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

Music as Medicine

Music as Medicine.jpeg

We've been playing music since the Paleolithic Era, 40,000 years ago. Music as therapy has been documented since at least biblical times. The first music therapy experiment was published in the Journal of the American Medical Association in 1914. As to why he placed a phonograph in the operating room as his patients lay fully conscious and awake during surgery, the surgeon explained it was "a means of calming and distracting my patients from the horror of the situation."

Now that we have anesthesia, music is used to calm nerves before surgery. Normally we use Valium-type drugs like midazolam (sold as Versed), but they can have a variety of side effects, including sometimes even making people more agitated. A study from Sweden sought to determine if relaxing music has a greater anxiety-reducing effect than a standard dose of midazolam. Researchers whipped out some Kenny G, and the music worked significantly better than the drug. Those listening to Mr. G had lower anxiety scores, heart rates, and blood pressures. This is perhaps the first report of any anti-anxiety therapy working not only as good as, but even better than, benzodiazepine drugs. The difference in side effects of relaxing music compared to the drug is obvious: There were none. Soft jazz causes no post-operative hangover. The researchers suggest we should start using music instead of midazolam.

Music may also reduce anxiety and pain in children undergoing minor medical and dental procedures, helping with blood draws and shots. It may even reduce the pain of spinal taps. However, Mozart is evidently powerless against the pain of circumcision.

It doesn't take a randomized controlled trial to demonstrate that listening to music can be relaxing. Tell me something I don't know. Well, if you take someone with a latex allergy and inject their skin with latex, they get a big, red, angry bump. But if you repeat the test after they've been listening to Mozart for 30 minutes, they develop a much smaller bump (as you can see in my video, Music as Medicine). That is, they have less of an allergic reaction. If you think that's wild, get ready for this: Beethoven didn't work. The subjects had the same reaction before and after listening to his music! Schubert, Hayden, and Brahms didn't work either, as all failed to reduce the allergic skin response. The reducing effect on allergic responses may be specific to Mozart.

So Mozart's looking pretty good, but what if he could be suppressing our immune systems in general? That would not be good. The same researchers also injected a chemical that causes reactions in everyone, not just in allergic people. Mozart had no effect. It seems Mozart suppresses only the pathological allergic reaction. If that isn't crazy enough for you, the researchers drew subjects' blood after the music, stuck their white blood cells in a petri dish with a little latex, and measured the allergic antibody response. The white blood cells from those exposed to Mozart had less of an allergic response even outside the body compared to cells taken from Beethoven blood. How cool is that?

Music may even impact our metabolism. This inquiry started with a 2012 study published in the journal Pediatrics, which found the resting energy expenditure (the number of calories burned when just lying around) was lower in preterm infants when researchers piped in Mozart. This may explain why infants exposed to music put on weight faster, so much so they are able to go home earlier.

Gaining weight faster is great for premature babies, but not necessarily for adults. Could listening to music slow our metabolism and contribute to weight gain? Well, one study found no effect on adults. But the researchers used Bach, not Mozart. Bach doesn't cause a drop in energy expenditure in babies either. These data suggest there may be "more a 'Mozart effect' than a universal 'music effect'."

What if we just listen to music of our choice? Does that affect our metabolism? We didn't know... until now. It turns out that listening to music appears to actually increase our metabolic rate, such that we burn an average of 27.6 more calories a day just lying in bed. That's only like six M&M's worth, though, so it's better to use music to get up and start dancing or exercising. Music can not only improve exercise enjoyment but also performance--a way to improve athletic performance that's legal.

Male bodybuilders may be less enthused music's effects. After listening to music for just 30 minutes, testosterone levels drop 14% in young men and go up 21% in young women. Do all kinds of music have this effect or just some types? Thirty minutes of silence had no effect on testosterone levels at all, while a half-hour of Mozart, jazz, pop, or Gregorian chants (no relation :) all suppressed testosterone. What about a half-hour of people's personal favorites? Testosterone levels were cut in half! Testosterone decreased in males under all music conditions, whereas testosterone increased in females. What is going on? Well, in men, testosterone is related to libido, dominance, and aggressiveness, whereas women get a bigger boost in testosterone from cuddling than from sex. So maybe we evolved using music as a way to ensure we all got along, like a melodious cold shower to keep everyone chill.

