumors themselves. However, there is a fundamental difference between the rodent models and human cancer. Rats only live a few years while humans can live dozens, so the opportunity for cancer causing mutations may be at least 30 times greater in humans. We now have at least 15 studies that show that bile acids can damage DNA, strongly suggesting they can initiate new cancers as well.

Bile acids are formed as a way of getting rid of excess cholesterol. Our liver dumps bile acids into the intestine for disposal, assuming our intestines will be packed with fiber to trap it and flush it out of the body. But if we haven't been eating enough fiber-rich whole plant foods, bile acids can be reabsorbed back into the body and build up in the breast.

Carcinogenic bile acids are found concentrated in the fluid of breast cysts at up to a hundred times the level found in the bloodstream. By radioactively tagging bile acids, researchers were able to show that intestinal bile acids rapidly gain access to the breast, where they can exert an estrogen-like cancer-promoting effect on breast tumor cells. This would explain why we see 50% higher bile acid levels in the bloodstream of newly diagnosed breast cancer victims. These findings support the concept of a relationship between intestinally-derived bile acids and risk of breast cancer. So how can we facilitate the removal of bile acids from our body?

Slowed colonic transit can increase bile acid levels. Therefore, to decrease absorption of bile acids, we can speed up the so-called "oro-anal transit time," the speed at which food goes from mouth to toilet, by eating lots of fiber. A diet packed with plants greatly increases bile acid excretion.

Fiber can bind up and remove other toxic elements like lead and mercury as well as cholesterol and bile acids. But plants can bind bile acids even independent of fiber. Vegan diets bind significantly more bile acid than lacto-ovo or non-vegetarian diets even at the same fiber intake, which could explain why individuals eating vegetarian might excrete less mutagenic feces in the first place.

I touched on this in my live presentation From Table to Able: Combating Disabling Diseases with Food, but what I didn't get to discuss is the relative bile acid binding abilities of different foods. I cover that in my video Which Vegetable Binds Bile Best?

What intestinal transit time should we be shooting for? See Food Mass Transit. That may be why Stool Size Matters. Also, How Many Bowel Movements Should You Have Every Day? We can improve speed and size by Bulking Up on Antioxidants and eating lots of whole plant foods (Prunes vs. Metamucil vs. Vegan Diet).

Fiber may also help women remove excess estrogen from their body. See my video Fiber vs. Breast Cancer. For more on the wonders of fiber, see Dr. Burkitt's F-Word Diet.

For more of my latest videos on breast cancer prevention and 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 Uprooting the Leading Causes of Death, More Than an Apple a Day, and Food as Medicine.

Image Credit: Photocapy / Flickr

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Is it Better to Bake, Boil, or Steam Sweet Potatoes?

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I previously talked about the cancer fighting properties of sweet potatoes (See Anti-Cancer Potential of Sweet Potato Proteins) and what would happen if you centered your diet around them (The Okinawa Diet: Living to 100). It seems that the only potential downside to eating too many sweet potatoes is that you could get yellow palms (or nose as you can see in the video, The Best Way to Cook Sweet Potatoes), a harmless condition called "carotenemia." Caused by elevated levels of beta carotene in the blood, it was first noticed a century ago when carrots were introduce into infant diets. It's treated mostly by just reassuring parents that it's harmless, but if we don't want our child's nose to be yellow, we can decrease their beta carotene intake and in a few months it will be gone.

When picking out varieties at the supermarket, the intensity of the yellow or orange flesh color of the sweet potato is directly correlated to its nutritional content, so the more intense the better. Though if you really want intensity, sweet potato varieties don't just range from white to yellow and orange, but from pink to deep purple. The natural pigments that cause these colors may have special anticancer effects.

What is the best way to cook sweet potatoes? Boiling may actually retain most of the antioxidant power of sweet potatoes, compared to roasting and steaming. If we compare baking to boiling microscopically, boiling helps thin out the cell walls and gelatinize the starch, which may enhance the bioavailability of nutrients. At the same time, the glycemic index of boiled sweet potatoes was found to be about half that of baking or roasting, so boiled sweet potatoes give us less of a blood sugar spike.

Make sure to keep the skin on, though. The peel of a sweet potato has nearly ten times the antioxidant power as the flesh (an antioxidant capacity comparable to that of blueberries). However, the peel's nutrition really takes a hit when baked, which wipes out over two thirds of the antioxidants, whereas microwaving or boiling are comparatively much gentler. The same is true for the rest of the sweet potato. Baking can also cause an 80% drop in vitamin A levels, twice as much as boiling. Therefore, from a nutritional standpoint, boiling rather than baking should be recommended for cooking sweet potato.

Boiling may theoretically be best, but sweet potatoes are so incredibly healthy that the actual best way to prepare them is whichever way will get you to eat the most of them! The exception is deep frying, which can lead to the formation of acrylamide, a potential human carcinogen.

What about cooking methods for other vegetables? See my video Best Cooking Method.

Want more information about acrylamide, the potential crispy carb carcinogen? See my video Cancer Risk from French Fries. And for why deep frying in general might not be good, Deep Frying Toxins and Carcinogens in the Smell of Frying Bacon.

-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: Avital Pinnick / Flickr

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