Is that crazy or what? I'm fascinated by the whole topic. For more, see Music for Anxiety: Mozart vs. Metal.

Sounds are the only sensory-stimulators that can have an effect on us--so can scents! See:

Exposure to industrial pollutants may also affect both allergic diseases and testosterone levels:

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

Music as Medicine

Music as Medicine.jpeg

We've been playing music since the Paleolithic Era, 40,000 years ago. Music as therapy has been documented since at least biblical times. The first music therapy experiment was published in the Journal of the American Medical Association in 1914. As to why he placed a phonograph in the operating room as his patients lay fully conscious and awake during surgery, the surgeon explained it was "a means of calming and distracting my patients from the horror of the situation."

Now that we have anesthesia, music is used to calm nerves before surgery. Normally we use Valium-type drugs like midazolam (sold as Versed), but they can have a variety of side effects, including sometimes even making people more agitated. A study from Sweden sought to determine if relaxing music has a greater anxiety-reducing effect than a standard dose of midazolam. Researchers whipped out some Kenny G, and the music worked significantly better than the drug. Those listening to Mr. G had lower anxiety scores, heart rates, and blood pressures. This is perhaps the first report of any anti-anxiety therapy working not only as good as, but even better than, benzodiazepine drugs. The difference in side effects of relaxing music compared to the drug is obvious: There were none. Soft jazz causes no post-operative hangover. The researchers suggest we should start using music instead of midazolam.

Music may also reduce anxiety and pain in children undergoing minor medical and dental procedures, helping with blood draws and shots. It may even reduce the pain of spinal taps. However, Mozart is evidently powerless against the pain of circumcision.

It doesn't take a randomized controlled trial to demonstrate that listening to music can be relaxing. Tell me something I don't know. Well, if you take someone with a latex allergy and inject their skin with latex, they get a big, red, angry bump. But if you repeat the test after they've been listening to Mozart for 30 minutes, they develop a much smaller bump (as you can see in my video, Music as Medicine). That is, they have less of an allergic reaction. If you think that's wild, get ready for this: Beethoven didn't work. The subjects had the same reaction before and after listening to his music! Schubert, Hayden, and Brahms didn't work either, as all failed to reduce the allergic skin response. The reducing effect on allergic responses may be specific to Mozart.

So Mozart's looking pretty good, but what if he could be suppressing our immune systems in general? That would not be good. The same researchers also injected a chemical that causes reactions in everyone, not just in allergic people. Mozart had no effect. It seems Mozart suppresses only the pathological allergic reaction. If that isn't crazy enough for you, the researchers drew subjects' blood after the music, stuck their white blood cells in a petri dish with a little latex, and measured the allergic antibody response. The white blood cells from those exposed to Mozart had less of an allergic response even outside the body compared to cells taken from Beethoven blood. How cool is that?

Music may even impact our metabolism. This inquiry started with a 2012 study published in the journal Pediatrics, which found the resting energy expenditure (the number of calories burned when just lying around) was lower in preterm infants when researchers piped in Mozart. This may explain why infants exposed to music put on weight faster, so much so they are able to go home earlier.

Gaining weight faster is great for premature babies, but not necessarily for adults. Could listening to music slow our metabolism and contribute to weight gain? Well, one study found no effect on adults. But the researchers used Bach, not Mozart. Bach doesn't cause a drop in energy expenditure in babies either. These data suggest there may be "more a 'Mozart effect' than a universal 'music effect'."

What if we just listen to music of our choice? Does that affect our metabolism? We didn't know... until now. It turns out that listening to music appears to actually increase our metabolic rate, such that we burn an average of 27.6 more calories a day just lying in bed. That's only like six M&M's worth, though, so it's better to use music to get up and start dancing or exercising. Music can not only improve exercise enjoyment but also performance--a way to improve athletic performance that's legal.

Male bodybuilders may be less enthused music's effects. After listening to music for just 30 minutes, testosterone levels drop 14% in young men and go up 21% in young women. Do all kinds of music have this effect or just some types? Thirty minutes of silence had no effect on testosterone levels at all, while a half-hour of Mozart, jazz, pop, or Gregorian chants (no relation :) all suppressed testosterone. What about a half-hour of people's personal favorites? Testosterone levels were cut in half! Testosterone decreased in males under all music conditions, whereas testosterone increased in females. What is going on? Well, in men, testosterone is related to libido, dominance, and aggressiveness, whereas women get a bigger boost in testosterone from cuddling than from sex. So maybe we evolved using music as a way to ensure we all got along, like a melodious cold shower to keep everyone chill.

Is that crazy or what? I'm fascinated by the whole topic. For more, see Music for Anxiety: Mozart vs. Metal.

Sounds are the only sensory-stimulators that can have an effect on us--so can scents! See:

Exposure to industrial pollutants may also affect both allergic diseases and testosterone levels:

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

How to Treat High Blood Pressure with Diet

How to Treat High Blood Pressure with Diet.jpeg

High blood pressure ranks as the number-one risk factor for death and disability in the world. In my video, How to Prevent High Blood Pressure with Diet, I showed how a plant-based diet may prevent high blood pressure. But what do we do if we already have it? That's the topic of How to Treat High Blood Pressure with Diet.

The American Heart Association, the American College of Cardiology, and the Centers for Disease Control and Prevention recommend lifestyle modification as the first-line treatment. If that doesn't work, patients may be prescribed a thiazide diuretic (commonly known as a water pill) before getting even more meds until their blood pressure is forced down. Commonly, people will end up on three drugs, though researchers are experimenting with four at a time. Some patients even end up on five different meds.

What's wrong with skipping the lifestyle modification step and jumping straight to the drugs? Because drugs don't treat the underlying cause of high blood pressure yet can cause side effects. Less than half of patients stick with even the first-line drugs, perhaps due to such adverse effects as erectile dysfunction, fatigue, and muscle cramps.

What are the recommended lifestyle changes? The AHA, ACC, and CDC recommend controlling one's weight, salt, and alcohol intake, engaging in regular exercise, and adopting a DASH eating plan.

The DASH diet has been described as a lactovegetarian diet, but it's not. It emphasizes fruits, vegetables, and low-fat dairy, but only a reduction in meat consumption. Why not vegetarian? We've known for decades that animal products are significantly associated with blood pressure. In fact, if we take vegetarians and give them meat (and pay them enough to eat it!), we can watch their blood pressures go right up.

I've talked about the benefits to getting blood pressure down as low as 110 over 70. But who can get that low? Populations centering their diets around whole plant foods. Rural Chinese have been recorded with blood pressures averaging around 110 over 70 their whole lives. In rural Africa, the elderly have perfect blood pressure as opposed to hypertension. What both diets share in common is that they're plant-based day-to-day, with meat only eaten on special occasion.

How do we know it's the plant-based nature of their diets that was so protective? Because in the Western world, as the American Heart Association has pointed out, the only folks getting down that low were those eating strictly plant-based diets, coming out about 110 over 65.

So were the creators of the DASH diet just not aware of this landmark research done by Harvard's Frank Sacks? No, they were aware. The Chair of the Design Committee that came up with the DASH diet was Dr. Sacks himself. In fact, the DASH diet was explicitly designed with the number-one goal of capturing the blood pressure-lowering benefits of a vegetarian diet, yet including enough animal products to make it "palatable" to the general public.

You can see what they were thinking. Just like drugs never work--unless you actually take them. Diet never work--unless you actually eat them. So what's the point of telling people to eat strictly plant-based if few people will do it? So by soft-peddling the truth and coming up with a compromise diet you can imagine how they were thinking that on a population clae they might be doing more good. Ok, but tell that to the thousand U.S. families a day that lose a loved one to high blood pressure. Maybe it's time to start telling the American public the truth.

Sacks himself found that the more dairy the lactovegetarians ate, the higher their blood pressures. But they had to make the diet acceptable. Research has since shown that it's the added plant foods--not the changes in oil, sweets, or dairy--that appears to the critical component of the DASH diet. So why not eat a diet composed entirely of plant foods?

A recent meta-analysis showed vegetarian diets are good, but strictly plant-based diets may be better. In general, vegetarian diets provide protection against cardiovascular diseases, some cancers, and even death. But completely plant-based diets seem to offer additional protection against obesity, hypertension, type-2 diabetes, and heart disease mortality. Based on a study of more than 89,000 people, those eating meat-free diets appear to cut their risk of high blood pressure in half. But those eating meat-free, egg-free, and dairy-free may have 75% lower risk.

What if we're already eating a whole food, plant-based diet, no processed foods, no table salt, yet still not hitting 110 over 70? Here are some foods recently found to offer additional protection: Just a few tablespoons of ground flaxseeds a day was 2 to 3 times more potent than instituting an aerobic endurance exercise program and induced one of the most powerful, antihypertensive effects ever achieved by a diet-related intervention. Watermelon also appears to be extraordinary, but you'd have to eat around 2 pounds a day. Sounds like my kind of medicine, but it's hard to get year-round (at least in my neck of the woods). Red wine may help, but only if the alcohol has been taken out. Raw vegetables or cooked? The answer is both, though raw may work better. Beans, split peas, chickpeas, and lentils may also help a bit.

Kiwifruits don't seem to work at all, even though the study was funded by a kiwifruit company. Maybe they should have taken direction from the California Raisin Marketing Board, which came out with a study showing raisins can reduce blood pressure, but only, apparently, compared to fudge cookies, Cheez-Its, and Chips Ahoy.

The DASH diet is one of the best studied, and it consistently ranks as US News & World Report's #1 diet. It's one of the few diets that medical students are taught about in medical school. I was so fascinated to learn of its origins as a compromise between practicality and efficacy.

I've talked about the patronizing attitude many doctors have that patients can't handle the truth in:

What would hearing the truth from your physician sound like? See Fully Consensual Heart Disease Treatment and The Actual Benefit of Diet vs. Drugs.

For more on what plants can do for high blood pressure, 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

How to Treat High Blood Pressure with Diet

How to Treat High Blood Pressure with Diet.jpeg

High blood pressure ranks as the number-one risk factor for death and disability in the world. In my video, How to Prevent High Blood Pressure with Diet, I showed how a plant-based diet may prevent high blood pressure. But what do we do if we already have it? That's the topic of How to Treat High Blood Pressure with Diet.

The American Heart Association, the American College of Cardiology, and the Centers for Disease Control and Prevention recommend lifestyle modification as the first-line treatment. If that doesn't work, patients may be prescribed a thiazide diuretic (commonly known as a water pill) before getting even more meds until their blood pressure is forced down. Commonly, people will end up on three drugs, though researchers are experimenting with four at a time. Some patients even end up on five different meds.

What's wrong with skipping the lifestyle modification step and jumping straight to the drugs? Because drugs don't treat the underlying cause of high blood pressure yet can cause side effects. Less than half of patients stick with even the first-line drugs, perhaps due to such adverse effects as erectile dysfunction, fatigue, and muscle cramps.

What are the recommended lifestyle changes? The AHA, ACC, and CDC recommend controlling one's weight, salt, and alcohol intake, engaging in regular exercise, and adopting a DASH eating plan.

The DASH diet has been described as a lactovegetarian diet, but it's not. It emphasizes fruits, vegetables, and low-fat dairy, but only a reduction in meat consumption. Why not vegetarian? We've known for decades that animal products are significantly associated with blood pressure. In fact, if we take vegetarians and give them meat (and pay them enough to eat it!), we can watch their blood pressures go right up.

I've talked about the benefits to getting blood pressure down as low as 110 over 70. But who can get that low? Populations centering their diets around whole plant foods. Rural Chinese have been recorded with blood pressures averaging around 110 over 70 their whole lives. In rural Africa, the elderly have perfect blood pressure as opposed to hypertension. What both diets share in common is that they're plant-based day-to-day, with meat only eaten on special occasion.

How do we know it's the plant-based nature of their diets that was so protective? Because in the Western world, as the American Heart Association has pointed out, the only folks getting down that low were those eating strictly plant-based diets, coming out about 110 over 65.

So were the creators of the DASH diet just not aware of this landmark research done by Harvard's Frank Sacks? No, they were aware. The Chair of the Design Committee that came up with the DASH diet was Dr. Sacks himself. In fact, the DASH diet was explicitly designed with the number-one goal of capturing the blood pressure-lowering benefits of a vegetarian diet, yet including enough animal products to make it "palatable" to the general public.

You can see what they were thinking. Just like drugs never work--unless you actually take them. Diet never work--unless you actually eat them. So what's the point of telling people to eat strictly plant-based if few people will do it? So by soft-peddling the truth and coming up with a compromise diet you can imagine how they were thinking that on a population clae they might be doing more good. Ok, but tell that to the thousand U.S. families a day that lose a loved one to high blood pressure. Maybe it's time to start telling the American public the truth.

Sacks himself found that the more dairy the lactovegetarians ate, the higher their blood pressures. But they had to make the diet acceptable. Research has since shown that it's the added plant foods--not the changes in oil, sweets, or dairy--that appears to the critical component of the DASH diet. So why not eat a diet composed entirely of plant foods?

A recent meta-analysis showed vegetarian diets are good, but strictly plant-based diets may be better. In general, vegetarian diets provide protection against cardiovascular diseases, some cancers, and even death. But completely plant-based diets seem to offer additional protection against obesity, hypertension, type-2 diabetes, and heart disease mortality. Based on a study of more than 89,000 people, those eating meat-free diets appear to cut their risk of high blood pressure in half. But those eating meat-free, egg-free, and dairy-free may have 75% lower risk.

What if we're already eating a whole food, plant-based diet, no processed foods, no table salt, yet still not hitting 110 over 70? Here are some foods recently found to offer additional protection: Just a few tablespoons of ground flaxseeds a day was 2 to 3 times more potent than instituting an aerobic endurance exercise program and induced one of the most powerful, antihypertensive effects ever achieved by a diet-related intervention. Watermelon also appears to be extraordinary, but you'd have to eat around 2 pounds a day. Sounds like my kind of medicine, but it's hard to get year-round (at least in my neck of the woods). Red wine may help, but only if the alcohol has been taken out. Raw vegetables or cooked? The answer is both, though raw may work better. Beans, split peas, chickpeas, and lentils may also help a bit.

Kiwifruits don't seem to work at all, even though the study was funded by a kiwifruit company. Maybe they should have taken direction from the California Raisin Marketing Board, which came out with a study showing raisins can reduce blood pressure, but only, apparently, compared to fudge cookies, Cheez-Its, and Chips Ahoy.

The DASH diet is one of the best studied, and it consistently ranks as US News & World Report's #1 diet. It's one of the few diets that medical students are taught about in medical school. I was so fascinated to learn of its origins as a compromise between practicality and efficacy.

I've talked about the patronizing attitude many doctors have that patients can't handle the truth in:

What would hearing the truth from your physician sound like? See Fully Consensual Heart Disease Treatment and The Actual Benefit of Diet vs. Drugs.

For more on what plants can do for high blood pressure, 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

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.

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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

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